Citation

## Material Information

Title:
High-Pressure GH2/GO2 Combustion Dynamics
2008

## Subjects

Subjects / Keywords:
Combustion ( jstor )
Combustion chambers ( jstor )
Combustion temperature ( jstor )
Exhaust nozzles ( jstor )
Flames ( jstor )
Heat flux ( jstor )
Oxidizers ( jstor )
Propellants ( jstor )
Sensors ( jstor )
Thermocouples ( jstor )

## Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Embargo Date:
8/31/2006

Full Text

HIGH-PRESSURE GH2/GO2 COMBUSTION DYNAMICS

By

CLARK ALEXANDER CONLEY

A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA

2006

by

Clark Alexander Conley

I dedicate this thesis to my wonderful wife Wendy and my very supportive and loving
family: Mom, Dad, Ben, and Julie.

ACKNOWLEDGMENTS

I thank my wife, Wendy, for being so supportive and loving. I thank my parents

for supporting me and keeping me out of trouble. I thank my brother, Ben, and my sister,

Julie, for getting me into trouble. I thank Dr. Corin Segal for guiding me in this research

and providing this wonderful opportunity to progress my education and research abilities.

I thank all of my fellow researchers in the combustion lab that assisted me in this

research. Finally, I thank NASA Marshall for its support in this research.

page

A C K N O W L E D G M E N T S ................................................................................................. iv

LIST OF TA BLE S ............... ........................... ... ... ... ....... ............ .. vii

LIST OF FIGURES ................... ...................... .. ................... viii

L IST O F O B JE C T S .... ....................................................... .. ....... .............. xvi

N O M E N C L A T U R E ....................................................................................................... xvii

ABSTRACT .............. ............................................ xix

CHAPTER

1 IN TR OD U CTION ............................................... .. ......................... ..

Safer, Cheaper, and More Reliable Rocket Engines.............................................2
L literature R review ............................ ............................ .... ........ .............. .

2 M E T H O D S .......................................................................................................1 0

The H2/02 Injection/Combustion Process .............. .............................................10
H 2-0 2 R action Chem istry ............................................................... ............. 11
Propellant Flow Properties and Calculations ............................................... 12
H eat Flux Calculations .......................................................... ............... 15
D ata Processing M ethodologies ........................................... .......................... 17
The R ole of M atlab ........................................... .... .... .............. ... 17
Standardized filenam es.................................................................................. 17
D ata processing program s ............................................................................17

3 HIGH-PRESSURE COMBUSTION FACILITY...............................................20

Combustor System .................. ..................................... ........ .... ... 20
C om bu stion C ham b er............................................................... .....................20
Cham ber m material ...................... ...... ........ ................ 21
Cham ber geom etry .................................... ..................................21
O ptical access .................................................................. ............... 22
O their cham ber features ........................................... .......... ............... 25

v

Inj e cto r .................................. ............................................ 2 6
Injector material ............ ........ .... ............... .... ..... ..... 26
Injector geom etry ............ ...... ................... ............... .............. 27
Other Combustor System Components .................................... ............... 28
E x h au st n o zzle ........................................................................................ 2 8
Cham ber extensions .............................................................................. 29
Igniter ..... ....................... .................. 29
Propellant Feed System ...................................... ................... ..... .... 30
Control/D A Q System ........ ........................ ........ ... .... ...... .............. 35
E electronics system ............. ........................................ ................. 36
C ontrol/D A Q H ardw are ........................................................... .....................36
Computer hardware ................................................ 37
D A Q sen sors ............................................................3 7
Laser and im aging system s ........................................ ....... ............... 42
L ab v iew G U I ..............................................................................................4 3
H PCF A ssem bly and O peration........................................... ........................... 44

4 R E S U L T S .............................................................................5 9

5 DISCUSSION AND CONCLUSION ..... .................... ...............102

High-Pressure Combustion Facility Obstacles and Improvements ........................102
High-Pressure GH2/GO2 Combustion Dynamics ............................................. 104
Initial U nstable/U nsteady Flow .................................... ........ ............... 105
Pressure Effect on Wall Heat Flux ..... ...................... ..............106
Effect of Chamber Length ...... .............................................. .. ............... 110
High-Frequency Pressure Transducer ................................. ....................... 110
Im aging D discussion ............. ..................... .............................. ...111
Conclusion ......... ................. ..................... .... 112

APPENDIX

A LABVIEW AND M ATLAB CODES ......................... .....................................114

B OPERATIONAL PROCEDURE AND ASSEMBLY INSTRUCTIONS FOR UF
H P C F ......... ..... ........... ................ ....... .................... ............... 1 16

C CALIBRATION CURVES AND EQUATIONS...............................................124

L IST O F R E F E R E N C E S ...................................................................... ..................... 13 1

BIOGRAPHICAL SKETCH ............................................................. ............... 134

LIST OF TABLES

Table p

1-1 Coaxial-shear injector features comparison. Includes UF injectors, Penn State
injectors, Space Shuttle Main Engine injectors, and Gas-Gas Injector
Technology Injectors........... ...... .............................. ..... .. ........ ........ .. ..

3-1 Distances from the injector face to the heat flux sensors for all injector
position/chamber arrangement combinations. All dimensions in inches ..............54

3-2 Description of each component on the HPCF Control Interface and HPCF-HFPT
Interface front panels (Labview GUI's). Numbers are referenced to Figures 3-
15 an d 3-16 ......... ...... ... ............................................................... 57

4-1 Combustion test configurations, operating conditions, and included figures..........61

B-l Extension stem sleeve designation for the three different injector positions.........121

B-2 List of DAQ channel/thermocouple usage. ................... .................... 123

C-l Table of calibration factors for the chamber and propellant line pressure
transducers..................................... ................................ ......... 130

LIST OF FIGURES

Figure pge

2-1 Standardized filename code for all saved main combustion test data files. High-
frequency pressure transducer test data files use the same code except for the
addition of "hfpt" before the test number (i.e., 010106UF 1P3CA3SAhfptT01). ...19

3-1 ProEngineer/ProMechanica stress models for the combustion chamber loaded at
10 MPa internal pressure. A) is the normal stress (MPa). B) is the shear stress
(M P a) ................ ......... ............................. ............................45

3-2 ProEngineer/ProMechanica transient thermal analysis on the combustion
chamber with heat flux conditions based on a stoichiometric flame. Maximum
temperature (y-axis) represents the hottest point anywhere in the chamber............46

3-3 Cross sectional drawing of the combustion chamber and chamber extensions.
All dimensions are in inches. The thermocouple holes at the top of the figure
are for the pair of thermocouples that form each heat flux sensor (HFS)...............46

3-4 Cross-sectional CAD image of the window mounting. The two o-ring grooves
completely circumnavigate the window. The viewable diameter through the
w window is 0.81".......................................... ...... ................. 47

3-5 Cross-sectional CAD image of the injector assembly. Indicates various
components as well as the dimensions of the 3 UF HPCF injectors: UFO
(GH2/Air), UF1 (GH2/GO2), UF2 (GH2/G2). .....................................................47

3-6 Cross-sectional drawing of injector indicating the distance from the outer face of
the chamber/chamber extension to the face of the injector for the three injector
positions IP 1, IP2, and IP3 ......... ............................................................................ 48

3-7 Cross-sectional CAD image of the injector assembly and the exhaust nozzle
assembly attached to the combustion chamber. ............................ ...................48

3-8 Pictorial of the different chamber arrangements possible for the HPCF. Flow
path is left to right. CC combustion chamber. SE short chamber extension.
L E long cham ber extension ................................ .............................................49

3-9 Drawing of the injector face, indicating notable dimensions of the injector
assembly face and locations of the injector face thermocouples. Dimensions in
in c h e s ......................................................................... 5 0

3-10 Schematic drawing of the HPCF propellant/purge feed system. Number on
bottles indicates the number of bottles in the array for that gas ............................51

3-11 Flowchart of the control/DAQ system. ............. ................. ................................ 52

3-12 Circuit diagram for the electronics system...................... .................. .......... 53

3-13 Circuit diagram for the non-inverting operational amplifier.................................55

3-14 Picture of the combustor system assembled, including the combustion chamber,
injector assembly, exhaust nozzle assembly, two short chamber extensions, and
in strum entation ..... .... .. ...... .. .. .......... ............................ ....................55

3-15 HPCF Control Interface front panel (Labview GUI). Numbers referenced to
T ab le 3 -2 ......................................................... ................ 5 6

3-16 HPCF-HFPT Interface front panel (Labview GUI). Numbers are referenced to
T ab le 3 -2 ......................................................... ................ 5 7

4-1 Chamber pressure versus time for a GH2/G02 combustion test with Pchamber =
6.21 MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s, H2 = 144.2 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement = CA3 SA. Ignition and shutdown times indicated for this full data
set ......................................................... ................................. 62

4-2 Heat flux versus time for a GH2/G02 combustion test with Pchamber = 6.21 MPa,
mo2/mH2 = 3.97, and vo2/vH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s,
vH2 = 144.2 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement= CA3SA. Legend indicates distance from injector face to heat
flux sensor. Ignition and shutdown times indicated for this full data set. Heat
flux calculations performed using steady state heat flux equation (Equation
2.15)..................... .............................................. ............... 63

4-3 Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/G02 combustion test with Pchamber = 6.21
MPa, mo2/mH2 = 3.97, and vo2/vH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s, H2 = 144.2 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement = CA3 SA. The legend indicates r as the radial distance from the
injector center axis to the injector face thermocouple. Ignition and shutdown
tim es indicated for this full data set. ............................................. ............... 64

4-4 Chamber pressure versus time for a GH2/G02 combustion test with Pchamber =
4.86 MPa, mo2/mH2 = 3.97, and vo2/vH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s, vH2 = 197.4 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangem ent = CA 3 SA .................................................. ........................................... 65

4-5 Heat flux versus time for a GH2/G02 combustion test with Pchamber = 4.86 MPa,
mo2/mH2 = 3.97, and vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s,
H2 = 197.4 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement= CA3SA. Legend indicates distance from injector face to heat
flux sensor. Heat flux calculations performed using steady state heat flux
equation (Equation 2.15). ............................................... .............................. 66

4-6 Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/G02 combustion test with Pchamber = 4.86
MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s, VH2 = 197.4 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement = CA3 SA. The legend indicates r as the radial distance from the
injector center axis to the injector face thermocouple...........................................67

4-7 Chamber pressure versus time for a GH2/G02 combustion test with Pchamber =
4.55 MPa, mo2/mH2 = 3.97, and V02/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s, VH2= 235.0 m/s). Injector = UF. Injector position = IP3. Chamber
arrangem ent = CA 3 SA .................................................. ........................................... 68

4-8 Heat flux versus time for a GH2/G02 combustion test with Pchamber = 4.55 MPa,
mo2/mH2 = 3.97, and Vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s,
vH2= 235.0 m/s). Injector = UF. Injector position = IP3. Chamber
arrangement= CA3SA. Legend indicates distance from injector face to heat
flux sensor. Heat flux calculations performed using steady state heat flux
equation (Equation 2.15). ............................................... .............................. 69

4-9 Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/G02 combustion test with Pchamber = 4.55
MPa, mo2/mH2 = 3.97, and vo2/vH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s, vH2= 235.0 m/s). Injector = UF. Injector position = IP3. Chamber
arrangement = CA3 SA. The legend indicates r as the radial distance from the
injector center axis to the injector face thermocouple...........................................70

4-10 Chamber pressure versus time for a GH2/G02 combustion test with Pchamber =
2.76 MPa, D mo2/mH2 = 3.97, and vo2/vH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2
= 0.396 g/s, H2 = 468.3 m/s). Injector = UF1. Injector position= IP3.
Chamber arrangement = CA3 SA. .......... ..................................... ................71

4-11 Heat flux versus time for a GH2/G02 combustion test with Pchamber = 2.76 MPa,
D mo2/mH2 = 3.97, and vo2/H2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 = 0.396
g/s, vH2 = 468.3 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement= CA3SA. Legend indicates distance from injector face to heat
flux sensor. Heat flux calculations performed using steady state heat flux
equation (Equation 2.15). ............................................... .............................. 72

4-12 Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/GO2 combustion test with Pchamber = 2.76
MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s, VH2 = 468.3 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement = CA3 SA. The legend indicates r as the radial distance from the
injector center axis to the injector face thermocouple...........................................73

4-13 Chamber pressure versus time for a GH2/G02 combustion test with Pchamber =
6.21 MPa, mo2/mH2 = 5.97, and V2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2
= 0.285 g/s, VH2 = 102.5 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3 SA. .......... ..................................... ................74

4-14 Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa,
mo2/mH2 = 5.97, and Vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s,
H2 = 102.5 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement= CA3SA. Legend indicates distance from injector face to heat
flux sensor. Heat flux calculations performed using steady state heat flux
equation (Equation 2.15). ............................................... .............................. 75

4-15 Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/G02 combustion test with Pchamber = 6.21
MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2 =
0.285 g/s, H2 = 102.5 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement = CA3 SA. The legend indicates r as the radial distance from the
injector center axis to the injector face thermocouple...........................................76

4-16 Chamber pressure versus time for a GH2/G02 combustion test with Pchamber =
4.86 MPa, mo2/mH2 = 5.97, and Vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2
= 0.285 g/s, H2 = 140.0 m/s). Injector = UF. Injector position = IP3.
Chamber arrangement = CA3 SA. .......... ..................................... ................77

4-17 Heat flux versus time for a GH2/G02 combustion test with Pchamber = 4.86 MPa,
mo2/mH2 = 5.97, and vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s,
vH2 = 140.0 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement= CA3SA. Legend indicates distance from injector face to heat
flux sensor. Heat flux calculations performed using steady state heat flux
equation (Equation 2.15). ............................................... .............................. 78

4-18 Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/G02 combustion test with Pchamber = 4.86
MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2 =
0.285 g/s, H2 = 140.0 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement = CA3 SA. The legend indicates r as the radial distance from the
injector center axis to the injector face thermocouple...........................................79

4-19 Chamber pressure versus time for a GH2/G02 combustion test with Pchamber =
4.55 MPa, mo2/mH2 = 5.97, and o2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2
= 0.285 g/s, VH2 = 166.1 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3 SA. ..................................................................80

4-20 Heat flux versus time for a GH2/G02 combustion test with Pchamber = 4.55 MPa,
mo2/mH2 = 5.97, and Vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s,
H2 = 166.1 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement= CA3SA. Legend indicates distance from injector face to heat
flux sensor. Heat flux calculations performed using steady state heat flux
equation (Equation 2.15). ............................... ...... .. ...... .............. 1

4-21 Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/G02 combustion test with Pchamber = 4.55
MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2 =
0.285 g/s, VH2 = 166.1 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement = CA3 SA. The legend indicates r as the radial distance from the
injector center axis to the injector face thermocouple...........................................82

4-22 Chamber pressure versus time for a GH2/G02 combustion test with Pchamber =
2.76 MPa, mo2/mH2 = 5.97, and Vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2
= 0.285 g/s, vH2 = 322.9 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3 SA. .......... ..................................... ................83

4-23 Heat flux versus time for a GH2/G02 combustion test with Pchamber = 2.76 MPa,
mo2/mH2 = 5.97, and Vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s,
vH2= 322.9 m/s). Injector = UF. Injector position = IP3. Chamber
arrangement= CA3SA. Legend indicates distance from injector face to heat
flux sensor. Heat flux calculations performed using steady state heat flux
equation (Equation 2.15). ..... ........................... ........................................84

4-24 Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/G02 combustion test with Pchamber = 2.76
MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2 =
0.285 g/s, vH2 = 322.9 m/s). Injector = UF1. Injector position = IP3. Chamber
arrangement = CA3 SA. The legend indicates r as the radial distance from the
injector center axis to the injector face thermocouple...........................................85

4-25 Heat flux versus distance from injector face for GH2/G02 combustion tests with
mo2/mH2 = 3.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55
MPa, and 2.76 MPa (D = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s). Injector =
UF1. Injector position = IP3. Chamber arrangement = CA3SA. Error bars
indicate +/- the standard deviation for the averaged test data. Chamber pressures
increased by decreasing exhaust nozzle diameter. Heat flux calculations
performed using steady state heat equation (Equation 2.15). ............................. 86

4-26 Heat flux versus distance from injector face for GH2/G02 combustion tests with
mo2/mH2 = 3.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55
MPa, and 2.76 MPa (D = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s). Injector =
UF1. Injector position = IP3. Chamber arrangement = CA3SA. Chamber
pressures increased by decreasing exhaust nozzle diameter. Heat flux
calculations performed using steady state heat flux plus heat absorption equation
(E equation 2.16)........................................................................ ............ 87

4-27 Heat flux versus distance from injector face for GH2/G02 combustion tests with
mo2/mH2 = 5.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55
MPa, and 2.76 MPa (D = 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s). Injector =
UF1. Injector position = IP3. Chamber arrangement = CA3SA. Error bars
indicate +/- the standard deviation for the averaged test data. Chamber pressures
increased by decreasing exhaust nozzle diameter. Heat flux calculations
performed using steady state heat flux equation (Equation 2.15). ...........................88

4-28 Heat flux versus distance from injector face for GH2/G02 combustion tests with
mo2/mH2 = 5.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55
MPa, and 2.76 MPa (D = 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s). Injector =
UF1. Injector position = IP3. Chamber arrangement = CA3SA. Chamber
pressures increased by decreasing exhaust nozzle diameter. Heat flux
calculations performed using steady state heat flux plus heat absorption equation
(E equation 2.16)........................................................................ ............ 89

4-29 Chamber wall temperature versus distance from injector face for GH2/GO2
combustion tests with mo2/mH2 = 3.97 and four different chamber pressures:
6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement =
CA3 SA. Error bars indicate +/- the standard deviation for the averaged test
data. Chamber pressures increased by decreasing exhaust nozzle diameter.
Wall temperature calculations performed using Equation 2.17. ...........................90

4-30 Chamber wall temperature versus distance from injector face for GH2/GO2
combustion tests with mo2/mH2 = 5.97 and four different chamber pressures:
6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa (D = 1.33, mo2 = 1.693 g/s, mH2
= 0.285 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement =
CA3 SA. Error bars indicate +/- the standard deviation for the averaged test
data. Chamber pressures increased by decreasing exhaust nozzle diameter.
Wall temperature calculations performed using Equation 2.17. ...........................91

4-31 Injector face temperature versus chamber pressure for GH2/G02 combustion
tests with mo2/mH2 = 3.97 (D = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s). Injector
= UF Injector position = IP3. Chamber arrangement = CA3 SA. Legend
indicates r as the radial distance from the injector center axis to the injector face
thermocouple. Bars indicate +/- the standard fluctuation from the average
temperature. Chamber pressures increased by decreasing exhaust nozzle
d ia m ete r .......................................................................... 9 2

4-32 Injector face temperature versus chamber pressure for GH2/G02 combustion
tests with mo2/mH2 = 5.97 (D = 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s). Injector
= UF Injector position = IP3. Chamber arrangement = CA3 SA. Legend
indicates r as the radial distance from the injector center axis to the injector face
thermocouple. Bars indicate +/- the standard fluctuation from the average
temperature. Chamber pressures increased by decreasing exhaust nozzle
d ia m ete r .......................................................................... 9 3

4-33 Injector face temperatures versus radial distance from injector center axis for
GH2/G02 combustion tests at mo2/mH2 = 3.97 and 5.97 and Pchamber = 6.21 MPa,
4.86 MPa, 4.55 MPa, and 2.76 MPa. Chamber pressures increased by
decreasing exhaust nozzle diameter. ............................................. ............... 94

4-34 Injector face temperature versus chamber length for GH2/G02 combustion tests
with Pchamber = 4.86 MPa, mo2/mH2 = 3.97, and vo2/vH2 = 0.46 (D = 2.0, mo2 =
1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Legend
indicates r as the radial distance from the injector center axis to the injector face
thermocouple. Error bars indicate +/- the standard deviation for the averaged
test data ............... ........ ................................ ..................... .......... ...... 94

4-35 Heat flux versus distance from injector face for GH2/G02 combustion tests with
mo2/mH2 = 3.97 (D = 2.0), vo2/vH2 = 0.46, vH2 = 207.4 m/s, and a variety of
chamber pressures. Chamber pressure increased by increasing flow rates.
Exhaust nozzle diameter = 1.70 mm (0.670 in.). Injector = UF Injector
position = IP3. Chamber arrangement = CA3 SA. Heat flux values calculated
using steady state heat flux plus heat absorption equation (Equation 2.16).............95

4-36 Normalized heat flux versus distance from injector face for GH2/GO2
combustion tests with mo2/mH2 = 3.97 (P = 2.0), vo2/vH2 = 0.46, vH2 = 207.4
m/s, and a variety of chamber pressures. Chamber pressure increased by
increasing flow rates. Exhaust nozzle diameter = 1.70 mm (0.670 in.). Injector
= UF 1. Injector position = IP3. Chamber arrangement = CA3 SA. Heat flux
values calculated using steady state heat flux plus heat absorption equation
(Equation 2.16). Heat flux values normalized by (2.75 MPa/P)08.......................96

4-37 Normalized heat flux versus distance from injector face for GH2/GO2
combustion tests with mo2/mH2 = 3.97 (P = 2.0), vo2/vH2 = 0.46, vH2 = 207.4
m/s, and a variety of chamber pressures. Chamber pressure increased by
increasing flow rates. Exhaust nozzle diameter = 1.70 mm (0.670 in.). Injector
= UF 1. Injector position = IP3. Chamber arrangement = CA3 SA. Heat flux
values calculated using steady state heat flux plus heat absorption equation
(Equation 2.16). Heat flux values normalized by (2.75 MPa/P)06......................97

4-38 Normalized heat flux versus distance from injector face for GH2/G02
combustion tests with mo2/mH2 = 3.97 (O = 2.0), vo2/VH2 = 0.46, vH2 = 207.4
m/s, and a variety of chamber pressures. Chamber pressure increased by
increasing flow rates. Exhaust nozzle diameter = 1.70 mm (0.670 in.). Injector
= UF 1. Injector position = IP3. Chamber arrangement = CA3 SA. Heat flux
values calculated using steady state heat flux plus heat absorption equation
(Equation 2.16). Heat flux values normalized by (0.187 g/s / mH2) 05. .................98

4-39 High-frequency pressure transducer data (chamber pressure versus time) for a
1.8 second window of a GH2/G02 combustion test with D = 2.0, mo2 = 1.565
g/s, and mH2 = 0.396 g/s. Injector = UF1. Injector position = IP3. Chamber
arrangement= CA3SA. Sample rate = 50 kHz. ............................ ..................99

4-40 Power spectrum analysis of high-frequency pressure data shown in Figure 4-33.
Analysis performed via Fast-Fourier Transform method ............... ...............99

4-41 0-3500 Hz window of power spectrum shown in Figure 4-34.............................100

4-42 Average flame profile of a GH2/G02 flame with operating conditions of Pchamber
= 4.86 MPa, D = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s, and Vo2/VH2 = 0.46.
Images of broadband flame emission. Exposure time = 500 ns. Average of 132
images. Injector center axis located at y = 0 and injector face located at x = 0....100

4-43 Instantaneous flame image of a GH2/G02 flame with operating conditions of
Chamber = 4.86 MPa, D = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s, and Vo2/VH2 =
0.46. Image of broadband flame emission. Exposure time = 500 ns. Injector
center axis located at y = 0 and injector face located at x = 0...........................101

C-l Calibration curve (Cv versus number of turns) for the B-SS4 and SS-SS4-VH
m entering valves. .....................................................................125

C-2 Calibration curve (Cv versus number of turns) for the SS-31RS4 and SS-31RF4
m entering valves. .....................................................................126

C-3 Calibration curve (Cv versus number of turns) for the SS-1RS4 needle valve,
w which has a 0.172 inch orifice......... ................. ............................................ .... 127

C-4 Calibration curve (Cv versus number of turns) for the SS-1RF4 neele valve,
w which has a 0.250 inch orifice......................................... ........................... 128

C-5 Calibration curve (amplification factor versus output voltage) for the operational
am p lifier. ........................................................................ 12 9

LIST OF OBJECTS

Object page

A-i Complete Labview code (block diagram) for Labview GUI "HPCF Control
Interface" (5.52 M B, object-al.pdf) .................................................................... 114

A-2 Complete Labview code (block diagram) for Labview GUI "HPCF-HFPT
Interface" (565 KB, object-a2.pdf). ........... ............................. ............... 115

A-3 Matlab code for "HPCFData_Proceessor" (19 KB, obj ect-a3.txt)...................... 115

A-4 Matlab code for "HFPT_Compare" (5 KB, object-a4.txt)............................... 115

A-5 Matlab code for "HPCF_ImageProcessor" (1 KB, object-a5.txt)....................... 115

A-6 Matlab code for "HPCF AvgFlameSpeed" (3 KB, object-a6.txt)........................ 115

NOMENCLATURE

A area [m2]

c heat capacity [J kg1 K-1]

Cv flow coefficient [1]

Gg specific gravity [1]

GO2 gaseous oxygen

GH2 gaseous hydrogen

GUI Graphical User Interface

HFPT High-Frequency Pressure Transducer

k thermal conductivity [W m1 K-1]

M Mach number [1]

th mass flow rate [kg/s]

m mass [kg]

mo2 oxygen mass flow rate [g/s]

mH2 hydrogen flow rate [g/s]

OH-PLIF Hydroxyl Planar Laser-Induced Fluorescence

p pressure [Pa]

Pchamber chamber pressure [Pa]

po stagnation pressure [Pa]

q volumetric flow rate [scfm]

qA heat flux per unit area [W m-2]

R

T

To

Twall

u

UF-HPCF

AT

At

Ax

density [kg m-3]

specific heat ratio [1]

xviii

gas constant [m2 S-2 T-1]

temperature [K, C]

stagnation temperature [K, C]

chamber wall temperature [K, C]

velocity [m/s]

High Pressure Combustion Facility

temperature difference [K, C]

time difference [s]

distance between temperature measurement locations [m]

S(m2 / H2 )actual / equivalence ratio [1]
(ino2/ nH2 stoch..metnc

Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

HIGH-PRESSURE GH2/GO2 COMBUSTION DYNAMICS

By

Clark Alexander Conley

August 2006

Chair: Corin Segal
Major Department: Mechanical and Aerospace Engineering

A high-pressure combustion facility was designed at the University of Florida

Mechanical and Aerospace Engineering Combustion Lab. Features of the facility include

optical access into the combustor during operation, a full set of temperature and pressure

diagnostic capabilities, remote control through a graphical user interface, and run times

upwards of 10 seconds. The facility is capable of operating pressure from 0.1 MPa to

6.25 MPa. Propellants used include gaseous hydrogen as the fuel and oxygen as the

oxidizer, although other fuels and oxidizer can be adapted to the facility. Current

injectors investigated are of coaxial shear jet type. Diagnostic capabilities include

chamber wall heat flux measurements along the length of the chamber, injector face

temperature measurements, exhaust nozzle temperature measurements, high-frequency

pressure measurements, and flame imaging. Through operation of the facility, several

key obstacles were identified which warrant future improvements. An injector

incorporating an ignition torch and propellant injection temperature/pressure

measurements is one such improvement, which is currently being designed. Integration

of a water-cooled nozzle will allow combustion test times beyond the current maximum

of 10 seconds. Finally, maintaining a proper seat between the heat flux sensors and the

The facility was used to investigate the dynamics of high-pressure GH2/GO2, with

operating conditions typical of rocket engines. Namely, two oxygen to hydrogen mass

flow ratios of 3.97 and 5.97 (D = 2.0 and D = 1.33, respectively) were investigated. Fuel

flow rates ranged from 0.187g/s to 0.470 g/s. Operational chamber pressures of 6.21,

4.86, 4.55, and 2.76 MPa were investigated by keeping the propellant mass flow rates

constant and changing the exhaust nozzle diameter. In addition, four operational

chamber pressures of 5.87, 4.93, 3.90, and 2.75 MPa were investigated by keeping the

exhaust nozzle diameter constant and changing the propellant mass flow rates. A period

of instability seems to exist in the combusting flow for the first 4 or 5 seconds after

ignition due to the increasing chamber pressure and the corresponding decrease in gas

injection velocities. Maximum heat release occurs 60 mm (2.35 in.) from the injector

face. In general, the injector face temperatures have little to no dependence on chamber

pressure. The profiles of heat flux and chamber wall temperatures seem to have no

pressure dependence and only a slight dependence on propellant injection velocities. A

scaling of heat flux values based on fuel mass flow rate, instead of chamber pressure, is

suggested. The lack of pressure dependence and only slight dependence on the propellant

injection velocities, as shown by the similarity in heat flux profiles, suggest that the basic

dynamic structures of the combusting flow are mainly dominated by geometrical effects.

CHAPTER 1
INTRODUCTION

The goals of this research were (i) to design and construct a combustion facility

capable of operating pressures from 0.1 to 6.25 MPa (1 to 62 atm), designated the

University of Florida High Pressure Combustion Facility (UF HPCF), and (ii) to

experimentally investigate the high-pressure combustion dynamics of GH2/GO2 flames at

operating conditions in the aforementioned pressure range, mo2/mH2 = 3.97 and 5.97 (D =

2.0 and 1.33, respectively) and a range of velocity ratios. Other capabilities of the facility

imaging systems, and controllability via graphical user interface (GUI). Diagnostic

capabilities include combustion chamber wall heat fluxes, injector face temperatures, exit

nozzle temperatures, flame temperatures, and chamber pressure fluctuations, all of which

were obtained for a variety of hot-fire tests in the aforementioned operational conditions.

flame emission images were obtained for a few combustion tests. These images are

useful in determining such characteristics as flame lift-off distance, shear layer growth,

instantaneous flame propagation phenomena, and average flame speeds. Furthermore,

preliminary investigation into the use of OH Planar Laser Induced Fluorescence (OH-

PLIF) laser-based diagnostic technique was conducted. This thesis presents the described

research, including the facility design/construction stages, future improvements to the

facility, data from high-pressure GH2/GO2 combustion tests, and discussion on the

implication of the data to the dynamics of the combustion process.

Safer, Cheaper, and More Reliable Rocket Engines

Although the research presented has applicability to many different types of

combustion engines, it is directed more toward study of the heat characteristics related to

rocket engines. More specifically, this research is directed at rocket engines employing

hydrogen and oxygen as the propellants and a shear coaxial jet injector. Rocket engines

are mainly used in satellite deployment, missile technologies, and space exploration, all

of which involve the transport of expensive equipment and/or human life. Therefore,

there is a constant drive for safer, cheaper, and more reliable rocket engines. In order to

build such rocket engines, the dynamics of the rocket engine combustion process need to

be better understood. However, the very nature of rocket engines makes this goal hard to

accomplish. The high-pressure and high-heat operational conditions of a rocket engine

make in-situ measurements inside the combustion environment difficult. Also, testing on

full size prototypes or actual engines can be time consuming and costly once all

development factors, materials, and testing facility costs are factored in.

One common away around this problem is through the use of Computational Fluid

Dynamics (CFD). CFD allows engineers to model the rocket engine in a computer to

determine design flaws and improvements, eliminating much time, effort, and cost in

building and testing physical prototypes. CFD essentially allows a rocket engine to be

safely designed to a final or near-final stage before a physical model must be built for

actual hot-fire testing. Unfortunately, two main problems have limited the application of

CFD in the rocket engine design process. First, in the past solutions have required huge

amounts of time and computer power to provide valid results for even simple models, not

to mention more complicated multi-element injector and intricate cooling systems.

Secondly, the CFD models at present lack abundant validation from actual combustion

data, especially for the higher pressures at which rocket engines operate. With computer

technology improving by leaps and bounds every day, the problems with computationally

expensive models are becoming fewer, meaning that more CFD results can be produced

quicker than ever. Unfortunately, the second problem has not been sufficiently

addressed. More validation of the CFD models means more trust in the model results,

giving way to quicker and cheaper design/build times for many components of the rocket

engines, including injectors, combustors, and cooling systems.1

To compound these difficulties, only recently has investigation into unsteady

combustion systems begun. Most CFD model results in the past have been based on

steady state 1-D analyses, when the combustion process inside rocket engines is largely

unsteady and 3-D. Furthermore, heat transfer into the combustor walls has rarely been

addressed, even though the strength, lifecycle, and cooling system effectiveness of the

combustor are heavily dependent on the heat transfer into and out of the chamber wall.2

This lack of research also applies to experimental investigation, with the only notable

study, by Marshall et al.,3 appearing only recently.

Therefore, it is worthwhile to not only experimentally investigate high-pressure

combustion dynamics, but to also work alongside CFD researchers to optimize

interaction between experimental testing and CFD modeling so that reliable rocket engine

models can be produced efficiently. This research seeks to advance the understanding of

high-pressure combustion dynamics through experimental testing and present the data for

CFD model validation so that cheaper, safer, and more reliable rocket engines become a

reality.

Literature Review

Before designing the UF HPCF, a literature search was conducted for other high-

pressure combustion diagnostic facilities, including those of the university, government,

and industry sectors. The goal of this search was to see what current high-pressure

combustion research existed, avoid potential road blocks that others had encountered and

documented, and verify that this research was unique and necessary for the aerospace

industry. Many key topics were searched for within the literature, including chamber

design, injector design, optical access design for imaging diagnostic purposes, non-

optical diagnostics for high-pressure combustion, and laser diagnostic techniques in high-

pressure combustion.

Several high-pressure combustion diagnostic facilities with optical access were

reviewed for different aspects of their designs.4-8 These facilities encompass gas turbine

combustors and rocket engine combustors, although other high-pressure combustion

diagnostic facilities exist for other uses, such as internal combustion engines. Allen and

Miller4 of Physical Sciences, Inc. present an optically accessible high-pressure gas

turbine combustor. While this facility is designed for gas turbine studies, the injector and

propellants are practically the only difference from the facilities for rocket engine studies.

Their facility can operate up to 50 atm and is equipped with a heater that can deliver air at

530 K at maximum pressure and a flow rate of 1 kg/s. The development of the high-

pressure gaseous burner at NASA's Glenn Research Center is presented in the Kojima

and Nguyen5 study. This facility is capable of running non-premixed and premixed

propellants at operating pressures up to 60 atm. Optical access and adaptability for

different fuels gives the ability for calibration of different optical diagnostic techniques.

Purdue University's high-pressure combustion facility, presented by Carter et al.,6

employs a flat flame burner for spectroscopic studies. Locke et al.7 briefly present the

high-pressure combustor facility at NASA's Glenn Research Center. This facility burns

JP-5, incorporates a ceramic liner, and is equipped with a nitrogen cooling film over the

windows. Finally, the facility at Pennsylvania State University is described the paper by

Foust et al.8 This high-pressure combustion facility is similar in design and use as the UF

HPCF, comprised of a modular combustor section with optical access and pressure-fed

propellant supplies. This facility uses a shear coaxial injector and has the capability for

liquid oxygen supply, in addition to gaseous propellants.

While many design aspects of the UF HPCF were covered from the aforementioned

papers, there was not enough information there to finalize the injector parameters. In

fact, Penn State's facility was the only one of those reviewed above that explicitly

incorporated a shear coaxial injector. Therefore further review was necessary to

determine proper injector characteristics. As mentioned, Foust et al.8 reported the

dimensions of their injector and their flow parameters for use with GH2/G02 at Penn

State's facility, which are presented in Table 1-1. The injector designs that came out of

the Gas-Gas Injector Technology (GGIT) study for the Reusable Launch Vehicle (RLV)

are reported by Tucker et al.9 These four injector designs and corresponding flow

conditions are also presented in Table 1-1. In addition, the injector and flow parameters

of the Space Shuttle Main Engine (SSME) fuel preburner are presented in Table 1-1,

which were reported in Ferraro et al.10 The current phase of this research is only

concerned with shear coaxial injectors, and hence no studies of swirl injectors, impinging

injectors, or other injector designs are reviewed here.

Laser-based diagnostics as applied to high-pressure combustion were also reviewed

for this research to understand facility requirements and prepare for the facility design

phase. Laser-Induced Fluorescence (LIF) is one such diagnostic technique. The LIF

technique has been extensively validated for atmospheric and sub-atmospheric

combustion, but the amount of LIF data available decreases rapidly as the pressure

increases. This is largely due to the difficulties in obtaining meaningful results because

of high-pressure effects on LIF. Because OH Planar Laser Induced Fluorescence (OH

PLIF) is the preferred species/technique for this research, it was reviewed in this

research. First and foremost, two extensive publications, Kohse-Hoinghaus and Jeffries11

and Eckbreth,12 provide ample information on laser-based diagnostic techniques as

applied to combustion through technical detail about the techniques themselves and

extensive referencing. Santoro13 provides a brief, but informative description of several

laser-based diagnostic techniques as applied to rocket and gas turbine combustors,

including Laser Doppler Velocimetry (LDV), Raman spectroscopy, and LIF at the Penn

State facility. The LIF setup described includes excitation of the Qi(8) transition of the

OH radical with 2 mJ/pulse at a pressure of 0.47 MPa and the resulting images were

compared to CFD results.

Frank et al.14 report OH PLIF measurements in a spray flame of heptane and Jet-A

fuel at pressures up to 20 atm using the facility at Physical Sciences, Inc. The PLIF setup

is described as excitation of the Qi(8) transition (X=283.55 nm) with a 3 mJ/pulse and

detection centered at 313 nm using a narrow bandpass interference filter (FWHM=25

nm). Significant laser attenuation and beam steering was noted as the pressures

increased. Edwards et al.15 report their investigation of OH LIF in high-pressure solid

propellant flames. Excitation was at 306.42 nm with 300 mJ/pulse and detection at 310.6

nm and 315.1 nm. The authors suggest that high-pressure effects on excitation/detection

strategies for LIF are less of a problem than the lack of high pressure kinetic and

spectroscopic data. Arnold et al.16 report quantitative measurements of OH concentration

fields using two-dimensional LIF of laminar, premixed methane/air flat flames at

pressures up to 20 atm. Excitation was at 290 nm with 1 mJ/pulse and detection at 314

nm. The authors report significant decrease in OH fluorescence signal with higher

pressures due to absorption line width broadening, increase of electronic quenching, and

increase in beam steering. Atakan et al.17 report the LIF spectra of OH in the exhaust of a

laminar premixed methane/air flame at pressures from 5 bar to 36 bar. Excitation was at

280 nm with 14 mJ/pulse and detection was centered around 309 nm.

Allen et al.18 report OH PLIF in high-pressure spray-flames burning heptane,

ethanol, and methanol at pressures from 0.1 to 1.0 MPa. Excitation was at 283 nm with 3

mJ/pulse and detection was in the range of 316 nm to 371 nm. The authors provide an in-

depth study of the high-pressure effects on PLIF, both through theoretical analysis and

through experimental validation. Stocker et al.19 report OH LIF in atmospheric pressure

flames for both a methane/air Bunsen burner and a hydrogen/oxygen welding torch with

excitation provided by an tunable OPO (type II) laser system. This in-depth study

thoroughly investigated four OH excitation wavelength ranges, all within the range of

321.0 nm to 241.1 nm, with detection between 305 nm and 330 nm and 5 mJ/pulse. This

study shows excitation of OH in the 280 nm to 285 nm to be reasonable. Singla et al.20

report OH PLIF of cryogenic Lox/GH2 jet flames at 6.3 MPa. Excitation is at 284 nm

with 42 mJ/pulse and detection is in the range of 306-320 nm. Much effort is presented

in imaging of the injector post lip flame holding region and the unsteadiness that the flow

exhibits there.

While this sample of reported literature in no way represents the entirety of

research on laser-based diagnostics, or even OH LIF for that matter, it does fairly

represent the spectrum of the research foci. This shows that while there is a fair amount

of research focused on high-pressure combustion OH LIF, a small percentage seems to be

focused on typical rocket engine injectors, such as shear coaxial jet and swirl injectors.

Furthermore, while considerable effort is being put towards the development of the LIF

technique, there seems to be very little effort put toward understanding other aspects of

rocket combustion, such as characterization of injector face temperatures and combustion

chamber wall heat fluxes. As mentioned earlier, only recently has wall heat flux data for

a GH2/GO2 combustor been presented. This benchmark study, by Marshall et al.,3

investigates the nature of heat flux inside a single element combustor, similar to that of

the UF HPCF. Unfortunately, this study is the first of its kind and still leaves many

questions about the dynamics of high-pressure GH2/GO2 combustion. The UF HPCF

aims to support this effort by providing a reliable, repeatable and safe combustion

environment to investigate all aspects of high-pressure combustion, including the

development and application of laser-based diagnostic and non-optical diagnostic

techniques to support the CFD modeling efforts.

Table 1-1. Coaxial-shear injector features comparison. Includes UF injectors, Penn State
injectors, Space Shuttle Main Engine injectors, and Gas-Gas Injector
Technology Injectors.

UF2

PSU

SSME IGGIT 1 IGGIT 2

GGIT 3

GGIT 4

ID of GO2 Post, 0.3051 0.0876 0.173 0.173 0.173 0.173
in.(mm) 0.0472 (1.2) 0.0591 (1.5) (7.75) (2.226) (4.394) (4.394) (4.394) (4.394)
ID of GH2
Annulus, in. 0.3752 0.148 0.203 0.203 0.203 0.203
(mm) 0.0866 (2.2) 0.0984 (2.5) (9.53) (3.76) (5.156) (5.156) (5.156) (5.156)
OD of GH2
Annulus, in. 0.1058 0.1058 0.5 0.1980 0.227 0.231 0.235 0.249
(mm) (2.687) (2.687) (12.7) (5.03) (5.766) (5.867) (5.969) (6.325)
GO2/GH2
Injection Area
Ratio 0.6 2.32 0.85 2.9 2.46 2.14 1.44
GO2/GH2
Velocity Ratio 0.1 0.7 0.1 -0.5 0.29 0.126 0.148 0.17 0.257

GO2/GH2 Mass
Flow Ratio 0.96- 5.97 3.68- 18.2 4.0 5.9 5.9 5.9 5.9

S___8.25 1.33 2.15 0.44 1.98 1.35 1.35 1.35 1.35
02 Velocity dependent dependent
(m/s) on nozzle on nozzle 51 78.6 78.6 78.6 78.6
Chamber
Pressure (atm) 0-60 0-60 12.9 75 75 75 75

CHAPTER 2
METHODS

This chapter discusses the H2/02 injection/combustion process, including reaction

chemistry, propellant flow rate calculations, and combustion test operation methodology.

This will give a complete understanding behind the control of the HPCF operating

conditions. Furthermore, the data processing methodology is presented within this

chapter, including the use of Matlab in this research for calibration, data processing, and

data organization.

The H2/02 Injection/Combustion Process

Fundamental understanding of the propellant reaction chemistry and flow

parameters is necessary for the control of the HPCF and understanding the data. The

HPCF uses gaseous hydrogen and gaseous oxygen for propellants and a coaxial shear

injector. The coaxial shear injector injects the hydrogen annularly around a center-stream

of oxygen. The two propellants are injected from equal pressure lines into a chamber

having some operational pressure nominally equal to the propellant line pressures.

Because the pressure difference between the two streams is small, the mixing process

between the hydrogen and oxygen is due to the shear occurring at the interface of the two

unequal velocity propellants. This shear causes the propellants to mix together in the

shear layer, where the combustion process occurs. Although the injection equivalence

ratio of the propellants may be non-stoichiometric, the reaction at the shear layer occurs

at stoichiometric conditions. Using the propellant chemistry and flow parameters allows

control of the HPCF operational conditions from one test to the next and processing of

the data.

H2-02 Reaction Chemistry

The reaction between hydrogen and oxygen can be written for a single reaction

mechanism, as shown in Equation 2-1.

aH2 + bO2 <> cH20 + dH2 +eO2 (2-1)

The coefficients in Equation 2-1 are determined from the reacting mixture composition.

A rich reaction (D>1.0) will result in excess hydrogen (e = 0), while a lean reaction

(1D<1.0) will result in excess oxygen (d = 0). In a perfectly stoichiometric reaction

(D=1.0), all of the hydrogen and oxygen reacts together, leaving only water as the final

product (d = 0, e = 0). The chemical equation for the stoichiometric reaction of H2/02 is

given in Equation 2-2.

1H2 +0.502 <: H20 (2-2)

STANJAN,21 a reaction chemistry program, was used in this research for determining the

properties of the exhaust gas assuming complete combustion based on the injection

equivalence ratio. This information is then used in the injection flow property

calculations presented in the next section to get an approximate value for desired

propellant flow rates.

Another important aspect of the propellant reaction is the inter-combustion species

that appear mid-reaction. The complete H2-02 reaction process is much more

complicated than Equations 2-1 and 2-2. In between the initial and final states reside

intermediate chain-reacting and chain-terminating reactions involving inter-combustion

species. A complete review of the H2-02 reaction is beyond the scope of this discussion,

however a more complete review is presented in Turns.22 One such inter-combustion

species for the H2-O2 reaction is hydroxyl (OH). OH predominantly appears in the

reaction zone, meaning it is an excellent indicator of the shear reacting layer, or flame

region. The presence of OH in the shear reacting layer enables the use of laser based

diagnostic technique OH-Planar Laser Induced Fluorescence (OH-PLIF), a heavily

researched tool in investigating combusting H2/02 flows.

Propellant Flow Properties and Calculations

The propellants are injected into the chamber at a certain injection equivalence

ratio. The injection equivalence ratio is a measure of the ratio between the mass flow rate

of the hydrogen to the mass flow rate of the oxygen for the actual experimental

conditions compared to the stoichiometric conditions, as shown in Equations 2-3 and 2-4.

nH 1 0(lmol)(2g /nmol) 2g
S=H2 (0.mol)(31.9g/mol) 2g= 0.125 (2-3)
o2 s(0. 5mol)(31.999g / mnol) 16g
stoicho ietrzc

= H2 / hH\ -- -H = -H (2-4)
S actual 2 stoichometric 2 actual K 2 stoichiometric

This gives a numerical basis for how rich or lean the propellant injection is. Therefore,

the equivalence ratio is an important parameter in the HPCF operating conditions,

specifically in the determination of the propellant mass flow rates.

Because the operation of the chamber relies on the exhaust gases choking at the

exhaust nozzle at a certain pressure, it is convenient to specify an operational chamber

pressure and equivalence ratio for the propellants and work backwards to the propellant

flow rates. An equation can be derived that is dependent only on the exhaust gas

properties, exhaust nozzle geometry, and operational chamber pressure as follows. First,

a simple form for mass flow rate and gas velocity is given in Equation 2-5 and Equation

2-6, respectively.

h = puA

(2-5)

(2-6)

In addition, the ideal gas law and several isentropic flow equations, given in Equations

2-7 through 2-9, are used.

S=RT

(2-7)

(2-8)

To = T 1+2 1 iff

Ao = P 1 2/ iff
]~ {1Y12~

(2-9)

Substituting Equations 2-8 and 2-9 into Equation 2-7 gives Equation 2-10.

(2-10)

Substituting Equation 2-8 into Equation 2-6 gives Equation 2-11.

u= M RT1 1+1M2

(2-11)

Finally, substituting Equations 2-10 and 2-11 into Equation 2-5 and simplifying gives

Equation 2-12.

(2-12)

fi= 7 PO A M
0R To 1+ MiM /2()2-1)
I 2 7

U = MJRTK

+ lff2/Yo-'

P=
R To,

Equation 2-12 allows the mass flow rate of the exhaust gases to be calculated from the

exhaust gas properties, operational chamber pressure, exhaust nozzle geometry, and the

fact that the flow will choke (M=1.0) at the exhaust nozzle. For example, plugging the

equivalence ratio into STANJAN21 for a constant pressure reaction gives the flame

temperature, specific heat ratio, and gas constant for the exhaust gases. In addition, the

area of the exhaust nozzle opening is known. It is also desired that the flow chokes at the

exhaust nozzle exit, or the Mach number equals 1.0. The desired operational chamber

pressure is known. Plugging the above information into Equation 2-12 will result in the

flow rate of the exhaust gases.

From the exhaust gas flow rate, using the set equivalence ratio and Equation 2-4

gives the individual flow rates of the fuel and oxidizer. These HPCF is then setup for the

calculated propellant flow rates through the use of the Labview GUI discussed in the next

chapter and Equation 2-13.

q= 0.471ACp,1 (2-13)
p 1 (2-13)

Equation 2-13 relates the flow rate through the metering valves in the propellant lines for

a choked flow (downstream pressure is less than half of upstream pressure) to the

following:

* Cv, the flow coefficient of the valve
* pi, the upstream pressure
* Ti = 300K (540 R), the gas temperature
0.06988 (GH2)
* G = 1.10915 (GO2) the specific gravity of the gas
1.00000 (Air)
* A1 = 22.67 (for units of scfm for q, psia for pi, and R for T1)

The Cv of the metering valve is directly related to the number of turns on the valve

handle. The Cv calibration curves and equations for all of the metering valves are located

in Appendix C. The upstream pressure is obtained from a pressure transducer.

Furthermore, the propellant injection velocities can be calculated iteratively solving

for the Mach number, M, through Equation 2-14 and plugging the result into Equation

2-11.

Ii/ T2 /()'+I) + 2(. TO
1 R~AJ M -M 2 ) + =0 (2-14)
2 pYoA 7 poA

All of the parameters in Equation 2-14 are gas specific, meaning the individual propellant

mass flow rate, gas constant, stagnation temperature, stagnation pressure, specific heat

ratio, and injection area are used to obtain the Mach number at injection for each

propellant.

Heat Flux Calculations

One of the desired data sets obtained from this research is the combustion chamber

wall heat flux. The calculation of heat flux values from the sensors is described here,

while the design, construction, and placement of the heat flux sensors is discussed in

Chapter 3. Each heat flux sensor measures the temperature inside the chamber wall at

two locations essentially in line with each other and perpendicular outwards from the

inner chamber surface, as depicted in Figure 3-3. The two temperatures are measured at

a distance of 0.25 in. from each other. Using the instantaneous temperature difference

AT, the distance between the measurement locations Ax, and the thermal conductivity k,

the steady state heat flux per unit area, qA, can be calculated according to Equation 2-15.23

qA= AT (2-15)
Ax

The thermal conductivity for Copper 110 is approximately 388 W/m-K, with a decrease

of about 5% at 600 K. Initially, heat flux calculations were performed using Equation

2-15. However discrepancies were observed between the results obtained in this research

and those presented by Marshall et al.3 Upon observation, this discrepancy appeared to

stem from the absence of a heat absorption correction in Equation 2-15. Essentially,

while the temperature difference could be the same between two tests, the actual

temperatures could be higher. Since the temperatures are higher, a higher heat flux was

experienced and the chamber absorbed more heat in one case than the other. Equation

2-15 does not account for this heat absorption. Solving the differential form of the heat

flux equation while accounting for the transient heat flux (heat absorption) yields

Equation 2-16 when the AT/At of both thermocouples is equal (same slope).

qA (,2 o,2) (2 ) (2-16)
Ax 2 At

The density, p, and heat capacity, c, for Copper 110 are 8700 kg/m3 and 385 J/(kg K),

respectively. The temperature subscript "i" represents the thermocouple closest to the

inner chamber wall, "o" represents the thermocouple farthest from the inner chamber

wall, "1" represents an initial time, and "2" represents a final time. All combustion tests

were reanalyzed using Equation 2-16 for the heat flux calculations to compare

differences. Results using both heat flux calculations are presented in Chapter 4. Note

that both heat flux calculations are one dimensional.

Once a heat flux value is known, the inside chamber wall temperature can be

inferred by rearranging Equation 2-15 into Equation 2-17.

qA'(
Twa- = + + (2-17)
k

In Equation 2.15, qA is the heat flux per unit area obtained from the experiment, Ax is the

distance between the deeper thermocouple detection point and the inner chamber wall,

and Ti is the temperature measured by the deeper thermocouple.

Data Processing Methodologies

Each combustion test can provide data from five thermocouples, 14 heat flux

sensors, and three pressure transducers at 40 Hz, in conjunction with large amounts of

images and high-frequency pressure transducer (HFPT) data at 50 kHz. This large

amount of data from each combustion test necessitates a sophisticated data processing

methodology for clarity and efficiency. The data processing package built-up for the

HPCF is extensive, employing Matlab to perform the majority of the processing.

The Role of Matlab

Each combustion test can provide two text files produced by the Labview GUIs and

a batch of images from the intensified CCD camera. Because of the extensive amount of

data, several Matlab programs were written to help quicken and ease the data processing.

Standardized filenames

The HPCF has the ability to operate in many different configurations. These

options include two oxidizer choices, three different injector positions, and 26 different

chamber arrangements. The filename for the saved data sets is standardized to allow easy

recognition of the operating configuration for the user and Matlab program. The

standardized filename code is presented in Figure 2-1.

Data processing programs

Several Matlab data processing programs were developed for the HPCF. The main

Matlab program for the HPCF is titled "HPCFDataProcessor" and performs processing

on both the main data file from the Labview GUI "HPCF Control Interface" and the high-

frequency pressure transducer data from the Labview GUI "HPCF-HFPT Interface".

This program reads in the main data file, reads in the HFPT data file, sorts the data sets,

calculates the heat fluxes from the thermocouple readings, plots many operational

parameters versus time, performs frequency analysis on the data, and logs the test into the

"Combustion Test Master Log" file. The tests are logged in the master log file by

filename and include other test information such as operational chamber pressure,

equivalence ratio, propellant flow rates, and confirmation of availability of HFPT and

image data for the test. This makes finding old tests based on desired operation

parameters easy.

In addition, there were several other Matlab programs developed to aid in various

aspects of the HPCF. First, there is program titled "HFPT_Compare" that directly

compares the high-frequency pressure transducer data from several different tests via

plots of the data versus time and frequency analysis. A program titled

"HPCF_ImageProcessor" reads the images from the combustion test and allows further

analysis from the user, such as average flame profile calculation. A program titled

"HPCF_AvgFlameSpeed" reads the image pairs from the combustion test and calculates

the average flame speed through a correlation analysis of the high speed image pairs.

The codes for all of these Matlab programs are presented in Appendix A. Several other

programs were developed as well, but are not presented here. They include programs

used to determine laser intensity profile and various imaging calibration techniques.

0101060

Date of Test
(MM/DD/YY)

Oxidizer:
0 = Oxygen
A = Air

Injector: See
Fig. 3-5

IP3

T01

STest Number
(T##)

Chamber
Arrangement:
See Fig. 3-8

Figure 2-1. Standardized filename code for all saved main combustion test data files.
High-frequency pressure transducer test data files use the same code except
for the addition of"hfpt" before the test number (i.e.
0101060UF 1IP3CA3 SAhfptT01).

CHAPTER 3
HIGH-PRESSURE COMBUSTION FACILITY

This chapter discusses in detail the design and construction of the University of

Florida High-Pressure Combustion Facility (UF HPCF). This discussion incorporates

every aspect of the facility, generally broken down into the combustor system, the

propellant feed system, and the control/data acquisition (DAQ) system. Some of these

general systems are further divided into components for design/discussion purposes. The

combustor system consists of the combustion chamber, injector, and other combustor

system components. The control/DAQ system consists of the electronics, control/DAQ

hardware, and the Labview GUI. Furthermore, discussion of how all of these systems

work and function together to form the UF HPCF is presented.

Combustor System

As previously mentioned, the combustor system is broken down into the

combustion chamber, injector, and other combustor system components for

design/discussion purposes. Each of these components presented their own design

challenges worthy of discussion. The combustor system employs each of these

components together for proper functionality.

Combustion Chamber

For the HPCF, the main design goal of the combustion chamber was to house

extremely high temperature combustion at high pressure with optical access to the inside

of the chamber. This goal played directly into choosing both the chamber material and

chamber geometry.

Chamber material

The chamber material chosen had to provide ample strength and thermal

characteristics. The extremely high flame temperatures seemed to suggest going with a

refractory metal as the chamber material, such as tungsten. However, many of the

refractory metals oxidize quickly in the presence of oxygen, making them unusable. The

high pressure operation (6.25 MPa) suggested going with a high strength material, such

as steel. However, the melting temperature and thermal conductivity of steel is low.

Therefore, a steel chamber might develop local hot spots, resulting in failure of the

chamber due to steel's inability to dissipate heat quickly. Copper manages to balance

strength, melting temperature, and thermal conductivity. Copper has a yield strength and

melting temperature comparable to steel. However, copper has a very high thermal

conductivity, allowing the material to pump heat away from hot spots and distribute it

throughout its bulk quickly. This capability of copper lends itself to short durations at

extremely high temperature and even longer durations if a cooling system is

implemented. Copper 110 was chosen as the chamber material for these reasons.

Chamber geometry

The chamber geometry was chosen to eliminate stress concentration areas and hot

spots while allowing maximum optical access capabilities. Initially a cylindrical chamber

was designed due to ease of manufacturing. However, a round chamber made having

optical access without recesses in the chamber flow path impossible. Because the

windows needed flat faces to keep distortion of the optics to a minimum, creating a

window to match the inside cylindrical surface was not an option. Therefore, for ease of

implementing optical access, a square internal chamber cross-section was chosen. It is

known that sharp corners, or extremely small radii, result in high stress concentration. To

optimize the design of the chamber, ProEngineer/ProMechanica was used to perform

stress and strain modeling on several different chamber design possibilities. A stress

model for the final chamber geometry is shown in Figure 3-1. A transient thermal

analysis was performed on the chamber as well, the results of are shown in Figure 3-2.

The analysis indicated that the maximum chamber wall temperature after a 10 second run

would be 450 K, well below the melting point of copper. Experiments with test runs of 8

seconds have shown wall temperatures of approximately 550 600 K. The difference

exists due to the discrepancy between the higher flow rates of the combustion tests and

the lower flow rates used to calculate the heat load in the transient analysis during the

design phase. As expected, the higher flow rates results in a higher heat release and

higher heat load, and thus a higher wall temperature. Optimization between reducing

stress due to pressure and maximizing optical access resulted in replacing the sharp

corners of the square with 3.18 mm (0.125 in.) radius, as shown in Figure 3-3. This

design drastically reduced the stress in the chamber while rendering a large percentage of

the chamber cross section visible. The combustion chamber geometry was finalized with

a 25.4 by 25.4 mm (1 by 1 in.) square with 3.175 mm (0.125 in.) radius corners cut

through the center of a 63.5 by 63.5 by 101.6 mm (2.5 by 2.5 by 4 in.) piece of Copper

110.

Optical access

Designing optical access into the high-pressure combustion chamber proved to be

challenging. The first consideration for the optical access was window material.

Because of the high flame temperatures and desired laser diagnostic capabilities, a

material had to be chosen with a high melting temperature, low coefficient of thermal

expansion, and the ability to transmit a large percentage of the light spectrum, including

ultraviolet. UV-grade fused silica was chosen as the window material, with a softening

temperature above 16000C and the ability to transmit the light spectrum from 225nm

through 1000+ nm.24

The next consideration for the optical access was shape/size of the window. The

windows needed to be sufficiently thick to take the high pressure combustion regimes, as

well as sit flush to the inner wall of the chamber. Because the maximum dimension

inside of the chamber is 25.4 mm (1 in.), the window did not need to exceed 25.4 mm (1

in.) in width. After reviewing several fused silica suppliers and considering the chamber,

a round 25.4 mm (1 in.) outer diameter (OD) UV-grade fused silica window was chosen,

supplied by Esco Products. Although the round window causes a decrease in the viewing

area as compared to a square window, the combination of small length scale interest for

the combustion and the ease and availability of the round window made it a good choice.

Stress calculations confirmed that a 25.4 mm (1 in.) thick, 25.4 mm (1 in.) OD fused

The final consideration for the optical access was how to mount the windows

securely in the chamber wall. The biggest problem with mounting the windows in the

copper chamber resided in the huge difference in coefficients of thermal expansion for

the two materials. For example, the ratio of the coefficient of thermal expansion of the

copper to that of the fused silica is 42.5.24 As a result, copper will tend to expand much

more than the fused silica window. This can cause sealing problems by opening up larger

gaps between the windows and chamber during combustion. Another problem occurs

upon cooling of the chamber. Because of the gap growth between the copper and the

fused silica during combustion, the windows have the possibility to relax slightly crooked

in the chamber wall once the pressure reduces. As the copper cools and contracts, the

slightly crooked window will be forced by the wall back to its correct position. This

however can cause the window edges to catch in the metal and crack or break the

windows. Windows breaking in the chamber poses both a safety issue and a time/cost

effectiveness issue. To correct for these problems between the chamber and windows, a

radial o-ring system was designed into the window cavity in the chamber wall. Two

radial o-ring grooves were cut into the perimeter of the window cavity at two different

depths, cross-sectionally shown in Figure 3-4. The two radial o-rings allow the window

to essentially float in the center of the window cavity without touching the chamber wall.

Because of the tight tolerances, the o-rings have room to expand outwards with the

chamber wall while holding the window firmly in the center of the cavity and keeping a

tight seal. Using two radial o-rings spaced apart keeps the window upright and does not

allow the window to tilt in the cavity, which could cause the glass to catch an edge on the

metal and break upon cooling.

Another problem with mounting the windows was keeping them flush on the inner

wall of the chamber. The desire to keep the inner window surface flush with the inner

chamber wall was to ensure a smooth flow path and eliminate extraneous flame-holding

spots within the chamber. A step was machined by Esco Products into the end of the

window cavity and the end of the window. The steps in the chamber and window mate

when the window is inserted into the chamber, as shown in Figure 3-4. The mating

surface of the chamber step with the window step was polished to keep the window edge

from catching and resulting in a broken window. Another benefit of this glass-to-metal

seal is that it eliminates the need for a rubber seal to be located so close to the combustion

zone and high temperatures. With the window fully inserted into the chamber wall, the

outer surface is flush with a slightly larger recess in the chamber wall. A rubber gasket is

placed over this recess and covers the entire metal surface and the outer edge of the

window surface in the recess. A flange is then tightened down onto the chamber wall

with the use of 6 #10 bolts and nuts. This flange is designed to press the gasket against

the window when completely tightened down. The pressure from this gasket keeps the

window from trying to push out of its recess in the chamber during high pressure tests

while allowing slight movements due to thermal expansion. The flange also contains a

drill through hole with the same outer diameter as that of the recess in the inside of the

chamber, also shown in Figure 3-4, resulting in a viewable diameter of 20.6 mm (0.81

in.).

This optical access system provides a very large viewing area as compared to the

internal dimensions of the chamber and injector while maintaining structural integrity and

a tight seal. The combustion chamber, with optical access system installed, has been

pressure tested to over 6.7 MPa (1000 psi) without failure, leaking, or any noticeable

adverse affects. The tests were conducted with cold nitrogen gas first by slowly

increasing and decreasing the pressure. Then more strenuous tests were performed by

hammering the chamber with the high pressure nitrogen and exhausting the nitrogen as

quickly as possible. The windows stayed perfectly in place and did not fail or crack

during these tests cold nitrogen pressure tests.

Other chamber features

As described, the combustion chamber is made of copper 110 and offers optical

access on all four sides of the chamber. The chamber also incorporates /4-20 tapped

holes at each of the four covers of the two chamber mounting faces. These tapped holes

receive /4-20 threaded rod, allowing the injector, chamber extensions, and exhaust nozzle

to be attached to the main chamber. The chamber also incorporates ports for heat flux

sensors up one side, which are discussed in the DAQ section of this chapter.

Injector

The injector for the HPCF is currently a single-element, coaxial, shear injector.

Single-element refers to there being only one exit for the fuel and one exit for the

oxidizer into the chamber, as opposed to a multi-element injector which essentially

incorporates a matrix of single-element injectors. Coaxial indicates that the oxidizer and

the fuel flow symmetrically about the same axis. More specifically, the fuel injects

annularly around a center stream of oxidizer. A shear injector relies solely on the shear

between the fuel stream and oxidizer stream to mix them together, rather than employing

swirling or impinging techniques. This shear is achieved by injecting the propellants at

different relative velocities. The single-element, coaxial, shear injector for the HPCF was

designed with three goals: adaptability to many different flow regimes, ease of

assembly/integration into combustor system, and ease/cost of manufacturing. This

resulted in three components which collectively form the injector: the fuel annulus,

oxidizer nozzle, and injector housing.

Injector material

The material selection for the injector followed the same methodology as that for

the combustion chamber. For the same reasons that the chamber was made of copper, the

fuel annulus and oxidizer nozzle were made of copper. Being made of copper allows the

injector to have structural integrity by dissipating heat from flame-holding regions at the

tip of the injector. However, instead of copper 110 for the injector, oxygen-free copper

was used. The oxygen-free copper ensures that there is no impregnation of oxygen into

the fuel stream before it reaches the chamber. The injector housing, which the fuel

annulus and oxidizer nozzle mount to and which allows mounting of the injector

assembly to the injector, was made of steel for structural and ease/cost of manufacturing

purposes.

Injector geometry

The geometry for the injector housing allows simple mounting of the injector

assembly to the combustion chamber, integration of the fuel annulus and oxidizer nozzle,

and inclusion of nitrogen purging and injector face thermocouples. A cutout of the

injector is shown in Figure 3-5. The oxidizer nozzle is soldered to a stainless steel tube

that extends through the back of the injector housing through a tube fitting equipped with

a Teflon ferule. This oxidizer nozzle mounting method allows the tip of the nozzle to be

moved relative to the surface of the injector without permanently locking a metal ferule

onto the tube, effectively giving the ability for recessed, flush, and protruding

configurations. A spacer sleeve and a spacer baffle are used to hold the oxidizer nozzle

in the center of the injector housing. The spacer baffle also serves to uniformly distribute

the fuel flow around the oxidizer nozzle.

The oxidizer nozzle is shaped to inject the oxidizer straight into the chamber. The

fuel annulus surrounds the oxidizer nozzle and contains a length of straight passage to

straighten the fuel flow before injection into the chamber. The fuel annulus screws into

the face of the injector housing until its face and the face of the injector housing are flush.

The fuel annulus tightens down onto an o-ring to ensure no fuel is ejected through the

threaded portion. Currently the HPCF is equipped for three different injector positions,

the details of which are depicted in Figure 3-6. The injector assembly is attached to the

chamber via the 4 /4-20 bolts and the position of the injector inside the chamber is

determined by the use of spacer tubes, as indicated in Figure 3-7.

The dimensions of the injector were determined from a combination of literature

review (see Table 1-1) and careful examination of the goals of the HPCF. In order to

allow a range of flow conditions for GH2/G02, two injectors were designed, designated

UF1 and UF2. A third injector also exists for use in GH2/air experiments and is

designated UFO. The geometrical details of the three injectors can be found in Figure 3-

5. The fuel annulus remains the same for all three injectors. The oxidizer nozzle, on the

other hand, has different diameters for each injector, which are given in Figure 3-5.

Other Combustor System Components

The remaining combustor system components include the exhaust nozzle, chamber

extensions, and the igniter.

Exhaust nozzle

The exhaust nozzle allows the flow to choke at the exit of the chamber, resulting in

a rise in the chamber pressure. For the purposes of the UF HPCF, the exhaust nozzle was

not designed to optimize the exhaust flow for propulsion purposes. The exhaust nozzle

was designed to choke the flow for a certain chamber pressure, for long service life, and

ease of assembly/integration. For the same reasons listed for the chamber and injector,

the exhaust nozzle was also made of copper. Long service life from the nozzle required

all hot spots be eliminated. Because the exhaust nozzle endures direct contact with the

flame and recirculation regions of hot exhaust gases, the nozzle was smoothly contoured

down from the inlet face to a minimum diameter hole and contoured back out to the exit

face, as shown in Figure 3-7. This smooth contoured profile eliminates sharp corners and

the resulting hot spots, which could lead to premature wear or failure. The copper nozzle

disc is mounted between two mating flanges which mount to the chamber. O-rings seal

the nozzle within the flanges. This nozzle flange system allows many nozzles for

different flow conditions to be quickly made and replaced. A picture of the exhaust

nozzle assembly installed in the combustor is shown in Figure 3-14.

Chamber extensions

Chamber extensions serve to change the length of the chamber and/or to

incorporate DAQ/control or safety features into the chamber. Currently there are four

different chamber extensions, with two of the four being identical. All of the extension

pieces are made of copper 110, same as the chamber. The extensions also incorporate

through-holes and an o-ring groove on the mating surface to allow sealed attachment to

the chamber. The chamber extensions have the same cross section as the chamber, but

differ in length. The two identical extensions are 18.61 mm (0.7325 in.) long and each

incorporates a single heat flux sensor. The longer extension of length 38.1 mm (1.5 in.)

incorporates four heat flux sensors. The fourth chamber extension differs in function

from the other three in that it is always attached to the chamber immediately upstream of

the exhaust nozzle. This permanent extension has ports into the chamber on all four of its

sides. One port houses the igniter, one port houses a thermocouple that can protrude into

the chamber and a low frequency pressure transducer, another port houses a high

frequency pressure transducer and allows passage to a safety valve that opens in the event

of an over-pressure, and fourth port exists for extra DAQ hardware (currently plugged).

A picture of the chamber extension installed in the combustor is shown in Figure 3-14.

Igniter

The igniter places a 10,000 volt spark inside the chamber, allowing the propellants

to ignite. The igniter consists of two main components: the igniter lead and the

transformer. The igniter lead was built by gluing two pieces of copper wire inside an

Omega high-temp ceramic sheath containing two bore holes. The copper leads end about

a quarter of an inch short of the combustor end of the ceramic and protrude out of the

back of the ceramic tube. Insulation is wrapped on the bare copper wire out of the back

of ceramic tube to the point where the wires connect to the transformer cable. Graphite

powder is packed into a portion of the remaining space in the ceramic tube holes on the

combustor side. Then two small copper wire leads are stuck into the holes against the

graphite powder, placing about half of the lead in the ceramic tube and half of the lead in

the chamber as an electrode. The igniter is stuck into the chamber wall such that the

ceramic tube ends short of the inside chamber surface and the small copper electrode tips

protrude into the chamber. Each combustion test will melt the ends of the electrodes

together, requiring them to be replaced between each test. The graphite powder gives an

electrically conductive buffer between the copper lead wires and the copper electrode tips

without allowing them to weld together during sparking. The igniter is sealed via a

Swagelok bore-through tube fitting using a Teflon ferule. The Teflon ferule allows a

tight seal to be placed on the ceramic tube without cracking it. The igniter copper wire

leads are connected to a 10,000 volt transformer. Power and control for the igniter comes

via the DAQ/control system.

Propellant Feed System

The propellant feed system supplies the propellants and a nitrogen purge to the

combustor system. More specifically, the HPCF propellant feed system can provide

either gaseous oxygen (GO2) or air as the oxidizer and gaseous hydrogen (GH2) as the

fuel. The entire system is a pressure fed system, meaning there are no pumps. The

propellants and the nitrogen are all supplied via high-pressure gas bottles through an

intricate network of tubing, valves, and regulators. A schematic of the propellant feed

system is shown in Figure 3-10. The propellant feed system offers a reliable and

controllable supply of propellants and nitrogen purge to the combustor system.

As mentioned, this pressure fed system relies on high-pressure gas bottles. For the

air supply, an array of 6 bottles at 17.9 MPa (2600 psi) are connected in parallel and is

located inside the combustion lab. The GO2 supply is provided by an array of 10 bottles

at 17.9 MPa (2600 psi), all connected in parallel. The GO2 bottles are located outside

under a covered shed for safety. The GH2 supply is provided by a single hydrogen bottle

at 17.9 MPa (2600 psi), which is located inside the combustion lab. An array of 6

hydrogen bottles at 15.2 MPa (2200 psi) located outside the building is available for

future integration if the need for longer tests arises. For the purpose of this study,

however, the fuel mass flow rates are low enough to warrant one bottle of hydrogen,

which can deliver upwards of 20-30 tests. The nitrogen purge supply is provided by 1

bottle of nitrogen at 17.9 MPa (2600 psi) located inside the combustion lab. This

nitrogen bottle is connected to both the oxidizer and fuel lines, as well as the chamber

purge line into the back of the injector housing, allowing complete nitrogen purge of the

propellant supply lines, injector, and chamber. This setup also offers the capability to

purge nitrogen throughout the experiment or pre-pressurization of the chamber

immediately before the combustion test.

The entirety of the oxidizer lines is 9.53 mm (0.375 in.) OD stainless steel tubing.

Beyond the valves located on each of the oxidizer bottles, numerous ball valves are

placed in the oxidizer lines to provide shutoff capabilities at several key locations,

switching capability between the oxidizer GO2 and air feeds, and nitrogen purge

capability. The GO2 line incorporates a ball valve at the lab entry point for safety. There

is also a ball valve inline close to the tanks outside, allowing excess oxygen to be bled off

safely and allow a place for purging nitrogen to exit the line. Two ball valves directly

upstream of the oxidizer pressure regulator allow the oxidizer to be switched to either

G02 or air, depending on which ball valve is open. The nitrogen purge for the oxidizer

line is supplied by opening another ball valve at the back of the air line, allowing full

purge of both the air and GO2 lines, as well as the oxidizer supply line that connects to

the injector. Every component in the oxidizer supply line is rated for more than 20.7

MPa (3000 psi), incorporating a good safety margin.

The fuel line is 6.35 mm (0.25 in.) OD stainless steel tubing. There is only one ball

valve located in the fuel line. This ball valve is located near the bottle on a line that tees

into the main fuel line, providing a nitrogen purge to the fuel line when the fuel bottle is

shut off and the ball valve is open. This nitrogen purges the entire line from the bottle all

the way through the injector. As with the oxidizer line, every component in the fuel

supply line is rate for more than 20.7 MPa (3000 psi).

The nitrogen purge line is 6.35 mm (0.25 in.) OD stainless steel tubing. The

nitrogen bottle connects to the oxidizer and fuel lines. Ball valves at both connections

allow control of the nitrogen purge into the propellant supply lines. Also, check valves

are in place before each ball valve to keep oxidizer or fuel from flowing back into the

main nitrogen line for safety reasons.

The propellant supply system previously described delivers both the fuel and

oxidizer to the injector and chamber. However, the propellants must be controlled to

certain pressures and mass flow rates. Also, the control system needs the ability to vary

the pressures and flow rates of the propellants to provide a range of combustion tests.

The propellant control system for the high pressure combustion facility provides the

capability to control the pressure and flow rates of the propellants through the use of

pressure regulators, solenoid valves, check valves, and regulating (needle) valves. It is

most convenient to discuss these regulators and valves in order of appearance in the

supply lines from closest to the gas battles to closest to the chamber. A pressure

regulator appears first in line for both the oxidizer and fuel. The pressure regulator

provides a constant propellant supply (downstream) pressure for a varying gas bottle

(upstream) pressure. The oxidizer pressure regulator is a Tescom 26-1100 series, having

a maximum outlet pressure of 20.7 MPa (3000 psi) and a maximum inlet pressure of 34.5

MPa (5000 psi), as well as being rated for oxygen service and a Cv of 1.5. This regulator

is dome loaded with a 1:1 ratio, meaning that the outlet pressure of the regulator is the

pressure applied to the dome. The dome is controlled via nitrogen and a Tescom 26-1000

series pressure regulator, with a maximum inlet and outlet pressure of 20.7 MPa (3000

psi). The fuel pressure regulator is a Tescom 44-1100 series pressure regulator, with a

maximum inlet and outlet pressure of 20.7 MPa (3000 psi) and a Cv of 0.8, and is rated

for use with hydrogen. Next in line are the needle valves. The needle valves allow

precise control of the flow rates of propellants by turning the fine metering handles a

certain number of turns and relating that number to the Cv via a calibration. Three

different needle valve series are used for both the oxidizer and the fuel, depending on the

desired flow rate, and are designated as Swagelok S-Series Metering Valve, Swagok 31-

Series Metering Valve, Swagelok 1-Series Integral-Bonnet Needle Valve. The

calibrations for these needle valves are given in Appendix C. The number of turns on

each valve is input to the Labview GUI, which is discussed later. The solenoid valves

appear next in both the oxidizer and fuel lines. They allow the flow of propellants to be

turned on and off remotely, precisely, and quickly. Both the oxidizer and fuel solenoid

valves are Marotta MV100 series solenoid valves, with maximum inlet and outlet

pressure of 20.7 MPa (3000 psi) and a Cv of 0.18. These Marotta valves require a 25

VDC input to activate the solenoid and open the valve. The power and control to the

solenoid valves is supplied via the control/DAQ system. The solenoid valves are located

immediately downstream of the needle valves to eliminate pressure hammering the

needle valves, which can lead to premature failure. Finally in the propellant supply lines

are the check valves. Both the oxidizer and fuel lines have a check valve located close to

the injector. These check valves are Swagelok CH4 series and require only 7 Pa (1 psi)

cracking pressure difference. The check valves allow the oxidizer and fuel to flow to the

injector when activated while disallowing backflow, effectively eliminating the

possibility of premixed gases traveling upstream into the propellant feed system. The

nitrogen purge control is less demanding than that of the propellants. A Victor pressure

regulator allows a nitrogen purge pressure up to 5.5 MPa (800 psi). An Omega SV128

series solenoid valve allows fast shut on/off of the nitrogen purge through the

DAQ/control system. Arrays of filters are used in the oxidizer and fuel feed lines to

ensure clean gas injection. As shown, the propellant feed system allows precise control

of the pressure and flow rate of both the oxidizer and fuel safely. In summary:

* Oxidizer Pressure Regulator: Tescom 26-1100 series. 1:1 Dome type. Maximum
outlet pressure = 20.7 MPa (3000 psi). Maximum inlet pressure = 34.5 MPa (5000
psi). Cv = 1.5.

* Nitrogen Dome Controlling Regulator: Tescom 26-1000 series. Maximum outlet
pressure = 20.7 MPa (3000 psi). Maximum inlet pressure = 20.7 MPa (3000 psi).

* Fuel Pressure Regulator: Tescom 44-1100 series. Maximum outlet pressure = 20.7
MPa (3000 psi). Maximum inlet pressure = 20.7 MPa (3000 psi). Cv = 0.8.

* Nitrogen Purge Regulator: Victor Pressure Regulator. Maximum outlet pressure =
5.5 MPa (800 psi). Maximum inlet pressure = 5.5 MPa (800 psi).

* Oxidizer/Fuel Low Flow Rate Metering Valve: Swagelok S-Series Metering Valve
(calibration in Appendix C).

* Oxidizer/Fuel Medium Flow Rate Metering Valve: Swagelok 31-Series Metering
Valve (calibration in Appendix C).

* Oxidizer/Fuel High Flow Rate Metering Valve: Swagelok 1-Series Integral-Bonnet
Needle Valve (calibration in Appendix C).

* Oxidizer Solenoid Valve: Marotta MV100 Series Solenoid Valve. Maximum inlet
pressure = 20.7 MPa (3000 psi). Maximum outlet pressure = 20.7 MPa (3000 psi).
Cv = 0.18.

* Fuel Solenoid Valve: Marotta MV100 Series Solenoid Valve. Maximum inlet
pressure = 20.7 MPa (3000 psi). Maximum outlet pressure = 20.7 MPa (3000 psi).
Cv = 0.18.

* Nitrogen Purge Solenoid Valve: Omega SV128 Series Solenoid Valve. Maximum
inlet pressure = 6.9 MPa (1000 psi). Maximum outlet pressure = 6.9 MPa (1000
psi).

* Oxidizer Injector Check Valve: Swagelok CH4 Series Check Valve. Cracking
pressure = 7 Pa (1 psi).

* Fuel Injector Check Valve: Swagelok CH4 Series Check Valve. Cracking pressure
= 7 Pa (1 psi).

Control/DAQ System

The HPCF control/DAQ system manages the power supply to all components of

the HPCF, gives the user complete control of the HPCF and the combustion tests, and

provides a variety of data acquisition capabilities for the combustion tests. A schematic

flowchart of the control/DAQ system is shown in Figure 3-11. The power management

is provided via the electronics system. The control/DAQ hardware provides responsive

control and data acquisition capabilities. A Labview GUI provides complete control of

the HPCF to the user from a remote location. All of these sub-systems work in parallel

and rely upon each other to form the HPCF control/DAQ system.

Electronics system

The electronics system for the HPCF provides the power management for the

igniter and the propellant and nitrogen purge solenoid valves. Figure 3-12 shows the

circuit diagram for the electronics system. The entire system is housed within a box that

is supplied with 120 VAC and 24 VDC. Inside the box resides five solid-state relays:

one for the oxidizer solenoid valve, one for the fuel valve, one for the nitrogen valve, and

one for each of the igniter leads. The propellant solid-state relays supply 24 VDC to the

solenoid valves with 5 VDC excitation. The nitrogen purge and igniter lead solid-state

relays supply 120 VAC with 5 VDC excitation. Two relays are used for the igniter

because of the exposed nature of the two igniter electrodes. Using a relay for each lead

ensures that one lead does not touch a ground and short out the system or injure someone.

The 5 VDC excitation for all relays is supplied by the control/DAQ hardware and

controlled via the Labview GUI, which will be discussed shortly. Connections to the

electronics system are made via BNC connectors and banana plugs.

Control/DAQ Hardware

The high-pressure combustion facility requires quick and accurate on-the-fly

control of the propellant/nitrogen purge flows and the ignition of the chamber, as well as

reading and recording of valuable test data. The control/DAQ system for the HPCF

provides all of the control and data recording capabilities required. The control/DAQ

hardware are responsible for managing the input/output of control signals and feedback

and all data acquisition signals. The hardware consists of the computer hardware, DAQ

sensors, and the laser and imaging systems. The computer hardware includes a National

Instruments PCI-MIO-16E-1/SCXI-1000 chassis, a National Instruments PCI-6259/BNC-

2110, and a fiberoptic/PCI board. The DAQ sensors include thermocouples, heat flux

sensors, standard pressure transducers, and a high-frequency pressure transducer. The

laser and imaging systems incorporate a laser, tunable OPO, and an intensified CCD

camera.

Computer hardware

As previously mentioned, the computer hardware consists of a National

Instruments PCI-MIO-16E-1/SCXI-1000 chassis, a National Instruments PCI-6259/BNC-

2110, and a fiberoptic/PCI board. The PCI-MIO-16E-1/SCXI-1000 chassis is used

exclusively for controlling the electronics system and reading all sensors, with the

exception of the high-frequency pressure transducer. The SCXI-1000 chassis houses a

SCXI-1100 module for 32 thermocouple channels, a SCXI-1140 module for 8 pressure

transducer channels, and a SCXI-1124 for 6 output channels of 0-10 VDC. The PCI-

6259/BNC-2110 board is used for reading the high-frequency pressure transducer. This

transducer had to be separated from the SCXI-1000 chassis to obtain high-frequency

response while allowing the interactive feedback from the combustion tests to the SCXI-

1000 chassis and to the computer/user. The fiberoptic/PCI board is used for image

acquisition and connects the intensified CCD camera to the same computer as the high-

frequency pressure transducer.

DAQ sensors

The DAQ sensors are used to collect valuable combustion test data, as well as to

provide in-situ feedback to the computer/user for test control and safety purposes. The

sensors include propellant line pressure transducers, chamber pressure transducer, a

thermocouple open to the chamber environment, injector face thermocouples, a

thermocouple located behind the injector housing, an exhaust nozzle thermocouple,

chamber wall heat flux sensors, and a high-frequency chamber pressure transducer. The

design, features, and placement of these sensors is discussed.

The propellant line and chamber pressure transducer are Omega PX303 series

transducers, with 0.1-20.7 MPa (0-3000 psig) measurement capabilities and 1 ms

response time. The propellant line pressure transducers are attached immediately

downstream of the pressure regulators. The chamber pressure transducer is attached to

the permanent combustion chamber extension and is open to the inside of the chamber.

All three pressure transducers are constantly monitored and recorded throughout each

experiment. The chamber pressure is monitored not only for test data, but for safety as

well. The combustion tests are designed to shut down completely if a set maximum

chamber pressure is exceeded, as controlled by the Labview GUI. The oxidizer and fuel

supply line pressures are required to set the oxidizer and fuel mass flow rates to known

values, through the use of Equations 2-12 and 2-13 and the Labview GUI. The

calibrations for these pressure transducers can be found in Appendix C.

Numerous thermocouples are employed in the HPCF that constantly take vital

temperature measurements for combustion test characterization. The first thermocouple,

and the only thermocouple to be monitored by the user during the actual combustion

tests, is capable of protruding into the chamber and hence into the flame. This

thermocouple, an Omega K-type thermocouple, effectively allows measurement of the

chamber environment or flame temperatures. This thermocouple has an inconel sheath

with a diameter of 1.59 mm (0.0625 in.), an exposed tip, and a response time of 15 ms. It

is attached to the chamber via the permanent combustion chamber extension. This

thermocouple sees the highest temperature of any of the thermocouples because it is open

the in-situ combustion chamber environment. The depth of protrusion into the chamber

is kept to a minimum, and is often recessed, during combustion tests, as the flame

temperature is approximately 3000 K, well above the melting temperature of the

thermocouple materials. In general, this thermocouple is monitored for easy recognition

of ignition in the chamber, as the quick response time allows near instantaneous

temperature increase at the onset of combustion, viewable through the Labview GUI.

The next two thermocouples measure the temperature at two different locations on

the injector face. These thermocouples are Omega K-type thermocouples. They have

inconel sheaths with 1.02 mm (0.04 in.) sheath diameters and exposed tips for fast

response times of 10 ms. These two thermocouples are set up to read the injector face

temperature at a distance of 2.11 mm (0.083 in.) and 4.24 mm (0.167 in.) radially

outward from the center axis of the injector, as shown in Figure 3-9. These

thermocouples provide valuable data about the recirculation regions that occur on the

injector face. Another thermocouple is located behind the injector housing. This

thermocouple has the same characteristics as the injector face thermocouples. It is used

to detect any indication of backflow or heat transfer through the gap between the injector

housing and the chamber wall. Finally, the exhaust nozzle thermocouple is an Omega K-

type thermocouple with an inconel sheath of 0.51 mm (0.02 in.) diameter, an exposed tip,

and a response time of 7 ms. This thermocouple is embedded into the back face of the

exhaust nozzle to a distance of 1.59 mm (0.0625 in.) to the combustion exposed face of

the exhaust nozzle. The data from this thermocouple gives insight into the effects of

direct exposure to the flame and provides a boundary condition for CFD modeling.

The chamber wall heat flux sensors provide heat flux data for the length of the

combustion chamber. Each heat flux sensor used in the HPCF were made in-house and

consist of two thermocouples located side-by-side that protrude into the chamber wall at

different depths. Because the thermocouples are small in diameter relative to the

chamber dimensions, the axial displacement between the two thermocouples (center to

center) is only 0.04 in., which is small relative to the chamber dimensions, and the

thermocouples can be approximated as axially linear. Therefore, the heat flux is

calculated via Equation 2.14 from the temperature difference between the two

thermocouples, the axial distance between the two thermocouple tips, and the heat

transfer coefficient of the chamber material.

Each thermocouple used in the heat flux sensors consists of an Omega 1.02 mm

(0.040 in.) OD double-hole ceramic thermocouple insulator, an Omega K-type bare wire

thermocouple, wire insulation, heat shrink tubing, and an Omega K-type mini connector.

The ceramic tubes were sheared to one of two different lengths. The thermocouple wires

were fed through the two holes in the ceramic tube until the junction of the thermocouple

was situated at the end of the ceramic tube. Wire insulation was placed over the

remainder of the thermocouple wires to keep them from touching, and heat shrink tubing

was used to hold the wire insulation against the back of the ceramic tube. The ends of the

thermocouple wire were attached to the insulated mini connector. By having a portion of

the thermocouple flexible, i.e. the portion using wire insulation around the wires, the risk

for accidentally breaking the ceramic portion and possibly losing electrical isolation is

minimized. For each pair, the longer of the thermocouple pair protrudes into the chamber

wall to a distance of 3.18 mm (0.125 in.) from the inner chamber wall, while the shorter

of the thermocouple pair protrudes to a distance of 9.53 mm (0.375 in.) from the inner

chamber wall, giving a depth difference of 6.35 mm (0.25 in.). This is the value of Ax

used in Equation 2-15 for calculating the heat flux. As explained, the two thermocouples

are located side-by-side, so that the center axis of each thermocouple are only 1.02 mm

(0.040 in.) apart, as viewed perpendicular to the wall or down the lengths of the

thermocouples. The placement of the heat flux sensor thermocouples is shown in Figure

3-3. These custom made thermocouples have a response time of approximately 5 ms.

The heat flux sensors are all located along one face of the combustion chamber and

extensions. On the combustion chamber there are 8 heat flux sensors. The two shorter

chamber extensions each have a single heat flux sensor and the longer chamber extension

has 4 heat flux sensors. In total, this can give as few as 8 heat flux sensors and as many

as 14 heat flux sensors, depending on the chamber arrangement. Table 3-1 lists the

distance from the injector face to each heat flux sensor depending on both the injector

position and the chamber arrangements, which are depicted in Figure 3-6 and Figure 3-8

respectively. In the cases where all three chamber extensions are used in conjunction

with the combustion chamber, limitations in the DAQ channels require that the lowest

heat flux sensor (beside or behind the injector) go unused, as explained in the operational

procedure in Appendix B.

The high-frequency chamber pressure transducer is used to monitor dominant

frequencies inherent to the combustion process, as well as the combustor system. The

goal of using this sensor is to determine what effect the chamber length, mass flow rates,

and chamber pressure have on the frequencies of the combustion process. The sensor is

an Entran EPX series static transducer with a full scale range of 6.9 MPa (1000 psi), a

maximum pressure of 13.8 MPa (2000 psi), and accurate frequency response up to 50

kHz. The sensor ouput ranges from 0-100 mV for 0.1-6.9 MPa (0-1000psig) excitation.

The sensor is attached to the permanent combustion chamber extension.

A problem arose due to the high-frequency pressure transducers output of only 100

mV at 6.9 MPa (1000 psi). Reading the mV signal into the computer resulted in

extremely high noise content of 0.7 MPa (100 psi) after conversion. With the cabling

from the transducer to the DAQ board shielded, the mV order noise seemed to be at the

DAQ system and hence unavoidable. Therefore, an inline operational amplifier had to be

built to increase the output to the order of 10 V at 6.9 MPa (1000 psi) due to the high

noise content in the mV range. The amplifier chip is a Texas Instruments TLV2373 rail-

to-rail op-amp with 3MHz response. The circuit was built inside a small electronics box

with BNC input/outputs. The circuit diagram for the op-amp is shown in Figure 3-13.

The amplifier was calibrated using known output voltages to create a calibration curve

for output voltage vs. amplification factor, which can be found in Appendix C. The

amplifier reduced the noise to less than 30 Pa (5 psi).

Laser and imaging systems

The laser and imaging systems in the HPCF include a laser, a tunable OPO, and an

intensified CCD Camera. The laser is a Continuum Surelite Nd:YAG Laser, with a 355

nm output and a maximum power of 170 mJ. The beam from the laser is directed into a

Continuum Panther OPO, capable of tunable ouput in the UV and visible spectrums. The

doubler allows tuning of the beam wavelength to 283 nm for OH excitation. The camera

is a Cooke DiCam-Pro intensified CCD camera, capable of taking 1280x1024 images at

10 fps and 1280x480 images at 20 fps with exposure times down to 5 ns. The camera is

triggered from the laser and can be delayed if required.

Labview GUI

The Labview graphical user interface (GUI) allows the user to remotely control the

HPCF. This is accomplished via direct control/monitoring of the electronics system and

the control/DAQ hardware through simple to use interfaces on remote computers. One

Labview GUI, titled "HPCF Control Interface", is dedicated to control/monitoring of the

entire HPCF, with the exception of the high-frequency pressure transducer, which has its

own Labview GUI, and the laser and imaging systems, which are controlled via their own

software packages. On a separate computer, another Labview GUI is used to take data

from the high-frequency pressure transducer and is titled "HPCF-HFPT Interface".

The "HPCF Control Interface" is the main Labview GUI for the facility. Through

this GUI the user can control the propellant/nitrogen purge valves, ignition, various

combustion test timings, data acquisition channel selection, and the on/off of the

combustion tests, as well as monitor in-situ chamber pressure and temperature and the

combustion test progress through various indicators and graphs. Figure 3-15 shows the

"HPCF Control Interface" as the user sees it when the Labview GUI is operational. Each

component of the GUI is labeled with a number and is explained in Table 3-2. Some key

features of the "HPCF Control Interface" include:

* Front panel control of all valves and spark.

* Front panel monitoring of chamber temperature and pressure, propellant flow rates,
and combustion test progress.

* Front panel control of combustion test time features.

* One button combustion test activation.

* One button emergency shutdown.

The "HPCF-HFPT Interface" gives the user control of the data acquisition from the

high-frequency pressure transducer. This simple interface simply gives the user the

ability to start the experiment and set the save file path. Once run, the data is presented in

the graph on the interface. This interface is shown in Figure 3-16, with the components

numbered and explained in Table 3-2.

HPCF Assembly and Operation

The assembly and operational procedures for the UF HPCF are located in

Appendix B. The assembly procedure includes complete assembly of the combustor

system and subcomponents, maintenance of components between testing, and

disassembly/troubleshooting. The operational procedure completely details from start to

finish how to safely and effectively operate the UF HPCF.

| 000e,07
-1.857+B7
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1.143e+07
l- 000e+7
8.571e+06
7.143e+06
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4.286+G6
n 2.857e+B6
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7. 30b Obh
F-093 06
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3.667 Ob6
2. 514 O
1.2'41 06

B

Figure 3-1. ProEngineer/ProMechanica stress models for the combustion chamber

loaded at 10 MPa internal pressure. A) is the normal stress (MPa). B) is the

shear stress (MPa).

450

425

c 400
C.
E 375
I-
E 350
E
| 325

300

2 4 6 8
Time (s)

Figure 3-2. ProEngineer/ProMechanica transient thermal analysis on the combustion
chamber with heat flux conditions based on a stoichiometric flame.
Maximum temperature (y-axis) represents the hottest point anywhere in the
chamber.

0.0625 Thernocouple holes (0,0625 OD)
50.0625 at different depths.
0.3750
0.6250

S0.7500
2.5000

T
0.7500 1.0000 2.5000

0.7500

1

Figure 3-3. Cross sectional drawing of the combustion chamber and chamber extensions.
All dimensions are in inches. The thermocouple holes at the top of the figure
are for the pair of thermocouples that form each heat flux sensor (HFS).

- 0,1250

RO,1250

RndlF 0-uni.
Gioo's LIV I i i,

R, O- II \s nldo\\
( op|?>i In_<.iI G;a_4kei

Figure 3-4. Cross-sectional CAD image of the window mounting. The two o-ring
grooves completely circumnavigate the window. The viewable diameter
through the window is 0.81".

D1,
in(mm)

0.02
(0.508)

0.0472
(1.2)

11-

Injector
Support(Spacer

D2,
in(mm)
D3,
in(mm)

0.04
(1.016)

0.0866
(2.2)

0.1058 0.1058 0.1058
(2.687) (2.687) (2.687)

No//lk

Iiinl.O101
HotIsIIn,

Figure 3-5. Cross-sectional CAD image of the injector assembly. Indicates various
components as well as the dimensions of the 3 UF HPCF injectors: UFO
(GH2/Air), UF1 (GH2/GO2), UF2 (GH2/G02).

0.0591
(1.5)

0.0984
(2.5)

1 1-11 1 I I I I 1 '2

-IPL--

Injector IPL
Position (inches)
IP1 0.125
IP2 0.8575
IP3 1.59

Figure 3-6. Cross-sectional drawing of injector indicating the distance from the outer
face of the chamber/chamber extension to the face of the injector for the three
injector positions IP1, IP2, and IP3.

Injector
Housing
Spacer Tube

I1

Fxhauit
No,, ic

E\Iultli Nozzle
Fhw.,ci

Figure 3-7. Cross-sectional CAD image of the injector assembly and the exhaust nozzle
assembly attached to the combustion chamber.

CA# Physical Chamber Arrangement CA# Physical Chamber Arrangement

CAOOSA cc

CA01SA cc SE CA01RA SE cc

CA02SA cc SE SE CA02RA SE SE CC

CAO3SA cc SE SE LE CA03RA SE SE LE cc

CA03SB cc SE LE SE CA03RB SE LE SE CC

CA03SC cc LE SE SE CA03RC LE SE SE cc

CA04SA cc LE CA04RA LE cc

CA05SA cc SE LE CA05RA SE LE cc

CA05SB cc LE SE CA05RB LE SE cc

CA06SA SE cc LE CA06RA LE cc SE

CA07SA SE SE CC LE CA07RA LE CC SE SE

CA08SA SE CC SE LE CA08RA SE LE CC SE

CA08SB SE CC LE SE CA08RB LE SE CC SE

CA09SA SE cc SE

Figure 3-8. Pictorial of the different chamber arrangements possible for the HPCF.
Flow path is left to right. CC combustion chamber. SE short chamber
extension. LE long chamber extension.

v.u.,D/ -\ / Fuel Annulus ID
/Oxldlzer Stem 0

Oxidizer
/Stem ED

InJector
Face
ThermocoupLe
Locations
I 4 0.7100

2'50
00.3333

0,7100 R0,1250

Figure 3-9. Drawing of the injector face, indicating notable dimensions of the injector
assembly face and locations of the injector face thermocouples. Dimensions
in inches.

Operation Mode Key
-* GH2/GO
-----. GH2/Air
- Complete System N2 Purge
- h Reverse Air Purge/
Water Removal
W Ovcrprcssurc
Exhaust

4--

10

Ball Valve [
Check Valve
Filter
Needle Valve I>T<
Pressure
Transducer

Pressure Regulator
Dome Pressure
R egilatnr
3-way Ball
Valve
Thermocouple

HSolenoid Valve

S Overpressure
Relief Valve
L^3

Figure 3-10. Schematic drawing of the HPCF Propellant/Purge Feed System. Number
on bottles indicates the number of bottles in the array for that gas.

Exhaust

Hi

Figure 3-11. Flowchart of the Control/DAQ system.

N2 Valve
Trigger Signal
(5VDC)

Igniter 1
Trigger Signal
(5VDC)

Igniter 2
Trigger Signal O-
(5VDC)

V,n (24 VDC) 0

Fuel Valve
Trigger Signal
(5 VDC)

Oxidizer Valve
Trigger Signal
(5 VDC)

Oxidizer Valve 6 Fuel Valve
Vout (24 VDC) Vout (24 VDC)

Figure 3-12. Circuit diagram for the electronics system.

54

Table 3-1. Distances from the injector face to the heat flux sensors for all injector

position/chamber arrangement combinations. All dimensions in inches.
Injector
Position/
Chamber
Arrangement -\- Axial Distance from Injector Face to Heat Flux Sensor (inches)
Identifier HFS1 HFS2 HFS3 HFS4 HFS5 HFS6 HFS7 HFS8 HFS9 HFS10 HFS11 HFS12 HFS13 HFS14
IP1CAOSA 0 04 08 12 255 295 335 375 0 0 0 0 0 C
IP1CA1SA 0 04 08 12 255 295 335 375 424125 0 0 0 0 C
IP1CA2SA 0 04 08 12 255 295 335 375 424125 497375 0 0 0 C
IP1CA3SA 0 04 08 12 255 295 335 375 424125 497375 549 589 629 669
IP1CA3SB 0 04 08 1 2 255 295 335 375 424125 475755 1575 55575 59575 64737
IP1CA3SC 0 04 08 12 255 295 335 375 4025 4425 4825 5225 574125 647375
IP1CA4SA 0 04 08 12 255 295 335 375 4025 425 4825 5225 0 C
IP1CA5SA 0 04 08 12 255 295 335 375 424125 47575 51575 55575 59575 C
IP1CA5SB 0 04 08 12 255 295 335 375 4025 4425 4825 5225 574125 C
IP1CA6SA 024125 07325 11325 15325 19325 32825 36825 40825 44825 47575 51575 55575 59575 C
IP1CA7SA 024125 097375 1465 1865 2265 2665 4015 4415 4815 5215 549 589 629 669
IP1CA8SA 024125 07325 11325 15325 19325 32825 36825 40825 44825 497375 549 589 629 669
IP1CA8SB 024125 07325 11325 15325 1 9325 32825 36825 40825 4 5 47575 1575 5 5575 59575 647375
IP1CA9SA 024125 07325 1 13 125 1 9325 32825 36825 4 0825 5 4 97375 0 0 0 C
IP1CA1RA 024125 07325 1 1325 1 5325 1 9325 32825 36825 40825 44825 0 0 0 0 C
IP1CA2RA 024125 097375 1 1 865 2265 2665 4015 4415 4815 5215 0 0 0 C
IP1CA3RA 024125 097375 149 189 229 269 2965 3365 3765 4165 5515 5915 6315 6715
IP1CA3RB 024125 07575 1 1 5575 19575 247375 2965 3365 3765 4165 5515 5915 6315 6715
IP1CA3RC 0025 0425 0825 1225 174125 247375 2965 3365 3765 4165 5515 5915 6315 6715
IP1CA4RA 0025 0425 0825 1225 15 19 23 27 405 445 485 525 0 C
IP1CA5RA 024125 07575 11575 15575 19575 22325 26325 30325 34325 47825 51825 55825 59825 C
IP1CA5RB 0025 0425 0825 1225 174125 22325 26325 30325 34325 47825 51825 55825 59825 C
IP1CA6RA 0025 0425 0825 1225 15 19 23 27 405 445 485 525 574125 C
IP1CA7RA 0025 0425 0825 1225 15 19 23 27 405 445 485 525 574125 647375
IP1CA8RA 024125 07575 1 1575 15575 19575 22325 26325 30325 34325 47825 51825 55825 59825 647375
IP1CA8RB 0025 0425 0825 1 225 174125 22325 26325 30325 34325 47825 55 182 5825 5985 6 47375
IP2CAOSA -07325 -03325 00675 04675 1 8175 22175 26175 30175 0 0 0 0 0 C
IP2CA1SA -07325 -03325 00675 04675 1 8175 22175 26175 30175 350875 0 0 0 0 C
IP2CA2SA -07325 -03325 00675 04675 18175 22175 26175 30175 350875 424125 0 0 0 C
IP2CA3SA -07325 -03325 00675 04675 18175 22175 26175 30175 350875 424125 47575 51575 55575 59575
IP2CA3SB -07325 -03325 00675 04675 18175 22175 26175 30175 350875 4025 4425 4825 5225 574125
IP2CA3SC -07325 -03325 00675 04675 1 8175 22175 26175 30175 32925 36925 40925 4925 500875 57412
IP2CA4SA -07325 -03325 00675 04675 18175 22175 26175 3017 32925 36925 40925 44925 0 C
IP2CA5SA -07325 -0332 00675 04675 1 8175 22175 26175 30175 350875 4025 4425 4825 5225 C
IP2CA5SB -07325 -03325 00675 04675 1 8175 22175 26175 30175 32925 36925 40925 44925 500875 C
IP2CA6SA -049125 0 04 08 12 255 295 335 375 4025 4425 4825 5225 C
IP2CA7SA -049125 024125 07325 11325 15325 19325 32825 36825 40825 44825 47575 51575 55575 59575
IP2CA8SA -049125 0 04 08 12 2 55 2 95 3 375 424125 47575 51575 55575 59575
IP2CA8SB -049125 0 04 08 1 2 255 295 335 375 4025 4425 4825 5225 574125
IP2CA9SA -049125 0 04 08 12 255 295 335 375 424125 0 0 0 C
IP2CA1RA -049125 0 04 08 1 22 255 295 335 375 0 0 0 0 C
IP2CA2RA -049125 024125 07325 1 1325 1 5325 1 9325 32825 36825 40825 44825 0 0 0 C
IP2CA3RA -049125 024125 07575 11575 15575 19575 22325 26325 30325 34325 47825 51825 55825 59825
IP2CA3RB -049125 0025 0425 0825 1225 1 74125 22325 2632 30325 34325 47825 51825 55825 59825
IP2CA3RC -07075 -03075 00925 04925 1 00875 174125 22325 26325 30325 34325 47825 51825 55825 5 982
IP2CA4RA -07075 -03075 00925 04925 07675 11675 15675 19675 33175 37175 41175 45175 0 C
IP2CA5RA -049125 0025 0425 0825 1225 1 5 1 9 23 27 405 445 485 525 C
IP2CA5RB -07075 -03075 00925 04925 1 00875 1 5 1 9 23 27 405 445 485 525 C
IP2CA6RA -07075 -03075 00925 04925 07675 1 1 1 9675 33175 37175 41175 45175 500875 C
IP2CA7RA -07075 -03075 00925 0 4925 07675 1 19675 33175 37175 41175 45175 500875 574125
IP2CA8RA -049125 0025 0425 0825 1225 1 5 1 9 23 27 405 445 485 525 574125
IP2CA8RB -07075 -03075 00925 04925 1 00875 1 5 1 9 23 27 405 445 485 525 574125
IP3CAOSA -1 1 065 -0665 -0265 1 085 1 485 1 885 2285 0 0 0 0 0 C
IP3CA1SA -1 465 1 065 -0665 -0265 1 085 1 485 1 885 2285 277625 0 0 0 0 C
IP3CA2SA -1 4 1 065 -0665 -0265 1085 1485 1885 2285 277625 350875 0 0 0 C
IP3CA3SA -1 4 1 065 -0665 -0265 1085 1485 1885 2285 277625 350875 4 4425 4825 5 22
IP3CA3SB -1 4 1 065 -0665 -0265 1085 1485 1885 22 277625 32925 36925 40925 44925 5 0087
IP3CA3SC -1 465 -1065 -0665 -0265 1085 1485 1885 2285 256 296 336 376 427625 500875
IP3CA4SA -1465 -1065 -0665 -0265 1085 15 1 1885 2285 256 2 96 336 376 0 C
IP3CA5SA -1 465 -106 -0665 -0265 1 085 1485 885 2285 277625 32925 36925 40925 44925 C
IP3CA5SB -1 1 065 -0665 -0265 1 085 1 485 1 885 2285 256 296 336 376 427625 C
IP3CA6SA -1 22375 -07325 -03325 00675 04675 18175 22175 26175 30175 32925 36925 40925 44925 C
IP3CA7SA -122375 -049125 0 04 08 1 22 255 295 335 375 4025 4425 4825 5 225
IP3CA8SA -1 22375 -07325 -03325 00675 04675 1 8175 22175 26175 30175 350875 4025 4425 4825 5 225
IP3CA8SB -1 22375 -07325 -03325 00675 04675 18175 22175 26175 30175 32925 36925 40925 44925 500875
IP3CA9SA -122375 -07325 -03325 00675 04675 18175 22175 26175 30175 350875 0 0 0 C
IP3CA1RA -1 22375 -07325 -03325 00675 04675 18175 22175 26175 30175 0 0 0 0 C
IP3CA2RA -122375 -049125 0 04 08 12 255 295 335 375 0 0 0 C
IP3CA3RA -1 22375 -049125 0025 0425 0825 1 225 1 5 1 9 23 27 405 445 485 525
IP3CA3RB -122375 -07075 -03075 00925 04925 100875 1 5 1 9 23 27 4 445 485 525
IP3CA3RC -1 44 -104 -064 -024 027625 100875 1 5 19 23 27 405 445 485 525
IP3CA4RA -144 -104 -064 -024 0 04 0835 1235 2585 2985 385 3785 0 C
IP3CA5RA -122375 -07075 -03075 00925 04925 07675 11675 15675 19675 33175 37175 41175 45175 C
IP3CA5RB -144 104 -064 -024 027625 07675 11675 15675 19675 33175 37175 41175 45175 C

IP3CA6RA

-1 04

-064

-024 0035

0435

0835

1 23E

2585

2985

3385

3785 427625

-1 44 -1 04 -0 64 -0 24 0035 0435 0835 1 235 2585 2985 3385 3785 427625 500875
-122375 -07075 -03075 00925 04925 07675 11675 15675 19675 33175 37175 41175 45175 500875
-1 44 -1 04 -064 -024 027625 07675 11675 15675 19675 33175 37175 41175 45175 500875

Vout

Figure 3-13. Circuit diagram for the non-inverting operational amplifier.

Nozzle
Igniter \

Chamber
Extension

Chamber Wall
Thermocouples <
(for heat flux
measurements)

Fused Silica
Optical
Windows

Chamber
Thermocouple
(protrudes into
chamber)

-Chamber
Pressure
Transducer (open
to chamber)

- Injector

7

Figure 3-14. Picture of the combustor system assembled, including the combustion
chamber, injector assembly, exhaust nozzle assembly, two short chamber
extensions, and instrumentation.

High Pressre Combution Facility Pro gess Indicator

1 oas CRmk Al Rin ThSeti ad Tare Pr re TranducersI
1 JRN ON EXAL5ST FANI

Oider Valve Hvydrogen Valve rwrogen vave Ignron Sper

2 = 10 11 = 17 4

Time to Test In atIon Ie Number of Tuns on Oxidizer
3 12 Peiang valve(0o-10 wn

4 spa K Number of Turns on Fud
13 Pe mangu valve i-10 turns
Valve -o:eni Cel Time (sec) I Charber T

5

6 Test Run TIte (st)
6 4

Estrogen Purge Time (sec)

8 (wsc) afre vaIe Cpen

-aximum Aowtens
WO:hrbi if-.it

Oxidizer Seledt
Air
14 18

rMtiogen chamber
Presurization
On
15
Off
mki ogen Puge '"iOff 19
On
16 M

Off

tSLrtSt.:'p Co:mtustiori RLn

21 Oxk zer vve

22 9KdHogenvt.e

23 spark
24 ratogenP wes5suason

25 *rtrogen Purg

efnm Mu e Motro.

Ohamb Temp M 32

27.0
26.0
25.0-
24.0-
23.0
22.0-
907

Camber Temperature (

Chabue Plue-me (psIg)

xidzer Inpectio Pessue (ps,

Hydrogen InteT Presswe (p
.16 |TREI

Oxdier Mass Flw Rate (gs)
[.011611

Fuel Mass Flow Rate (9Is)

*:IF Miss Flow Pate

Equvjaence PaIo

Raw Data FMe Path

MvAogen rede valve Selector

SS-31RS4

Oxaer Neede Valve Selector

SS -1RF4

T1 hermocouple channels
41 (obO'I I mdl 8 )
JJIt I c I l md I 0:30

5rsn Rate
42

43
U SsrcleiS
IEZZc*

1010 34

Camber Pressure Pfot 0

300.0
100.0

0.0
3e3 4es

Slop CPT (ACI)

Slope APT (AC:)
6p18.(25 |
Slp. HIPT (AC3)
|606.241|

Figure 3-15. HPCF Control Interface front panel (Labview GUI). Numbers referenced to Table 3-2.

4- -

Figure 3-16. HPCF-HFPT Interface front panel (Labview GUI). Numbers are referenced
to Table 3-2.

Table 3-2. Description of each component on the HPCF Control Interface and HPCF-
HFPT Interface front panels (Labview GUI's). Numbers are referenced to
Figures 3-15 and 3-16.
Componen
t# Description
1 Indicates progress of combustion test. Displays messages for user.
2 Toggles oxidizer valve on/off from front panel. Use for testing valve functionality.
3 Time in seconds from pressing #20 until the spark begins (SPARK ON). Allows time
for other computer/DAQ devices to be activated. DAQ running. Set by user.
4 Time in seconds that the spark stays on. SPARK ON to SPARK OFF time. DAQ
running. Set by user.
5 Time in seconds from SPARK ON to the opening of the propellant valves
(PROPELLANTS ON). SPARK ON before PROPELLANTS ON keeps the chamber
from filling with premixed gases before combustion begins. DAQ running. Set by
user.
6 Time in seconds from SPARK OFF to the closing of the propellant valves
(PROPELLANTS OFF). Essentially the FLAME ON to FLAME OFF time. DAQ
running. Set by user.
7 Time in seconds from PROPELLANTS OFF/FLAME OFF that nitrogen is purging
the combustion chamber. DAQ running.
8 Time in seconds from PROPELLANTS ON until nitrogen pressurization of the

test. DAQ running. Set by user.
9 Maximum allowed chamber pressure before combustion test is prematurely shut
down. If exceeded during test, all valves and spark are shutoff immediately. Set by
user.
10 Toggles fuel valve on/off from front panel. Use for testing valve functionality.
11 Toggles nitrogen valve on/off from front panel. Use for testing valve functionality.
12 Input for the position of the oxidizer regulating needle valve. The number of turns
enters directly into the oxidizer flow rate calculation. Set by user.
13 Input for the position of the fuel regulating needle valve. The number of turns enters
directly into the fuel flow rate calculation. Set by user.
14 Toggle switch for oxidizer. Sets either oxygen or air. Affects flow rate calculations.
Set by user.

Table 3-2. Continued
15 Toggles nitrogen pressurization on/off. Allows the chamber to be pre-pressurized with
nitrogen, beginning 3 seconds before SPARK ON and lasting until the number of
seconds beyond PROPELLANTS ON as set by #8. Set by user.
16 Toggles nitrogen purge at PROPELLANTS/FLAME OFF on/off. Set by user.
17 Toggles spark on/off from front panel. Use for testing spark functionality.
18 Active monitor of chamber temperature thermocouplee open to chamber environment,
Celsius) during front panel and combustion tests. Easy recognition of successful
combustion.
19 Active monitor of chamber pressure (psig) during combustion tests only.
20 Turns combustion test on/off. Once pressed, a predefined combustion test will proceed
from beginning to end unless ended prematurely by user or exceeding of maximum
chamber pressure. User controlled. If user ended and nitrogen purge is set to ON
position, the chamber will purge with nitrogen before front panel operation resumes.
21 Indicator light for oxidizer valve operation.
22 Indicator light for fuel valve operation.
23 Indicator light for spark operation.
24 Indicator light for nitrogen pressurization of the chamber.
25 Indicator light for nitrogen purging.
26 Numerical indicator of chamber temperature (Celsius).
27 Numerical indicator of chamber pressure (psig). TARE button allows atmospheric
condition to be set to 0 psig by activating an offset value.
28 Numerical indicator of oxidizer line pressure (psig) before the needle valve. TARE
button allows atmospheric condition to be set to 0 psig by activating an offset value.
29 Numerical indicator of fuel line pressure (psig) before the needle valve. TARE button
allows atmospheric condition to be set to 0 psig by activating an offset value.
30 Numerical indicator for oxidizer mass flow rate (g/s).
31 Numerical indicator for fuel mass flow rate (g/s).
32 Numerical indicator for oxidizer/fuel mass flow ratio.
33 Numerical indicator for equivalence ratio.
34 File path for combustion test data save. Data is automatically saved to set file path at
the end of each combustion test. Set by user.
35 Calibration slope for chamber pressure transducer. Set by user from periodic
calibrations.
36 Calibration slope for oxidizer pressure transducer. Set by user from periodic
calibrations.
37 Calibration slope for fuel pressure transducer. Set by user from periodic calibrations.
38 Selector for fuel regulating needle valve in operation. Allows high degree of control at
a large range of desired flow rates. Choice affects Cv calibration curve. Set by user.
39 Selector for oxidizer regulating needle valve in operation. Allows high degree of
control at a large range of desired flow rates. Choice affects Cv calibration curve. Set
by user.
40 Emergency shutoff of HPCF. Can be pressed at any time to shutdown all valves and
spark, no matter what settings are in place. Data will lost if pressed. User controlled.
41 Allows user to identify which thermocouple channels are being used for DAQ.
Eliminates unused channels from contaminating used channels. Set by user.
42 Scan rate for temperature, pressure, and heat flux data in Hz. Set by user.
43 Number of samples averaged for each data point.
44 Displays high-frequency pressure transducer data after a combustion test.
45 File path for high-frequency pressure transducer combustion test data save. Data is
automatically saved to set file path at end of each combustion test. Set by user.

CHAPTER 4
RESULTS

The results for high-pressure GH2/G02 combustion tests at oxygen to hydrogen

mass flow ratios of 3.97 and 5.97 (O = 2.0 and 1.33) and a range of operational chamber

pressures are presented here. The results include various plots showing chamber

pressure, heat flux, injector face temperature, exhaust nozzle temperature, and wall

temperature data that give insight into the dynamics of high-pressure GH2/G02

combustion. A sample of the high-frequency pressure data is also presented to showcase

the capabilities of the facility. In addition, image data is presented for a single

combustion test to show visual aspects of the combustion process.

Table 4-1 shows the combustion test matrix conducted in the HPCF, including the

operating conditions for each test setup and the figures containing data from those tests.

The operating conditions include the facility setup, chamber pressure, oxygen to fuel

mass flow and velocity ratios, equivalence ratio, hydrogen mass flow rate and injection

velocity, nozzle diameter, and chamber length.

Essentially two different data sets were obtained in this research. The data sets

differ by the method in which the different chamber pressures were achieved. The first

method was to keep the propellant mass flow rates constant and change the exhaust

nozzle diameter. Figure 4-1 through Figure 4-33 present the results from the combustion

tests using this method of changing the exhaust nozzle diameter to modify the chamber

pressure. The second method was to keep the exhaust nozzle diameter constant and

change the propellant mass flow rates. This second method is that used by Marshall et

al.3 Figure 4-35 through Figure 4-38 present the results from the combustion tests using

this method of changing the propellant mass flow rates to modify the chamber pressure.

Furthermore, both data sets (data from both methods of modifying the chamber

pressure) were analyzed using the two different heat flux equations presented in Chapter

2, namely Equation 2-15 for the steady state heat flux calculation and Equation 2-16 for

the steady state heat flux plus heat absorption calculation. If the figure presents heat flux

values, the caption will indicate which heat flux equation was used in the calculations.

Discussion of these results occurs in Chapter 5.

61

Table 4-1. Combustion test configurations, operating conditions, and included figures.
miO2 V02 Nozzle Chamber
P, H2, VH2 ID, Length,
Facility Setup MPa mH2 VH2 ( g/s m/s mm (in.) mm (in.) Figures
UFIP3CA3SA 6.21 3.97 0.46 2.0 0.396 144.2 1.36 169.3 4-1,4-2,4-3,
(0.0535) (6.66) 4-25, 4-26, 4-29,
4-31, 4-33, 4-39,
4-40, 4-41
UF1IP3CA3SA 4.86 3.97 0.46 2.0 0.396 197.4 1.59 169.3 4-4, 4-5, 4-6, 4-
(0.0625) (6.66) 25, 4-26, 4-29,
4-31, 4-33, 4-34,
4-42, 4-43
UF1IP3CA3SA 4.55 3.97 0.46 2.0 0.396 235.0 1.70 169.3 4-7, 4-8, 4-9, 4-
(0.0670) (6.66) 25, 4-26, 4-29,
4-31,4-33
UF1IP3CA3SA 2.76 3.97 0.46 2.0 0.396 468.3 2.38 169.3 4-10,4-11,4-12,
(0.0938) (6.66) 4-25, 4-26, 4-29,
4-31,4-33
UFIP3CA3SA 6.21 5.97 0.70 1.33 0.285 102.5 1.36 169.3 4-13,4-14,4-15,
(0.0535) (6.66) 4-27, 4-28, 4-30,
4-32, 4-33
UFIP3CA3SA 4.86 5.97 0.70 1.33 0.285 140.0 1.59 169.3 4-16,4-17,4-18,
(0.0625) (6.66) 4-27, 4-28, 4-30,
4-32, 4-33
UF1IP3CA3SA 4.55 5.97 0.70 1.33 0.285 166.1 1.70 169.3 4-19,4-20,4-21,
(0.0670) (6.66) 4-27, 4-28, 4-30,
4-32, 4-33
UFIP3CA3SA 2.76 5.97 0.70 1.33 0.285 322.9 2.38 169.3 4-22, 4-23, 4-24,
(0.0938) (6.66) 4-26, 4-28, 4-30,
4-32, 4-33
UFIP3CA5SA 4.86 3.97 0.46 2.0 0.396 197.4 1.59 150.7 4-34
(0.0625) (5.93)
UFIP3CA4SA 4.86 3.97 0.46 2.0 0.396 197.4 1.59 132.1 4-34
(0.0625) (5.20)
UF1IP3CA1SA 4.86 3.97 0.46 2.0 0.396 197.4 1.59 112.6 4-34
(0.0625) (4.43)
UF1IP3CAOSA 4.86 3.97 0.46 2.0 0.396 197.4 1.59 94.0 4-34
(0.0625) (3.70)
UF1IP3CA3SA 2.75 3.97 0.46 2.0 0.187 207.4 1.70 169.3 4-35, 4-36, 4-37,
(0.0670) (6.66) 4-38
UFIP3CA3SA 3.90 3.97 0.46 2.0 0.280 207.4 1.70 169.3 4-35, 4-36, 4-37,
(0.0670) (6.66) 4-38
UFIP3CA3SA 4.93 3.97 0.46 2.0 0.377 207.4 1.70 169.3 4-35, 4-36, 4-37,
(0.0670) (6.66) 4-38
UFIP3CA3SA 5.87 3.97 0.46 2.0 0.470 207.4 1.70 169.3 4-35, 4-36, 4-37,
(0.0670) (6.66) 4-38

Chamber Pressure vs Time
Chamber = 6.21 MPa, momH2 = 3.97, V0o H2 = 0.46
(4= 2.0, m02 =1.565 g/s, mH2 = 0.396 g/s, VH =144.2 m/s)

6 -

5

= 3

2

0
0

14000 16000 18000

Figure 4-1. Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber =
6.21 MPa, mo2/mH2 = 3.97, and V02/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2
= 0.396 g/s, VH2 = 144.2 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3SA. Ignition and shutdown times indicated for
this full data set.

2000 4000 6000 8000 10000 12000
Time (ms)

3

2.5

2

"1
E

S1.5-
LL

0
0

Heat Flux vs Time
Chamber = 6.21 MPa, m0m H2= 3.97, V02v = 0.46
( = 2.0, mo = 1.565 g/s, mH2 = 0.396 g/s, VH = 144.2 mis)

5000 10000
Time (ms)

15000

Figure 4-2. Heat flux versus time for a GH2/G02 combustion test with Pchamber = 6.21
MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH =
0.396 g/s, VH2 = 144.2 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3SA. Legend indicates distance from injector
face to heat flux sensor. Ignition and shutdown times indicated for this full
data set. Heat flux calculations performed using steady state heat flux
equation (Equation 2-15).

x = 37.72 mm (1.485 in.)
x = 47.88 mm (1.885 ini.)
x = 58.04 mm (2.285 in.)
x = 70.52 mm (2.776 in.)
x = 83.63 mm (3.293 in.)
x = 93.79 mm (3.693 in.)
x = 103.95 mm (4.093 in.)
x = 127.22 mm (5.009 in.)

Temperatures vs Time
Chamber = 6.21 MPa, m02mH = 3.97, vo21H = 0.46
(#= 2.0, m2 = 1.565 g/s, mH2 = 0.396 g/s, V = 144.2 m/s)

1000

900

800

700

600 -

r 500
C-
E 400
I-
300 -

200

100

0
0

12000 14000
12000 14000

16000 18000

Figure 4-3. Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/G02 combustion test with Pchamber = 6.21
MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s, VH2 = 144.2 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement= CA3SA. The legend indicates r as the radial distance
from the injector center axis to the injector face thermocouple. Ignition and
shutdown times indicated for this full data set.

2000 4000 6000 8000 10000
Time (ms)

Chamber Pressure vs Time
Chamber = 4.86 MPa, m02mH2 = 3.97, Vo0/V = 0.46
( = 2.0, m2 = 1.565 g/s, m H2 = 0.396 g/s, vH = 197.4 m/s)

0 1000 2000 3000 4000
Time (ms)

5000 6000 7000 8000

Figure 4-4. Chamber pressure versus time for a GH2/G02 combustion test with Pchamber =
4.86 MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 ( = 2.0, mo2 = 1.565 g/s, mH2
= 0.396 g/s, VH2 = 197.4 m/s). Injector = UF Injector position = IP3.
Chamber arrangement = CA3 SA.

cL

S2.,

2E

Heat Flux vs Time
Chamber = 4.86 MPa, m2/m2 = 3.97, v02/H2 = 0.46
(# = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 197.4 m/s)

4

3.5

3

E 2.5

:I
2

i 1.5

1

0.5

0

0 1000 2000 3000 4000 5000 6000 7000 8000
Time (ms)

Figure 4-5. Heat flux versus time for a GH2/G02 combustion test with Pchamber = 4.86
MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s, VH2 = 197.4 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3SA. Legend indicates distance from injector
face to heat flux sensor. Heat flux calculations performed using steady state
heat flux equation (Equation 2-15).

37.72 mm (1.485 in.)
47.88 mm (1.885 in.)
58.04 mm (2.285 in.)
70.52 min (2.776 in.)
83.63 mm (3.293 in.)
93.79 min (3.693 in.)
103.95 mm (4.093 in.)
127.22 mnm 5.009 in.)

Temperatures vs Time
Chamber = 4.86 MPa, mzmH2 = 3.97, 02oVH2 = 0.46
(0 = 2.0, m02 = 1.565 gls, mH2 = 0.396 gs, vH2 =197.4 m/s)
1000 l .. i i

900 Injector Face, r = 2.11 mm (0.083 in.)
Tinjector Face, r = 424 mm (0.167 in.)
800 TBehind Injector

700 TExhaust Nozzle

S300

200
100
0 I I I I L L
0 1000 2000 3000 4000 5000 6000 7000 8000
Time (ms)

Figure 4-6. Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.86
MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2 =
0.396 g/s, VH2 = 197.4 m/s). Injector = UF 1. Injector position = IP3.
Chamber arrangement = CA3SA. The legend indicates r as the radial distance
from the injector center axis to the injector face thermocouple.

68

Chamber Pressure vs Time
Chamber = 4.55 MPa, mo02mH2 = 3.97, V02H2 = 0.46
( = 2.0, mo0 = 1.565 g/s, mH2 = 0.396 g/s, vH = 235.0 m/s)

c. 3
S2.1

S2
CL

0 1000 2000 3000 4000
Time (ms)

5000 6000 7000 8000

Figure 4-7. Chamber pressure versus time for a GH2/G02 combustion test with Pchamber =
4.55 MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 ( = 2.0, mo2 = 1.565 g/s, mH2
= 0.396 g/s, VH2= 235.0 m/s). Injector= UFI. Injector position = IP3.
Chamber arrangement = CA3 SA.

Heat Flux vs Time
Chamber = 4.55 MPa, mo2/mH = 3.97, a02/VH2 = 0.46
(# = 2.0, mo = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 235.0 m/s)
T "II 1

2.5 1

1000 2000 3000

4000
Time (ms)

5000 6000 7000 8000

Figure 4-8. Heat flux versus time for a GH2/G02 combustion test with Pchamber = 4.55
MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s, mH2
0.396 g/s, VH2 = 235.0 m/s). Injector = UF. Injector position = IP3.
Chamber arrangement = CA3SA. Legend indicates distance from injector
face to heat flux sensor. Heat flux calculations performed using steady state
heat flux equation (Equation 2-15).

x = 37.72 mmI (1.485 in.)
x = 47.88 mm (1.885 in.)
- x = 58.04 mmi (2.285 in.)
x = 70.52 mm (2.776 in.)
- x = 83.63 mm (3.293 in.)
x = 93.79 mm (3.693 in.)
- x = 103.95 mm (4.093 in.)

- x = 127.22 mm (5
11121

.009 ill.)
..0 9 i .. .. .. ........ *

...-_-... --..T

1-11I ........",1 1,1, ?,"' 1" "

I I I I

Temperatures vs Time
Chamber = 4.55 MPa, m 02mH = 3.97, vo2VH2 = 0.46
(# = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 235.0 mi

1000 2000 3000 4000
Time (ms)

5000 6000 7000 8000

Figure 4-9. Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.55
MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 ( = 2.0, mo2 = 1.565 g/s, mH2
0.396 g/s, VH2 = 235.0 m/s). Injector = UF. Injector position = IP3.
Chamber arrangement= CA3SA. The legend indicates r as the radial distance
from the injector center axis to the injector face thermocouple.

1000

900

800

700
o"
& 600
6-
500
6-
0.
E 400

300

Chamber Pressure vs Time
Chamber = 2.76 MPa, mz02mHz = 3.97, vv = 0.46
( = 2.0, m02 = 1.565 g/s, mH2 = 0.396 gs, VH2 = 468.3 mis)

s.

1.5
3.
. 1

0.5

0 1000 2000 3000 4000
Time (ms)

5000 6000 7000 8000

Figure 4-10. Chamber pressure versus time for a GH2/G02 combustion test with Pchamber
= 2.76 MPa, D mo2/mH2 = 3.97, and vo2/VH2 = 0.46 (D = 2.0, mo2 = 1.565 g/s,
mH2 = 0.396 g/s, VH2 = 468.3 m/s). Injector = UFI. Injector position = IP3.
Chamber arrangement = CA3 SA.

Heat Flux vs Time
Chamber = 276 MPa, m02mH2 = 3.97, V021VH2 = 0.46
(4 = 2.0, m02 = 1.565 g/s, mH = 0.396 g/s, VH = 468.3 m/s)
S x = 37.72 mm (1.485 in.)
3.5- x = 47.88 mm (1.885 in.)
= 58.04 mm (2.285 in.)
x = 70.52 mm (2.776 in.)
3 x = 83.63 mm (3.293 in.)
x = 93.79 mm (3.693 in].)
S2.5 x = 103.95 mmi (4.093 in.)
-- x = 127.22 mm (5.009 in.)

2 I2

= 1.5- .... 1, : .,_. .-,.

1 I" -

0
0 1000 2000 3000 4000 5000 6000 7000 8000
Time (ms)

Figure 4-11. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 2.76
MPa, $mo2/mH2 = 3.97, and vo2/VH2 = 0.46 ($ = 2.0, mo2 = 1.565 g/s, mH2
0.396 g/s, VH2 = 468.3 m/s). Injector = UFl. Injector position = IP3.
Chamber arrangement = CA3SA. Legend indicates distance from injector
face to heat flux sensor. Heat flux calculations performed using steady state
heat flux equation (Equation 2-15).

Temperatures vs Time
Chamber = 2.76 MPa, m02ImH = 3.97, v"OvH2 = 0.46
(# = 2.0, mo2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 468.3 m/s)

1000

900

800

700

600

500

400

300

200

100

0
0

5000 6000 7000 8000

Figure 4-12. Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/G02 combustion test with Pchamber = 2.76
MPa, mo2/mH2 = 3.97, and vo2/VH2 = 0.46 ( = 2.0, mo2 = 1.565 g/s, mH2
0.396 g/s, VH2 = 468.3 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement= CA3SA. The legend indicates r as the radial distance
from the injector center axis to the injector face thermocouple.

1000 2000 3000 4000
Time (ms)

Chamber Pressure vs Time
Chamber = 6.21 MPa, momH2? = 5.97, v2/v.H2 = 0.70
( = 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 102.5 m/s)

5

"4
E.

3

CI
2

1

0 1000 2000 3000 4000
Time (ms)

5000 6000 7000 8000

Figure 4-13. Chamber pressure versus time for a GH2/G02 combustion test with Pchamber
= 6.21 MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s,
mH2 = 0.285 g/s, VH2 = 102.5 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3 SA.

Heat Flux vs Time
Chamber = 6.21 MPa, m02mH2 = 5.97, vvH2 = 0.70
( = 1.33, m2 = 1.693 g/s, mH = 0.285 g/s, vH = 102.5 m/s
(*13 m =193H

- x = 37.72 mm (1.485 in.)
- x = 47.88 mm (1.885 in.)
- x = 58.04 mm (2.285 in.)
x = 70.52 mm (2.776 in.)
- x = 83.63 mm (3.293 in.)
x = 93.79 mm (.693 in.)
Sx = 103.95 mm (4.093 in.)
Sx = 127.22 mm (5.009 in.)

__ J

I.. AI
IV 2

1000 2000 3000 4000
Time (ms)

5000 6000 7000 8000

Figure 4-14. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 6.21
MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2 =
0.285 g/s, VH2 = 102.5 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3SA. Legend indicates distance from injector
face to heat flux sensor. Heat flux calculations performed using steady state
heat flux equation (Equation 2-15).

2.5 I

Temperatures vs Time
Chamber = 6.21 MPa, mO/mHa = 5.97, vlVH = 0.70
(o = 1.33, m,, = 1.693 g/s, m,, = 0.285 g/s, v,, = 102.5 m/s)

1000 2000 3000 4000
Time (ms)

5000 6000 7000 8000

Figure 4-15. Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/GO2 combustion test with Pchamber = 6.21
MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 ( = 1.33, mo2 = 1.693 g/s, mH2
0.285 g/s, VH2 = 102.5 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement= CA3SA. The legend indicates r as the radial distance
from the injector center axis to the injector face thermocouple.

1000

900

800

700

Chamber
(= 1.33, m,

0 1000 2000 3000 4000
Time (ms)

5000 6000 7000 8000

Figure 4-16. Chamber pressure versus time for a GH2/G02 combustion test with Pchamber
= 4.86 MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s,
mH2 = 0.285 g/s, VH2 = 140.0 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3 SA.

Chamber Pressure vs Time
= 4.86 MPa, mo2mH2 = 5.97, Vo2/vH2 = 0.70
, = 1.693 g/s, m., = 0.285 g/s, v., = 140.0 m/s)

Heat Flux vs Time
Chamber = 4.86 MPa, momH2 = 5.97, v"o2/v = 0.70
(# = 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 140.0 m/s

= 37.72 mm (1.485 in.)
x = 47.88 mm (1.885 in.)
- x = 58.04 mm (2.285 in.)
x = 70.52 mm (2.776 in.)
- x = 83.63 mm (3.293 in.)
x = 93.79 mm (3.693 in.)
- x = 103.95 mm (4.093 in.)
S x = 127.22 mm (5.009 in.)

4

3.5

3

E 2.5

2

I 1.5
r

1000 2000 3000

4000
Time (ms)

5000 6000

Figure 4-17. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 4.86
MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s, mH2 =
0.285 g/s, VH2 = 140.0 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3SA. Legend indicates distance from injector
face to heat flux sensor. Heat flux calculations performed using steady state
heat flux equation (Equation 2-15).

.j -.
C^.
--

0.5-

4 r
I 4i^ -'-* -

7000 8000

aWE

~-r-*"""l"~"~l~~

i, i

Temperatures vs Time
Chamber = 4.86 MPa, m02mH = 5.97, vO2H2 = 0.70
(#= 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 140.0 m/s)
IL I I I I I I

1000 2000 3000 4000
Time (ms)

5000 6000 7000 8000

Figure 4-18. Injector face temperatures, behind injector temperature, and exhaust nozzle
temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.86
MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 ( = 1.33, mo2 = 1.693 g/s, mH2
0.285 g/s, VH2 = 140.0 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement= CA3SA. The legend indicates r as the radial distance
from the injector center axis to the injector face thermocouple.

1000

900

800

700

Chamber Pressure vs Time
Chamber = 4.55 MPa, m o2mH = 5.97, V02VH2 = 0.70
(# = 1.33, mo2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 166.1 m/s)

0 1000 2000 3000 4000
Time (ms)

5000 6000 7000 8000

Figure 4-19. Chamber pressure versus time for a GH2/G02 combustion test with Pchamber
= 4.55 MPa, mo2/mH2 = 5.97, and vo2/VH2 = 0.70 (D = 1.33, mo2 = 1.693 g/s,
mH2 = 0.285 g/s, VH2 = 166.1 m/s). Injector = UF1. Injector position = IP3.
Chamber arrangement = CA3 SA.

Full Text
%High Pressure Combustion Facility Data Processor
%Created by: Alex Conley
%Date Created: 05/15/05
%This program asks the user for the data file set from the combustion tests
%and plots the temperatures, pressures, heat fluxes, etc. as a function of
%time. This program also performs Fourier Analysis on specific data sets
%and plots the resulting power spectrums to identify dominant frequencies.
%HFPT analysis is included as well.

clear all;
close all;
warning off;

currd=cd;
%***You will need to change the directory here to your own directory.***
cd('C:\Documents and Settings\aconley\Desktop\aconley\labview\Combustion Tests');
hfslengthch = textread('HFSLengthStandard.txt','%s %*f %*f %*f %*f %*f %*f %*f %*f %*f %*f %*f %*f %*f %*f');
hfslengthch = char(hfslengthch);
mstrlogname = textread('MasterLog.txt','%s %*f %*f %*f %*f %*c %*c %*f');
mstrlogname = char(mstrlogname);
[mstrloger,mstrlogcp,mstrlogofr,mstrlogffr,mstrlogim,mstrloghfpt,mstrlogcl] = textread('MasterLog.txt','%*s %f %f %f %f %c %c %f');
[filename, pathname] = uigetfile('*.*', 'Select test data file.');
if isequal(filename,0) | isequal(pathname,0)
disp('User pressed cancel')
a = 0;
else
disp(['User selected ', fullfile(pathname, filename)])
a = 1;
end

for q=1:length(hfslengthch)
if hfslengthch(q,3)==filename(13) & hfslengthch(q,6:8)==filename(16:18)
range = [q 1 q 14];
else
end
end

cd(currd);

if a==0;
disp('No test data file selected.')
else

disp(' ');
disp('High Pressure Combustion Facility Data Analyzer running...');
disp(' ');

%Find latest test in data and eliminate previous tests.
j=find(data(:,1)==0);
if length(j)==1.0
data = data(j(1):end,:);
else
test = input(['There are ',num2str(length(j)),' combustion tests in this file. Please enter the desired test number. ']);
if test==length(j)
data = data(j(test):end,:);
else
jb=j(test);
je=j(test+1);
data = data(jb:je-1,:);
end
end

test2 = input('Is there HFPT data for this combustion test (Y/N)? ','s');
test3 = input('Is there image data for this combustion test (Y/N)? ','s');

t=data(:,1);
CT=data(:,2);
cP=data(:,3);
oP=data(:,4);
fP=data(:,5);
oMFR=data(:,6);
fMFR=data(:,7);
ofMR=data(:,8);
ER=data(:,9);
ITL=data(:,10);
ITS=data(:,11);
BIT=data(:,12);
WT = zeros(length(data(:,1)),length(data(1,:))-13);

if char(filename(16:17))=='3S' | char(filename(16:17))=='3R' | char(filename(16:17))=='7S' | char(filename(16:17))=='7R' | char(filename(16:17))=='8S' | char(filename(16:17))=='8R'
for i = 1:(length(data(1,:))-13)-2
%eval(['LT' num2str(i) '=data(:,i+12);']);
WT(:,i) = data(:,i+14);
end
WT(:,(length(WT(1,:))-1))=data(:,13);
WT(:,(length(WT(1,:))))=data(:,14);
cueball = 1;
else
for i = 1:(length(data(1,:))-13)
%eval(['LT' num2str(i) '=data(:,i+12);']);
WT(:,i) = data(:,i+12);
end
cueball = 0;
end

DT = zeros(length(WT(:,1)),((length(WT(1,:)))/2));
for i = 1:(length(WT(1,:))/2)
DT(:,i) = WT(:,((2*i)-1))-WT(:,(2*i));
end
HF=(388/0.00635)*DT/1000000;
ENT=data(:,length(data(1,:)));

%Plot data.
figure(1);
plot(t,CT);
title('Chamber Temperature vs Time');
xlabel('Time (ms)');
ylabel('Temperature (\circC)');
axis([0 max(t) 0 1500]);
hold on;

figure(2);
hold on;
plot(t,ITL,'b');
plot(t,ITS,'g');
plot(t,BIT,'r');
plot(t,ENT,'c');
title('Injector Face, Injector Back, and Exhaust Nozzle Temperatures vs Time');
xlabel('Time (ms)');
ylabel('Temperature (\circC)');
axis([0 max(t) 0 600]);
legend('Injector Face Thermocouple Long','Injector Face Thermocouple Short','Behind Injector Thermocouple','Exhaust Nozzle Thermocouple');
hold off;
hold on;

figure(3);
plot(t,cP);
title('Chamber Pressure vs Time');
xlabel('Time (ms)');
ylabel('Pressure (psig)');
axis([0 max(t) 0 1000]);
hold on;

figure(4);
legd4=32*ones(length(WT(1,:))/2,5);
for i = 1:length(WT(1,:))/2,
legd4(i,1:2)='LT';
if i<10,
legd4(i,3)=num2str(i);
else
legd4(i,3:4)=num2str(i);
end;
end;
plot(t,WT(:,1:2:end-1));
title('Chamber Wall LT Temperature vs Time');
xlabel('Time (ms)');
ylabel('Temperature (\circC)');
axis([0 max(t) 0 150]);
legend(char(legd4));
hold on;

figure(5);
legd5=32*ones(length(WT(1,:))/2,5);
for i = 1:length(WT(1,:))/2
legd5(i,1:2)='ST';
if i<10,
legd5(i,3)=num2str(i);
else
legd5(i,3:4)=num2str(i);
end;
end;
plot(t,WT(:,2:2:end));
title('Chamber Wall ST Temperature vs Time');
xlabel('Time (ms)');
ylabel('Temperature (\circC)');
axis([0 max(t) 0 150]);
legend(char(legd5));
hold on;

figure(6);
legd6=32*ones(length(DT(1,:)),5);
for i = 1:length(WT(1,:))/2
legd6(i,1:2)='DT';
if i<10,
legd6(i,3)=num2str(i);
else
legd6(i,3:4)=num2str(i);
end;
end;
plot(t,DT(:,1:1:end));
title('(LT-ST) \DeltaTemperature vs Time');
xlabel('Time (ms)');
ylabel('\DeltaTemperature (\circC)');
axis([0 max(t) 0 50]);
legend(char(legd6));
hold on;

figure(7);
legd7=32*ones(length(HF(1,:)),5);
for i = 1:length(WT(1,:))/2
legd7(i,1:3)='HFS';
if i<10,
legd7(i,4)=num2str(i);
else
legd7(i,4:5)=num2str(i);
end;
end;
plot(t,HF(:,1:1:end));
title('Heat Flux vs Time');
xlabel('Time (ms)');
ylabel('Heat Flux (MW/m^2)');
axis([0 max(t) 0 1]);
legend(char(legd7));
str1(1) = {'Distance from Injector Face'};
for p = 1:length(HF(1,:));
if cueball == 1
str1(p+1) = {num2str(hfslength(p+1))};
else
str1(p+1) = {num2str(hfslength(p))};
end
end
text(0,0,str1,'VerticalAlignment','middle','EdgeColor','black');
hold on;

figure(8);
hold on;
plot(t,oP,'b');
plot(t,fP,'r');
title('Propellant Line Pressures vs Time');
xlabel('Time (ms)');
ylabel('Pressure (psig)');
axis([0 max(t) 0 1500]);
legend('Oxidizer','Fuel');
hold off;
hold on;

figure(9);
hold on;
plot(t,oMFR,'b');
plot(t,fMFR,'r');
title('Propellant Mass Flow Rates vs Time');
xlabel('Time (ms)');
ylabel('Mass Flow Rate (g/s)');
axis([0 max(t) 0 1]);
legend('Oxidizer','Fuel');
hold off;
hold on;

figure(10);
hold on;
plot(t,ofMR,'b');
plot(t,ER,'r');
title('GO_2/GH_2 Mass Flow Ratio and \phi vs Time');
xlabel('Time (ms)');
ylabel('GO_2/GH_2 Mass Flow Ratio and \phi');
axis([0 max(t) 0 10]);
legend('GO_2/GH_2 Mass Flow Ratio', '\phi');
hold off;
hold on;

%Fourier Transform Analysis

fa = input('Proceed with Fourier Analysis? (Y/N)','s');
if fa=='Y' | fa=='y'

ts=0;
for i = 1:length(t)
if t(i)>=6000 & ts==0;
ts = i;
else
end
end

FRQINT = 0;
counter = 0;
for i = 1:length(t)-1
FRQINT = FRQINT + (t(i+1)-t(i));
counter = counter + 1;
end
FRQ = 1/((FRQINT/counter)*0.001);

disp(' ');
disp(['Frequency of data points (Hz) = ',num2str(FRQ)]);

figure(11)
CTM = CT(ts:end,1);
FTCT = fft(CTM,(length(CTM)));
PCT = FTCT.* conj(FTCT) / length(CTM);
fCT = FRQ*(0:(length(CTM)/2))/length(CTM);
semilogy(fCT,PCT(1:((length(CTM)/2)+1)))
title('Power Spectrum of Chamber Temperature')
xlabel('frequency (Hz)')

figure(12)
ITCM(:,1) = ITL(ts:end,1);
ITCM(:,2) = ITS(ts:end,1);
ITCM(:,3) = BIT(ts:end,1);
ITCM(:,4) = ENT(ts:end,1);
FTITC = fft(ITCM,(length(ITCM(:,1))));
PITC = FTITC.* conj(FTITC) / length(ITCM(:,1));
fITC = FRQ*(0:(length(ITCM(:,1))/2))/length(ITCM(:,1));
semilogy(fITC,PITC(1:((length(ITCM(:,1))/2)+1),:));
title('Power Spectrum of Injector Face, Behind Injector, and Exhaust Nozzle Thermocouples')
xlabel('frequency (Hz)')
legend('Injector Face Thermocouple Long','Injector Face Thermocouple Short','Behind Injector Thermocouple','Exhaust Nozzle Thermocouple');

figure(13)
cPM = cP(ts:end,1);
FTcP = fft(cPM,(length(cPM)));
PcP = FTcP.* conj(FTcP) / length(cPM);
fcP = FRQ*(0:(length(cPM)/2))/length(cPM);
semilogy(fcP,PcP(1:((length(cPM)/2)+1)))
title('Power Spectrum of Chamber Pressure')
xlabel('frequency (Hz)')

figure(14)
for i = 1:(length(WT(1,:))/2)
LTM(:,i) = WT(ts:end,((i*2)-1));
end
legd14=32*ones((length(WT(1,:))/2),5);
for i = 1:length(WT(1,:))/2
legd14(i,1:2)='LT';
if i<10,
legd14(i,3)=num2str(i);
else
legd14(i,3:4)=num2str(i);
end
end
FTLT = fft(LTM,(length(LTM(:,1))));
PLT = FTLT.* conj(FTLT) / length(LTM(:,1));
fLT = FRQ*(0:(length(LTM(:,1))/2))/length(LTM(:,1));
semilogy(fLT,PLT(1:((length(LTM(:,1))/2)+1),:));
title('Power Spectrum of Chamber Wall Long Thermocouples')
xlabel('frequency (Hz)')
legend(char(legd14));

figure(15)
for i = 1:(length(WT(1,:))/2)
STM(:,i) = WT(ts:end,(i*2));
end
legd15=32*ones((length(WT(1,:))/2),5);
for i = 1:length(WT(1,:))/2
legd15(i,1:2)='ST';
if i<10,
legd15(i,3)=num2str(i);
else
legd15(i,3:4)=num2str(i);
end
end
FTST = fft(STM,(length(STM(:,1))));
PST = FTST.* conj(FTST) / length(STM(:,1));
fST = FRQ*(0:(length(STM(:,1))/2))/length(STM(:,1));
semilogy(fST,PST(1:((length(STM(:,1))/2)+1),:));
title('Power Spectrum of Chamber Wall Short Thermocouples')
xlabel('frequency (Hz)')
legend(char(legd15));

figure(16)
for i = 1:(length(DT(1,:)))
DTM(:,i) = DT(ts:end,i);
end
legd16=32*ones((length(DT(1,:))),4);
for i = 1:length(DT(1,:))
legd16(i,1:2)='DT';
if i<10,
legd16(i,3)=num2str(i);
else
legd16(i,3:4)=num2str(i);
end
end
FTDT = fft(DTM,(length(DTM(:,1))));
PDT = FTDT.* conj(FTDT) / length(DTM(:,1));
fDT = FRQ*(0:(length(DTM(:,1))/2))/length(DTM(:,1));
semilogy(fDT,PDT(1:((length(DTM(:,1))/2)+1),:));
title('Power Spectrum of (LT-ST) \DeltaTemperatures')
xlabel('frequency (Hz)')
legend(char(legd16));

figure(17)
for i = 1:(length(HF(1,:)))
HFM(:,i) = HF(ts:end,i);
end
legd17=32*ones((length(HF(1,:))),5);
for i = 1:length(HF(1,:))
legd17(i,1:3)='HFS';
if i<10,
legd17(i,4)=num2str(i);
else
legd17(i,4:5)=num2str(i);
end
end
FTHF = fft(HFM,(length(HFM(:,1))));
PHF = FTHF.* conj(FTHF) / length(HFM(:,1));
fHF = FRQ*(0:(length(HFM(:,1))/2))/length(HFM(:,1));
semilogy(fHF,PHF(1:((length(HFM(:,1))/2)+1),:));
title('Power Spectrum of Heat Fluxes')
xlabel('frequency (Hz)')
legend(char(legd17));

else
end

end

%High-Frequency Pressure Transducer Analysis

test5=input('Proceed with HFPT Analysis (Y/N)? ','s');
if test5=='Y' | test5=='y'

cd('C:\Documents and Settings\aconley\Desktop\aconley\labview\Combustion Tests');

[filename2, pathname2] = uigetfile('*.*', ['Select Amplifier Calibration File. ',num2str(i)]);
if isequal(filename2,0) | isequal(pathname2,0)
disp('User pressed cancel')
aa = 0;
else
disp(['User selected ', fullfile(pathname2, filename2)])
disp(['User selected calibration file as ',char([pathname2 filename2])]);
aa = 1;
end

[filename3, pathname3] = uigetfile('*.*', 'Select high speed pressure data file.');
if isequal(filename3,0) | isequal(pathname3,0)
disp('User pressed cancel')
b = 0;
else
disp(['User selected ', fullfile(pathname3, filename3)])
b = 1;
end

cd(currd);

if b==0
disp('No high speed pressure data file selected.')
else

FRQINT = 0;
counter = 0;
for i = 1:length(datap(:,1))-1
FRQINT = FRQINT + (datap(i+1,1)-datap(i));
counter = counter + 1;
end
FRQ = 1/((FRQINT/counter));

disp(' ');
disp(['Frequency of high speed pressure data (Hz) = ',num2str(FRQ)]);

figure(18)
plot(datap(:,1),datap(:,2));

llhsp = input('Input the lower limit of time window for FFT Analysis. ');
ulhsp = input('Input the upper limit of time window for FFT Analysis. ');

testul=0;
testll=0;
for i=1:length(datap(:,1));
if llhsp<=datap(i,1) && testll==0
ll=i
testll=1;
else
end
if ulhsp<=datap(i,1) && testul==0
ul=i
testul=1;
else
end
end

%Apply Amplification Calibration
for k = 1:length(datap(ll:ul,2))
for s = 1:length(calib(:,1))-1
if datap(ll+(k-1),2)>=calib(s,2) && datap(ll+(k-1),2) if datap(ll+(k-1),1)==calib(s,2)
datapc(k,2) = (datap(ll+(k-1),2)/calib(s,3))*9469.7;
datapc(k,1) = datap(ll+(k-1),1);
else
datapc(k,2) = (datap(ll+(k-1),2)/((((datap(ll+(k-1),2)-calib(s,2))/(calib(s+1,2)-calib(s,2)))*(calib(s+1,3)-calib(s,3)))+calib(s,3)))*9469.7;
datapc(k,1) = datap(ll+(k-1),1);
end
else
end
end
z=k
end

figure(18);
plot(datapc(:,1),datapc(:,2));

diff=(ul-ll)+1;
HSPM=zeros(diff,1);
FTHSP=zeros(diff,1);
PHSP=zeros(diff,1);
fHSP=zeros(ceil(diff/2),1);

figure(19);
HSPM(:) = datapc(:,2).*hann(length(datapc(:,2)));
FTHSP(:) = fft(HSPM(:),(length(HSPM(:))));
PHSP(:) = FTHSP(:).* conj(FTHSP(:)) / length(HSPM(:));
const1=FRQ;
const2=length(HSPM(:));
const3=const2/2;
fHSP(:) = (const1*(0:const3)/const2)';
plot(fHSP(:),PHSP(1:((length(HSPM(:))/2)+1)));
title('Power Spectrum of High Frequency Pressure Data');
xlabel('frequency (Hz)');
figure (20);
plot(fHSP(:),10*log10(PHSP(1:((length(HSPM(:))/2)+1))));
title('Power Spectrum of High Frequency Pressure Data');
xlabel('frequency (Hz)');
ylabel('dB');
end

else
end

test7=0;
test13=0;
for x=1:length(mstrlogname(:,1))
if mstrlogname(x,:)==filename(1,:)
test1=input('This test has already been logged, would you like to overwrite (Y/N)? ','s');
if test1=='Y' | test1=='y'
mstrlogname(x,:)=filename;
mstrloger(x,1)=ER(1,1);
mstrlogcp(x,1)=max(cP(230:length(cP(:,1)),1));
mstrlogofr(x,1)=oMFR(1,1);
mstrlogffr(x,1)=fMFR(1,1);
if test2=='Y' | test2=='y'
mstrloghfpt(x,1)='Y';
else
mstrloghfpt(x,1)='N';
end
if test3=='Y' | test3=='y'
mstrlogim(x,1)='Y';
else
mstrlogim(x,1)='N';
end
mstrlogcl(x,1)=1.0;
test7=1.0;
else
test13=1.0;
end
else
end
end
if test7==0 & test13==0
mstrlogname(length(mstrlogname(:,1))+1,:)=filename;
mstrloger(length(mstrloger(:,1))+1,1)=ER(1,1);
mstrlogcp(length(mstrlogcp(:,1))+1,1)=max(cP(230:length(cP(:,1)),1));
mstrlogofr(length(mstrlogofr(:,1))+1,1)=oMFR(1,1);
mstrlogffr(length(mstrlogffr(:,1))+1,1)=fMFR(1,1);
if test2=='Y' | test2=='y'
mstrloghfpt(length(mstrloghfpt(:,1))+1,1)='Y';
else
mstrloghfpt(length(mstrloghfpt(:,1))+1,1)='N';
end
if test3=='Y' | test3=='y'
mstrlogim(length(mstrlogim(:,1))+1,1)='Y';
else
mstrlogim(length(mstrlogim(:,1))+1,1)='N';
end
mstrlogcl(length(mstrlogcl(:,1))+1,1)=1.0;
else
end
fid=fopen('C:\Documents and Settings\aconley\Desktop\aconley\labview\Combustion Tests\MasterLog.txt','w');
for y=1:length(mstrlogname(:,1))
fprintf(fid,[mstrlogname(y,1:21),'\t']);
fprintf(fid,[num2str(mstrloger(y,1)),'\t']);
fprintf(fid,[num2str(mstrlogcp(y,1)),'\t']);
fprintf(fid,[num2str(mstrlogofr(y,1)),'\t']);
fprintf(fid,[num2str(mstrlogffr(y,1)),'\t']);
fprintf(fid,[mstrlogim(y,1),'\t']);
fprintf(fid,[mstrloghfpt(y,1),'\t']);
fprintf(fid,[num2str(mstrlogcl(y,1)),'\n']);
end
fclose(fid);

%High-Frequency Pressure Transducer Compare
%Created by: Alex Conley
%Date Created: 10/28/05

%This program allows the user to select mutliple data files from the
%high-frequency pressure transducer and cross-correlate between them to
%determine dominant frequency differences between cases with different
%flow conditions or to determine repeatability between cases with similar
%flow conditions.

warning off;
clear all;
close all;

currd=cd;
z=0;

disp([' ']);
dscomp = input('Input the number of high-frequency pressure transducer data sets to compare. ');

cd('C:\Documents and Settings\aconley\Desktop\aconley\labview\');

flnm=32*ones(dscomp,100);

[filename, pathname] = uigetfile('*.*', ['Select Amplifier Calibration File. ',num2str(i)]);
disp(['User selected calibration file as ',char([pathname filename])]);

for i = 1:dscomp
[filename, pathname] = uigetfile('*.*', ['Select high speed pressure data file. ',num2str(i)]);
flnm(i,1:length([pathname filename]))=[pathname filename];
disp(['User selected data file ',num2str(i),' as ',char([pathname filename])]);
end

cd(currd);

for i = 1:dscomp
FRQINT = 0;
counter = 0;
for k = 1:length(datap(:,1,i))-1
FRQINT = FRQINT + (datap(k+1,1,i)-datap(k,1,i));
counter = counter + 1;
end
FRQ(i) = 1/((FRQINT/counter));

disp(' ');
disp(['Frequency of high speed pressure data file ',num2str(i),' (Hz) = ',num2str(FRQ(i))]);

figure(((i*2)-1));
plot(datap(:,1,i),datap(:,2,i));

llhsp(i) = input(['Input the lower limit of time window for FFT Analysis, Figure ',num2str((i*2)-1),'. ']);
ulhsp(i) = input(['Input the upper limit of time window for FFT Analysis, Figure ',num2str((i*2)-1),'. ']);

testul=0;
testll=0;
for j=1:length(datap(:,1,i));
if llhsp(i)<=datap(j,1,i) && testll==0
ll(i)=j;
testll=1;
else
end
if ulhsp(i)<=datap(j,1,i) && testul==0
ul(i)=j;
testul=1;
else
end
end
end

%Apply Amplification Calibration
for k = 1:length(datap(ll(i):ul(i),2,i))
for s = 1:length(calib(:,1))-1
if datap(ll(i)+(k-1),2,i)>=calib(s,2) && datap(ll(i)+(k-1),2,i) if datap(ll(i)+(k-1),1,i)==calib(s,2)
datapc(k,2,i) = (datap(ll(i)+(k-1),2,i)/calib(s,3))*9469.7;
datapc(k,1,i) = datap(ll(i)+(k-1),1,i);
else
datapc(k,2,i) = (datap(ll(i)+(k-1),2,i)/((((datap(ll(i)+(k-1),2,i)-calib(s,2))/(calib(s+1,2)-calib(s,2)))*(calib(s+1,3)-calib(s,3)))+calib(s,3)))*9469.7;
datapc(k,1,i) = datap(ll(i)+(k-1),1,i);
end
else
end
end
z=k
end

figure(((i*2)-1));
plot(datapc(:,1,i),datapc(:,2,i));

diff=(ul(i)-ll(i))+1;
HSPM=zeros(max(diff),dscomp);
FTHSP=zeros(max(diff),dscomp);
PHSP=zeros(max(diff),dscomp);
fHSP=zeros(ceil(max(diff)/2),dscomp);

for i = 1:dscomp
figure(i*2);
HSPM(:,i) = datapc(:,2,i).*hann(length(datapc(:,2,i)));
FTHSP(:,i) = fft(HSPM(:,i),(length(HSPM(:,i))));
PHSP(:,i) = FTHSP(:,i).* conj(FTHSP(:,i)) / length(HSPM(:,i));
const1=FRQ(i);
const2=length(HSPM(:,i));
const3=const2/2;
fHSP(:,i) = (const1*(0:const3)/const2)';
plot(fHSP(:,i),PHSP(1:((length(HSPM(:,i))/2)+1),i));
title('Power Spectrum of High Frequency Pressure Data');
xlabel('frequency (Hz)');
end

%Correllation between the tests.
b=0;
disp([' ']);
ca = input('Proceed with Correlation Analysis? (Y/N) ','s');
if ca=='Y' | ca=='y'
for a=1:20
if b==0
disp([' ']);
disp(['Which files would you like to compare?']);
for n=1:dscomp
disp([num2str(n),': ',char(flnm(n,:))]);
end
n1=input('First test number: ');
n2=input('Second test number: ');
figure(49+a);
PSdiff(:,1)=PHSP(1:((length(HSPM(:,n1))/2)+1),n1)-PHSP(1:((length(HSPM(:,n2))/2)+1),n2);
plot(fHSP(:,1),PSdiff(:,1));
disp([' ']);
ba=input('Would you like to do another correlation? (Y/N) ','s');
if ba=='Y' | ba=='y'
b=0;
else
b=1;
end
else
end
end
else
end

PAGE 1

HPCF-HFPT Interface.vi HPCF-HFPT Interface.vi Connector Pane Front Panel Controls and Indicators File Name Specifies the name of the file to which you want to write data. Waveform Graph Block Diagram List of SubVIs and Express VIs with Configuration Information Write LabVIEW Measurement File Write LabVIEW Measurement File Writes data to a LabVIEW measurement data file. -------------------This Express VI is configured as follows: Mode: Save to one file Filename: test.lvm If a file already exists: Rename and keep existing file Description: DAQ Assistant2 DAQ Assistant Creates, edits, and runs tasks using NI-DAQmx. Refer to the DAQ Quick Start Guide for information on devices supported by NI-DAQmx. When you place this Express VI on the block diagram, the DAQ Assistant launches to create a new task. After you create a task, you can double-click the DAQ Assistant Express VI in order to edit that task. For continuous measurement or generation, place a loop around the DAQ Assistant Express VI. For continuous single-point input or output, the DAQ Assistant Express VI might not provide satisfactory performance. Refer to examples\DAQmx\Analog In\Measure Voltage.llb\Cont Acq&Graph Voltage-Single Point Optimization.vi for techniques to create higher-performance, single-point I/O applications. VI Revision History"HPCF-HFPT Interface.vi History" Current Revision: 52 Position in Hierarchy file:///F|/Data%20Files/Copy%20of%20thesis/Alex's%20Masters%20Thesis%20Stuff/template/Template72-XP/HPCF-HFPT%20Interface/HPCF-HFPT%20Interface.html4/28/2006 8:47:07 AM

clear all;
close all;

%Reference Picture information gives 1mm = 53.7 pixels.

FP = zeros(896,1280);

%Set Injector location pixel.

ILX = 150;
ILY = 220;

%Laser Profile Image Acquisition and Averaging
path2='C:\Documents and Settings\aconley\flame images\110505H2O2UF1CP3 flame vis tests\flameliftoff\test4\';
d2=dir('C:\Documents and Settings\aconley\flame images\110505H2O2UF1CP3 flame vis tests\flameliftoff\test4\*.tif');
FPI1 = zeros(length(d2),448,1280);
FPI2 = zeros(length(d2),448,1280);
for i=1:length(d2)
for j = 1:length(FP(:,1))
if j<=448
FPI1(i,j,:) = FP(j,:);
else
FPI2(i,j-448,:) = FP(j,:);
end
end
end

%Create X and Y axis from reference picture information.
PS = 1/54.9;
XL = 0-ILX;
XH = 1280-ILX;
YL = 0-ILY;
YH = 448-ILY;
Y=PS*YL:PS:PS*(YH-1);
X=PS*XL:PS:PS*(XH-1);

%Plot avg. laser profile and std. deviation.
imgnum = 20;
figure(1);
subplot(2,1,1);
imagesc(X,Y,squeeze(FPI1(imgnum,:,:)));
title('Instantaneous Flame Image');
xlabel('Height (mm)');
ylabel('Width (mm)');
colormap(gray);
axis equal;
axis tight;
subplot(2,1,2);
imagesc(X,Y,squeeze(FPI2(imgnum,:,:)));
title('Instantaneous Flame Image');
xlabel('Height (mm)');
ylabel('Width (mm)');
colormap(gray);
axis equal;
axis tight;

%Calculate correlation between images.

CORR1 = 0;
CORR2 = 10000000;
counter = 0;
OFFSET1 = zeros(1,length(d2));
OFFSET2 = zeros(1,length(d2));
for i = 1:length(d2)
for m = 0:30
for j = 1:length(FPI1(1,:,1))
for k = 1:length(FPI1(1,1,:))
if k+m<=1280
CORR1 = CORR1 + abs(FPI1(i,j,k)-FPI2(i,j,k+m));
counter = counter + 1;
else
CORR1 = CORR1 + 0;
end
end
end
if CORR1/counter < CORR2
CORR2 = CORR1/counter;
CORR1 = 0;
OFFSET1(1,i) = CORR2;
OFFSET2(1,i) = m;
counter = 0;
else
OFFSET1(1,i) = CORR1/counter;
CORR1 = 0;
counter = 0;
end
end
CORR1 = 0;
CORR2 = 1000000;
end

OFFSET2

clear all;
close all;

%Reference Picture information gives 1mm = 53.7 pixels.

FP = zeros(896,1280);

%Set Injector location pixel.

ILX = 150;
ILY = 220;

%Laser Profile Image Acquisition and Averaging
path2='C:\Documents and Settings\aconley\flame images\110505H2O2UF1CP3 flame vis tests\flameliftoff\test5\';
d2=dir('C:\Documents and Settings\aconley\flame images\110505H2O2UF1CP3 flame vis tests\flameliftoff\test5\*.tif');
FPI = zeros(length(d2),896,1280);
for i=1:length(d2)
FPI(i,:,:) = FP(:,:);
end

%Create X and Y axis from reference picture information.
PS = 1/54.9;
XL = 0-ILX;
XH = 1280-ILX;
YL = 0-ILY;
YH = 448-ILY;
Y=PS*YL:PS:PS*(YH-1);
X=PS*XL:PS:PS*(XH-1);

%Plot avg. laser profile and std. deviation.
figure(1);
imagesc(X,Y,squeeze(FPI(18,:,:)));
title('Instantaneous Flame Image');
xlabel('Height (mm)');
ylabel('Width (mm)');
colormap(gray);
axis equal;

PAGE 1

HIGH-PRESSURE GH2/GO2 COMBUSTION DYNAMICS By CLARK ALEXANDER CONLEY A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2006

PAGE 2

Copyright 2006 by Clark Alexander Conley

PAGE 3

I dedicate this thesis to my wonderful wi fe Wendy and my very supportive and loving family: Mom, Dad, Ben, and Julie.

PAGE 4

iv ACKNOWLEDGMENTS I thank my wife, Wendy, for being so suppor tive and loving. I thank my parents for supporting me and keeping me out of trouble. I thank my brother, Ben, and my sister, Julie, for getting me into trouble. I thank Dr Corin Segal for guiding me in this research and providing this wonderful opportunity to pr ogress my education and research abilities. I thank all of my fellow researchers in the combustion lab that assisted me in this research. Finally, I thank NASA Marsha ll for its support in this research.

PAGE 5

v TABLE OF CONTENTS page ACKNOWLEDGMENTS.................................................................................................iv LIST OF TABLES............................................................................................................vii LIST OF FIGURES.........................................................................................................viii LIST OF OBJECTS.........................................................................................................xvi NOMENCLATURE.......................................................................................................xvii ABSTRACT.....................................................................................................................xi x CHAPTER 1 INTRODUCTION........................................................................................................1 Safer, Cheaper, and More Reliable Rocket Engines.....................................................2 Literature Review.........................................................................................................4 2 METHODS.................................................................................................................10 The H2/O2 Injection/Combustion Process..................................................................10 H2-O2 Reaction Chemistry..................................................................................11 Propellant Flow Properties and Calculations......................................................12 Heat Flux Calculations........................................................................................15 Data Processing Methodologies.................................................................................17 The Role of Matlab..............................................................................................17 Standardized filenames........................................................................................17 Data processing programs...................................................................................17 3 HIGH-PRESSURE COMBUSTION FACILITY.......................................................20 Combustor System......................................................................................................20 Combustion Chamber..........................................................................................20 Chamber material.........................................................................................21 Chamber geometry.......................................................................................21 Optical access...............................................................................................22 Other chamber features................................................................................25

PAGE 6

vi Injector.................................................................................................................26 Injector material...........................................................................................26 Injector geometry.........................................................................................27 Other Combustor System Components...............................................................28 Exhaust nozzle..............................................................................................28 Chamber extensions.....................................................................................29 Igniter...........................................................................................................29 Propellant Feed System..............................................................................................30 Control/DAQ System..................................................................................................35 Electronics system...............................................................................................36 Control/DAQ Hardware......................................................................................36 Computer hardware......................................................................................37 DAQ sensors................................................................................................37 Laser and imaging systems..........................................................................42 Labview GUI.......................................................................................................43 HPCF Assembly and Operation..................................................................................44 4 RESULTS...................................................................................................................59 5 DISCUSSION AND CONCLUSION......................................................................102 High-Pressure Combustion Facility Obstacles and Improvements..........................102 High-Pressure GH2/GO2 Combustion Dynamics.....................................................104 Initial Unstable/Unsteady Flow.........................................................................105 Pressure Effect on Wall Heat Flux....................................................................106 Effect of Chamber Length.................................................................................110 High-Frequency Pressure Transducer...............................................................110 Imaging Discussion...........................................................................................111 Conclusion................................................................................................................112 APPENDIX A LABVIEW AND MA TLAB CODES......................................................................114 B OPERATIONAL PROCEDURE AND ASSEMBLY INSTRUCTIONS FOR UF HPCF........................................................................................................................116 C CALIBRATION CURV ES AND EQUATIONS.....................................................124 LIST OF REFERENCES.................................................................................................131 BIOGRAPHICAL SKETCH...........................................................................................134

PAGE 7

vii LIST OF TABLES Table page 1-1 Coaxial-shear injector features comp arison. Includes UF injectors, Penn State injectors, Space Shuttle Main Engine injectors, and Gas-Gas Injector Technology Injectors..................................................................................................9 3-1 Distances from the injector face to the heat flux sensors for all injector position/chamber arrangement combinations. All dimensions in inches................54 3-2 Description of each component on the HPCF Control Interf ace and HPCF-HFPT Interface front panels (Labview GUIs). Numbers are referenced to Figures 315 and 3-16...............................................................................................................57 4-1 Combustion test confi gurations, operating conditi ons, and included figures..........61 B-1 Extension stem sleeve designation for th e three different in jector positions.........121 B-2 List of DAQ channel/thermocouple usage.............................................................123 C-1 Table of calibration factors for th e chamber and propell ant line pressure transducers..............................................................................................................130

PAGE 8

viii LIST OF FIGURES Figure page 2-1 Standardized filename code for all save d main combustion test data files. Highfrequency pressure transducer test data files use the same code except for the addition of hfpt before the test number (i.e., 010106UF1IP3CA3SAhfptT01)....19 3-1 ProEngineer/ProMechanica stress models for the combustion chamber loaded at 10 MPa internal pressure. A) is the normal stress (MPa). B) is the shear stress (MPa)........................................................................................................................45 3-2 ProEngineer/ProMechanica transien t thermal analysis on the combustion chamber with heat flux conditions based on a stoichiometric flame. Maximum temperature (y-axis) represents the ho ttest point anywhere in the chamber............46 3-3 Cross sectional drawing of the comb ustion chamber and chamber extensions. All dimensions are in inches. The ther mocouple holes at the top of the figure are for the pair of thermocouples that form each heat flux sensor (HFS)................46 3-4 Cross-sectional CAD image of the window mounting. The two o-ring grooves completely circumnavigate the window The viewable diameter through the window is 0.81........................................................................................................47 3-5 Cross-sectional CAD image of the in jector assembly. Indicates various components as well as the dimensions of the 3 UF HPCF injectors: UF0 (GH2/Air), UF1 (GH2/GO2), UF2 (GH2/GO2).........................................................47 3-6 Cross-sectional drawing of injector i ndicating the distance from the outer face of the chamber/chamber extension to the face of the injector for the three injector positions IP1, IP2, and IP3.......................................................................................48 3-7 Cross-sectional CAD image of the in jector assembly and the exhaust nozzle assembly attached to the combustion chamber........................................................48 3-8 Pictorial of the different chamber ar rangements possible for the HPCF. Flow path is left to right. CC combustion ch amber. SE short chamber extension. LE long chamber extension...................................................................................49 3-9 Drawing of the injector face, indica ting notable dimensions of the injector assembly face and locations of the injector face thermocouples. Dimensions in inches........................................................................................................................5 0

PAGE 9

ix 3-10 Schematic drawing of the HPCF prop ellant/purge feed system. Number on bottles indicates the number of bottl es in the array for that gas...............................51 3-11 Flowchart of the control/DAQ system.....................................................................52 3-12 Circuit diagram for th e electronics system...............................................................53 3-13 Circuit diagram for the non-i nverting operational amplifier....................................55 3-14 Picture of the combustor system asse mbled, including the combustion chamber, injector assembly, exhaust nozzle assemb ly, two short chamber extensions, and instrumentation.........................................................................................................55 3-15 HPCF Control Interface front panel (L abview GUI). Numbers referenced to Table 3-2..................................................................................................................56 3-16 HPCF-HFPT Interface front panel (Labvi ew GUI). Numbers are referenced to Table 3-2..................................................................................................................57 4-1 Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 144.2 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Ignition and shutdow n times indicated for this full data set............................................................................................................................ .62 4-2 Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 144.2 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Legend indicates distance from injector face to heat flux sensor. Ignition and shut down times indicated for this full data set. Heat flux calculations performed using stea dy state heat flux equation (Equation 2.15).......................................................................................................................... 63 4-3 Injector face temperatures, behind in jector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 144.2 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The legend indicates r as the radial distance from the injector center axis to the injector face thermocouple. Ignition and shutdown times indicated for this full data set.........................................................................64 4-4 Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 197.4 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.............................................................................................65

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x 4-5 Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 197.4 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Legend indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed usi ng steady state heat flux equation (Equation 2.15)..........................................................................................66 4-6 Injector face temperatures, behind in jector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 197.4 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The legend indicates r as the radial distance from the injector center axis to th e injector face thermocouple..............................................67 4-7 Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 235.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.............................................................................................68 4-8 Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 235.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Legend indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed usi ng steady state heat flux equation (Equation 2.15)..........................................................................................69 4-9 Injector face temperatures, behind in jector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 235.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The legend indicates r as the radial distance from the injector center axis to th e injector face thermocouple..............................................70 4-10 Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 468.3 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.............................................................................71 4-11 Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 468.3 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Legend indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed usi ng steady state heat flux equation (Equation 2.15)..........................................................................................72

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xi 4-12 Injector face temperatures, behind in jector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 468.3 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The legend indicates r as the radial distance from the injector center axis to th e injector face thermocouple..............................................73 4-13 Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 102.5 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.............................................................................74 4-14 Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 102.5 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Legend indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed usi ng steady state heat flux equation (Equation 2.15)..........................................................................................75 4-15 Injector face temperatures, behind in jector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 102.5 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The legend indicates r as the radial distance from the injector center axis to th e injector face thermocouple..............................................76 4-16 Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 140.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.............................................................................77 4-17 Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 140.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Legend indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed usi ng steady state heat flux equation (Equation 2.15)..........................................................................................78 4-18 Injector face temperatures, behind in jector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 140.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The legend indicates r as the radial distance from the injector center axis to th e injector face thermocouple..............................................79

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xii 4-19 Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 166.1 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.............................................................................80 4-20 Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 166.1 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Legend indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed usi ng steady state heat flux equation (Equation 2.15)..........................................................................................81 4-21 Injector face temperatures, behind in jector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 166.1 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The legend indicates r as the radial distance from the injector center axis to th e injector face thermocouple..............................................82 4-22 Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 322.9 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.............................................................................83 4-23 Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 322.9 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Legend indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed usi ng steady state heat flux equation (Equation 2.15)..........................................................................................84 4-24 Injector face temperatures, behind in jector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 322.9 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The legend indicates r as the radial distance from the injector center axis to th e injector face thermocouple..............................................85 4-25 Heat flux versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Chambe r arrangement = CA3SA. Error bars indicate +/the standard de viation for the averaged test data. Chamber pressures increased by decreasing exhaust nozzl e diameter. Heat flux calculations performed using steady state heat equation (Equation 2.15)...................................86

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xiii 4-26 Heat flux versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Cham ber arrangement = CA3SA. Chamber pressures increased by decreasing ex haust nozzle diameter. Heat flux calculations performed using steady state heat flux plus heat absorption equation (Equation 2.16).........................................................................................................87 4-27 Heat flux versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 5.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s). Injector = UF1. Injector position = IP3. Chambe r arrangement = CA3SA. Error bars indicate +/the standard de viation for the averaged test data. Chamber pressures increased by decreasing exhaust nozzl e diameter. Heat flux calculations performed using steady state heat flux equation (Equation 2.15)............................88 4-28 Heat flux versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 5.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s). Injector = UF1. Injector position = IP3. Cham ber arrangement = CA3SA. Chamber pressures increased by decreasing ex haust nozzle diameter. Heat flux calculations performed using steady state heat flux plus heat absorption equation (Equation 2.16).........................................................................................................89 4-29 Chamber wall temperature versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Error bars indicate +/the sta ndard deviation for the averaged test data. Chamber pressures increased by d ecreasing exhaust nozzle diameter. Wall temperature calculations pe rformed using Equation 2.17...............................90 4-30 Chamber wall temperature versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 5.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Error bars indicate +/the sta ndard deviation for the averaged test data. Chamber pressures increased by decreasing exhaust nozzle diameter. Wall temperature calculations pe rformed using Equation 2.17...............................91 4-31 Injector face temperature versus chamber pressure for GH2/GO2 combustion tests with mO2/mH2 = 3.97 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Ch amber arrangement = CA3SA. Legend indicates r as the radial distance from the injector center axis to the injector face thermocouple. Bars indicate +/the st andard fluctuation from the average temperature. Chamber pressures in creased by decreasing exhaust nozzle diameter....................................................................................................................92

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xiv 4-32 Injector face temperature versus chamber pressure for GH2/GO2 combustion tests with mO2/mH2 = 5.97 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s). Injector = UF1. Injector position = IP3. Ch amber arrangement = CA3SA. Legend indicates r as the radial distance from the injector center axis to the injector face thermocouple. Bars indicate +/the st andard fluctuation from the average temperature. Chamber pressures in creased by decreasing exhaust nozzle diameter....................................................................................................................93 4-33 Injector face temperatures versus radi al distance from injector center axis for GH2/GO2 combustion tests at mO2/mH2 = 3.97 and 5.97 and Pchamber = 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa. Chamber pressures increased by decreasing exhaust nozzle diameter.........................................................................94 4-34 Injector face temperatur e versus chamber length for GH2/GO2 combustion tests with Pchamber = 4.86 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Legend indicates r as the radial distance from the injector center axis to the injector face thermocouple. Error bars indicate +/the standard deviation for the averaged test data.....................................................................................................................9 4 4-35 Heat flux versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 ( = 2.0), vO2/vH2 = 0.46, vH2 = 207.4 m/s, and a variety of chamber pressures. Chamber pressure increased by increasing flow rates. Exhaust nozzle diameter = 1.70 mm (0.670 i n.). Injector = UF1. Injector position = IP3. Chamber arrangement = CA 3SA. Heat flux values calculated using steady state heat flux plus he at absorption equation (Equation 2.16).............95 4-36 Normalized heat flux versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 ( = 2.0), vO2/vH2 = 0.46, vH2 = 207.4 m/s, and a variety of chamber pressu res. Chamber pressure increased by increasing flow rates. Exhaust nozzle diameter = 1.70 mm (0 .670 in.). Injector = UF1. Injector position = IP3. Cham ber arrangement = CA3SA. Heat flux values calculated using steady state h eat flux plus heat absorption equation (Equation 2.16). Heat flux values normalized by (2.75 MPa/Pc)0.8.........................96 4-37 Normalized heat flux versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 ( = 2.0), vO2/vH2 = 0.46, vH2 = 207.4 m/s, and a variety of chamber pressu res. Chamber pressure increased by increasing flow rates. Exhaust nozzle diameter = 1.70 mm (0 .670 in.). Injector = UF1. Injector position = IP3. Cham ber arrangement = CA3SA. Heat flux values calculated using steady state h eat flux plus heat absorption equation (Equation 2.16). Heat flux values normalized by (2.75 MPa/Pc)0.6.........................97

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xv 4-38 Normalized heat flux versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 ( = 2.0), vO2/vH2 = 0.46, vH2 = 207.4 m/s, and a variety of chamber pressu res. Chamber pressure increased by increasing flow rates. Exhaust nozzle diameter = 1.70 mm (0 .670 in.). Injector = UF1. Injector position = IP3. Cham ber arrangement = CA3SA. Heat flux values calculated using steady state h eat flux plus heat absorption equation (Equation 2.16). Heat flux valu es normalized by (0.187 g/s / mH2)0.5....................98 4-39 High-frequency pressure tr ansducer data (chamber pressure versus time) for a 1.8 second window of a GH2/GO2 combustion test with = 2.0, mO2 = 1.565 g/s, and mH2 = 0.396 g/s. Injector = UF1. In jector position = IP3. Chamber arrangement = CA3SA. Sample rate = 50 kHz.......................................................99 4-40 Power spectrum analysis of high-freque ncy pressure data shown in Figure 4-33. Analysis performed via Fast -Fourier Transform method.........................................99 4-41 0-3500 Hz window of power spectrum shown in Figure 4-34...............................100 4-42 Average flame profile of a GH2/GO2 flame with operating conditions of Pchamber = 4.86 MPa, = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, and vO2/vH2 = 0.46. Images of broadband flame emission. Exposure time = 500 ns. Average of 132 images. Injector center axis located at y = 0 and inject or face located at x = 0....100 4-43 Instantaneous flame image of a GH2/GO2 flame with opera ting conditions of Pchamber = 4.86 MPa, = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, and vO2/vH2 = 0.46. Image of broadband flame emission. Exposure time = 500 ns. Injector center axis located at y = 0 and injector face located at x = 0................................101 C-1 Calibration curve (Cv versus number of turns) for the B-SS4 and SS-SS4-VH metering valves......................................................................................................125 C-2 Calibration curve (Cv versus number of turns) for the SS-31RS4 and SS-31RF4 metering valves......................................................................................................126 C-3 Calibration curve (Cv versus number of turns) for the SS-1RS4 needle valve, which has a 0.172 inch orifice................................................................................127 C-4 Calibration curve (Cv versus number of turns) for the SS-1RF4 neele valve, which has a 0.250 inch orifice................................................................................128 C-5 Calibration curve (amplification factor versus output voltage) for the operational amplifier.................................................................................................................129

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xvi LIST OF OBJECTS Object page A-1 Complete Labview code (block di agram) for Labview GUI HPCF Control Interface (5.52 MB, object-a1.pdf).......................................................................114 A-2 Complete Labview code (block di agram) for Labview GUI HPCF-HFPT Interface (565 KB, object-a2.pdf)........................................................................115 A-3 Matlab code for HPCF_Data_P roceessor (19 KB, object-a3.txt).......................115 A-4 Matlab code for HFPT_Compare (5 KB, object-a4.txt).....................................115 A-5 Matlab code for HPCF_Image_Pr ocessor (1 KB, object-a5.txt)........................115 A-6 Matlab code for HPCF_AvgF lameSpeed (3 KB, object-a6.txt).........................115

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xvii NOMENCLATURE A area [m2] c heat capacity [J kg-1 K-1] Cv flow coefficient [1] Gg specific gravity [1] GO2 gaseous oxygen GH2 gaseous hydrogen GUI Graphical User Interface HFPT High-Frequency Pressure Transducer k thermal conductivity [W m-1 K-1] M Mach number [1] m mass flow rate [kg/s] m mass [kg] mO2 oxygen mass flow rate [g/s] mH2 hydrogen flow rate [g/s] OH-PLIF Hydroxyl Planar Laser-Induced Fluorescence p pressure [Pa] Pchamber chamber pressure [Pa] p0 stagnation pressure [Pa] q volumetric flow rate [scfm] qA heat flux per unit area [W m-2]

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xviii R gas constant [m2 s-2 T-1] T temperature [K, oC] T0 stagnation temperature [K, oC] Twall chamber wall temperature [K, oC] u velocity [m/s] UF-HPCF High Pressure Combustion Facility T temperature difference [K, oC] t time difference [s] x distance between temperature measurement locations [m] 22 22 OH actual OH s toichiometricmm mm equivalence ratio [1] density [kg m-3] specific heat ratio [1]

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xix Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science HIGH-PRESSURE GH2/GO2 COMBUSTION DYNAMICS By Clark Alexander Conley August 2006 Chair: Corin Segal Major Department: Mechanic al and Aerospace Engineering A high-pressure combustion facility was de signed at the University of Florida Mechanical and Aerospace Engineering Combusti on Lab. Features of the facility include optical access into the combustor during opera tion, a full set of temperature and pressure diagnostic capabilities, remote control thr ough a graphical user interface, and run times upwards of 10 seconds. The f acility is capable of operati ng pressure from 0.1 MPa to 6.25 MPa. Propellants used include gaseous hydrogen as the fuel and oxygen as the oxidizer, although other fuels and oxidizer can be adapted to the facility. Current injectors investigated are of coaxial shear jet type. Diagnostic capabilities include chamber wall heat flux measurements along th e length of the chamber, injector face temperature measurements, exhaust nozzle temperature measurements, high-frequency pressure measurements, and flame imaging. Through operation of the facility, several key obstacles were identified which warra nt future improvements. An injector incorporating an ignition torch and prope llant injection temperature/pressure measurements is one such improvement, which is currently being de signed. Integration

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xx of a water-cooled nozzle will allow combus tion test times beyond the current maximum of 10 seconds. Finally, maintaining a proper seat between the heat flux sensors and the chamber needs further addressing. The facility was used to investig ate the dynamics of high-pressure GH2/GO2, with operating conditions typical of rocket engi nes. Namely, two oxygen to hydrogen mass flow ratios of 3.97 and 5.97 ( = 2.0 and = 1.33, respectively) were investigated. Fuel flow rates ranged from 0.187g/s to 0.470 g/s. Operational chamber pressures of 6.21, 4.86, 4.55, and 2.76 MPa were investigated by k eeping the propellant mass flow rates constant and changing the exhaust nozzle diameter. In addition, four operational chamber pressures of 5.87, 4.93, 3.90, and 2.75 MP a were investigated by keeping the exhaust nozzle diameter constant and changi ng the propellant mass flow rates. A period of instability seems to exist in the combusting flow for the first 4 or 5 seconds after ignition due to the increasing chamber pre ssure and the corresponding decrease in gas injection velocities. Maximum heat releas e occurs 60 mm (2.35 in.) from the injector face. In general, the inject or face temperatures have litt le to no dependence on chamber pressure. The profiles of heat flux and ch amber wall temperatures seem to have no pressure dependence and only a slight depende nce on propellant inject ion velocities. A scaling of heat flux values based on fuel mass flow rate, instead of chamber pressure, is suggested. The lack of pressure dependen ce and only slight dependence on the propellant injection velocities, as shown by the similarity in heat flux pr ofiles, suggest that the basic dynamic structures of the combusting flow ar e mainly dominated by geometrical effects.

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1 CHAPTER 1 INTRODUCTION The goals of this research were (i) to design and construct a combustion facility capable of operating pressures from 0.1 to 6.25 MPa (1 to 62 atm), designated the University of Florida High Pressure Com bustion Facility (UF HPCF), and (ii) to experimentally investigate the highpressure combustion dynamics of GH2/GO2 flames at operating conditions in the afor ementioned pressure range, mO2/mH2 = 3.97 and 5.97 ( = 2.0 and 1.33, respectively) and a range of velocity ratios. Other capabilit ies of the facility include optical access to the chamber, temperature and pr essure diagnostic capabilities, imaging systems, and controllability via gr aphical user interface (GUI). Diagnostic capabilities include combustion chamber wall h eat fluxes, injector face temperatures, exit nozzle temperatures, flame temperatures, and ch amber pressure fluctuations, all of which were obtained for a variety of hot-fire tests in the aforementioned operational conditions. In addition, instantaneous broadband flam e emission images and average broadband flame emission images were obtained for a few combustion tests. These images are useful in determining such characteristics as flame lift-off distance, shear layer growth, instantaneous flame propagation phenomena, and average flame speeds. Furthermore, preliminary investigation into the use of OH Planar Laser Induced Fluorescence (OHPLIF) laser-based diagnostic technique was c onducted. This thesis presents the described research, including the facility design/construction stages, future improvements to the facility, data from high-pressure GH2/GO2 combustion tests, and discussion on the implication of the data to the dyna mics of the combustion process.

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2 Safer, Cheaper, and More Reliable Rocket Engines Although the research presnt ed has applicability to many different types of combustion engines, it is directed more toward study of the heat characteristics related to rocket engines. More specifically, this res earch is directed at rocket engines employing hydrogen and oxygen as the propella nts and a shear coaxial jet injector. Rocket engines are mainly used in satellite deployment, missile technologies, and space exploration, all of which involve the transport of expensive equipment and/or human life. Therefore, there is a constant drive for safer, cheaper, and more reliable rocket engines. In order to build such rocket engines, the dynamics of th e rocket engine combustion process need to be better understood. However, the very nature of rocket engines ma kes this goal hard to accomplish. The high-pressure and high-heat operational conditions of a rocket engine make in-situ measurements inside the combus tion environment difficult. Also, testing on full size prototypes or actual engines can be time consuming and costly once all development factors, materials, and te sting facility costs are factored in. One common away around this problem is through the use of Computational Fluid Dynamics (CFD). CFD allows engineers to model the rocket engine in a computer to determine design flaws and improvements, elim inating much time, effort, and cost in building and testing physical prot otypes. CFD essentially allo ws a rocket engine to be safely designed to a final or near-final st age before a physical model must be built for actual hot-fire testing. Unfort unately, two main problems have limited the application of CFD in the rocket engine design process. Fi rst, in the past solutions have required huge amounts of time and computer power to provid e valid results for even simple models, not to mention more complicated multi-element injector and intricate cooling systems. Secondly, the CFD models at present lack abundant validation from actual combustion

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3 data, especially for the higher pressures at wh ich rocket engines opera te. With computer technology improving by leaps and bounds every day, the problems with computationally expensive models are becoming fewer, meaning that more CFD results can be produced quicker than ever. Unfortunately, the second problem has not been sufficiently addressed. More validation of the CFD mode ls means more trust in the model results, giving way to quicker and cheaper design/build times for many components of the rocket engines, including injectors, co mbustors, and cooling systems.1 To compound these difficulties, only r ecently has investigation into unsteady combustion systems begun. Most CFD model re sults in the past have been based on steady state 1-D analyses, when the combustion process inside rocket engines is largely unsteady and 3-D. Furthermore, heat transfer into the combustor walls has rarely been addressed, even though the strength, lifecycle, and cooling system effectiveness of the combustor are heavily dependent on the heat transfer into and out of the chamber wall.2 This lack of research also applies to expe rimental investigation, with the only notable study, by Marshall et al.,3 appearing only recently. Therefore, it is worthwhile to not only experimentally investigate high-pressure combustion dynamics, but to also work alongside CFD researchers to optimize interaction between experimental testing and CF D modeling so that reliable rocket engine models can be produced efficiently. This rese arch seeks to advance the understanding of high-pressure combustion dynamics through experi mental testing and present the data for CFD model validation so that ch eaper, safer, and more reliable rocket engines become a reality.

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4 Literature Review Before designing the UF HPCF, a literature search was conducted for other highpressure combustion diagnostic facilities, including those of the university, government, and industry sectors. The goal of this sear ch was to see what current high-pressure combustion research existed, avoid potential ro ad blocks that others had encountered and documented, and verify that this research was unique and necessary for the aerospace industry. Many key topics were searched fo r within the literatur e, including chamber design, injector design, optical access de sign for imaging diagnostic purposes, nonoptical diagnostics for high-pressure combus tion, and laser diagnostic techniques in highpressure combustion. Several high-pressure com bustion diagnostic facilities with optical access were reviewed for different aspects of their designs.4-8 These facilities encompass gas turbine combustors and rocket engine combustors although other highpressure combustion diagnostic facilities exist for other uses, such as internal combustion engines. Allen and Miller4 of Physical Sciences, Inc. present an optically accessible high-pressure gas turbine combustor. While this facility is designed for gas turbine studies, the injector and propellants are practically the only difference fr om the facilities for rocket engine studies. Their facility can operate up to 50 atm and is eq uipped with a heater th at can deliver air at 530 K at maximum pressure and a flow rate of 1 kg/s. The development of the highpressure gaseous burner at NAS As Glenn Research Center is presented in the Kojima and Nguyen5 study. This facility is capable of running non-premixed and premixed propellants at operating pressures up to 60 atm. Optical access and adaptability for different fuels gives the ability for calibration of different optical di agnostic techniques. Purdue Universitys high-p ressure combustion facility, presented by Carter et al.,6

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5 employs a flat flame burner for spec troscopic studies. Locke et al.7 briefly present the high-pressure combustor facility at NASAs Gl enn Research Center. This facility burns JP-5, incorporates a ceramic liner, and is e quipped with a nitrogen cooling film over the windows. Finally, the facility at Pennsylvania State University is described the paper by Foust et al.8 This high-pressure combustion facility is similar in design and use as the UF HPCF, comprised of a modular combustor section with op tical access and pressure-fed propellant supplies. This facility uses a sh ear coaxial injector and has the capability for liquid oxygen supply, in additi on to gaseous propellants. While many design aspects of the UF HP CF were covered from the aforementioned papers, there was not enough information there to finalize the injector parameters. In fact, Penn States facility was the only one of those reviewed a bove that explicitly incorporated a shear coaxial injector. Th erefore further review was necessary to determine proper injector characterist ics. As mentioned, Foust et al.8 reported the dimensions of their injector and th eir flow parameters for use with GH2/GO2 at Penn States facility, which are presented in Table 1-1. The injector designs that came out of the Gas-Gas Injector Technology (GGIT) st udy for the Reusable Launch Vehicle (RLV) are reported by Tucker et al.9 These four injector de signs and corresponding flow conditions are also presented in Table 1-1. In addition, the injector and flow parameters of the Space Shuttle Main Engine (SSME) fuel preburner are presented in Table 1-1, which were reported in Ferraro et al.10 The current phase of this research is only concerned with shear coaxial injectors, and hence no studies of swirl injectors, impinging injectors, or other injector designs are reviewed here.

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6 Laser-based diagnostics as a pplied to high-pressure com bustion were also reviewed for this research to understand facility requi rements and prepare for the facility design phase. Laser-Induced Fluorescence (LIF) is one such diagnostic technique. The LIF technique has been extensively validated for atmospheric and sub-atmospheric combustion, but the amount of LIF data ava ilable decreases rapidl y as the pressure increases. This is largely due to the diffi culties in obtaining meaningful results because of high-pressure effects on LIF. Because OH Planar Laser Induced Fluorescence (OH PLIF) is the preferred species /technique for this research, it was reviewed in this research. First and foremost, two extensiv e publications, Kohse-Hoinghaus and Jeffries11 and Eckbreth,12 provide ample information on lase r-based diagnostic techniques as applied to combustion through technical detail about the techniques themselves and extensive referencing. Santoro13 provides a brief, but informative description of several laser-based diagnostic techni ques as applied to rocket and gas turbine combustors, including Laser Doppler Velocimetry (LDV) Raman spectroscopy, and LIF at the Penn State facility. The LIF setup desc ribed includes excitation of the Q1(8) transition of the OH radical with 2 mJ/pulse at a pressure of 0.47 MPa and the resulting images were compared to CFD results. Frank et al.14 report OH PLIF measurements in a spray flame of heptane and Jet-A fuel at pressures up to 20 atm using the facility at Physical Sciences, Inc. The PLIF setup is described as excitation of the Q1(8) transition ( =283.55 nm) with a 3 mJ/pulse and detection centered at 313 nm using a narrow bandpass interference filter (FWHM=25 nm). Significant laser attenuation and b eam steering was noted as the pressures increased. Edwards et al.15 report their investigation of OH LIF in high-pressure solid

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7 propellant flames. Excitation was at 306.42 nm with 300 mJ/pulse and detection at 310.6 nm and 315.1 nm. The authors suggest that hi gh-pressure effects on excitation/detection strategies for LIF are less of a problem th an the lack of high pressure kinetic and spectroscopic data. Arnold et al.16 report quantitative measurements of OH concentration fields using two-dimensional LIF of lamina r, premixed methane/air flat flames at pressures up to 20 atm. Excitation was at 290 nm with 1 mJ/pulse and detection at 314 nm. The authors report significant decreas e in OH fluorescence signal with higher pressures due to absorption line width broade ning, increase of el ectronic quenching, and increase in beam steering. Atakan et al.17 report the LIF spectra of OH in the exhaust of a laminar premixed methane/air flame at pressure s from 5 bar to 36 bar. Excitation was at 280 nm with 14 mJ/pulse and dete ction was centered around 309 nm. Allen et al.18 report OH PLIF in high-pressure spray-flames burning heptane, ethanol, and methanol at pre ssures from 0.1 to 1.0 MPa. Excitation was at 283 nm with 3 mJ/pulse and detection was in the range of 316 nm to 371 nm. The authors provide an indepth study of the high-pressure effects on PL IF, both through theore tical analysis and through experimental validation. Stocker et al.19 report OH LIF in atmospheric pressure flames for both a methane/air Bunsen bur ner and a hydrogen/oxygen welding torch with excitation provided by an tunable OPO (type II) laser system. This in-depth study thoroughly investigated four OH excitation wavelength ranges, all within the range of 321.0 nm to 241.1 nm, with detection between 305 nm and 330 nm and 5 mJ/pulse. This study shows excitation of OH in the 280 nm to 285 nm to be reasonable. Singla et al.20 report OH PLIF of cryogenic Lox/GH2 jet flames at 6.3 MPa. Excitation is at 284 nm with 42 mJ/pulse and detection is in the ra nge of 306-320 nm. Much effort is presented

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8 in imaging of the injector post lip flame hol ding region and the unstead iness that the flow exhibits there. While this sample of reported literatur e in no way represents the entirety of research on laser-based diagnostics, or even OH LIF for that matter, it does fairly represent the spectru m of the research foci. This show s that while there is a fair amount of research focused on high-pressure combusti on OH LIF, a small percentage seems to be focused on typical rocket engine injectors, such as shear coaxial jet and swirl injectors. Furthermore, while considerable effort is being put towards the development of the LIF technique, there seems to be very little effo rt put toward understand ing other aspects of rocket combustion, such as characterization of injector face temperatures and combustion chamber wall heat fluxes. As mentioned earlie r, only recently has wall heat flux data for a GH2/GO2 combustor been presented. This benchmark study, by Marshall et al.,3 investigates the nature of heat flux inside a single element combustor, similar to that of the UF HPCF. Unfortunately, this study is th e first of its kind and still leaves many questions about the dynami cs of high-pressure GH2/GO2 combustion. The UF HPCF aims to support this effort by providing a reliable, repeatable and safe combustion environment to investigate all aspects of high-pressure combustion, including the development and application of laser-base d diagnostic and no n-optical diagnostic techniques to support th e CFD modeling efforts.

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9 Table 1-1. Coaxial-shear inject or features comparison. Incl udes UF injectors, Penn State injectors, Space Shuttle Main Engine injectors, and Gas-Gas Injector Technology Injectors. UF1UF 2PSUSSMEGGIT 1GGIT 2GGIT 3GGIT 4 ID of GO2 Post, in.(mm)0.0472 (1.2)0.0591 (1.5) 0.3051 (7.75) 0.0876 (2.226) 0.173 (4.394) 0.173 (4.394) 0.173 (4.394) 0.173 (4.394) ID of GH2 Annulus, in. (mm)0.0866 (2.2)0.0984 (2.5) 0.3752 (9.53) 0.148 (3.76) 0.203 (5.156) 0.203 (5.156) 0.203 (5.156) 0.203 (5.156) OD of GH2 Annulus, in. (mm) 0.1058 (2.687) 0.1058 (2.687) 0.5 (12.7) 0.1980 (5.03) 0.227 (5.766) 0.231 (5.867) 0.235 (5.969) 0.249 (6.325) GO2/GH2 Injection Area Ratio0.62.320.85-2.92.462.141.44 GO2/GH2 Velocity Ratio0.1 0.70.1 0.50.29-0.1260.1480.170.257 GO2/GH2 Mass Flow Ratio0.96 5.973.68 18.24.0-5.95.95.95.9 8.25 1.332.15 0.441.98-1.351.351.351.35 O2 Velocity (m/s) dependent on nozzle dependent on nozzle51-78.678.678.678.6 Chamber Pressure (atm) 0 600 6012.9-75757575

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10 CHAPTER 2 METHODS This chapter discusses the H2/O2 injection/combustion pro cess, including reaction chemistry, propellant flow rate calculations and combustion test operation methodology. This will give a complete understanding be hind the control of the HPCF operating conditions. Furthermore, the data proce ssing methodology is presented within this chapter, including the use of Matlab in this research for calibration, data processing, and data organization. The H2/O2 Injection/Combustion Process Fundamental understanding of the prope llant reaction chemistry and flow parameters is necessary for the control of the HPCF and understanding the data. The HPCF uses gaseous hydrogen and gaseous oxygen for propellants and a coaxial shear injector. The coaxial shear injector injects the hydrogen annularly around a center-stream of oxygen. The two propellants are injected fr om equal pressure lines into a chamber having some operational pressure nominally e qual to the propellant line pressures. Because the pressure difference between the two streams is small, the mixing process between the hydrogen and oxygen is due to the sh ear occurring at the interface of the two unequal velocity propellants. This shear cause s the propellants to mix together in the shear layer, where the combustion process occurs. Although the in jection equivalence ratio of the propellants may be non-stoichiome tric, the reaction at the shear layer occurs at stoichiometric conditions. Using the prope llant chemistry and flow parameters allows

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11 control of the HPCF operational conditions from one test to the next and processing of the data. H2-O2 Reaction Chemistry The reaction between hydrogen and oxygen can be written for a single reaction mechanism, as shown in Equation 2-1. 22222aHbOcHOdHeO (2-1) The coefficients in Equation 2-1 are determin ed from the reacting mixture composition. A rich reaction ( >1.0) will result in excess hydrogen (e = 0), while a lean reaction ( <1.0) will result in excess oxygen (d = 0). In a perfectly stoi chiometric reaction ( =1.0), all of the hydrogen and oxygen reacts to gether, leaving only water as the final product (d = 0, e = 0). The chemical equa tion for the stoichiome tric reaction of H2/O2 is given in Equation 2-2. 22210.5 HOHO (2-2) STANJAN,21 a reaction chemistry program, was used in this research for determining the properties of the exhaust gas assuming co mplete combustion based on the injection equivalence ratio. This information is th en used in the injection flow property calculations presented in the next section to get an approximate value for desired propellant flow rates. Another important aspect of the propellant reaction is the inter-combustion species that appear mid-reaction. The complete H2-O2 reaction process is much more complicated than Equations 2-1 and 2-2. In be tween the initial and final states reside intermediate chain-reacting and chain-terminating reactions involving inter-combustion species. A complete review of the H2-O2 reaction is beyond the scope of this discussion,

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12 however a more complete review is presented in Turns.22 One such inter-combustion species for the H2-O2 reaction is hydroxyl (OH). OH predominantly appears in the reaction zone, meaning it is an excellent indi cator of the shear reacting layer, or flame region. The presence of OH in the shear r eacting layer enables the use of laser based diagnostic technique OH-Planar Laser I nduced Fluorescence (OH-PLIF), a heavily researched tool in investigating combusting H2/O2 flows. Propellant Flow Properties and Calculations The propellants are injected into the ch amber at a certain injection equivalence ratio. The injection equivalence ratio is a m easure of the ratio betw een the mass flow rate of the hydrogen to the mass flow rate of the oxygen for the actual experimental conditions compared to the stoichiometric conditions, as shown in Equations 2-3 and 2-4. 2 212/ 2 0.125 0.531.999/16H O stoichiometricm molgmol g mmolgmolg (2-3) 22 22 22 22HH HH OO OO actualstoichiometric actualstoichiometricmm mm mm mm (2-4) This gives a numerical basis fo r how rich or lean the propella nt injection is. Therefore, the equivalence ratio is an important pa rameter in the HPCF operating conditions, specifically in the determination of the propellant mass flow rates. Because the operation of the chamber relies on the exhaust gases choking at the exhaust nozzle at a certain pressure, it is convenient to specify an operational chamber pressure and equivalence rati o for the propellants and work backwards to the propellant flow rates. An equation can be derived that is dependent only on the exhaust gas properties, exhaust nozzle geometry, and operatio nal chamber pressure as follows. First,

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13 a simple form for mass flow rate and gas ve locity is given in E quation 2-5 and Equation 2-6, respectively. muA (2-5) uMRT (2-6) In addition, the ideal gas law and several isen tropic flow equations, given in Equations 2-7 through 2-9, are used. pRT (2-7) 2 01 1 2 TTM (2-8) 1 2 01 1 2 ppM (2-9) Substituting Equations 28 and 2-9 into Equation 2-7 gives Equation 2-10. 1 1 2 0 01 1 2 p M RT (2-10) Substituting Equation 2-8 into Equation 2-6 gives Equation 2-11. 1 2 2 01 1 2 uMRTM (2-11) Finally, substituting Equations 2-10 and 2-11 into Equation 2-5 and simplifying gives Equation 2-12. 0 1 021 21 1 2 p M mA RT M (2-12)

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14 Equation 2-12 allows the mass flow rate of the exhaust gases to be calculated from the exhaust gas properties, operational chamber pressure, exhaust nozzle geometry, and the fact that the flow will choke (M=1.0) at th e exhaust nozzle. For example, plugging the equivalence ratio into STANJAN21 for a constant pressure reaction gives the flame temperature, specific heat ratio, and gas consta nt for the exhaust gase s. In addition, the area of the exhaust nozzle opening is known. It is also desired that the flow chokes at the exhaust nozzle exit, or the Mach number e quals 1.0. The desired operational chamber pressure is known. Plugging the above inform ation into Equation 2-12 will result in the flow rate of the exhaust gases. From the exhaust gas flow rate, using th e set equivalence ratio and Equation 2-4 gives the individual flow rates of the fuel and oxidizer. These HPCF is then setup for the calculated propellant flow rates through the use of the Labview GUI discussed in the next chapter and Equation 2-13. 11 11 0.471v gqACp GT (2-13) Equation 2-13 relates the flow rate through the metering valves in the propellant lines for a choked flow (downstream pressure is less than half of upstream pressure) to the following: Cv, the flow coefficient of the valve p1, the upstream pressure T1 = 300K (540 R), the gas temperature 2 20.06988 (GH) 1.10915 (GO) 1.00000 (Air)gG the specific gravity of the gas A1 = 22.67 (for units of scfm for q, psia for p1, and R for T1)

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15 The Cv of the metering valve is directly rela ted to the number of turns on the valve handle. The Cv calibration curves and equations for a ll of the metering valves are located in Appendix C. The upstream pressure is obtained from a pressure transducer. Furthermore, the propellant injection veloci ties can be calculated iteratively solving for the Mach number, M, through Equation 2-14 and plugging the result into Equation 2-11. 2121 21 11 1 2 00 001 0 2 TT RR mMMm pApA (2-14) All of the parameters in Equation 2-14 are gas specific, meaning th e individual propellant mass flow rate, gas constant, stagnation temp erature, stagnation pressure, specific heat ratio, and injection area are used to obta in the Mach number at injection for each propellant. Heat Flux Calculations One of the desired data sets obtained from this research is the combustion chamber wall heat flux. The calculation of heat flux values from the sensors is described here, while the design, construction, and placement of the heat flux sensors is discussed in Chapter 3. Each heat flux sensor measures the temperature inside the chamber wall at two locations essentially in line with each other and perpe ndicular outwards from the inner chamber surface, as depicted in Figure 33. The two temperatures are measured at a distance of 0.25 in. from each other. Using the instantaneous temperature difference T, the distance between the measurement locations x, and the thermal conductivity k, the steady state heat flux per unit area, qA, can be calculated acco rding to Equation 2-15.23 Ak qT x (2-15)

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16 The thermal conductivity for Copper 110 is approximately 388 W/m-K, with a decrease of about 5% at 600 K. Initially, heat fl ux calculations were performed using Equation 2-15. However discrepancies were observed be tween the results obtained in this research and those presented by Marshall et al.3 Upon observation, this discrepancy appeared to stem from the absence of a heat absorpti on correction in Equation 2-15. Essentially, while the temperature difference could be the same between two tests, the actual temperatures could be higher. Since the temp eratures are higher, a higher heat flux was experienced and the chamber absorbed more heat in one case than the other. Equation 2-15 does not account for this heat absorption. Solving the differential form of the heat flux equation while accounting for the transient heat flux (heat absorption) yields Equation 2-16 when the T/ t of both thermocouples is equal (same slope). ,2,1 ,2,22oo AioTT kcx qTT xt (2-16) The density, and heat capacity, c, for Copper 110 are 8700 kg/m3 and 385 J/(kg K), respectively. The temperature subscript i represents the thermo couple closest to the inner chamber wall, o repres ents the thermocouple farthest from the inner chamber wall, represents an initial time, and represents a final time. All combustion tests were reanalyzed using Equation 2-16 fo r the heat flux calculations to compare differences. Results using both heat flux calcu lations are presented in Chapter 4. Note that both heat flux calcula tions are one dimensional. Once a heat flux value is known, the in side chamber wall temperature can be inferred by rearranging Equation 2-15 into Equation 2-17. A walliqx TT k (2-17)

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17 In Equation 2.15, qA is the heat flux per unit area obtained from the experiment, x is the distance between the deeper thermocouple de tection point and the inner chamber wall, and Ti is the temperature measured by the deeper thermocouple. Data Processing Methodologies Each combustion test can provide data from five thermocouples, 14 heat flux sensors, and three pressure transducers at 40 Hz, in conjunction with large amounts of images and high-frequency pressure transduc er (HFPT) data at 50 kHz. This large amount of data from each combustion test n ecessitates a sophisticated data processing methodology for clarity and efficiency. The data processing package built-up for the HPCF is extensive, employing Matlab to perform the majority of the processing. The Role of Matlab Each combustion test can provide two text files produced by the Labview GUIs and a batch of images from the intensified CCD ca mera. Because of the extensive amount of data, several Matlab programs were written to help quicken and ease the data processing. Standardized filenames The HPCF has the ability to operate in many different configurations. These options include two oxidizer choices, three different injector positions, and 26 different chamber arrangements. The filename for the sa ved data sets is standardized to allow easy recognition of the operating configuration for the user and Matlab program. The standardized filename code is presented in Figure 2-1. Data processing programs Several Matlab data processing programs were developed for the HPCF. The main Matlab program for the HPCF is titled H PCF_Data_Processor and performs processing on both the main data file from the Labview GUI HPCF Control In terface and the high-

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18 frequency pressure transdu cer data from the Labview GU I HPCF-HFPT Interface. This program reads in the main data file, reads in the HFPT data file, sorts the data sets, calculates the heat fluxes from the ther mocouple readings, plots many operational parameters versus time, performs frequency anal ysis on the data, and logs the test into the Combustion Test Master Log file. The te sts are logged in the master log file by filename and include other test information such as operational chamber pressure, equivalence ratio, propellant flow rates, a nd confirmation of availability of HFPT and image data for the test. This makes fi nding old tests based on desired operation parameters easy. In addition, there were seve ral other Matlab pr ograms developed to aid in various aspects of the HPCF. First, there is program titled HFPT_Compare that directly compares the high-frequency pressure transdu cer data from several different tests via plots of the data versus time and frequency analysis. A program titled HPCF_Image_Processor reads the images fr om the combustion test and allows further analysis from the user, such as average flame profile calculation. A program titled HPCF_AvgFlameSpeed reads the image pairs from the combustion test and calculates the average flame speed through a correlation an alysis of the high speed image pairs. The codes for all of these Matlab programs are presented in Appendix A. Several other programs were developed as well, but are no t presented here. They include programs used to determine laser intensity profile and various imaging calibration techniques.

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19 Figure 2-1. Standardized filename code for all saved main combustion test data files. High-frequency pressure tran sducer test data files use the same code except for the addition of hfpt before the test number (i.e. 010106OUF1IP3CA3SAhfptT01). 010106 O UF1 IP3 CA3SA T01 Date of Test (MM/DD/YY) Oxidizer: O = Oxygen A = Ai r Injector: See Fig. 3-5 Injector Position: See Fig. 3-6 Chamber Arrangement: See Fig. 3-8 Test Number (T##)

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20 CHAPTER 3 HIGH-PRESSURE COMBUSTION FACILITY This chapter discusses in detail the desi gn and construction of the University of Florida High-Pressure Combustion Facility (U F HPCF). This discussion incorporates every aspect of the facility, generally broken down into the co mbustor system, the propellant feed system, and the control/data acquisition (DAQ) system. Some of these general systems are further divided into com ponents for design/disc ussion purposes. The combustor system consists of the combusti on chamber, injector, and other combustor system components. The control/DAQ system consists of the electronics, control/DAQ hardware, and the Labview GUI. Furthermore, discussion of how all of these systems work and function together to fo rm the UF HPCF is presented. Combustor System As previously mentioned, the combustor system is broken down into the combustion chamber, injector, and other combustor system components for design/discussion purposes. Each of thes e components presented their own design challenges worthy of discussion. The combustor system employs each of these components together for proper functionality. Combustion Chamber For the HPCF, the main design goal of the combustion chamber was to house extremely high temperature combustion at high pr essure with optical access to the inside of the chamber. This goal played directly into choosing both the chamber material and chamber geometry.

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21 Chamber material The chamber material chosen had to provide ample strength and thermal characteristics. The extremely high flame te mperatures seemed to suggest going with a refractory metal as the chamber material, su ch as tungsten. However, many of the refractory metals oxidize quickly in the pr esence of oxygen, making them unusable. The high pressure operation (6.25 MPa) suggested going with a high stre ngth material, such as steel. However, the melting temperature and thermal conductivity of steel is low. Therefore, a steel chamber might develop lo cal hot spots, resulting in failure of the chamber due to steels inability to dissipate heat quickly. Copper manages to balance strength, melting temperature, and thermal c onductivity. Copper has a yield strength and melting temperature comparable to steel. However, copper has a very high thermal conductivity, allowing the material to pump heat away from hot spots and distribute it throughout its bulk quickly. This capability of copper lends itself to short durations at extremely high temperature and even longe r durations if a cooling system is implemented. Copper 110 was chosen as the chamber material for these reasons. Chamber geometry The chamber geometry was chosen to elim inate stress concentration areas and hot spots while allowing maximum optical access capa bilities. Initially a cylindrical chamber was designed due to ease of manufacturing. However, a round chamber made having optical access without recesses in the cham ber flow path impossible. Because the windows needed flat faces to keep distorti on of the optics to a minimum, creating a window to match the inside cyli ndrical surface was not an opti on. Therefore, for ease of implementing optical access, a square internal chamber cross-section was chosen. It is known that sharp corners, or extremely small radi i, result in high stress concentration. To

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22 optimize the design of the chamber, ProEngi neer/ProMechanica was used to perform stress and strain modeling on several differe nt chamber design possibilities. A stress model for the final chamber geometry is shown in Figure 3-1. A transient thermal analysis was performed on the chamber as well the results of are shown in Figure 3-2. The analysis indicated that the maximum chamber wall temp erature after a 10 second run would be 450 K, well below the melting point of copper. Experiments with test runs of 8 seconds have shown wall temperatures of approximately 550 600 K. The difference exists due to the discrepanc y between the higher flow rate s of the combustion tests and the lower flow rates used to calculate the he at load in the transient analysis during the design phase. As expected, the higher flow rates results in a higher heat release and higher heat load, and thus a higher wall te mperature. Optimization between reducing stress due to pressure and maximizing op tical access resulted in replacing the sharp corners of the square with 3.18 mm (0.125 in.) radius, as shown in Figure 3-3. This design drastically reduced the stress in the ch amber while rendering a large percentage of the chamber cross section visible. The com bustion chamber geometry was finalized with a 25.4 by 25.4 mm (1 by 1 in.) square with 3.175 mm (0.125 in.) radius corners cut through the center of a 63.5 by 63.5 by 101.6 mm (2.5 by 2.5 by 4 in.) piece of Copper 110. Optical access Designing optical access into the high-pre ssure combustion chamber proved to be challenging. The first consideration fo r the optical access was window material. Because of the high flame temperatures a nd desired laser diag nostic capabilities, a material had to be chosen with a high me lting temperature, low coefficient of thermal expansion, and the ability to transmit a larg e percentage of the light spectrum, including

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23 ultraviolet. UV-grade fused silica was chosen as the window material, with a softening temperature above 1600C and the ability to transmit the light spectrum from 225nm through 1000+ nm.24 The next consideration for the optical access was shape/size of the window. The windows needed to be sufficiently thick to ta ke the high pressure combustion regimes, as well as sit flush to the inner wall of the chamber. Because the maximum dimension inside of the chamber is 25.4 mm (1 in.), the window did not need to exceed 25.4 mm (1 in.) in width. After reviewing several fuse d silica suppliers and considering the chamber, a round 25.4 mm (1 in.) outer diameter (OD) UV-grade fused silica window was chosen, supplied by Esco Products. Although the round window causes a decrease in the viewing area as compared to a square window, the co mbination of small length scale interest for the combustion and the ease a nd availability of the round window made it a good choice. Stress calculations confirmed that a 25.4 mm (1 in.) thick, 25.4 mm (1 in.) OD fused silica window was sufficient to take the pressure loading. The final consideration for the optical access was how to mount the windows securely in the chamber wall. The biggest problem with mounti ng the windows in the copper chamber resided in the huge difference in coefficients of thermal expansion for the two materials. For example, the ratio of the coefficient of thermal expansion of the copper to that of the fused silica is 42.5.24 As a result, copper will tend to expand much more than the fused silica window. This can cause sealing problems by opening up larger gaps between the windows and chamber durin g combustion. Another problem occurs upon cooling of the chamber. Because of the gap growth between the copper and the fused silica during combustion, the windows have the possibility to relax slightly crooked

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24 in the chamber wall once the pressure reduces As the copper cool s and contracts, the slightly crooked window will be forced by the wall back to its correct position. This however can cause the window edges to catch in the metal and crack or break the windows. Windows breaking in the chamber poses both a safety issue and a time/cost effectiveness issue. To correct for thes e problems between the chamber and windows, a radial o-ring system was designed into th e window cavity in the chamber wall. Two radial o-ring grooves were cu t into the perimeter of the window cavity at two different depths, cross-sectionally show n in Figure 3-4. The two radial o-rings allow the window to essentially float in the cen ter of the window cavity without touching the chamber wall. Because of the tight tolerances, the o-rings have room to expand outwards with the chamber wall while holding the window firmly in the center of the cavity and keeping a tight seal. Using two radial o-rings spaced apart keeps the window upright and does not allow the window to tilt in the cavity, which could cause the gl ass to catch an edge on the metal and break upon cooling. Another problem with moun ting the windows was keeping them flush on the inner wall of the chamber. The desire to keep the inner window surface flush with the inner chamber wall was to ensure a smooth flow pa th and eliminate extraneous flame-holding spots within the chamber. A step was mach ined by Esco Products into the end of the window cavity and the end of the window. Th e steps in the chamber and window mate when the window is inserted into the chamber, as shown in Figure 3-4. The mating surface of the chamber step w ith the window step was polished to keep the window edge from catching and resulting in a broken window Another benefit of this glass-to-metal seal is that it eliminates the need for a rubber seal to be located so close to the combustion

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25 zone and high temperatures. With the window fully inserted into the chamber wall, the outer surface is flush with a sli ghtly larger recess in the cham ber wall. A rubber gasket is placed over this recess and cove rs the entire metal surface and the outer edge of the window surface in the recess. A flange is then tightened down onto the chamber wall with the use of 6 #10 bolts and nuts. This fl ange is designed to press the gasket against the window when completely tightened down. The pressure from this gasket keeps the window from trying to push out of its recess in the chamber during high pressure tests while allowing slight movements due to therma l expansion. The flange also contains a drill through hole w ith the same outer diameter as that of the recess in the inside of the chamber, also shown in Figure 3-4, resulting in a viewable diameter of 20.6 mm (0.81 in.). This optical access system provides a very large viewing area as compared to the internal dimensions of the chamber and inject or while maintaining structural integrity and a tight seal. The combustion chamber, with optical access system installed, has been pressure tested to over 6.7 MPa (1000 psi) without failure, leaking, or any noticeable adverse affects. The tests were conducte d with cold nitrogen gas first by slowly increasing and decreasing the pressure. Th en more strenuous tests were performed by hammering the chamber with the high pressu re nitrogen and exhaus ting the nitrogen as quickly as possible. The windows stayed pe rfectly in place and di d not fail or crack during these tests cold ni trogen pressure tests. Other chamber features As described, the combustion chamber is made of copper 110 and offers optical access on all four sides of the chamber. The chamber also incorporates -20 tapped holes at each of the four corners of the tw o chamber mounting faces. These tapped holes

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26 receive -20 threaded rod, allowing the injector, chamber extensions, and exhaust nozzle to be attached to the main chamber. The ch amber also incorporates ports for heat flux sensors up one side, which are discussed in the DAQ section of this chapter. Injector The injector for the HPCF is currently a single-element, coaxial, shear injector. Single-element refers to ther e being only one exit for the fuel and one exit for the oxidizer into the chamber, as opposed to a multi-element injector which essentially incorporates a matrix of single-element inject ors. Coaxial indicates that the oxidizer and the fuel flow symmetrically about the same axis. More specifica lly, the fuel injects annularly around a center stream of oxidizer. A shear injector relies solely on the shear between the fuel stream and oxidizer stream to mix them together, rather than employing swirling or impinging techniques. This shear is achieved by injecting the propellants at different relative velocities. The single-element, coaxial, shear injector for the HPCF was designed with three goals: adaptability to many different flow regimes, ease of assembly/integration into combustor system, and ease/cost of manufacturing. This resulted in three components which collectiv ely form the injector: the fuel annulus, oxidizer nozzle, and injector housing. Injector material The material selection for the injector followed the same methodology as that for the combustion chamber. For the same reasons that the chamber was made of copper, the fuel annulus and oxidizer nozzle were made of copper. Being made of copper allows the injector to have structural integrity by di ssipating heat from flame-holding regions at the tip of the injector. However, instead of copper 110 for the inject or, oxygen-free copper was used. The oxygen-free copper ensures that there is no impregnation of oxygen into

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27 the fuel stream before it reaches the chambe r. The injector housing, which the fuel annulus and oxidizer nozzle mount to and which allows mounting of the injector assembly to the injector, was made of steel for structural and ease/ cost of manufacturing purposes. Injector geometry The geometry for the injector housing a llows simple mounting of the injector assembly to the combustion chamber, integrati on of the fuel annulus and oxidizer nozzle, and inclusion of nitrogen purging and inject or face thermocouples. A cutout of the injector is shown in Figure 3-5. The oxidizer nozzle is solder ed to a stainless steel tube that extends through the back of the injector housing through a tube fitting equipped with a Teflon ferule. This oxidizer nozzle mounting method allows the tip of the nozzle to be moved relative to the surface of the injector without permanently locking a metal ferule onto the tube, effectively gi ving the ability for recesse d, flush, and protruding configurations. A spacer sleev e and a spacer baffle are used to hold the oxidizer nozzle in the center of the injector housing. The sp acer baffle also serves to uniformly distribute the fuel flow around the oxidizer nozzle. The oxidizer nozzle is shaped to inject the oxidizer straight into the chamber. The fuel annulus surrounds the oxidi zer nozzle and contains a leng th of straight passage to straighten the fuel flow before injection into the chamber. The fuel annulus screws into the face of the injector housing until its face and the f ace of the injector housing are flush. The fuel annulus tightens down onto an o-ring to ensure no fuel is ejected through the threaded portion. Currently the HPCF is e quipped for three different injector positions, the details of which are depicted in Figure 3-6. The injector assembly is attached to the

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28 chamber via the 4 -20 bolts and the position of the injector inside the chamber is determined by the use of spacer tube s, as indicated in Figure 3-7. The dimensions of the injector were dete rmined from a combination of literature review (see Table 1-1) and careful examinati on of the goals of the HPCF. In order to allow a range of flow conditions for GH2/GO2, two injectors were designed, designated UF1 and UF2. A third injector also exis ts for use in GH2/air experiments and is designated UF0. The geometrical details of the three injectors can be found in Figure 35. The fuel annulus remains the same for a ll three injectors. Th e oxidizer nozzle, on the other hand, has different diameters for each injector, which are given in Figure 3-5. Other Combustor System Components The remaining combustor system component s include the exhaust nozzle, chamber extensions, and the igniter. Exhaust nozzle The exhaust nozzle allows the flow to choke at the exit of the chamber, resulting in a rise in the chamber pressure. For the pur poses of the UF HPCF, the exhaust nozzle was not designed to optimize the exhaust flow for propulsion purposes. The exhaust nozzle was designed to choke the flow for a certain chamber pressure, for long service life, and ease of assembly/integration. For the same reasons listed for the chamber and injector, the exhaust nozzle was also made of copper. Long service life from the nozzle required all hot spots be eliminated. Because the e xhaust nozzle endures direct contact with the flame and recirculation regions of hot exhaus t gases, the nozzle was smoothly contoured down from the inlet face to a minimum diamet er hole and contoured back out to the exit face, as shown in Figure 3-7. This smooth c ontoured profile eliminates sharp corners and the resulting hot spots, which could lead to premature wear or failure. The copper nozzle

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29 disc is mounted between two mating flanges wh ich mount to the chamber. O-rings seal the nozzle within the flanges. This nozzl e flange system allows many nozzles for different flow conditions to be quickly made and replaced. A picture of the exhaust nozzle assembly installed in the co mbustor is shown in Figure 3-14. Chamber extensions Chamber extensions serve to change the length of the chamber and/or to incorporate DAQ/control or safety features in to the chamber. Currently there are four different chamber extensions, with two of the four being identical. All of the extension pieces are made of copper 110, same as the ch amber. The extensions also incorporate through-holes and an o-ring groove on the mati ng surface to allow sealed attachment to the chamber. The chamber extensions have the same cross section as the chamber, but differ in length. The two identical exte nsions are 18.61 mm (0. 7325 in.) long and each incorporates a single heat flux sensor. The longer extension of lengt h 38.1 mm (1.5 in.) incorporates four heat flux sensors. The fourth chamber extension differs in function from the other three in that it is always at tached to the chamber immediately upstream of the exhaust nozzle. This permanent extension has ports into the chamber on all four of its sides. One port houses the igniter, one port houses a thermocouple that can protrude into the chamber and a low frequency pressure transducer, another port houses a high frequency pressure transducer a nd allows passage to a safety valve that opens in the event of an over-pressure, and fourth port exists fo r extra DAQ hardware (currently plugged). A picture of the chamber exte nsion installed in the combus tor is shown in Figure 3-14. Igniter The igniter places a 10,000 volt spark inside the chamber, allowing the propellants to ignite. The igniter consists of two ma in components: the igniter lead and the

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30 transformer. The igniter lead was built by gl uing two pieces of copper wire inside an Omega high-temp ceramic sheath containing two bore holes. The c opper leads end about a quarter of an inch short of the combustor end of the ceramic and protrude out of the back of the ceramic tube. In sulation is wrapped on the bare copper wire out of the back of ceramic tube to the point where the wires connect to the transformer cable. Graphite powder is packed into a porti on of the remaining space in the ceramic tube holes on the combustor side. Then two small copper wire leads are stuck into the holes against the graphite powder, placing about ha lf of the lead in the ceramic tube and half of the lead in the chamber as an electrode. The igniter is stuck into the chamber wall such that the ceramic tube ends short of the inside cham ber surface and the small copper electrode tips protrude into the chamber. Each combustion test will melt the ends of the electrodes together, requiring them to be replaced between each test. The graphite powder gives an electrically conductive buffer be tween the copper lead wires a nd the copper electrode tips without allowing them to weld together duri ng sparking. The igni ter is sealed via a Swagelok bore-through tube fitt ing using a Teflon ferule. The Teflon ferule allows a tight seal to be placed on the ceramic tube without cracking it. The igniter copper wire leads are connected to a 10,000 volt transformer. Power and control for the igniter comes via the DAQ/control system. Propellant Feed System The propellant feed system supplies the propellants and a nitrogen purge to the combustor system. More specifically, the HPCF propellant feed system can provide either gaseous oxygen (GO2) or air as the oxidizer and gaseous hydrogen (GH2) as the fuel. The entire system is a pressure fe d system, meaning there are no pumps. The propellants and the nitrogen are all supp lied via high-pressure gas bottles through an

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31 intricate network of tubing, valves, and regul ators. A schematic of the propellant feed system is shown in Figure 3-10. The prope llant feed system offers a reliable and controllable supply of propellants and nitr ogen purge to the combustor system. As mentioned, this pressure fed system relies on high-pressure gas bottles. For the air supply, an array of 6 bottles at 17.9 MPa (2600 psi) are connected in parallel and is located inside the combustion lab. The GO2 supply is provided by an array of 10 bottles at 17.9 MPa (2600 psi), all conne cted in parallel. The GO2 bottles are located outside under a covered shed for safety. The GH2 supply is provided by a single hydrogen bottle at 17.9 MPa (2600 psi), which is located inside the combustion lab. An array of 6 hydrogen bottles at 15.2 MPa ( 2200 psi) located outside the building is available for future integration if the need for longer tests arises. For the purpose of this study, however, the fuel mass flow rates are lo w enough to warrant one bottle of hydrogen, which can deliver upwards of 20-30 tests. The nitrogen purge s upply is provided by 1 bottle of nitrogen at 17.9 MPa (2600 psi) lo cated inside the com bustion lab. This nitrogen bottle is connected to both the oxi dizer and fuel lines, as well as the chamber purge line into the back of the injector housing, allowing co mplete nitrogen purge of the propellant supply lines, injector, and chamber. This setup also offers the capability to purge nitrogen throughout the experiment or pre-pressurization of the chamber immediately before the combustion test. The entirety of the oxidizer lines is 9.53 mm (0.375 in.) OD stai nless steel tubing. Beyond the valves located on each of the oxi dizer bottles, numerous ball valves are placed in the oxidizer lines to provide shut off capabilities at several key locations, switching capability be tween the oxidizer GO2 and air feeds, and nitrogen purge

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32 capability. The GO2 line incorporates a ball valve at the lab entry point for safety. There is also a ball valve inline close to the tanks outside, allowing excess oxygen to be bled off safely and allow a place for purging nitrogen to exit the line. Two ball valves directly upstream of the oxidizer pressure regulator al low the oxidizer to be switched to either GO2 or air, depending on which ball valve is open. The nitrogen purge for the oxidizer line is supplied by opening another ball valve at the back of the air line, allowing full purge of both the air and GO2 lines, as well as the oxidize r supply line that connects to the injector. Every component in the oxidize r supply line is rated for more than 20.7 MPa (3000 psi), incorporati ng a good safety margin. The fuel line is 6.35 mm (0.25 in.) OD stai nless steel tubing. Th ere is only one ball valve located in the fuel line. This ball valv e is located near the bot tle on a line that tees into the main fuel line, providing a nitrogen purge to the fuel line when the fuel bottle is shut off and the ball valve is open. This nitrogen purges the entire line from the bottle all the way through the injector. As with the oxidizer line, every component in the fuel supply line is rate for more than 20.7 MPa (3000 psi). The nitrogen purge line is 6.35 mm (0. 25 in.) OD stainless steel tubing. The nitrogen bottle connects to the oxidizer and fuel lines. Ball valves at both connections allow control of the nitrogen purge into the propellant supply lines. Also, check valves are in place before each ball valve to keep oxi dizer or fuel from flowing back into the main nitrogen line for safety reasons. The propellant supply system previously described delivers both the fuel and oxidizer to the injector and chamber. Howeve r, the propellants must be controlled to certain pressures and mass flow rates. Also, the control system needs the ability to vary

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33 the pressures and flow rates of the propellants to provide a range of combustion tests. The propellant control system for the high pressure combustion f acility provides the capability to control the pressure and flow rates of the propellants through the use of pressure regulators, solenoid valves, check va lves, and regulating (need le) valves. It is most convenient to discuss th ese regulators and valves in order of appearance in the supply lines from closest to the gas battles to closest to the chamber. A pressure regulator appears first in lin e for both the oxidizer and fuel The pressure regulator provides a constant propellant supply (downstream) pressure for a varying gas bottle (upstream) pressure. The oxidizer pressure regulator is a Tescom 26-1100 series, having a maximum outlet pressure of 20.7 MPa (3000 psi) and a maximum inlet pressure of 34.5 MPa (5000 psi), as well as being rated for oxygen service and a Cv of 1.5. This regulator is dome loaded with a 1:1 ratio, meaning that the outlet pressure of the regulator is the pressure applied to the dome. The dome is controlled via nitrogen and a Tescom 26-1000 series pressure regulator, with a maximum inlet and outlet pressu re of 20.7 MPa (3000 psi). The fuel pressure regul ator is a Tescom 44-1100 series pressure regulator, with a maximum inlet and outlet pressure of 20.7 MPa (3000 psi) and a Cv of 0.8, and is rated for use with hydrogen. Next in line are the needle valves. The needle valves allow precise control of the flow rates of propella nts by turning the fine metering handles a certain number of turns and relating that number to the Cv via a calibration. Three different needle valve series are used for both the oxidizer and the fuel, depending on the desired flow rate, and are designated as Sw agelok S-Series Metering Valve, Swagok 31Series Metering Valve, Swagelok 1-Series Integral-Bonnet Needle Valve. The calibrations for these needle valves are gi ven in Appendix C. The number of turns on

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34 each valve is input to the Labview GUI, whic h is discussed later. The solenoid valves appear next in both the oxidizer and fuel lines. They allow the flow of propellants to be turned on and off remotely, precisely, and qui ckly. Both the oxidizer and fuel solenoid valves are Marotta MV100 series solenoid valves, with maximu m inlet and outlet pressure of 20.7 MPa (3000 psi) and a Cv of 0.18. These Marotta valves require a 25 VDC input to activate the sole noid and open the valve. Th e power and control to the solenoid valves is supplied via the control/ DAQ system. The solenoid valves are located immediately downstream of the needle valv es to eliminate pressure hammering the needle valves, which can lead to premature fa ilure. Finally in the propellant supply lines are the check valves. Both the oxidizer and fu el lines have a check valve located close to the injector. These check valves are Swagel ok CH4 series and require only 7 Pa (1 psi) cracking pressure difference. The check valves allow the oxidizer and fuel to flow to the injector when activated while disallowi ng backflow, effectively eliminating the possibility of premixed gases traveling upstream into the propellant feed system. The nitrogen purge control is less demanding than that of the prop ellants. A Victor pressure regulator allows a nitrogen purge pressure up to 5.5 MPa (800 psi). An Omega SV128 series solenoid valve allows fast shut on/off of the nitrogen purge through the DAQ/control system. Arrays of filters are us ed in the oxidizer and fuel feed lines to ensure clean gas injection. As shown, the propellant feed system allows precise control of the pressure and flow rate of both th e oxidizer and fuel safely. In summary: Oxidizer Pressure Regulator: Tescom 261100 series. 1:1 Dome type. Maximum outlet pressure = 20.7 MPa (3000 psi). Maximum inlet pressure = 34.5 MPa (5000 psi). Cv = 1.5. Nitrogen Dome Controlling Regulator: Tescom 26-1000 series. Maximum outlet pressure = 20.7 MPa (3000 psi). Maximu m inlet pressure = 20.7 MPa (3000 psi).

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35 Fuel Pressure Regulator: Tescom 44-1100 series. Maxi mum outlet pressure = 20.7 MPa (3000 psi). Maximum inlet pre ssure = 20.7 MPa (3000 psi). Cv = 0.8. Nitrogen Purge Regulator: Victor Pressure Regulator. Maximum outlet pressure = 5.5 MPa (800 psi). Maximum inle t pressure = 5.5 MPa (800 psi). Oxidizer/Fuel Low Flow Rate Metering Va lve: Swagelok S-Series Metering Valve (calibration in Appendix C). Oxidizer/Fuel Medium Flow Rate Meteri ng Valve: Swagelok 31-Series Metering Valve (calibration in Appendix C). Oxidizer/Fuel High Flow Rate Metering Va lve: Swagelok 1-Series Integral-Bonnet Needle Valve (calibration in Appendix C). Oxidizer Solenoid Valve: Marotta MV100 Series Solenoid Valve. Maximum inlet pressure = 20.7 MPa (3000 psi). Maximu m outlet pressure = 20.7 MPa (3000 psi). Cv = 0.18. Fuel Solenoid Valve: Marotta MV100 Se ries Solenoid Valve. Maximum inlet pressure = 20.7 MPa (3000 psi). Maximu m outlet pressure = 20.7 MPa (3000 psi). Cv = 0.18. Nitrogen Purge Solenoid Valv e: Omega SV128 Series Solenoid Valve. Maximum inlet pressure = 6.9 MPa (1000 psi). Maximum outlet pressure = 6.9 MPa (1000 psi). Oxidizer Injector Check Valve: Swag elok CH4 Series Check Valve. Cracking pressure = 7 Pa (1 psi). Fuel Injector Check Valve: Swagelok CH4 Series Check Valve. Cracking pressure = 7 Pa (1 psi). Control/DAQ System The HPCF control/DAQ system manages th e power supply to all components of the HPCF, gives the user complete control of the HPCF and the combustion tests, and provides a variety of data acqui sition capabilities for the combustion tests. A schematic flowchart of the control/DAQ system is show n in Figure 3-11. The power management is provided via the electroni cs system. The control/DAQ hardware provides responsive control and data acquisition capabilities. A Labview GUI provides complete control of

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36 the HPCF to the user from a remote location. All of these sub-systems work in parallel and rely upon each other to form the HPCF control/DAQ system. Electronics system The electronics system for the HPCF provides the power management for the igniter and the propellant and nitrogen purge solenoid valves. Figure 3-12 shows the circuit diagram for the electronics system. The entire system is hous ed within a box that is supplied with 120 VAC and 24 VDC. Inside the box resides five solid-state relays: one for the oxidizer solenoid valve, one for th e fuel valve, one for the nitrogen valve, and one for each of the igniter leads. The propell ant solid-state relays supply 24 VDC to the solenoid valves with 5 VDC excitation. The nitrogen purge and igniter lead solid-state relays supply 120 VAC with 5 VDC excitation. Two relays are us ed for the igniter because of the exposed nature of the two igni ter electrodes. Using a relay for each lead ensures that one lead does not touch a ground and shor t out the system or injure someone. The 5 VDC excitation for all relays is s upplied by the control/DAQ hardware and controlled via the Labview GUI, which will be discussed shortly. Connections to the electronics system are made via BNC connectors and banana plugs. Control/DAQ Hardware The high-pressure combustion facility re quires quick and accurate on-the-fly control of the propellant/nitrogen purge flows a nd the ignition of the chamber, as well as reading and recording of valuable test da ta. The control/DAQ system for the HPCF provides all of the control a nd data recording capabilities required. The control/DAQ hardware are responsible for managing the i nput/output of control signals and feedback and all data acquisition signals. The hardware consists of the computer hardware, DAQ sensors, and the laser and imaging systems. The computer hardware includes a National

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37 Instruments PCI-MIO-16E-1/S CXI-1000 chassis, a Nationa l Instruments PCI-6259/BNC2110, and a fiberoptic/PCI board. The DAQ sensors include thermocouples, heat flux sensors, standard pressure transducers, a nd a high-frequency pressure transducer. The laser and imaging systems incorporate a lase r, tunable OPO, and an intensified CCD camera. Computer hardware As previously mentioned, the comput er hardware consists of a National Instruments PCI-MIO-16E-1/S CXI-1000 chassis, a Nationa l Instruments PCI-6259/BNC2110, and a fiberoptic/PCI board. The PCI-MIO-16E-1/SCXI-1000 chassis is used exclusively for controlling the electronics system and reading all sensors, with the exception of the high-frequency pressure tr ansducer. The SCXI-1000 chassis houses a SCXI-1100 module for 32 thermocouple channe ls, a SCXI-1140 module for 8 pressure transducer channels, and a SCXI-1124 for 6 output channels of 0-10 VDC. The PCI6259/BNC-2110 board is used for reading the hi gh-frequency pressure transducer. This transducer had to be separated from th e SCXI-1000 chassis to obtain high-frequency response while allowing the inte ractive feedback from the co mbustion tests to the SCXI1000 chassis and to the computer/user. The fiberoptic/PCI board is used for image acquisition and connects the intensified CCD camera to the same computer as the highfrequency pressure transducer. DAQ sensors The DAQ sensors are used to collect valuab le combustion test da ta, as well as to provide in-situ feedback to the computer/user for test control and sa fety purposes. The sensors include propellant line pressure tran sducers, chamber pressure transducer, a thermocouple open to the chamber environment, injector face thermocouples, a

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38 thermocouple located behind the injector housing, an exhaust nozzle thermocouple, chamber wall heat flux sensors, and a high-fr equency chamber pressure transducer. The design, features, and placement of these sensors is discussed. The propellant line and chamber pressure transducer are Omega PX303 series transducers, with 0.1-20.7 MPa (0-3000 psig) measurem ent capabilities and 1 ms response time. The propellant line pressu re transducers are attached immediately downstream of the pressure regu lators. The chamber pressure transducer is attached to the permanent combustion chamber extension and is open to the inside of the chamber. All three pressure transducers are consta ntly monitored and recorded throughout each experiment. The chamber pressure is monitore d not only for test data, but for safety as well. The combustion tests are designed to shut down completely if a set maximum chamber pressure is exceeded, as controlled by the Labview GUI. The oxidizer and fuel supply line pressures are require d to set the oxidizer and fu el mass flow rates to known values, through the use of Equations 2-12 and 2-13 and the Labview GUI. The calibrations for these pressure tran sducers can be found in Appendix C. Numerous thermocouples are employed in the HPCF that constantly take vital temperature measurements for combustion test characterization. Th e first thermocouple, and the only thermocouple to be monitored by the user during th e actual combustion tests, is capable of protru ding into the chamber and hence into the flame. This thermocouple, an Omega K-type thermocouple, effectively allows measurement of the chamber environment or flame temperatures. This thermocouple has an inconel sheath with a diameter of 1.59 mm (0.0625 in.), an ex posed tip, and a response time of 15 ms. It is attached to the chamber via the perman ent combustion chamber extension. This

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39 thermocouple sees the highest temperature of any of the thermocouples because it is open the in-situ combustion chamber environment. The depth of protrusion into the chamber is kept to a minimum, and is often rece ssed, during combustion tests, as the flame temperature is approximately 3000 K, we ll above the melting temperature of the thermocouple materials. In general, this th ermocouple is monitored for easy recognition of ignition in the chamber, as the quick response time allows near instantaneous temperature increase at the onset of co mbustion, viewable through the Labview GUI. The next two thermocouples measure the te mperature at two different locations on the injector face. These thermocouples ar e Omega K-type thermocouples. They have inconel sheaths with 1.02 mm (0.04 in.) sh eath diameters and exposed tips for fast response times of 10 ms. These two thermocoupl es are set up to read the injector face temperature at a distance of 2.11 mm (0. 083 in.) and 4.24 mm (0.167 in.) radially outward from the center axis of the injector, as shown in Figure 3-9. These thermocouples provide valuable data about the recirculation regi ons that occur on the injector face. Another thermocouple is lo cated behind the injector housing. This thermocouple has the same characteristics as th e injector face thermocouples. It is used to detect any indication of backflow or heat transfer through the gap between the injector housing and the chamber wall. Finally, the exhaust nozzle thermocouple is an Omega Ktype thermocouple with an inconel sheath of 0.51 mm (0.02 in.) diameter, an exposed tip, and a response time of 7 ms. This thermoc ouple is embedded into the back face of the exhaust nozzle to a distance of 1.59 mm (0.0625 in.) to the combustion exposed face of the exhaust nozzle. The data from this th ermocouple gives insight into the effects of direct exposure to the flam e and provides a boundary condi tion for CFD modeling.

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40 The chamber wall heat flux sensors provide heat flux data for the length of the combustion chamber. Each heat flux sensor used in the HPCF were made in-house and consist of two thermocouples located side-by-si de that protrude into the chamber wall at different depths. Because the thermocouples are small in diameter relative to the chamber dimensions, the axial displacement between the two thermo couples (center to center) is only 0.04 in., which is small relative to the chamber dimensions, and the thermocouples can be approximated as axia lly linear. Therefore, the heat flux is calculated via Equation 2.14 from the temperature difference between the two thermocouples, the axial dist ance between the two thermocouple tips, and the heat transfer coefficient of the chamber material. Each thermocouple used in the heat flux sensors consists of an Omega 1.02 mm (0.040 in.) OD double-hole ceramic thermocouple insulator, an Omega K-type bare wire thermocouple, wire insulation, heat shrink tu bing, and an Omega K-t ype mini connector. The ceramic tubes were sheared to one of tw o different lengths. The thermocouple wires were fed through the two holes in the ceramic tube until the juncti on of the thermocouple was situated at the end of the ceramic tube. Wire insulation was placed over the remainder of the thermocouple wires to keep them from touching, and heat shrink tubing was used to hold the wire insulation against the back of the ceramic tube. The ends of the thermocouple wire were attached to the insu lated mini connector. By having a portion of the thermocouple flexible, i.e. the portion us ing wire insulation around the wires, the risk for accidentally breaking the ceramic portion and possibly losing electrical isolation is minimized. For each pair, the longer of the th ermocouple pair protrudes into the chamber wall to a distance of 3.18 mm (0.125 in.) fr om the inner chamber wall, while the shorter

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41 of the thermocouple pair prot rudes to a distance of 9.53 mm (0.375 in.) from the inner chamber wall, giving a depth difference of 6. 35 mm (0.25 in.). This is the value of x used in Equation 2-15 for calculating the heat flux. As explained, the two thermocouples are located side-by-side, so that the cent er axis of each thermocouple are only 1.02 mm (0.040 in.) apart, as viewed perpendicula r to the wall or down the lengths of the thermocouples. The placement of the heat fl ux sensor thermocouples is shown in Figure 3-3. These custom made thermocouples ha ve a response time of approximately 5 ms. The heat flux sensors are all located al ong one face of the co mbustion chamber and extensions. On the combusti on chamber there are 8 heat flux sensors. The two shorter chamber extensions each have a single heat flux sensor and the longer chamber extension has 4 heat flux sensors. In total, this can gi ve as few as 8 heat flux sensors and as many as 14 heat flux sensors, depending on the chamber arrangement. Table 3-1 lists the distance from the injector face to each h eat flux sensor depending on both the injector position and the chamber arrangements, which are depicted in Figur e 3-6 and Figure 3-8 respectively. In the cases where all three chamber extensions are used in conjunction with the combustion chamber, limitations in the DAQ channels require that the lowest heat flux sensor (beside or behind the injector) go unused, as explained in the operational procedure in Appendix B. The high-frequency chamber pressure tran sducer is used to monitor dominant frequencies inherent to the combustion process, as well as the combustor system. The goal of using this sensor is to determine what effect the chamber length, mass flow rates, and chamber pressure have on the frequencies of the combustion process. The sensor is an Entran EPX series static transducer with a full scale range of 6.9 MPa (1000 psi), a

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42 maximum pressure of 13.8 MPa (2000 psi), and accurate frequency response up to 50 kHz. The sensor ouput ranges from 0-100 mV for 0.1-6.9 MPa (0-1000psig) excitation. The sensor is attached to the permanent combustion chamber extension. A problem arose due to the high-frequenc y pressure transducers output of only 100 mV at 6.9 MPa (1000 psi). Reading the mV signal into the com puter resulted in extremely high noise content of 0.7 MPa (100 psi) after conversion. With the cabling from the transducer to the DAQ board shielded the mV order noise seemed to be at the DAQ system and hence unavoidable. Therefore, an inline operational amplifier had to be built to increase the output to the order of 10 V at 6.9 MPa (1000 psi) due to the high noise content in the mV range. The amplif ier chip is a Texas Instruments TLV2373 railto-rail op-amp with 3MHz response. The circ uit was built inside a small electronics box with BNC input/outputs. The circuit diagra m for the op-amp is shown in Figure 3-13. The amplifier was calibrated using known output voltages to create a calibration curve for output voltage vs. amplification factor which can be found in Appendix C. The amplifier reduced the noise to less than 30 Pa (5 psi). Laser and imaging systems The laser and imaging systems in the HPCF include a laser, a tunable OPO, and an intensified CCD Camera. The laser is a C ontinuum Surelite Nd:YAG Laser, with a 355 nm output and a maximum power of 170 mJ. The beam from the laser is directed into a Continuum Panther OPO, capable of tunable ou put in the UV and visible spectrums. The doubler allows tuning of the beam wavelength to 283 nm for OH excitation. The camera is a Cooke DiCam-Pro insten sified CCD camera, capable of taking 1280x1024 images at 10 fps and 1280x480 images at 20 fps with exposure times down to 5 ns. The camera is triggered from the laser and can be delayed if required.

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43 Labview GUI The Labview graphical user in terface (GUI) allows the user to remotely control the HPCF. This is accomplished via direct cont rol/monitoring of the electronics system and the control/DAQ hardware through simple to use interfaces on remote computers. One Labview GUI, titled HPCF Control Interface, is dedicated to control/monitoring of the entire HPCF, with the exception of the high-fr equency pressure transducer, which has its own Labview GUI, and the laser and imaging sy stems, which are controlled via their own software packages. On a separate computer, another Labview GUI is used to take data from the high-frequency pressure transdu cer and is titled H PCF-HFPT Interface. The HPCF Control Interface is the main Labview GUI for the facility. Through this GUI the user can control the propella nt/nitrogen purge valves, ignition, various combustion test timings, data acquisition ch annel selection, and the on/off of the combustion tests, as well as monitor in-situ chamber pressure and temperature and the combustion test progress through various indi cators and graphs. Figure 3-15 shows the HPCF Control Interface as the user sees it when the Labview GUI is operational. Each component of the GUI is labeled with a number and is explained in Table 3-2. Some key features of the HPCF Control Interface include: Front panel control of all valves and spark. Front panel monitoring of chamber temperat ure and pressure, propellant flow rates, and combustion test progress. Front panel control of com bustion test time features. One button combustion test activation. One button emergency shutdown.

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44 The HPCF-HFPT Interface gives the user co ntrol of the data acquisition from the high-frequency pressure transducer. This simple interface simply gives the user the ability to start the experiment and set the save file path. Once run, the data is presented in the graph on the interface. This interface is shown in Figure 3-16, with the components numbered and explained in Table 3-2. HPCF Assembly and Operation The assembly and operational procedures for the UF HPCF are located in Appendix B. The assembly procedure includes complete assembly of the combustor system and subcomponents, maintenance of components between testing, and disassembly/troubleshooting. The operational pr ocedure completely details from start to finish how to safely and effectively operate the UF HPCF.

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45 Figure 3-1. ProEngineer/ProMechanica st ress models for the combustion chamber loaded at 10 MPa internal pressure. A) is the normal stress (MPa). B) is the shear stress (MPa). A B

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46 300 325 350 375 400 425 450 0246810 Time (s)Maximum Temperature (K) (K) Figure 3-2. ProEngineer/ProMechanica tran sient thermal analysis on the combustion chamber with heat flux conditions ba sed on a stoichiometric flame. Maximum temperature (y-axis) represents the hottest point anywhere in the chamber. Figure 3-3. Cross sectional drawing of the combustion cham ber and chamber extensions. All dimensions are in inches. The ther mocouple holes at the top of the figure are for the pair of thermocouples th at form each heat flux sensor (HFS).

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47 Figure 3-4. Cross-sectional CAD image of the window mounting. The two o-ring grooves completely circumnavigate th e window. The viewable diameter through the window is 0.81. Figure 3-5. Cross-sectional CAD image of the injector assembly. Indicates various components as well as the dimensions of the 3 UF HPCF injectors: UF0 (GH2/Air), UF1 (GH2/GO2), UF2 (GH2/GO2). UV Fused Silica Window Or Copper Insert Window Flange Radial O-ring Grooves Window Gasket Injector Housing Oxidizer Nozzle Fuel Annulus Injector Support/Spacer UF0 UF1 UF2 D1, in(mm) 0.02 (0.508) 0.0472 (1.2) 0.0591 (1.5) D2, in(mm) 0.04 (1.016) 0.0866 (2.2) 0.0984 (2.5) D3, in(mm) 0.1058 (2.687) 0.1058 (2.687) 0.1058 (2.687)

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48 Figure 3-6. Cross-sectional drawing of injector indicati ng the distance from the outer face of the chamber/chamber extension to the face of the injector for the three injector positions IP1, IP2, and IP3. Figure 3-7. Cross-sectional CAD image of th e injector assembly and the exhaust nozzle assembly attached to the combustion chamber. Injector Position IPL (inches) IP1 0.125 IP2 0.8575 IP3 1.59 Injector Housing Spacer Tube Oxidizer Injector Inlet Fuel Injector Inlet Exhaust Nozzle Flanges Exhaust Nozzle

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49 Figure 3-8. Pictorial of th e different chamber arrangement s possible for the HPCF. Flow path is left to right. CC co mbustion chamber. SE short chamber extension. LE long chamber extension.

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50 Figure 3-9. Drawing of the injector face, in dicating notable dimensions of the injector assembly face and locations of the injector face thermocouples. Dimensions in inches.

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51 Figure 3-10. Schematic drawing of the HPCF Propellant/Purge Feed System. Number on bottles indicates the number of bo ttles in the array for that gas.

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52 Figure 3-11. Flowchart of the Control/DAQ system. SCXI 1000 Chassis SCXI 1100 SCXI 1140 SCXI 1124 Injector Face Thermocouple Long/Short Chamber Wall Heat Flux Sensors Exhaust Nozzle/ Behind Injector Thermocouple Oxidizer/Fuel Line Pressure Transducers Chamber Pressure Transducer 5 VDC Ouputs to Electronics System for Propellant and N2 Valves and Igniter BNC-2110 Amplifier High-Frequency Pr essu r e Tran sducer Intensified CCD C am e ra

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53 Figure 3-12. Circuit diagram for the electronics system. Solid State Relay 31 2 4 Solid State Relay 31 2 4Vin (24 VDC) Oxidizer Valve Trigger Signal (5 VDC) Fuel Valve Trigger Signal ( 5 VDC ) Oxidizer Valve Vout (24 VDC) Fuel Valve Vout (24 VDC) Vin (120 VAC) Lead 1 Solid State Relay 31 2 4 Solid State Relay 31 2 4 Solid State Relay 3 1 2 4 Vin (120 VAC) Lead 2 Igniter 1 Trigger Signal (5VDC) Igniter 2 Trigger Signal (5VDC) N2 Valve Trigger Signal (5VDC) N2 Valve Vout ( 120VAC ) Igniter Vout ( 120VAC )

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54 Table 3-1. Distances from the injector face to the heat flux sensors for all injector position/chamber arrangement combinations. All dimensions in inches. HFS1HFS2HFS3HFS4HFS5HFS6HFS7HFS8HFS9HFS10HFS11HFS12HFS13HFS14 IP1CA0SA00.40.81.22.552.953.353.75000000 IP1CA1SA00.40.81.22.552.953.353.754.2412500000 IP1CA2SA00.40.81.22.552.953.353.754.241254.973750000 IP1CA3SA00.40.81.22.552.953.353.754.241254.973755.495.896.296.69 IP1CA3SB00.40.81.22.552.953.353.754.241254.75755.15755.55755.95756.47375 IP1CA3SC00.40.81.22.552.953.353.754.0254.4254.8255.2255.741256.47375 IP1CA4SA00.40.81.22.552.953.353.754.0254.4254.8255.22500 IP1CA5SA00.40.81.22.552.953.353.754.241254.75755.15755.55755.95750 IP1CA5SB00.40.81.22.552.953.353.754.0254.4254.8255.2255.741250 IP1CA6SA0.241250.73251.13251.53251.93253.28253.68254.08254.48254.75755.15755.55755.95750 IP1CA7SA0.241250.973751.4651.8652.2652.6654.0154.4154.8155.2155.495.896.296.69 IP1CA8SA0.241250.73251.13251.53251.93253.28253.68254.08254.48254.973755.495.896.296.69 IP1CA8SB0.241250.73251.13251.53251.93253.28253.68254.08254.48254.75755.15755.55755.95756.47375 IP1CA9SA0.241250.73251.13251.53251.93253.28253.68254.08254.48254.973750000 IP1CA1RA0.241250.73251.13251.53251.93253.28253.68254.08254.482500000 IP1CA2RA0.241250.973751.4651.8652.2652.6654.0154.4154.8155.2150000 IP1CA3RA0.241250.973751.491.892.292.692.9653.3653.7654.1655.5155.9156.3156.715 IP1CA3RB0.241250.75751.15751.55751.95752.473752.9653.3653.7654.1655.5155.9156.3156.715 IP1CA3RC0.0250.4250.8251.2251.741252.473752.9653.3653.7654.1655.5155.9156.3156.715 IP1CA4RA0.0250.4250.8251.2251.51.92.32.74.054.454.855.2500 IP1CA5RA0.241250.75751.15751.55751.95752.23252.63253.03253.43254.78255.18255.58255.98250 IP1CA5RB0.0250.4250.8251.2251.741252.23252.63253.03253.43254.78255.18255.58255.98250 IP1CA6RA0.0250.4250.8251.2251.51.92.32.74.054.454.855.255.741250 IP1CA7RA0.0250.4250.8251.2251.51.92.32.74.054.454.855.255.741256.47375 IP1CA8RA0.241250.75751.15751.55751.95752.23252.63253.03253.43254.78255.18255.58255.98256.47375 IP1CA8RB0.0250.4250.8251.2251.741252.23252.63253.03253.43254.78255.18255.58255.98256.47375 IP2CA0SA-0.7325-0.33250.06750.46751.81752.21752.61753.0175000000 IP2CA1SA-0.7325-0.33250.06750.46751.81752.21752.61753.01753.5087500000 IP2CA2SA-0.7325-0.33250.06750.46751.81752.21752.61753.01753.508754.241250000 IP2CA3SA-0.7325-0.33250.06750.46751.81752.21752.61753.01753.508754.241254.75755.15755.55755.9575 IP2CA3SB-0.7325-0.33250.06750.46751.81752.21752.61753.01753.508754.0254.4254.8255.2255.74125 IP2CA3SC-0.7325-0.33250.06750.46751.81752.21752.61753.01753.29253.69254.09254.49255.008755.74125 IP2CA4SA-0.7325-0.33250.06750.46751.81752.21752.61753.01753.29253.69254.09254.492500 IP2CA5SA-0.7325-0.33250.06750.46751.81752.21752.61753.01753.508754.0254.4254.8255.2250 IP2CA5SB-0.7325-0.33250.06750.46751.81752.21752.61753.01753.29253.69254.09254.49255.008750 IP2CA6SA-0.4912500.40.81.22.552.953.353.754.0254.4254.8255.2250 IP2CA7SA-0.491250.241250.73251.13251.53251.93253.28253.68254.08254.48254.75755.15755.55755.9575 IP2CA8SA-0.4912500.40.81.22.552.953.353.754.241254.75755.15755.55755.9575 IP2CA8SB-0.4912500.40.81.22.552.953.353.754.0254.4254.8255.2255.74125 IP2CA9SA-0.4912500.40.81.22.552.953.353.754.241250000 IP2CA1RA-0.4912500.40.81.22.552.953.353.7500000 IP2CA2RA-0.491250.241250.73251.13251.53251.93253.28253.68254.08254.48250000 IP2CA3RA-0.491250.241250.75751.15751.55751.95752.23252.63253.03253.43254.78255.18255.58255.9825 IP2CA3RB-0.491250.0250.4250.8251.2251.741252.23252.63253.03253.43254.78255.18255.58255.9825 IP2CA3RC-0.7075-0.30750.09250.49251.008751.741252.23252.63253.03253.43254.78255.18255.58255.9825 IP2CA4RA-0.7075-0.30750.09250.49250.76751.16751.56751.96753.31753.71754.11754.517500 IP2CA5RA-0.491250.0250.4250.8251.2251.51.92.32.74.054.454.855.250 IP2CA5RB-0.7075-0.30750.09250.49251.008751.51.92.32.74.054.454.855.250 IP2CA6RA-0.7075-0.30750.09250.49250.76751.16751.56751.96753.31753.71754.11754.51755.008750 IP2CA7RA-0.7075-0.30750.09250.49250.76751.16751.56751.96753.31753.71754.11754.51755.008755.74125 IP2CA8RA-0.491250.0250.4250.8251.2251.51.92.32.74.054.454.855.255.74125 IP2CA8RB-0.7075-0.30750.09250.49251.008751.51.92.32.74.054.454.855.255.74125 IP3CA0SA-1.465-1.065-0.665-0.2651.0851.4851.8852.285000000 IP3CA1SA-1.465-1.065-0.665-0.2651.0851.4851.8852.2852.7762500000 IP3CA2SA-1.465-1.065-0.665-0.2651.0851.4851.8852.2852.776253.508750000 IP3CA3SA-1.465-1.065-0.665-0.2651.0851.4851.8852.2852.776253.508754.0254.4254.8255.225 IP3CA3SB-1.465-1.065-0.665-0.2651.0851.4851.8852.2852.776253.29253.69254.09254.49255.00875 IP3CA3SC-1.465-1.065-0.665-0.2651.0851.4851.8852.2852.562.963.363.764.276255.00875 IP3CA4SA-1.465-1.065-0.665-0.2651.0851.4851.8852.2852.562.963.363.7600 IP3CA5SA-1.465-1.065-0.665-0.2651.0851.4851.8852.2852.776253.29253.69254.09254.49250 IP3CA5SB-1.465-1.065-0.665-0.2651.0851.4851.8852.2852.562.963.363.764.276250 IP3CA6SA-1.22375-0.7325-0.33250.06750.46751.81752.21752.61753.01753.29253.69254.09254.49250 IP3CA7SA-1.22375-0.4912500.40.81.22.552.953.353.754.0254.4254.8255.225 IP3CA8SA-1.22375-0.7325-0.33250.06750.46751.81752.21752.61753.01753.508754.0254.4254.8255.225 IP3CA8SB-1.22375-0.7325-0.33250.06750.46751.81752.21752.61753.01753.29253.69254.09254.49255.00875 IP3CA9SA-1.22375-0.7325-0.33250.06750.46751.81752.21752.61753.01753.508750000 IP3CA1RA-1.22375-0.7325-0.33250.06750.46751.81752.21752.61753.017500000 IP3CA2RA-1.22375-0.4912500.40.81.22.552.953.353.750000 IP3CA3RA-1.22375-0.491250.0250.4250.8251.2251.51.92.32.74.054.454.855.25 IP3CA3RB-1.22375-0.7075-0.30750.09250.49251.008751.51.92.32.74.054.454.855.25 IP3CA3RC-1.44-1.04-0.64-0.240.276251.008751.51.92.32.74.054.454.855.25 IP3CA4RA-1.44-1.04-0.64-0.240.0350.4350.8351.2352.5852.9853.3853.78500 IP3CA5RA-1.22375-0.7075-0.30750.09250.49250.76751.16751.56751.96753.31753.71754.11754.51750 IP3CA5RB-1.44-1.04-0.64-0.240.276250.76751.16751.56751.96753.31753.71754.11754.51750 IP3CA6RA-1.44-1.04-0.64-0.240.0350.4350.8351.2352.5852.9853.3853.7854.276250 IP3CA7RA-1.44-1.04-0.64-0.240.0350.4350.8351.2352.5852.9853.3853.7854.276255.00875 IP3CA8RA-1.22375-0.7075-0.30750.09250.49250.76751.16751.56751.96753.31753.71754.11754.51755.00875 IP3CA8RB-1.44-1.04-0.64-0.240.276250.76751.16751.56751.96753.31753.71754.11754.51755.00875 Injector Position/ Chamber Arrangement Identifier Axial Distance from Injector Face to Heat Flux Sensor (inches)

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55 Figure 3-13. Circuit diagram for the non-inverting operational amplifier. Figure 3-14. Picture of the combustor sy stem assembled, including the combustion chamber, injector assembly, exhaus t nozzle assembly, two short chamber extensions, and instrumentation. Vin Vout Rf Rin 1f outin inR VV R Fused Silica Optical Windows Injector Exhaust Nozzle Igniter Chamber Extension Chamber Thermocouple (protrudes into chamber) Chamber Pressure Transducer (open to chamber) Chamber Wall Thermocouples (for heat flux measurements)

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56 Figure 3-15. HPCF Control Interf ace front panel (Labview GUI). Numbers referenced to Table 3-2. 1 2 3 4 5 6 7 8 9 10 11 17 12 16 18 19 14 15 13 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

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57 Figure 3-16. HPCF-HFPT Interface front pane l (Labview GUI). Nu mbers are referenced to Table 3-2. Table 3-2. Description of each component on the HPCF Control Interface and HPCFHFPT Interface front panels (Labview GUIs). Numbers are referenced to Figures 3-15 and 3-16. Componen t # Description 1 Indicates progress of combustion test. Displays messages for user. 2 Toggles oxidizer valve on/off from front pane l. Use for testing valve functionality. 3 Time in seconds from pressing #20 until th e spark begins (SPARK ON). Allows time for other computer/DAQ devices to be ac tivated. DAQ running. Set by user. 4 Time in seconds that the spark stays on SPARK ON to SPARK OFF time. DAQ running. Set by user. 5 Time in seconds from SPARK ON to th e opening of the propellant valves (PROPELLANTS ON). SPARK ON befo re PROPELLANTS ON keeps the chamber from filling with premixed gases before com bustion begins. DAQ running. Set by user. 6 Time in seconds from SPARK OFF to th e closing of the propellant valves (PROPELLANTS OFF). Essentially the FLAME ON to FLAME OFF time. DAQ running. Set by user. 7 Time in seconds from PROPELLANTS OFF/FLAME OFF that nitrogen is purging the combustion chamber. DAQ running. 8 Time in seconds from PROPELLANTS ON until nitrogen pressurization of the chamber is shut off. Can allow nitrogen pressurization/purge throughout combustion test. DAQ running. Set by user. 9 Maximum allowed chamber pressure before combustion test is prematurely shut down. If exceeded during te st, all valves and spark are shutoff immediately. Set by user. 10 Toggles fuel valve on/off from front panel. Use for testing valve functionality. 11 Toggles nitrogen valve on/off from front pa nel. Use for testing valve functionality. 12 Input for the position of the oxidizer regulating needle valve. The number of turns enters directly into the oxidizer flow rate calculation. Set by user. 13 Input for the position of the fuel regulating needle valve. The number of turns enters directly into the fuel flow rate calculation. Set by user. 14 Toggle switch for oxidizer. Sets either oxyge n or air. Affects flow rate calculations. Set by user. 44 45

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58 Table 3-2. Continued 15 Toggles nitrogen pressurization on/off. Allo ws the chamber to be pre-pressurized with nitrogen, beginning 3 seconds before SPARK ON and lasting until the number of seconds beyond PROPELLANTS ON as set by #8. Set by user. 16 Toggles nitrogen purge at PROPELLANTS/FLAME OFF on/off. Set by user. 17 Toggles spark on/off from front panel. Use for testing spark functionality. 18 Active monitor of chamber temperature (thermocouple open to chamber environment, Celsius) during front panel and combustion tests. Easy recognition of successful combustion. 19 Active monitor of chamber pressure (psig) during combustion tests only. 20 Turns combustion test on/off. Once presse d, a predefined combustion test will proceed from beginning to end unless ended premat urely by user or exceeding of maximum chamber pressure. User controlled. If us er ended and nitrogen purge is set to ON position, the chamber will purge with nitr ogen before front panel operation resumes. 21 Indicator light for oxidizer valve operation. 22 Indicator light for fu el valve operation. 23 Indicator light for spark operation. 24 Indicator light for nitrogen p ressurization of the chamber. 25 Indicator light for nitrogen purging. 26 Numerical indicator of chamber temperature (Celsius). 27 Numerical indicator of chamber pressure (psig). TARE button allows atmospheric condition to be set to 0 psig by activating an offset value. 28 Numerical indicator of oxidiz er line pressure (psig) before the needle valve. TARE button allows atmospheric condition to be set to 0 psig by activating an offset value. 29 Numerical indicator of fuel line pressure (p sig) before the needle valve. TARE button allows atmospheric co ndition to be set to 0 psig by activating an offset value. 30 Numerical indicator for oxid izer mass flow rate (g/s). 31 Numerical indicator for fuel mass flow rate (g/s). 32 Numerical indicator for oxidiz er/fuel mass flow ratio. 33 Numerical indicator for equivalence ratio. 34 File path for combustion test data save. Da ta is automatically saved to set file path at the end of each combusti on test. Set by user. 35 Calibration slope for chamber pressure tr ansducer. Set by user from periodic calibrations. 36 Calibration slope for oxidizer pressure transducer. Set by user from periodic calibrations. 37 Calibration slope for fuel pressure transducer. Set by user from periodic calibrations. 38 Selector for fuel regulating needle valve in operation. Allows high degree of control at a large range of desired flow rates. Choice affects Cv calibration curve. Set by user. 39 Selector for oxidizer regulating needle valve in operation. Allows high degree of control at a large range of desired flow rates. Choice affects Cv calibration curve. Set by user. 40 Emergency shutoff of HPCF. Can be presse d at any time to shut down all valves and spark, no matter what settings are in place. Data will lost if pressed. User controlled. 41 Allows user to identify which thermoco uple channels are being used for DAQ. Eliminates unused channels from contaminating used channels. Set by user. 42 Scan rate for temp erature, pressure, and heat flux data in Hz. Set by user. 43 Number of samples averaged for each data point. 44 Displays high-frequency pressure tran sducer data after a combustion test. 45 File path for high-frequency pressure trans ducer combustion test da ta save. Data is automatically saved to set file path at end of each combustion test. Set by user.

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59 CHAPTER 4 RESULTS The results for high-pressure GH2/GO2 combustion tests at oxygen to hydrogen mass flow ratios of 3.97 and 5.97 ( = 2.0 and 1.33) and a range of operational chamber pressures are presented here. The results include various plots showing chamber pressure, heat flux, injector face temperat ure, exhaust nozzle temperature, and wall temperature data that give insight into the dynamics of high-pressure GH2/GO2 combustion. A sample of the high-frequency pre ssure data is also presented to showcase the capabilities of the facility. In add ition, image data is presented for a single combustion test to show visual as pects of the combustion process. Table 4-1 shows the combustion test matr ix conducted in the HPCF, including the operating conditions for each test setup and the figures containing data from those tests. The operating conditions include the facility setup, chamber pressure, oxygen to fuel mass flow and velocity ratios, equivalence ratio, hydrogen mass flow rate and injection velocity, nozzle diameter, and chamber length. Essentially two different data sets were obt ained in this research. The data sets differ by the method in which the different ch amber pressures were achieved. The first method was to keep the propellant mass flow rates constant and change the exhaust nozzle diameter. Figure 4-1 through Figure 4-33 present the results from the combustion tests using this method of changing the exha ust nozzle diameter to modify the chamber pressure. The second method was to keep the exhaust nozzle diameter constant and change the propellant mass flow rates. This second method is that used by Marshall et

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60 al.3 Figure 4-35 through Figure 4-38 present the results from the combustion tests using this method of changing the propellant mass fl ow rates to modify the chamber pressure. Furthermore, both data sets (data from both methods of modifying the chamber pressure) were analyzed using the two differe nt heat flux equations presented in Chapter 2, namely Equation 2-15 for the steady stat e heat flux calculation and Equation 2-16 for the steady state heat flux plus heat absorption calculation. If the figure presents heat flux values, the caption will indicate which heat fl ux equation was used in the calculations. Discussion of these results occurs in Chapter 5.

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61 Table 4-1. Combustion test configurations, operating cond itions, and included figures. Facility Setup P, MPa 2 2O H m m 2 2 O Hv v 2 H m, g/s 2 H v, m/s Nozzle ID, mm (in.) Chamber Length, mm (in.) Figures UF1IP3CA3SA 6.21 3.97 0.46 2.0 0.396 144.2 1.36 (0.0535) 169.3 (6.66) 4-1, 4-2, 4-3, 4-25, 4-26, 4-29, 4-31, 4-33, 4-39, 4-40, 4-41 UF1IP3CA3SA 4.86 3.97 0.46 2.0 0.396 197.4 1.59 (0.0625) 169.3 (6.66) 4-4, 4-5, 4-6, 425, 4-26, 4-29, 4-31, 4-33, 4-34, 4-42, 4-43 UF1IP3CA3SA 4.55 3.97 0.46 2.0 0.396 235.0 1.70 (0.0670) 169.3 (6.66) 4-7, 4-8, 4-9, 425, 4-26, 4-29, 4-31, 4-33 UF1IP3CA3SA 2.76 3.97 0.46 2.0 0.396 468.3 2.38 (0.0938) 169.3 (6.66) 4-10, 4-11, 4-12, 4-25, 4-26, 4-29, 4-31, 4-33 UF1IP3CA3SA 6.21 5.97 0.70 1.33 0.285 102.5 1.36 (0.0535) 169.3 (6.66) 4-13, 4-14, 4-15, 4-27, 4-28, 4-30, 4-32, 4-33 UF1IP3CA3SA 4.86 5.97 0.70 1.33 0.285 140.0 1.59 (0.0625) 169.3 (6.66) 4-16, 4-17, 4-18, 4-27, 4-28, 4-30, 4-32, 4-33 UF1IP3CA3SA 4.55 5.97 0.70 1.33 0.285 166.1 1.70 (0.0670) 169.3 (6.66) 4-19, 4-20, 4-21, 4-27, 4-28, 4-30, 4-32, 4-33 UF1IP3CA3SA 2.76 5.97 0.70 1.33 0.285 322.9 2.38 (0.0938) 169.3 (6.66) 4-22, 4-23, 4-24, 4-26, 4-28, 4-30, 4-32, 4-33 UF1IP3CA5SA 4.86 3.97 0.46 2.0 0.396 197.4 1.59 (0.0625) 150.7 (5.93) 4-34 UF1IP3CA4SA 4.86 3.97 0.46 2.0 0.396 197.4 1.59 (0.0625) 132.1 (5.20) 4-34 UF1IP3CA1SA 4.86 3.97 0.46 2.0 0.396 197.4 1.59 (0.0625) 112.6 (4.43) 4-34 UF1IP3CA0SA 4.86 3.97 0.46 2.0 0.396 197.4 1.59 (0.0625) 94.0 (3.70) 4-34 UF1IP3CA3SA 2.75 3.97 0.46 2.0 0.187 207.4 1.70 (0.0670) 169.3 (6.66) 4-35, 4-36, 4-37, 4-38 UF1IP3CA3SA 3.90 3.97 0.46 2.0 0.280 207.4 1.70 (0.0670) 169.3 (6.66) 4-35, 4-36, 4-37, 4-38 UF1IP3CA3SA 4.93 3.97 0.46 2.0 0.377 207.4 1.70 (0.0670) 169.3 (6.66) 4-35, 4-36, 4-37, 4-38 UF1IP3CA3SA 5.87 3.97 0.46 2.0 0.470 207.4 1.70 (0.0670) 169.3 (6.66) 4-35, 4-36, 4-37, 4-38

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62 Figure 4-1. Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 144.2 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Ign ition and shutdown times indicated for this full data set.

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63 Figure 4-2. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 144.2 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Lege nd indicates distance from injector face to heat flux sensor. Ignition and shutdown times indicated for this full data set. Heat flux calculations pe rformed using steady state heat flux equation (Equation 2-15).

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64 Figure 4-3. Injector face te mperatures, behind injector te mperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 144.2 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The lege nd indicates r as the radial distance from the injector center ax is to the injector face th ermocouple. Ignition and shutdown times indicated for this full data set.

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65 Figure 4-4. Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 197.4 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.

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66 Figure 4-5. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 197.4 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Lege nd indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed using steady state heat flux equation (Equation 2-15).

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67 Figure 4-6. Injector face te mperatures, behind injector te mperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 197.4 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The lege nd indicates r as the radial distance from the injector center axis to the injector face thermocouple.

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68 Figure 4-7. Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 235.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.

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69 Figure 4-8. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 235.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Lege nd indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed using steady state heat flux equation (Equation 2-15).

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70 Figure 4-9. Injector face te mperatures, behind injector te mperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 235.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The lege nd indicates r as the radial distance from the injector center axis to the injector face thermocouple.

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71 Figure 4-10. Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 468.3 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.

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72 Figure 4-11. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 468.3 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Lege nd indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed using steady state heat flux equation (Equation 2-15).

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73 Figure 4-12. Injector face temperatures, be hind injector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 468.3 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The lege nd indicates r as the radial distance from the injector center axis to the injector face thermocouple.

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74 Figure 4-13. Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 102.5 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.

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75 Figure 4-14. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 102.5 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Lege nd indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed using steady state heat flux equation (Equation 2-15).

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76 Figure 4-15. Injector face temperatures, be hind injector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 6.21 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 102.5 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The lege nd indicates r as the radial distance from the injector center axis to the injector face thermocouple.

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77 Figure 4-16. Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 140.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.

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78 Figure 4-17. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 140.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Lege nd indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed using steady state heat flux equation (Equation 2-15).

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79 Figure 4-18. Injector face temperatures, be hind injector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.86 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 140.0 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The lege nd indicates r as the radial distance from the injector center axis to the injector face thermocouple.

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80 Figure 4-19. Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 166.1 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.

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81 Figure 4-20. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 166.1 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Lege nd indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed using steady state heat flux equation (Equation 2-15).

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82 Figure 4-21. Injector face temperatures, be hind injector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 4.55 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 166.1 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The lege nd indicates r as the radial distance from the injector center axis to the injector face thermocouple.

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83 Figure 4-22. Chamber pressure versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 322.9 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA.

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84 Figure 4-23. Heat flux versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 322.9 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Lege nd indicates distance from injector face to heat flux sensor. Heat flux ca lculations performed using steady state heat flux equation (Equation 2-15).

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85 Figure 4-24. Injector face temperatures, be hind injector temperature, and exhaust nozzle temperature versus time for a GH2/GO2 combustion test with Pchamber = 2.76 MPa, mO2/mH2 = 5.97, and vO2/vH2 = 0.70 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s, vH2 = 322.9 m/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. The lege nd indicates r as the radial distance from the injector center axis to the injector face thermocouple.

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86 0 0.5 1 1.5 2 2.5 3 3.5 020406080100120140 P = 6.21 MPa P = 4.86 MPa P = 4.55 MPa P = 2.76 MPa Distance from Injector Face (mm)Heat Flux (MW/m 2)Heat Flux vs Distance from Injector Face mO2/mH2 = 3.97, mO2 = 1.565 g/s, mH2 = 0.396 g/s, = 2.0 Figure 4-25. Heat flux versus di stance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Error bars indicate +/the standard de viation for the averaged test data. Chamber pressures increased by decreas ing exhaust nozzle diameter. Heat flux calculations performed using stea dy state heat equation (Equation 2-15).

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87 0 0.5 1 1.5 2 2.5 3 3.5 4 020406080100120140 P = 6.21 MPa P = 4.86 MPa P = 4.55 MPa P = 2.76 MPa Distance from Injector Face (mm)Heat Flux (MW/m 2)Heat Flux vs Distance from Injector Face mO2/mH2 = 3.97, mO2 = 1.565 g/s, mH2 = 0.396 g/s, = 2.0 Heat Flux calculations performed using steady state heat flux plus heat absorption equation (Equation 216). Figure 4-26. Heat flux versus di stance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Chamber pressures increased by decreas ing exhaust nozzle diameter. Heat flux calculations performed using steady state heat flux plus heat absorption equation (Equation 2-16).

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88 0 0.5 1 1.5 2 2.5 3 3.5 020406080100120140 P = 6.21 MPa P = 4.86 MPa P = 4.55 MPa P = 2.76 MPa Distance from Injector Face (mm)Heat Flux (MW/m 2)Heat Flux vs Distance from Injector Face mO2/mH2 = 5.97, mO2 = 1.693 g/s, mH2 = 0.285 g/s, = 1.33 Figure 4-27. Heat flux versus di stance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 5.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Error bars indicate +/the standard de viation for the averaged test data. Chamber pressures increased by decreas ing exhaust nozzle diameter. Heat flux calculations performed using stea dy state heat flux equation (Equation 2-15).

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89 0 0.5 1 1.5 2 2.5 3 3.5 4 020406080100120140 P = 6.21 MPa P = 4.86 MPa P = 4.55 MPa P = 2.76 MPa Distance from Injector Face (mm)Heat Flux (MW/m 2)Heat Flux vs Distance from Injector Face mO2/mH2 = 5.97, mO2 = 1.693 g/s, mH2 = 0.285 g/s, = 1.33 Heat Flux calculations performed using steady state heat flux plus heat absorption equation (Equation 216). Figure 4-28. Heat flux versus di stance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 5.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Chamber pressures increased by decreas ing exhaust nozzle diameter. Heat flux calculations performed using steady state heat flux plus heat absorption equation (Equation 2-16).

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0 50 100 150 200 250 300 350 020406080100120140 P = 6.21 MPa P = 4.86 MPa P = 4.55 MPa P = 2.76 MPa Distance from Injector Face (mm)Temperature ( oC)Chamber Wall Temperature vs Distance from Injector Face mO2/mH2 = 3.97, mO2 = 1.565 g/s, mH2 = 0.396 g/s, = 2.0 Figure 4-29. Chamber wall temperature versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Error bars indicate +/the st andard deviation for the averaged test data. Chamber pressures increased by decreasing exhaust nozzle diameter. Wall temperature calculations pe rformed using Equation 2-17.

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91 0 50 100 150 200 250 300 350 020406080100120140 P = 6.21 MPa P = 4.86 MPa P = 4.55 MPa P = 2.76 MPa Distance from Injector Face (mm)Temperature ( oC)Chamber Wall Temperature vs Distance from Injector Face mO2/mH2 = 5.97, mO2 = 1.693 g/s, mH2 = 0.285 g/s, = 1.33 Figure 4-30. Chamber wall temperature versus distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 5.97 and four different chamber pressures: 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Error bars indi cate +/the standard deviation for the averaged test data. Chamber pre ssures increased by decreasing exhaust nozzle diameter. Wall temperature cal culations performed using Equation 2-17.

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92 200 250 300 350 400 450 500 550 600 650 234567 r = 2.11 mm (0.083 in) r = 4.24 mm (0.167 in) Chamber Pressure (MPa)Temperature ( oC)Injector Face Temperature vs Chamber Pressure mO2/mH2 = 3.97, mO2 = 1.565 g/s, mH2 = 0.396 g/s, = 2.0 Figure 4-31. Injector face temperat ure versus chamber pressure for GH2/GO2 combustion tests with mO2/mH2 = 3.97 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Legend indicates r as the radial distance from the injector center axis to the injector face thermocouple. Bars indicat e +/the standard fluctuation from the average temperature. Chamber pressures increased by decreasing exhaust nozzle diameter.

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93 200 250 300 350 400 450 500 550 600 650 234567 r = 2.11 mm (0.083 in) r = 4.24 mm (0.167 in) Chamber Pressure (MPa)Temperature ( oC)Injector Face Temperature vs Chamber Pressure mO2/mH2 = 5.97, mO2 = 1.693 g/s, mH2 = 0.285 g/s, = 1.33 Figure 4-32. Injector face temperat ure versus chamber pressure for GH2/GO2 combustion tests with mO2/mH2 = 5.97 ( = 1.33, mO2 = 1.693 g/s, mH2 = 0.285 g/s). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Legend indicates r as the radial distance from the injector center axis to the injector face thermocouple. Bars indicat e +/the standard fluctuation from the average temperature. Chamber pressures increased by decreasing exhaust nozzle diameter.

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94 0 100 200 300 400 500 600 0246 Radial Distance from Injector Center Axis (mm)Temperature ( oC)Pchamber = 6.21 MPa, mO2/mH2 = 3.97 Pchamber = 4.86 MPa, mO2/mH2 = 3.97 Pchamber = 4.55 MPa, mO2/mH2 = 3.97 Pchamber = 2.76 MPa, mO2/mH2 = 3.97 Pchamber = 6.21 MPa, mO2/mH2 = 5.97 Pchamber = 4.86 MPa, mO2/mH2 = 5.97 Pchamber = 4.55 MPa, mO2/mH2 = 5.97 Pchamber = 2.76 MPa, mO2/mH2 = 5.97 Injector Face Temperature vs Radial Distance from Injector Center Axis Figure 4-33. Injector face temperatures versus radial distance from injector center axis for GH2/GO2 combustion tests at mO2/mH2 = 3.97 and 5.97 and Pchamber = 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa. Chamber pressures increased by decreasing exhaust nozzle diameter. 150 200 250 300 350 400 450 90110130150170 r = 2.11 mm (0.083 in) r = 4.24 mm (0.167 in) Chamber Length (mm)Injector Face Temperature ( oC )Injector Face Temperauture vs. Chamber Length Pchamber = 4.86 MPa, mO2/mH2 = 3.97, vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, vH2 = 197.4 m/s) Chamber Lengths mm (inch) 169.3 (6.66) 150.7 (5.93) 132.1 (5.20) 112.6 (4.43) 94.0 (3.70) Figure 4-34. Injector face temper ature versus chamber length for GH2/GO2 combustion tests with Pchamber = 4.86 MPa, mO2/mH2 = 3.97, and vO2/vH2 = 0.46 ( = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s). Injector = UF1. Injector position = IP3. Legend indicates r as the radial distance from the injector center axis to the injector face thermocouple. Error bars indicate +/the standard deviation for the averaged test data.

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95 0 0.5 1 1.5 2 2.5 3 3.5 4 050100150 Distance from Injector Face (mm)Heat Flux (MW/m 2)Heat Flux vs Distance from Injector Face mO2/mH2 = 3.97, vO2/vH2 = 0.46, vH2 = 207.4 m/s = 2.0, IDnozzle = 1.70 mm (0.670 in.)Pchamber = 2.75 MPa, mH2 = 0.187 g/s Pchamber = 2.75 MPa, mH2 = 0.187 g/s Pchamber = 3.90 MPa, mH2 = 0.280 g/s Pchamber = 3.90 MPa, mH2 = 0.280 g/s Pchamber = 4.93 MPa, mH2 = 0.377 g/s Pchamber = 4.93 MPa, mH2 = 0.377 g/s Pchamber = 5.87 MPa, mH2 = 0.470 g/s Pchamber = 5.87 MPa, mH2 = 0.470 g/s Heat Flux calculations performed using steady state heat flux plus heat absorption equation (Equation 2.16). Figure 4-35. Heat flux versus di stance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 ( = 2.0), vO2/vH2 = 0.46, vH2 = 207.4 m/s, and a variety of chamber pressures. Chamber pressure increased by increasing flow rates. Exhaust nozzle diameter = 1.70 mm (0.670 in.). Injector = UF1. Injector position = IP3. Chamber arrangement = CA 3SA. Heat flux values calculated using steady state heat flux plus he at absorption equation (Equation 2-16).

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96 0 0.5 1 1.5 2 2.5 3 050100150 Distance from Injector Face (mm)Heat Flux (MW/m 2)*(2.75 MPa/P c)0.8Heat Flux vs Distance from Injector Face, (2.75 MPa/Pc)0.8mO2/mH2 = 3.97, vO2/vH2 = 0.46, vH2 = 207.4 m/s = 2.0, IDnozzle = 1.70 mm (0.670 in.)Pchamber = 2.75 MPa, mH2 = 0.187 g/s Pchamber = 2.75 MPa, mH2 = 0.187 g/s Pchamber = 3.90 MPa, mH2 = 0.280 g/s Pchamber = 3.90 MPa, mH2 = 0.280 g/s Pchamber = 4.93 MPa, mH2 = 0.377 g/s Pchamber = 4.93 MPa, mH2 = 0.377 g/s Pchamber = 5.87 MPa, mH2 = 0.470 g/s Pchamber = 5.87 MPa, mH2 = 0.470 g/s Heat Flux calculations performed using steady state heat flux plus heat absorption equation (Equation 2.16). Figure 4-36. Normalized heat flux vers us distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 ( = 2.0), vO2/vH2 = 0.46, vH2 = 207.4 m/s, and a variety of chamber pressu res. Chamber pressure increased by increasing flow rates. Exhaust nozzl e diameter = 1.70 mm (0.670 in.). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Heat flux values calculated using stea dy state heat flux pl us heat absorption equation (Equation 2-16). Heat flux values normalized by (2.75 MPa/Pc)0.8.

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97 0 0.5 1 1.5 2 2.5 3 050100150 Distance from Injector Face (mm)Heat Flux (MW/m 2)*(2.75 MPa/P c)0.6Heat Flux vs Distance from Injector Face, (2.75 MPa/Pc)0.6mO2/mH2 = 3.97, vO2/vH2 = 0.46, vH2 = 207.4 m/s = 2.0, IDnozzle = 1.70 mm (0.670 in.)Pchamber = 2.75 MPa, mH2 = 0.187 g/s Pchamber = 2.75 MPa, mH2 = 0.187 g/s Pchamber = 3.90 MPa, mH2 = 0.280 g/s Pchamber = 3.90 MPa, mH2 = 0.280 g/s Pchamber = 4.93 MPa, mH2 = 0.377 g/s Pchamber = 4.93 MPa, mH2 = 0.377 g/s Pchamber = 5.87 MPa, mH2 = 0.470 g/s Pchamber = 5.87 MPa, mH2 = 0.470 g/s Heat Flux calculations performed using steady state heat flux plus heat absorption equation (Equation 2.16). Figure 4-37. Normalized heat flux vers us distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 ( = 2.0), vO2/vH2 = 0.46, vH2 = 207.4 m/s, and a variety of chamber pressu res. Chamber pressure increased by increasing flow rates. Exhaust nozzl e diameter = 1.70 mm (0.670 in.). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Heat flux values calculated using stea dy state heat flux pl us heat absorption equation (Equation 2-16). Heat flux values normalized by (2.75 MPa/Pc)0.6.

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98 0 0.5 1 1.5 2 2.5 3 050100150 Distance from Injector Face (mm)Heat Flux (MW/m 2)*(0.187 g/s / m H2)0.5Heat Flux vs Distance from Injector Face, (0.187 g/s / mH2)0.5mO2/mH2 = 3.97, vO2/vH2 = 0.46, vH2 = 207.4 m/s = 2.0, IDnozzle = 1.70 mm (0.670 in.)Pchamber = 2.75 MPa, mH2 = 0.187 g/s Pchamber = 2.75 MPa, mH2 = 0.187 g/s Pchamber = 3.90 MPa, mH2 = 0.280 g/s Pchamber = 3.90 MPa, mH2 = 0.280 g/s Pchamber = 4.93 MPa, mH2 = 0.377 g/s Pchamber = 4.93 MPa, mH2 = 0.377 g/s Pchamber = 5.87 MPa, mH2 = 0.470 g/s Pchamber = 5.87 MPa, mH2 = 0.470 g/s Heat Flux calculations performed using steady state heat flux plus heat absorption equation (Equation 2.16). Figure 4-38. Normalized heat flux vers us distance from injector face for GH2/GO2 combustion tests with mO2/mH2 = 3.97 ( = 2.0), vO2/vH2 = 0.46, vH2 = 207.4 m/s, and a variety of chamber pressu res. Chamber pressure increased by increasing flow rates. Exhaust nozzl e diameter = 1.70 mm (0.670 in.). Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Heat flux values calculated using stea dy state heat flux pl us heat absorption equation (Equation 2-16). Heat flux values normalized by (0.187 g/s / mH2)0.5.

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99 Figure 4-39. High-frequency pre ssure transducer data (chamber pressure versus time) for a 1.8 second window of a GH 2/GO2 combustion test with = 2.0, mO2 = 1.565 g/s, and mH2 = 0.396 g/s. Injector = UF1. Injector position = IP3. Chamber arrangement = CA3SA. Sample rate = 50 kHz. Figure 4-40. Power spectrum analysis of hi gh-frequency pressure data shown in Figure 4-33. Analysis performed via Fast-Fourier Transform method.

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100 Figure 4-41. 0-3500 Hz window of po wer spectrum shown in Figure 4-34. Figure 4-42. Average flame profile of a GH2/GO2 flame with operating conditions of Pchamber = 4.86 MPa, = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, and vO2/vH2 = 0.46. Images of broadband flame emission. Exposure time = 500 ns. Average of 132 images. Injector center axis located at y = 0 and injector face located at x = 0.

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101 Figure 4-43. Instantaneous flame image of a GH2/GO2 flame with operating conditions of Pchamber = 4.86 MPa, = 2.0, mO2 = 1.565 g/s, mH2 = 0.396 g/s, and vO2/vH2 = 0.46. Image of broadband flame emission. Exposure time = 500 ns. Injector center axis located at y = 0 and injector face located at x = 0.

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102 CHAPTER 5 DISCUSSION AND CONCLUSION The goals of this research were to firs t design and build a high-pressure combustion facility and then to investigate the dynamics of high-pressure GH2/GO2 combustion through experimental testing and provide thos e results for CFD model validation. The results from each of these two goals are discusse d. With regards to the facility, obstacles that required or are still re quiring extended troubleshooting ar e discussed. In addition, future improvements to the facility are sugge sted and discussed. Finally, the results presented in Chapter 4 are examined in deta il, and their implications on the dynamics of high-pressure GH2/GO2 combustion are discussed. High-Pressure Combustion Facili ty Obstacles and Improvements Since the HPCF went operational, there have been several obstacles encountered that were not foreseen during the design and construction stages. These obstacles include ignition, optical access, DAQ hardware operati onal problems, and OH-PLIF difficulties. Troubleshooting these obstacle s has led to a better unders tanding of the underlying problems and consequently to possible fixes through future improvements to the facility. The main obstacle encountered with the HPCF was with ignition. The original igniter sparked across two electr odes perpendicular to each ot her across the flow path of the chamber. Unfortunately this igniter design failed after a few tests due to the extreme temperatures melting the electrodes. The igniter has since evol ved through several iterations, with each iteration providing longe r lifetime and more reliability. However, major drawbacks to this type of igniter still exist. Because it is impossible to locate the

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103 igniter in the propellant stream, the igniter must sit out of the main flow and wait for mixed gases to make contact with it. This usually means the chamber fills with premixed gases before ignition, causing detonation and a huge pressure spik e. With the copper inserts in place of the windows, this pressure spike is not a problem. With the windows installed, though, this huge pr essure spike tends to crack th e windows, ruining the optical access. Also, the pressure spikes tend to ki ll the highly sensitive Entran high-frequency pressure transducers. The best solution is to integrate a torch igniter in the injector/injector face. This would ignite the propellants immediately upon injection, eliminating the pressure spike. Also, integrat ing the torch into the injector allows clean ignition no matter where the injector is locat ed within the chamber. The design of a injector with integrated ignition torch is currently in progress. Another obstacle is maintaining contact between the heat flux sensors and the chamber surface. It has been observed that some heat flux sensors tend to either lose contact or initiate contact duri ng the middle of a combustion te st due to the expansion of the copper chamber. Thermal grease was adde d to the contact point of the heat flux sensor and combustion chamber to try and main tain contact. While this did help some, the grease tends to dry out and crack, causing the sensors to lose contact again. One possible solution is to solder the heat flux sensors to the ch amber surface to establish a permanent contact. This solu tion is worth investigation. Next, there are several locations for DAQ sensors that have been identified as desirable since the facility went operational. More specifically, temperature and pressure measurements inside the injector immediat ely upstream of the injection point. This includes measurements within both the oxidi zer and fuel injector components. The

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104 temperature measurements are especially desi red because they would give insight into heat transfer upstream of the injection point However, the size and geometry of the injector make retrofitting these DAQ capabilit ies extremely difficult. Investigation into adding these DAQ sensors to the injector be ing designed with th e torch igniter is currently in progress. Another improvement would be implementing a water-cooled exhaust nozzle. While water-cooling the nozzle will take away the exhaust nozzle temperature reading as a boundary condition, it would allow longer run times of the chamber for longer studies, as the exhaust nozzle heats up much faster th an any other part of the combustor. A water-cooled nozzle has been designed fo r the HPCF and awaits construction and implementation. Finally, getting the OH-PLIF diagnostic t echnique to work proved to be very difficult. The laser sheet optics were setup properly and the UV output was tuned to the correct wavelength, but no fluorescence was obs erved. The most likely problem is too little power at the chamber. This stems fr om inefficiencies and misalignments in the OPO, doubler, and laser sheet optics. Currently effort is being put into maximizing the power out of the laser/OPO system and calibra ting the technique in a Methane/Air flame. High-Pressure GH2/GO2 Combustion Dynamics The results obtained in this research, incl uding those presented in Chapter 4, give much insight into the dyna mics of high-pressure GH2/GO2 combustion, as well as provide for CFD code validation. The result s mainly include heat flux and injector face temperature data for GH2/GO2 flames operating at mO2/mH2 = 3.97 and mO2/mH2 = 5.97 ( = 2.0 and = 1.33). For these two mass flow ratios, four operational chamber pressures were investigated by keeping th e propellant mass flow rates constant and

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105 changing the exhaust nozzle diameter, namely 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa. Pressure versus time, wall heat fl ux versus time (using two different heat flux equations), injector face temperatures versus time, heat flux versus distance from injector, chamber wall temperature versus distance from injector, and injector face temperatures versus chamber length are all presented for this method of changing the chamber pressure within Chapter 4. In addition, a second set of wall heat flux data was obtained for GH2/GO2 flames operating at mO2/mH2 = 3.97 for four different chamber pressures, which were increased by increasing the propellant mass flow rates but keeping the exhaust nozzle diameter constant. This method in wh ich this second set of data was obtained is similar to that used by Marshall et al.3 Initial Unstable/Unsteady Flow First, it is interesting to note that during all of the combustion tests, there seems to be an initial period where the internal flow is not stabilized, followed by a stabilized period where the heat fluxes level off and the injector face temperatures become relatively steady. Aspects of this can be seen in all the combustion tests from Figures 4-1 through Figures 4-24. This unstable period ap pears to last for several seconds after ignition. For example, Figure 4-10 shows th e two injector face temperatures making a transition to a higher (and admittedly more fluctuatory) value around 4.5 to 5 seconds after ignition. While all tests do not show this drastic change, most do show a change after several seconds of combustion. One possible source of this phenomenon could be an initial period of backflow in to the space behind the injector block. However, this was tested for by running tests with nitrogen pr e-pressurizing the chamber so that the area behind the injector was at th e same pressure or higher th an that of the chamber once combustion started. The same period of instab ility appeared in thes e tests as well.

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106 This effect is more likely due to the change in gas injection velocity during the ramping up of the chamber pressure. Immediat ely after the propellants are turned on they rush through the injector, possibly choking at the injector, until the chamber pressure rises due to the presence of the propellants. After ignition occurs, the chamber pressure begins to rise, which causes the propellant injection velocities to drop. Once the chamber pressure begins to level off to the nominal operating pressure, the propellant injection velocities sets up to their nominal operating conditions, at which point the internal flow is able to reach a more steady state than during the period of pressure/velocity change. This is when the recirculation regions next to the injector are able to set up to a more steady state, giving rise to the changes seen after several seconds of burn. Pressure Effect on Wall Heat Flux More interesting aspects of the combustion dynamics become evident when comparing the data from the two different data sets. More specifically, the data obtained by changing the chamber pressure via changi ng the exhaust nozzle a nd the data obtained by changing chamber pressure via changing th e propellant mass flow rates give different results in regards to the effect of chamber pressure on the wall heat flux. Figure 4-25 and Figure 4-27 cl early show that when th e exhaust nozzle diameter was decreased to increase the chamber pressure, the operational chamber pressure had little effect on the heat flux, no matter the ma ss flow ratio. Even with each data point being the average of 3 to 5 tests, there was very little variation based on chamber pressure. Note that the heat flux calcul ations for Figure 4-25 and Figure 4-27 were steady state heat flux only (Equa tion 2-15). In addition, a pplying the steady state heat flux plus heat absorption calcu lation (Equation 2-16) to the same set of data yields similarly profiled and patterned results, as shown in Figure 4-26 and Figure 4-28.

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107 Comparing the steady state heat flux results to the steady state heat flux plus heat absorption results (compare Figure 4-25 to Figure 4-26, Figure 4-27 to Figure 4-28) clearly shows that the only difference is in magnitude of the wall heat flux value. Specifically, the steady state heat flux plus heat absorption yields on average 10% higher values than the steady state heat flux alone. Even so, there is little to no difference in the heat flux values due to pressure effects. The slight variation seen in the heat fluxes across the different chamber pressures can be attributed to both the change in the propellant injection velocities a nd in smaller part to the +/5% error in the measured heat flux values. This pressure independence on the wall heat fluxes is also supported by the combustion tests where the chamber pressure was increased by increasing the propellant mass flow rates. The results from this set of combustion test data are presented in Figure 4-35, Figure 4-36, and Figure 437. Figure 4-35 clea rly indicates that as the propellant mass flow rates are increased, and hence th e chamber pressure increased, the heat flux values increase. The profiles seem to be similar between the different cases, though. Marshall et al.3 also present similar resu lts in their study. They argue a pressure scaling of the heat flux values available in the literature such that the heat tr ansfer coefficient, h, is proportional to pressure to the power of 0.8, as shown in Equation 5-1. Note that pressure to the power of 0.6, as shown in Fi gure 4-37, seems to give a tighter collapse of the data than to the power of 0.8. 0.8 ,2.75AnormalizedA cMPa qq P (5-1) While this pressure scaling does result in a collapse of the results to similar normalized heat flux values, as shown in Figur e 4-36, this researcher believes that the

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108 application of such a pressure scaling relation is inaccurate. This inaccuracy seems to be supported by the combustion test results for which the chamber pressure was increased by decreasing the exhaust nozzle diameter (p ropellant mass flow rates kept constant), where there was shown to be no pressure dependence, as shown in Figure 4-26 and Figure 4-28. This researcher believes that a more accurate scaling argument would be to scale the heat transfer coefficient, h, using a mass flow scaling based on the hydrogen mass flow rate, as shown in Equation 5-2. 0.5 20.187/AnormalizedA Hgs qq m (5-2) Note that the scaling factor of 0.5 was chosen because it gave the most visually compact collapse of the data. Using the mass flow rate scaling argument allows both sets of data to be accurate, since the data obtained from keeping the mass flow rates constant would not be affected by the scali ng and the data obtained by changing the mass flow rates collapses to similar heat flux values, resulting in very similar profiles and values from all of the combustion tests. If the mass flow sca ling is used, it becomes clear that there in no pressure dependence on the wall heat fl ux profile and wall heat flux values. This lack of pressure dependence compares favorably with that of Marshall et al.,3 even though different scaling arguments are a pplied. The fact that the profile remains similar across all pressures suggests that th e dynamic structures within the combusting flow are pressure independent if all other factors remain constant. Furthermore, the results from the combustion tests where the mass flow rates were held constant, in which the injection velocities must increase for the same injector geometry, indicate that the dynamic structures within the combusting flow are only slightly dependent on the injection velocity, as indicated by slightly vary ing values in the heat fluxes with similar

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109 profiles. This suggests that the basic dyna mic structures of the combusting flow are mostly dependent on the chamber geometry, w ith little dependence on injection velocities and no pressure dependence. The same conclusion is supported by the ch amber wall temperature profiles, shown in Figure 4-29 and Figure 4-30, which show very little variation across the different chamber pressure tests. The chamber wall temp erature plots do give insight into what the flame is doing inside the chamber though. Th e wall temperatures clearly increase, peak, and decrease along the length of the chamber. Th is seems to indicate that the shear layer, the hottest portion of the flame, contacts the chamber wall at the location of the peak wall temperature, or around 83 mm (3.27 in.) from the injector face for both equivalence ratios. However, the distance from the inje ctor face at which the highest heat release occurs appears to be at a different loca tion than the point of maximum chamber wall temperature. This point of maximum heat release occurs around 60 mm (2.35 in.) from the injector face. The maximum heat release point also appears to have little dependence on mass flow ratio and injection velocities, and no pressure dependence. Because the heat fluxes and chamber wall temperature profile s did not seem to be affected by changes in chamber pressure, mass flow ratios, velocity ratios, and injection velocities, they would appear to be dominated mainly by geometrical features. The injector face temperatures for mO2/mH2 = 3.97 ( = 2.0) also seem to have little pressure dependence, as shown in Figure 431 and Figure 4-33. There is only a slight increase for the two injector face temperatures at a chamber pressure of 4.55 MPa. The injector face temperatures for mO2/mH2 = 5.97 ( = 1.33) show slightly different results however, as shown in Figure 4-32 and Figur e 4-33. The lower pressure values

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110 correspond well with each other, as does the va lue for the injector face thermocouple that is at a distance of 4.24 mm (0.167 in.) from the injector center axis. However the value for the injector face thermocoupl e that is at a distance of 2.11 mm (0.087 in.) from the injector center axis increases by almost 200 oC, with a huge increase in fluctuation as well. The reason for this jump is unclear. Effect of Chamber Length Another study done in this re search was to investigate th e effect of ch amber length on the injector face temperatures, of which th e results are presented in Figure 4-34. The trend for the two injector face temperature lo cations is clear. The temperature measured 4.24 mm (0.167 in.) away from the center axis of the injector shows little change with a decrease in chamber length. The temperatur e measured 2.11 mm (0.087 in.) away from the center axis of the injector shows a sizeab le increase as the chamber length decreases. This increase is probably explained by one of two events. Either the recirculation region becomes more energetic with hotter gases as the chamber length decreases, or the flame is forced to spread more quickly due to the decreased length, resulting in the shear layer residing closer to the thermocouple. High-Frequency Pressure Transducer The reason for incorporating the high-freque ncy pressure transducer into the HPCF was to provide the capability to investigat e acoustic modes of the combustion process based on changes in chamber length, flow rates, and ch amber pressure. While the usefulness of this information to the CFD mode lers is still under review, preliminary data has been obtained for several combustion tests, one of which is presented in Figure 4-39. More specifically, a 1.8 s econd window of the combustion test is presented. The sampling rate of the transducer was 50 kHz, meaning a useful 25kHz frequency response

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111 could be obtained using Fast-F ourier Transform, as show in Figure 4-40. This plot clearly shows frequency ranges of high local energy. Figure 4-41 zooms in on Figure 434 to show the frequency response in the range of 0 to 3500 Hz. While these plots clearly show acoustic response, it is impossible to tell from just those single plots which frequencies are characteristic of certain aspects of th e flow, facility, or other environmental effects. Even comparing the high-frequency pressure transducer data from several different combustion tests yields very little differences. It is believed by this researcher that in order for operational condi tions and facility features to be accurately characterized by their acoustic response, a massive amount of tests would need to be performed, accompanied with a massive corr elation study. Unfort unately, the highly fragile nature of the Entran high-frequenc y pressure transducers combined with the current ignition method renders this improba ble. The torch ignition method described above has the potential to correct this problem. Imaging Discussion The imaging capabilities of the HPCF o ffer excellent opportunities to physically see and image the dynamics of high-pressure co mbustion. One such example is shown in Figure 4-42. This image shows the average flame profile of a mO2/mH2 = 3.97 ( = 2.0), Pchamber = 4.86 MPa GH2/GO2 combustion test. One piece of information that can be instantly pulled from this image is the flame liftoff distance, hliftoff, which is approximately 1mm in this case. Additionally, the shear layer is seen to bend toward the centerline (toward the oxidizer) as it m oves away from the injector, which is characteristic of fuel-rich shear layers.25 Also, shear layer growth rates can be inferred from the image. Figure 4-43 shows an in stantaneous image from the same combustion test as that for the average flame profile. This image clearly shows the transition from

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112 the laminar shear layer to the fully turbulent sh ear layer. Also, image pairs of this type, taken with a separation time of 500 ns or mo re, allows average flame velocities to be calculated based on intensity correlations. Conclusion There were two goals of this research. The first goal was to design and build a high-pressure combustion facility (UF HPCF ) capable of operating pressures up to 6.25 MPa (62 atm) and a range of equivalence ratios, with optical access and a host of diagnostic capabilities. The second goal was to experimenta lly investigate the dynamics of high-pressure GH2/GO2 combustion for oxygen to hydrogen mass flow ratios of 3.97 and 5.97 ( = 2.0 and 1.33) and a range of cham ber pressures including 6.21 MPa, 4.86 MPa, 4.55 MPa, and 2.76 MPa. The facility was made operational with capabilities including chamber wall heat flux measurements, injector face temp erature measurements, exhaust nozzle measurements, high-frequency chamber pres sure measurements, broadband and UV imaging, and complete controllability via remo te GUI. A full range of combustion tests have been performed in the HPCF, including those desired for this research. Several improvements should be made to the HPCF in the future. First is the integration of a torch igniter into the injector, which will e liminate the detonation and pressure spiking problem. Secondly, the water-cooled nozzle ca n be integrated for longer combustion test times. Finally, a better method for ensuring th e proper seat of the h eat flux sensors to the chamber should be incorporated. Certain aspects of high-pressure GH2/GO2 dynamics were investigated for mO2/mH2 = 3.97 and mO2/mH2 = 5.97 ( = 2.0 and = 1.33). For these two mass flow ratios, four operational chamber pressures were investig ated by keeping the propellant mass flow

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113 rates constant and changing the exhaust nozzl e diameter, namely 6.21, 4.86, 4.55, and 2.76 MPa. In addition, four operational cham ber pressures were investigated by keeping the exhaust nozzle diameter constant and changing the propellant mass flow rates, namely 5.87, 4.93, 3.90, and 2.75 MPa. A period of instability seems to exist in the flow inside the chamber for several seconds af ter ignition due to changing gas injection velocities. Maximum heat release occurs aroun d 60 mm (2.35 in.) from the injector face. In general, the injector face temperatures have no dependence on chamber pressure. The temperature measured at 2.11 mm (0.087 in.) radially outward from the injector center axis increases as the chamber length decreases, whereas the temperature measured at 4.24 mm (0.167 in.) shows no change with a decrease in chamber length. A massive amount of tests and correlations would be needed to make use of the hi gh-frequency pressure transducer data. Usefulness of broadb and average flame profiles and broadband instantaneous flame images includes experimental investigation of hliftoff, shear growth rate, and average flame speeds. The profiles of heat flux and chamber wall temperatures seem to have no pressure dependence a nd only a slight dependence on propellant injection velocities. A scaling of heat flux va lues based on fuel mass flow rate, instead of chamber pressure, is suggested. The lack of pressure dependence and only slight dependence on the propellant inject ion velocities, as shown by the similarity in heat flux profiles, suggests that the basic dynamic st ructures of the combusting flow are mainly dominated by geometrical effects.

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114 APPENDIX A LABVIEW AND MATLAB CODES Labview Codes The block diagrams for the Labview GU Is HPCF Control Interface and HPCFHFPT Interface, described in Chapter 3, are pr esented here. Due to the large size of the block diagram images, the images of the code are contained with the thesis but displayed within a PDF file which is linked here and included in this thesis. A sample image is shown here to give the reader an idea of what is shown by opening the PDF file. Click the hyperlink caption to open the PDF files and view the Labview block diagrams. Object A-1. Complete Labview code (blo ck diagram) for Labvi ew GUI HPCF Control Interface (5.52 MB, object-a1.pdf).

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115 Object A-2. Complete Labview code (blo ck diagram) for Labview GUI HPCF-HFPT Interface (565 KB, object-a2.pdf). Matlab Codes The codes for the Matlab programs describe d in Chapter 2 are included here. The included program codes are for HPC F_Data_Processor, HFPT_Compare, HPCF_Image_Processor, and HPCF_AvgFla meSpeed. Because of the length of some of the codes, they were saved into te xt files and linked here to conserve space. Object A-3. Matlab code for HPCF_ Data_Proceessor (19 KB, object-a3.txt). Object A-4. Matlab code for H FPT_Compare (5 KB, object-a4.txt). Object A-5. Matlab code for HPCF_ Image_Processor (1 KB, object-a5.txt). Object A-6. Matlab code for HPC F_AvgFlameSpeed (3 KB, object-a6.txt). Note: All Labview codes, Matlab codes, AutoCAD drawings, and combustion test data files are located on the Quest computer at C:\High Pressure Combustion Facility.

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116 APPENDIX B OPERATIONAL PROCEDURE AND ASSEMB LY INSTRUCTIONS FOR UF HPCF Operational Procedure Startup 1. Initiate Labview GUI HPCF Control Interf ace to ensure that all output channels are sending 0 VDC signals. 2. Turn on the power to the elec tronics system (120 VAC for N2 valve and igniter, 24 VDC for propellant valves). 3. Open the propellant solenoid valves from th e control interface to ensure that the lines are purged. 4. Tare the pressure sensors for th e chamber and the propellant lines. 5. Turn the two oxidizer ball valves immedi ately upstream of the oxidizer pressure regulator to the CLOSED position. For GO2 oxidizer: 6. Turn the oxidizer ball valve at the lab wall to the CLOSED position. 7. Open all bottles in the GO2 bottle array. 8. Turn the oxidizer ball valve at th e lab wall to the OPEN position. 9. Turn the oxidizer ball valve on the GO2 line immediately upstream of the oxidizer pressure regulator to the OPEN position. Skip to Step 13. For Air oxidizer: 10. Ensure that the ball valve upstream of the Air bottle array, which connects the Air and N2 lines, is in the CLOSED position. 11. Open all bottles in the Air bottle array. 12. Turn the oxidizer ball valve on the Air li ne immediately upstream of the oxidizer pressure regulator to the OPEN position. 13. Ensure that the ball valve connecting the GH2 and N2 lines is in the CLOSED position.

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117 14. Open the GH2 bottle. 15. Open the N2 bottle. 16. Set the propellant regulators to the desired downstream propellant line pressures. 17. Using the control interface, change values for the number of turns on the propellant needle valves to set the desired ma ss flow rates and equivalence ratio. 18. Set the propellant needle valves to the entered number from Step 17. 19. Ensure that igniter tips have been replaced from last experiment. 20. Open the propellant solenoid valves briefl y to ensure that pure propellants are delivered at the beginning of the experiment. 21. Purge the chamber with nitrogen to clear the propellants from the chamber. Testing 22. Change the filename save path on the control interface to direct the saved test data to the desired folder and filename, using the standardized filename presented in Chapter 2. Skip to Step 26 if not ac quiring high-frequency pressure transducer data. If acquiring high-frequency pr essure transducer data: 23. Open Labview GUI HPCF-HFPT Interface. 24. Change filename save path on this contro l interface to direct the saved HFPT test data to the desired folder and filename, using the standardized filename presented in Chapter 2. 25. Turn on the 10 VDC power supply to the HFPT and Op-Amp. 26. Skip to Step 29 if not acquiring images. If acquiring images: 27. The camera should be setup and focused before the Startup of the HPCF. 28. If the camera is setup, run the camera soft ware and set the desi red gate and shutter settings. 29. Set all test parameters to the desired values in the HPCF Control Interface. 30. Run the combustion test via the Star t/Stop Combustion Run button in HPCF Control Interface, making sure to initiate the HFPT and camera software (if being used) at the same time.

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118 31. IN CASE OF EMERGENCY, hit the large red EMERGENCY SHUTOFF button on the HPCF Control Interface. This im mediately closes the propellant valves, shuts off the ignition, and shuts the N2 valve. Test data for that run will be lost. 32. If successful, the combustion test should initiate and run according to the user settings on the control interface. The test will automatically shutdown at the end of the test run time, save the data, and return to the control interface pretest operational mode. 33. Allow the chamber to cool down after each test by monitoring the chamber and exhaust nozzle temperatures. 34. Replace the igniter tips. 35. Change the filename (usually just the test number) for the next test and change any testing parameters desired, such as pressures, flow rates, etc. 36. Repeat TESTING procedure. Shutdown 37. Allow the chamber to cool down somewhat. 38. Close the GH2 bottle. 39. Close the oxidizer ball valve at the lab wall if using GO2. Close the Air bottles if using Air. 40. Open the propellant solenoid valves to allo w the high-pressure propellants to purge out of the propellant feed lines. 41. Close the GO2 bottles if using GO2. 42. Skip to Step 45 if not pur ging propellant lines with N2. If purging propellant lines with N2: 43. With the propellant solenoid valves open ed, turn the ball valves connecting the N2 line to the propellant lines to the OPEN position, allowing the N2 to purge through the propellant lines into the chamber. 44. Once sufficiently purged, return the ball valves to the CLOSED position. 45. Close the N2 bottle. 46. Shut off the propellant solenoid valves. 47. Open the N2 solenoid valve to purge the remaining nitrogen out of the system, then shut it off.

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119 48. Disconnect power to the electronics system. Assembly Instructions Injector 1. Place the fuel baffle piece/oxidizer tube support and spacer sleeve onto the oxidizer nozzle tube such that the sleeve butts up ag ainst the back of the oxidizer nozzle and the fuel baffle/oxidizer tube s upport butts up against the sleeve. 2. Slide oxidizer nozzle/tube down into the inj ector housing so that the tube protrudes through the Swagelok fitting on the back of the inject or housing and the fuel baffle/oxidizer tube support is pressed into the injector housing, centering the oxidizer nozzle/tube in the injector housing. 3. Place o-ring (2-016 V1164-75) down into the fuel annulus socket on the injector housing block and into the o-ring groove. 4. Screw the fuel annulus down into the sock et on the injector ho using block using the tool holes on the fuel annulus face to tight en it down firmly against the o-ring. The grooves cut the fuel annulus face and the injector housing block face (for placement of injector face thermocouples) should line up when correctly assembled. 5. Tighten the oxidizer noz zle/tube using a Teflon ferule in the Swagelok fitting so that the nozzle tip is at the desired prot rusion/recession from the injector face. 6. Attach the oxidizer and fuel extension lines onto the corresponding ports on the back of the injector housing. 7. Insert the injector face thermocouples and behind injector thermocouple through the flange of the injector housing and seal. Fix the th ermocouples to the desired location on the injector face using glue. Chamber Windows or Copper Inserts and Heat Flux Sensors 8. Clean window/copper inse rt socket thoroughly. 9. Place two o-rings (2-022 V1475-75) into the radial o-ring grooves in the socket. 10. Wipe WD-40 on the o-rings and socket wa lls and around the circumference of the windows/copper inserts. 11. Set the window/insert into the socket (stepped and beveled edge towards inside of chamber) such that it rests level on top of the first o-ring. 12. Place the window flange on top of the window insert, loosely tightening a nut/washer on all 6 bolts.

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120 13. Tighten the flange down, pus hing the window/insert into th e socket. Make sure to tighten the flange down evenly so that the window/insert goes in straight and not crooked, which can break the windows. 14. Once the flange is tightened down to the wall, carefully loosen the flange (again evenly) and remove. 15. Place rubber gasket or copper washer on top of window/insert and retighten the flange with the gasket or washer sandwiched between the flange and the window/insert. Be careful not to over tig hten when using the copper washer with the window, as surface imperfections in either piece can result in a cracked window. Remember that the sealing is provi ded by the radial o-rings. The flange and gasket/washer just keep the window from being pressed out during tests. 16. Repeat for all four si des of the chamber. 17. Place heat flux sensors in the heat flux sens or ports in the chamber wall. Use RTV sealant to hold them in place. 18. Clean the inside surf ace of the chamber. Injector/Chamber Assembly 19. Screw 4 -20 pieces of threaded rod into the tapped holes on the chamber inlet surface. 20. Place the desired injector spacer correspondi ng to the desired injector position (IP1, IP2, IP3) on the chamber in let surface, using an o-ri ng (2-030 V1164-75) in the oring groove at each end of the in jector spacer, so that the spacer is contained within the -20 threaded rods. 21. Place the injector assembly such that th e injector housing block slides through the injector spacer and into the chamber, the flange of the injector housing squeezes the injector spacer between itself and the ch amber inlet surface, a nd the -20 threaded rod passes through the holes on the fl ange of the injector housing. 22. Slide the extension stem sleeves (cut tubi ng that is numbered 18) over the threaded rod and down onto the backside of the injector housing flange according to the following table. These allow the window height to be the same relative to the optical equipment no matter what the injector position is.

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121 Table B-1. Extension stem sleeve designation for the three different injector positions. Extension Stem Sleeves to Use Injector Position Threaded Rod 1 Threaded Rod 2 Threaded Rod 3 Threaded Rod 4 IP1 None None None None IP2 3 2 1 4 IP3 3 & 8 2 & 6 1 & 5 4 & 7 23. Place the steel support plate down over the threaded rod, squeezing the extension stem sleeves between the plate and the back side of the injector housing flange (in the case of IP1 the steel s upport plate and injector hous ing flange make contact with each other). 24. Tighten down the support plate using a nut/washer on each threaded rod, effectively connecting the injector housing and cham ber into one leak-proof assembly. Mounting Injector/Chamber Assembly on the Support Stand 25. Slide the injector f ace/behind injector thermocoupl e wires and the propellant line extensions down through the support stand su ch that the support plate seats in the recess on top of the support stand and the thermocouple wires and propellant line extensions protrude out the bottom of the support stand. 26. Tighten the steel support plat e to the support stand usi ng the two brackets and -20 allen bolts. 27. Connect the propellant line extensions (GO2,GH2,N2) to the corresponding propellant lines below the support stand. Exhaust Nozzle Assembly 28. Place o-rings (2-030 V1164-75) in the o-ring grooves on the insides of the exhaust nozzle flanges. 29. Sandwich the copper exhaust nozzle betw een the exhaust nozzle flanges and tighten using a nut-washer on each of the four threaded rod pieces. The o-rings placed in Step 28 seal the nozzle w ithin this exhaust nozzle assembly.

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122 Chamber Extension, Exhaust Nozzle, Exhaust Tube Attachments 30. Screw 4 -20 threaded rod pieces into th e tapped holes on the outlet face of the combustion chamber (on top in current orientation). 31. Slide desired chamber extensions down th readed rod and mate with chamber or extension surface, using an o-ring (2030 V1164-75) in the o-ring groove of the extensions to seal between the flat face of the chamber or extension backside and the grooved face of the next extension. 32. The permanent chamber extension (extensi on with igniter, pressure transducers, thermocouple, and over-pressure valve) is al ways attached farthest away from the injector and closest to the exhaust nozzle, meaning that all other extensions are placed before it. It is sealed against the other extensions or chamber outlet face using the same o-ring describe d for the other extensions. 33. The exhaust nozzle assembly is then pl aced over the threaded rod against the permanent chamber extension and is sealed with the same o-ring described for the chamber extensions. 34. Place an o-ring (2-030 V1164-75) into the o-ring groove on the backside (top) of the exhaust nozzle assembly. 35. Place the exhaust nozzle thermocouple down into the hole on the backside of the exhaust nozzle. 36. Place the exhaust tube over the threaded rod on top of the exhaust nozzle assembly, allowing the exhaust nozzle thermocouple sh eath to sit in th e groove cut on the exhaust tube flange. 37. Tighten the exhaust tube down on the exhaust nozzle assembly and chamber extensions using a nut/washer on each thread ed rod, effectively sealing the chamber together. DAQ Sensor, Igniter, and Over-pressure Valve Attachment 38. Attach the high-frequency pressure transdu cer to the branch off of the permanent chamber extension. 39. Attach the over-pressure relief valve to the other branch off of the same T connector. 40. Slide igniter through the Swagelok fitting on the perm anent chamber extension into the chamber and tighten using a Teflon feru le at the indicated point on the ceramic insulator of the igniter. 41. Connect all thermocouples (including those comprising the heat flux sensors) to the thermocouple extension cables marked with DAQ channels according to the

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123 following table. Note that each heat flux sensor uses two channels (two thermocouples, one long, one short). Also note that the exhaust nozzle thermocouple should always use the channel immediately available after final heat flux sensor channel for data processing purposes. Table B-2. List of DAQ channel/thermocouple usage. Thermocouple DAQ Channel Chamber/Flame Thermocouple 0 Injector Face Thermocouple Long (ITL) 1 Injector Face Thermocouple Short (ITS) 2 Behind Injector Thermocouple (BIT) 3 Heat Flux Sensor N Long Thermocouple 4 + (2N-2) [will always be even] Heat Flux Sensor N Short Thermocouple 5 + (2N-2) [will always be odd] Exhaust Nozzle Thermocouple 5 + (2N-2) + 1 Disassembly 42. Reverse assembly instructions to disassemble the combustor, ignoring unnecessary steps depending on partic ular disassembly goal.

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124 APPENDIX C CALIBRATION CURVES AND EQUATIONS Metering/Needle Valve Cv Calibration The following Cv calibration curves and equation s were taken from Swageloks data sheets for the corresponding valves. Data points were picked from the graphs Swagelok provided and a plot was made in Ex cel. Curve fitting was used to obtain an equation for Cv versus Number of Turns for each of the valves used in the HPCF. Rsquared values have been presented too for uncertainty analysis purposes. The equations are used in the Labview program to calcula te the mass flow rates of the propellants during the combustion tests. S Series Swagelok Metering Valve The following calibration curve and Equa tion C.1 is for the B-SS4 and SS-SS4-VH metering valves.

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125 y = -3E-06x3 + 8E-05x2 9E-05x + 0.0001 R2 = 0.9995 0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 0.0045 024681012 C v Number of Turns Figure C-1. Calibration curve (Cv versus number of turns) for the B-SS4 and SS-SS4-VH metering valves. 320.0000030.000080.000090.0001vCxxx (C.1) where x is the number of turns on the metering valve. 31 Series Swagelok Metering Valve The following calibration curve and Equa tion C.2 is for the SS-31RS4 and SS31RF4 metering valves.

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126 y = 0.0038x 0.0039 R2 = 1 y = 0.0002x3 0.0004x2 + 0.0023x R2 = 1 y = 0.0074x2 0.1309x + 0.6103 R2 = 0.9911 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 024681012 Number of TurnsC v Figure C-2. Calibration curve (Cv versus number of turns) for the SS-31RS4 and SS31RF4 metering valves. 2 320.00740.13090.6103 03.0 0.00380.0039 3.08.9 0.00020.00040.0023 8.910vxxx Cxx xxxx (C.2) where x is the number of turns on the metering valve. 1 Series Integral-Bonnet Needle Valve The following calibration curve and Equation C.3 is for the SS-1RS4 needle valve, which has a 0.172 inch orifice.

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127 y = 0.0002x4 0.0016x3 + 0.0048x2 + 0.0129x R2 = 0.9994 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0246810 CvNumber of Turns Figure C-3. Calibration curve (Cv versus number of turns) for the SS-1RS4 needle valve, which has a 0.172 inch orifice. 4320.00020.00160.00480.0129vCxxxx (C.3) where x is the number of turns on the needle valve. The following calibration curve and Equation C.4 is for the SS-1RF4 needle valve, which has a 0.250 inch orifice.

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128 y = 0.05x R2 = 1 y = 0.0067x3 0.0429x2 0.1617x + 1.3744 R2 = 0.9987 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 02468 C v Number of Turns Figure C-4. Calibration curve (Cv versus number of turns) fo r the SS-1RF4 neele valve, which has a 0.250 inch orifice. 32 320.00670.04290.16171.3744 06.0 0.00020.00040.0023 6.08vxxxx C xxxx (C.4) Operational-Amplifier Calibration The following calibration curve shows the amplification factor versus the output voltage for the non-inverting operational-amplif ier built for the HPCF The data points were obtained by sending a known voltage (0-120 mV DC) into the amplifier, recording the output voltage, and calculating the amplifi cation factor. Because directly recording the 0-100 mV signal out of the high-frequenc y pressure transducer resulted in noise levels on the order of 10-20% FS, only the 0-10 V signal out of the op-amp, which has noise levels on the order of 0.5% FS, is recorded. The calibration allows the amplification factor to be determined, thus allowing calculation of original mV signal from the high-frequency pressure transducer, which in turn gi ves the pressure value after multiplied by the pressure to voltage constant of the transducer. The data points from the calibration are loaded into the Matlab data processing program HFPT_Data_Analyzer.

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129 Multiple calibrations were performed on diffe rent days, and the calibration curve did not change. 0 10 20 30 40 50 60 70 80 90 0246810 Output Voltage (VDC)Amplification Factor Figure C-5. Calibration curve (amplificati on factor versus output voltage) for the operational amplifier. Pressure Transducer Calibration Propellant Line and Chamber Pressure Transducers The propellant line and chamber pressu re transducers were calibrated by connecting them to a manifold pressurized by Nitrogen and reading the pressure in the manifold via the Mensor calibra ting regulator and display. La bview was used to read in the voltage signals from the three transducer s and a curve was create d. This calibration was performed twice separated by several mont hs. The calibration constants for all three transducers were approximately the same bot h times. Because the transducers produce a linear voltage to pressure relationship, onl y the constant factors are presented here.

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130 Table C-1. Table of calibra tion factors for the chamber and propellant line pressure transducers. Pressure Transducer Calibration Factor (PSIG/Voltage) Combustion Chamber 605.105 Oxidizer Line 618.425 Fuel Line 606.421 High-Frequency Pressure Transducer Each Entran high-frequency pressure transducer came calibrated with a constant mV/FS value. The transducers were calibrated in the combustion lab as well and gave a value approximately equal to the constant calibration factor supp lied by Entran. Since there are several transducers and the indicated calibration factor on th e box is correct, the values will not be listed here due to their short lifetime.

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131 LIST OF REFERENCES 1. Tucker, K., West, J., Williams, R., Lin, J., Rocker, M., Canabal, F., Robles, B., and Garcia, R., Using CFD as a Rocket In jector Design Tool: Recent Progress at Marshall Space Flight Center, 5th International Symposium on Liquid Space Propulsion (CD-ROM), Chattanooga, TN, 2003. 2. Tramecourt, N., Masquelet, M., and Menon, S., Large-Eddy Simulation of Unsteady Wall Heat Transfer in a Hi gh Pressure Combus tion Chamber, AIAA2005-4124, 41st AIAA/ASME/SAE/ASEE Join t Propulsion Conference and Exhibit, Tuscon, AZ, 2005. 3. Marshall, W. M., Pal, S., Woodward, R. D., and Santoro, R. J., Benchmark Wall Heat Flux Data for a GO2/GH2 Singl e Element Combustor, AIAA 2005-3572, 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Tuscon, AZ, 2005. 4. Allen, M. G. and Miller, M. F., Opti cally-Accessible Gas Turbine Combustor for High Pressure Diagnostics Valid ation, AIAA 97-0116, AIAA 35th Aerospace Sciences Meeting, Reno, NV, 1997. 5. Kojima, J. and Nguyen, Q-V., Development of a High-Pressure Burner for Calibrating Optical Diagnostic T echniques, NASA/TM-2003-212738, Glenn Research Center, Cl eveland, OH, 2003. 6. Carter, C. D., King, G. B., and Laurendeau, N. M., A Combustion Facility for High-Pressure Flame Studies by Spectrosco pic Methods, American Institute of Physics, Review of Scien tific Instruments, Vol. 60, No. 8, August, 1989, pp. 26062609. 7. Locke, R. J., Hicks, Y. R., Anderson, R. C., and Ockunzzi, K. A., OH Imaging in a Lean Burning High-Pressure Combustor, AIAA Journal, Vol. 34, No. 3, March 1996, pp. 622-624. 8. Foust, M. J., Deshpande, M., Pal, S., Ni, T., Merkle, C. L., Santoro, R. J., Experimental and Analytical Characte rization of a Shear Coaxial Combusting GO2/GH2 flowfield, AIAA 96-0646, AIAA 34th Aerospace Sciences Meeting, Reno, NV, 1996.

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132 9. Tucker, P. K., Klem, M. D., Smith, T. D., Farhangi, S., Fisher, S. C., and Santoro, R. J., Design of Efficient GO2/GH2 Injectors: A NASA, I ndustry, and University Cooperative Effort, AIAA-1997-3350, 33rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhi bit, Seattle, WA, 1997. 10. Ferraro, M., Kujala, R. J., Thomas, J.-L ., Glogowski, M. J., and Micci, M. M., Measurements of Shear Co axial Injector Sprays Cold Flow and Hot Fire Experiments, AIAA 96-3028, 32nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Lake Buena Vista, FL, 1996. 11. Kohse-Hoinghaus, K. and Jeffries, J. B., Applied Combustion Diagnostics Combustion: An International Series, Taylor and Francis, New York, 2002. 12. Eckbreth, A. C., Laser Diagnostics for Combustion Temperature and Species 2nd ed., Combustion Science and Technology Book Series, Vol. 3, CRC, New York, 1996. 13. Santoro, R. J., Applications of Laser-B ased Diagnostics to Hi gh Pressure Rocket and Gas Turbine Combustor Studies, AIAA-1998-2698, 20th Advanced Measurement and Ground Testing T echnology Conference, Albuquerque, NM, 1998. 14. Frank, J. H., Miller, M. F., and Alle n, M. G., Imaging of Laser-Induced Fluorescence in a High-Pressure Combustor, AIAA-99-0773, AIAA 34th Aerospace Sciences Meeting, Reno, NV, 1999. 15. Edwards, T., Weaver, D. P., and Campbell, D. H., Laser-Induced Fluorescence in High Pressure Solid Propellant Flames, Applied Optics, Vol. 26, No. 17, September, 1987, pp. 3496-3509. 16. Arnold, A., Bombach, R., Kappeli, B ., and Schlegel, A., Quantitative Measurements of OH Concentration Fi elds by Two-Dimensional Laser-Induced Fluorescence, Applied Physics B: Lase r and Optics, Vol. 64, 1997, pp. 579-583. 17. Atakan, B., Heinze, J., and Meier, U. E ., OH Laser-Induced Fluorescence at High Pressures: Spectroscopic and Two-Dimens ional Measurements Exciting the A-X (1,0) Transition, Applied Physics B: La ser and Optics, Vol. 64, 1997, pp. 585-591. 18. Allen, M. G., McManus, K. R., Sonnenfroh, D. M., and Paul, P. H., Planar LaserInduced-Fluorescence Imaging Measurem ents of OH and Hydrocarbon Fuel Fragments in High-Pressure Spray-Flame Combustion, Applied Optics, Vol. 34, No. 27, September, 1995, pp. 6287-6300. 19. Stocker, R., Karl, J., and Hein, D., OH LIF in Atmospheric Pressure Flames Excited by a Tunable OPO (Type II) Lase r System, F3003, Proceedings of PSFVIP-3, Maui, HI, 2001.

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133 20. Singla, G., Scouflaire, P., Rolon, C., and Candel, S., Planar Laser-Induced Fluorescence of OH in High-Pressure Cryogenic LOx/GH2 Jet Flames, Combustion and Flame, Vo l. 144, 2006, pp. 151-169. 21. Reynolds, W. C., STANJAN a reaction chemistry computer program, Stanford University, 1987. 22. Turns, S. R., An Introduction to Combustion: Concepts and Applications 2nd ed., McGraw-Hill, Boston, 2000. 23. Holman, J. P., Heat Transfer 9th ed., McGraw-Hill, Boston, 2002. 24. Callister, W. D., Jr., Materials Science and Engi neering: An Introduction 5th ed., Wiley, New York, 2000. 25. Deshpande, M. and Merkle, C. L., Cha racterization of Unsteady Effects in GO2/GH2 Combustor Flow fields, AIAA-1996-3128, 32nd AIAA/ASME/SAE/ASEE Joint Propulsion C onference and Exhibit, Lake Buena Vista, FL, 1996. 26. Sutton, G. P. and Biblarz, O., Rocket Propulsion Elements 7th ed., WileyInterscience, New York, 2001. 27. Kim, S.C. and VanOverbeke, T. J., Performance and Flow Calculations for a Gaseous H2/O2 Thruster, AIAA J. Spacecraft, Vol. 28, No. 4, July-August, 1991, pp. 433-438. 28. Bazarov, V. G. and Yang, V., LiquidPropellant Rocket Engine Injector Dynamics, Journal of Propulsion and Powe r, Vol. 14, No. 5, September-October, 1998, pp. 797-806. 29. Dahm, W. J. A. and Dimotakis, P. E., Measurements of Entrainment and Mixing in Turbulent Jets, AIAA Journal, Vol. 25, No. 9, September, 1987, pp. 1216-1223. 30. Yeralan, S., Pal, S., and Santoro, R. J., Major Species and Temperature Profiles of LOX/GH2 Combustion, AIAA-1997-2974, 33rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhi bit, Seattle, WA, 1997.

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134 BIOGRAPHICAL SKETCH Alex Conley was born in Lafayette, LA, in 1982, but grew up in Sylacauga, AL. Careful balance of academics and sports landed Alex a scholarship to the University of Miami in 2000. Alex spent four years in Mi ami enjoying the big city life, the beach, and friends, while managing to graduate number two in his graduating class in May 2004 with B.S. in Mechanical Engineering. Alex met the love of his life, Wendy, through his antics on and off the rugby field while at Miami. Alex joined the Combustion Lab at the University of Florida in August 2004, where his wife, Wendy, bega n attending the School of Veterinary Medicine a year earlier. Alex has balanced husbandly duties, his dogs, his love of motorcycles, school, and research during his pursuit of a ma sters degree over the past two years. Upon graduation Alex will m ove to Huntsville, AL, where he has been offered and accepted a position as a Combusti on Engineer for the aerospace research company CFDRC. He will be doing contract work on the upper stage of the CLV at NASA Marshall. He looks forward to being back in good ole Alabama.

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HPCF Control Interface.vi Controls and Indicators Time to Test Initiation (sec) Valve Open Delay Time (sec) Test Run Time (sec) Start/Stop Combustion Run Maximum Allowable Chamber Pressure (psig) Ignition Time (sec) Oxidizer Valve Hydrogen Valve Ignition Spark CPT AIPT HIPT Slope CPT (AC1) Slope AIPT (AC2) Slope HIPT (AC3) Extra Run Time Number of Turns on Oxidizer Regulating Valve # of Turns on Fuel Regulating Valve trol%20Interface.html (2 of 53)4/28/2006 8:43:53 AM file:///F|/Data%20Files/Copy%20of%20thesis/Alex's%20Masters%20Thesis%20St.../Template72-XP/HPCF%20Control%20Interface/HPCF%20Con

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HPCF Control Interface.vi Oxidizer Selector Nitrogen Valve Nitrogen Purge Time (sec) Raw Data File Path file path is the path name of the file. If file path is empty (default value) or is Not A Path, the VI displays a File dialog box from which you can select a file. Error 43 occurs if the user cancels the dialog. PRS N2 Nitrogen Chamber Pressurization Hydrogen Needle Valve Selector Oxidizer Needle Valve Selector stop Thermocouple channels (ob0 sc1 md1 8:30) ([string]) channels: specifies the list of SCXI analog input channels to scan. The default channel list contains channels 0 through 3 on the module in slot 1 of SCXI chassis 1. The syntax for SCXI channel strings is: OBn SCx MDy a:b n is the onboard data acquisition channel x is the SCXI chassis ID (from the config utility) y is the SCXI slot number of the module a is the first channel of the SCXI channel range b is the ending channel in the SCXI channel range For one chassis applications, n = 0. If you have more than one chassis daisy-chained to the same data acquisition board, n = 1 for the second chassis in the chain, etc. If you only want to acquire from one SCXI channel, omit the ":b" from the end of the string. When you are scanning multiplexed SCXI modules, you must scan channels in ascending consecutive order; that is, b must be greater than a. To scan multiple modules, enter an SCXI string like the one above for each module in the channels array; one element in the array for each module to be scanned. You can also enter strings for modules in different chassis to be scanned at the same time. Remember to use the correct n and x values. channel (0) ([string]) channels: specifies the set of analog input channels to read. Scan Rate # Samples Nitrogen Purge On/ Off trol%20Interface.html (3 of 53)4/28/2006 8:43:53 AM file:///F|/Data%20Files/Copy%20of%20thesis/Alex's%20Masters%20Thesis%20St.../Template72-XP/HPCF%20Control%20Interface/HPCF%20Con

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HPCF Control Interface.vi Nitrogen Pressurization Time (sec) after Valve Open PF Oxidizer Valve PF Fuel Valve Ignition Method PFStat PFsparkfin Chamber Pressure (psig) Chamber Temperature (K) Oxidizer Injector Pressure (psig) Hydrogen Injector Pressure (psig) High Pressure Combustion Facility Progress Indicator Oxidizer Valve Hydrogen Valve Spark SC CP Tare Value AIP Tare Value HIP Tare Value Oxidizer Mass Flow Rate (g/ s) Fuel Mass Flow Rate (g/ s) Equivalence Ratio O/F Mass Flow Ratio Oxidizer Specific Gravity Stoichiometric Nitrogen Purge PMS N2 Chamber Pressure Nitrogen Pressurization trol%20Interface.html (4 of 53)4/28/2006 8:43:53 AM file:///F|/Data%20Files/Copy%20of%20thesis/Alex's%20Masters%20Thesis%20St.../Template72-XP/HPCF%20Control%20Interface/HPCF%20Con

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HPCF Control Interface.vi List of SubVIs and Express VIs with Configuration Information Write To Spreadsheet File.vi C:\Program Files\National Instruments\LabVIEW 7.0\vi.lib\Utility\file.llb\Write To Spreadsheet File.vi Acquire and Average.vi C:\Program Files\National Instruments\LabVIEW 7.0\vi.lib\DAQ\ZDAQUTIL.LLB\Acquire and Average.vi Acquire and Average (scaled array).vi C:\Program Files\National Instruments\LabVIEW 7.0\vi.lib\Daq\Zdaqutil.llb\Acquire and Average (scaled array).vi AO Update Channel.vi C:\Program Files\National Instruments\LabVIEW 7.0\vi.lib\DAQ\1EASYIO.LLB\AO Update Channel.vi AO Update Channel (scaled value).vi C:\Program Files\National Instruments\LabVIEW 7.0\vi.lib\Daq\1easyio.llb\AO Update Channel (scaled value).vi AO Update Channels.vi C:\Program Files\National Instruments\LabVIEW 7.0\vi.lib\DAQ\1EASYIO.LLB\AO Update Channels.vi AO Update Channels (scaled array).vi C:\Program Files\National Instruments\LabVIEW 7.0\vi.lib\Daq\1easyio.llb\AO Update Channels (scaled array).vi SCXI-1100 Thermocouplemod1.vi C:\Documents and Settings\aconley\Desktop\aconley\labview\Labview Controllers\SCXI-1100 Thermocouplemod1.vi VI Revision History"HPCF Control Interface.vi History" Current Revision: 315 Position in Hierarchy trol%20Interface.html (52 of 53)4/28/2006 8:43:54 AM file:///F|/Data%20Files/Copy%20of%20thesis/Alex's%20Masters%20Thesis%20St.../Template72-XP/HPCF%20Control%20Interface/HPCF%20Con

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