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Control of Combustion Zone Soot Formation in a Semi-Closed Cycle Gas Turbine

Permanent Link: http://ufdc.ufl.edu/UFE0022852/00001

Material Information

Title: Control of Combustion Zone Soot Formation in a Semi-Closed Cycle Gas Turbine
Physical Description: 1 online resource (133 p.)
Language: english
Creator: Ellis, William
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: combustion, diluent, flameless, mild, recirculation, soot, turbine
Mechanical and Aerospace Engineering -- Dissertations, Academic -- UF
Genre: Mechanical Engineering thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Spectroscopic measurements were made on the primary zone flame of a constant speed, semi-closed cycle, and recuperated gas turbine. This was undertaken at various loads while introducing cooled exhaust gas into the combustor reactant stream as a diluent. Operating conditions included equivalence ratios from 0.42 to 0.64 and reactant oxygen concentration from 15.4 to 20.7% at an average combustion pressure of 34.8 psia. The results demonstrated a power relationship between soot volume fraction and the oxygen concentration in the reactant gas mixture. An inverse power relationship between soot volume fraction and combustion pressure or equivalence ratio was observed. Soot formation was reduced by an order of magnitude when oxygen concentration was reduced to 17.5%. Soot temperature was found to be independent of equivalence ratio and more useful in predicting soot volume fraction than the adiabatic flame temperature. Two predictive models, based on data regression analysis, were developed for soot temperature as a function of pressure and oxygen concentration and for soot volume fraction as a function of equivalence ratio, oxygen concentration, soot temperature and combustion pressure. A third model was developed for adiabatic flame temperature as a function of equivalence ratio, oxygen concentration and combustion pressure. The models demonstrate a close agreement with data and predict soot temperature will increase with combustion pressure and oxygen concentration, while soot volume fraction increases with oxygen concentration but decreases with combustion pressure. The adiabatic flame temperature model predicts increasing temperature with both combustion pressure and equivalence ratio.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by William Ellis.
Thesis: Thesis (M.S.)--University of Florida, 2008.
Local: Adviser: Lear, William E.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0022852:00001

Permanent Link: http://ufdc.ufl.edu/UFE0022852/00001

Material Information

Title: Control of Combustion Zone Soot Formation in a Semi-Closed Cycle Gas Turbine
Physical Description: 1 online resource (133 p.)
Language: english
Creator: Ellis, William
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: combustion, diluent, flameless, mild, recirculation, soot, turbine
Mechanical and Aerospace Engineering -- Dissertations, Academic -- UF
Genre: Mechanical Engineering thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Spectroscopic measurements were made on the primary zone flame of a constant speed, semi-closed cycle, and recuperated gas turbine. This was undertaken at various loads while introducing cooled exhaust gas into the combustor reactant stream as a diluent. Operating conditions included equivalence ratios from 0.42 to 0.64 and reactant oxygen concentration from 15.4 to 20.7% at an average combustion pressure of 34.8 psia. The results demonstrated a power relationship between soot volume fraction and the oxygen concentration in the reactant gas mixture. An inverse power relationship between soot volume fraction and combustion pressure or equivalence ratio was observed. Soot formation was reduced by an order of magnitude when oxygen concentration was reduced to 17.5%. Soot temperature was found to be independent of equivalence ratio and more useful in predicting soot volume fraction than the adiabatic flame temperature. Two predictive models, based on data regression analysis, were developed for soot temperature as a function of pressure and oxygen concentration and for soot volume fraction as a function of equivalence ratio, oxygen concentration, soot temperature and combustion pressure. A third model was developed for adiabatic flame temperature as a function of equivalence ratio, oxygen concentration and combustion pressure. The models demonstrate a close agreement with data and predict soot temperature will increase with combustion pressure and oxygen concentration, while soot volume fraction increases with oxygen concentration but decreases with combustion pressure. The adiabatic flame temperature model predicts increasing temperature with both combustion pressure and equivalence ratio.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by William Ellis.
Thesis: Thesis (M.S.)--University of Florida, 2008.
Local: Adviser: Lear, William E.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0022852:00001


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1 CONTROL OF COMBUSTION ZONE SOOT FORMATION IN A SEMI-CLOSED CYCLE GAS TURBINE By WILLIAM J. ELLIS, JR. 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 2008

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2 2008 William J. Ellis, Jr.

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3 To my sister, Diana Brady, for her confidence and encouragement.

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4 ACKNOWLEDGMENTS This research was sponsored, in part, by th e Departm ent of Mech anical and Aerospace Engineering of the University of Florida, JEA Electric System of Jacks onville Florida, and the State University System of Florida Turbine In itiative. I am indebted to my supervisory committee members, (Dr. William E. Lear, Jr., Dr David W. Hahn and Dr. David W. Mikolaitis) for their guidance and participa tion. I extend special thanks to John F. Crittenden, Jr., for his perspective and assistance regarding ope ration of the experimental set-up.

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5 TABLE OF CONTENTS Page ACKNOWLEDGMENTS...............................................................................................................4 LIST OF TABLES................................................................................................................. ..........8 LIST OF FIGURES.........................................................................................................................9 LIST OF TERMS...........................................................................................................................11 Roman.....................................................................................................................................11 Greek.......................................................................................................................... .............12 Subscripts................................................................................................................................12 ABSTRACT...................................................................................................................................14 CHAP TER 1 INTRODUCTION..................................................................................................................16 2 EXPERIMENTAL APPARATUS......................................................................................... 20 Test Engine.............................................................................................................................20 Vapor Absorbsion Refrigeration System (Vars)............................................................. 22 Recuperator And Warm Gas Cooler................................................................................ 23 Instrumentation................................................................................................................ .......23 Optical Measurement....................................................................................................... 23 Gas Analysis....................................................................................................................24 Load Measurement..........................................................................................................25 Dynamometer...........................................................................................................25 Condensed water......................................................................................................25 Engine Speed Measurement............................................................................................ 25 Flow Measurement..........................................................................................................25 Air and Recirculation............................................................................................... 25 Fuel...........................................................................................................................25 Temperature Measurement.............................................................................................. 26 Pressure Measurement..................................................................................................... 26 Digital Acquisition System (Daq)................................................................................... 27 Signal conditioning.................................................................................................. 27 Operator interface terminal...................................................................................... 27 3 THEORETICAL BASIS FOR DATA ANALYSIS...............................................................29 Two-Color Pyrometry............................................................................................................ .29 Soot Temperature Calculation.........................................................................................29 Soot Volume Fraction......................................................................................................30

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6 Gas Composition................................................................................................................ ....32 Inlet Air Composition...................................................................................................... 32 Recirculation Gas Composition from Exhaust Analysis................................................. 33 Oxidizer (Air + Reci rculation Mixture). .........................................................................35 Equivalence Ratio ...............................................................................................................36 F/A Mass Ratio (Fuel/ Air-Recirculation Mix)............................................................... 36 Stoichiometric F/A Mass Ratio (Fuel/ Air-Recirculation Mix). ..................................... 38 4 EXPERIMENTAL METHOD................................................................................................ 40 Pre-Test Setup.........................................................................................................................40 Start-Up, Operation and Shut-Down...................................................................................... 41 Data Acquisition............................................................................................................... ......42 5 DATA REDUCTION AND ANALYSIS............................................................................... 44 Data Post-Processing........................................................................................................... ...44 Spectrometer................................................................................................................... .44 Data Acquisition System.................................................................................................45 Data Analysis..........................................................................................................................46 Soot Temperature And Volume Fraction........................................................................ 46 Sapphire window transmission.................................................................................46 Sampling distance.................................................................................................... 47 Optical fiber acceptance angle................................................................................. 48 Gas Analysis....................................................................................................................49 Equivalence Ratio............................................................................................................50 Adiabatic Flame Temperature......................................................................................... 50 6 RESULTS AND DISCUSSION............................................................................................. 53 Combustion Zone Parameters................................................................................................. 54 Regression Analysis Of Fvr Based on Combustion Zone Parameters..................................... 56 Measurement Error Analysis.................................................................................................. 59 7 CONCLUSIONS.................................................................................................................... 94 8 RECOMMENDATIONS........................................................................................................ 96 APPENDIX A OPERATING PROCEDURES............................................................................................... 99 The HPRTE Setup Procedure,................................................................................................ 99 The VARS Operating Procedure.......................................................................................... 103 Lab Data Acquisition System Procedure.............................................................................. 108 Spectrometer Operating Procedure....................................................................................... 112 The COSA 1600 IR Gas Analyzer Operating Procedure..................................................... 114 Digital Camera Set-up Procedure.........................................................................................116

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7 B DATA SHEETS.................................................................................................................... 118 C RELEVANT DATA.............................................................................................................126 Measurement Error Analysis................................................................................................ 129 LIST OF REFERENCES.............................................................................................................131 BIOGRAPHICAL SKETCH.......................................................................................................133

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8 LIST OF TABLES Table page 6-1 Regression equation coefficients for soot tem perature and adiabatic flame temperature.................................................................................................................... ....61 6-2 Regression equation coefficients for soot volum e fraction ratio.......................................61 6-3 Data uncertainty for major parameters..............................................................................61 C-1 Processed data............................................................................................................. .....126 C-2 Sample Labview output...................................................................................................128

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9 LIST OF FIGURES Figure page 3-1 Block diagram of HPRTE.................................................................................................. 28 5-1 Geometry and dimensions used to corre ct em ission intensity for sampling distance and optical fiber acceptance angle..................................................................................... 52 6-1 Soot volume fraction ratio vs. combustor inlet O2 %........................................................62 6-2 Emissivity at 525.03 nm vs. % O2.....................................................................................63 6-3 Emissivity at 675.01 nm vs. % O2.....................................................................................64 6-4 Soot volume fraction ratio vs. com bustor inlet eq uivalence ratio..................................... 65 6-5 Soot volume fraction ratio vs. com bustion pressure.......................................................... 66 6-6 Soot volume fraction ratio vs. oxyge n concentration at high fuel flow .............................67 6-7 Soot volume fraction ratio vs. soot temperature ................................................................ 68 6-8 Soot volume fraction ratio vs adiabatic flam e temperature.............................................. 69 6-9 Soot temperature vs. combustor inlet percent oxygen ....................................................... 70 6-10 Soot temperature vs. absolute combustion pressure..........................................................71 6-11 Soot temperature vs. combus tor inlet equivalence ratio .................................................... 72 6-12 Adiabatic flame temperature vs combustor inlet percent oxygen .....................................73 6-13 Adiabatic flame temperature vs. combustion pressure...................................................... 74 6-14 Adiabatic flame temperature vs. combustor inlet equivalence ratio .................................. 75 6-15 Soot temperature/adiabatic flame temperature vs. combustor inlet % O2.........................76 6-16 Soot temperature/adiabatic flame temperature vs. com bustion pressure........................... 77 6-17 Soot temperature/adiabatic flam e temperature vs. equivalence ratio ................................ 78 6-18 Regression and data soot temperat ure vs. com bustor inlet percent oxygen...................... 79 6-19 Regression and data adiabatic flame te m perature vs. combustor inlet percent................. 80 6-20 Run data and regression Fvr vs. combustor inlet % O2 using Tsoot for the temperature parameter...................................................................................................................... ......81

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10 6-21 Run data and regression Fvr vs. combustor inlet % O2 using Tad for the temperature parameter...................................................................................................................... ......82 6-22 Synthetic FvR vs. Pcomb, = 0.4 with 15 % and 20 % O2 using Tsoot.................................83 6-23 Synthetic FvR vs. Pcomb, = 0.65 with 15 % and 20 % combustor inlet O2 using Tsoot.....84 6-24 Synthetic FvR vs. Pcomb, = 0.4 with 15 % and 20 % combustor inlet O2 using Tad.........85 6-25 Synthetic FvR vs. Pcomb, = 0.65 with 15 % and 20 % combustor inlet O2 using Tad.......86 6-26 Run data and extreme case synthetic FvR vs. combustor inlet % O2 using Tsoot................87 6-27 Run data and extreme case synthetic FvR vs. combustor inlet % O2 using Tad..................88 6-28 Run data and extreme case synthetic FvR vs. combustor inlet e quivalence ratio using Tsoot.....................................................................................................................................89 6-29 Run data and extreme case synthetic FvR vs. combustor inlet e quivalence ratio using Tad.......................................................................................................................................90 6-30 Synthetic FvR vs. combustor inlet % O2 with variable combustor inlet .........................91 6-31 Synthetic Tsoot vs. combustor inlet % O2 with constant Pcomb............................................92 6-32 Synthetic Tsoot vs. Pcomb with constant combustor inlet % O2............................................93

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11 LIST OF TERMS Roman a Regression coefficient A Cross sectional area or stoichiometric moles of air C1 Planks first constant C2 Planks second constant Cabs Particle absorption cross section Cd Discharge coefficient Cext Particle extinction cross section Cscat Particle scattering cross section d Particle diameter F/A Fuel-to-air ratio Fv Soot volume fraction Fvmax Maximum soot volume fraction FvR Soot volume fraction ratio I Emission intensity ik Imaginary part of th e complex refractive index K Mole ratio Kext Extinction coefficient L Optical path length MW Molecular weight m Complex refractive index m Mass flow rate N Particle density

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12 n Moles or real part of the complex refractive index n Mole flow rate P Pressure R Mass-specific gas constant or recirculation ratio T Temperature V Velocity or valve V Volumetric flow rate Greek Particle size parameter Venturi contraction ratio Change in an associated term Emissivity Optical properties parameter Wavelength Density Stefan-Boltzmann constant Equivalence ratio Mole fraction Subscripts 0 Reference state, 300 Kelvin 1 State one 2 State two amb Ambient b Blackbody

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13 Bnr Combustor liner comb Combustor db Dry bulb dry Dry gas mixture fuel Property of fuel H2O Property of water HPRE High pressure recuperator exit i ith constituent of a mixture m Mass basis MAI Main air inlet max Maximum observed value n Molar basis N2 Property of nitrogen O2 Property of oxygen ox Reactant gas mixture ratio Ratio of parameters rec Recirculation sat Property at saturation conditions soot Value for soot stoic Stoichiometric throat Property at bell mouth throat wb Wet bulb

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14 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 COMBUSTION ZONE SOOT BEHAVIOR IN A SEMI-CLOSED CYCLE GAS TURBINE By William J. Ellis, Jr. December 2008 Chair: William E. Lear, Jr. Major: Mechanical Engineering Spectroscopic measurements were made on th e primary zone flame of a constant speed, semi-closed cycle, and recupera ted gas turbine. This was undertaken at various loads while introducing cooled exhaust gas in to the combustor reactant stream as a diluent. Operating conditions included equivalence ratios from 0.42 to 0.64 and reactant oxygen concentration from 15.4 to 20.7% at an average combustion pressure of 34.8 psia. The results demonstrated a power relationship between soot volume fraction and the oxygen concentration in the reactant gas mixture. An inverse power relationship between soot volume fraction and combustion pressure or equivalence ratio was observed. Soot formati on was reduced by an order of magnitude when oxygen concentration was reduced to 17.5%. Soot temperature was found to be independent of equivalence ratio and more useful in predicti ng soot volume fraction than the adiabatic flame temperature. Two predictive models, based on data regression analysis, we re developed for soot temperature as a function of pressure and oxygen concentration and for soot volume fraction as a function of equivalence ratio, oxygen concentrati on, soot temperature and combustion pressure. A third model was developed for adiabatic flame temperature as a function of equivalence ratio, oxygen concentration and combustion pressure.

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15 The models demonstrate a close agreement with data and predict soot temperature will increase with combustion pressure and oxygen concentration, while soot volume fraction increases with oxygen concentration but decreas es with combustion pressure. The adiabatic flame temperature model predicts increasing te mperature with both combustion pressure and equivalence ratio.

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16 CHAPTER 1 INTRODUCTION Soot produced by various combustion processes has been studied with increasing interest in recent decades. This is the result of concer ns regarding health, climate change and efficient utilization of resources. There is growing eviden ce from field observation s that a soot aerosol layer exists at 10-11 km alt itude [1, 2]. A correlation be tween the observed soot mass concentration and calculated fuel usage from air traffic suggests that ai rcraft fuel combustion may be the principal source of the soot aerosol layer in the stratosphere [7]. High altitude emission of soot particle s acting as condensation nuclei may s ubstantially affect the cirrus cloud formation [3]. Arguably, the effect of atmospheri c soot levels could be to perturb the Earths energy balance by altering these cloud formations If the impact of this perturbation is significant, it might be expected to lead to ch anges in climate [4, 5], although the effect on global temperature is still controversial due to comple x interactions with other aerosols. Soot, as a component of particulate matter (PM) air pol lution, has been the subject of hundreds of investigations over the last ten years. It is now generally accepted that these pollutants are a significant contributor to illness and mortality rate s. The influence is so strong that the EPA has issued periodically reviewed standards on PM em issions as required by the Clean Air Act. There is evidence of a nearly linear relation between increased risk of premature mortality and PM pollution [6]. The performance of gas turbines has con tinuously improved since their first practical application. With their performance, so has thei r popularity increased as appropriate application of the technology broadens. In aviation they ar e the primary choice of propulsion for all but the smallest aircraft, and as a stationary power source, they are now practical for tens of kilowatts to multimegawatt generation facilities.

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17 This popularity can be expected to increas e owing to the low cost, high efficiency, simplicity, reliability, multi-fuel capability, fast st art-up and short facility construction time. Gas turbine emissions are therefore of primary concern [7 ]. For civilian use, health, energy efficiency and environmental effects are the main priority. In military applications, the impact of efficiency on fuel logistics and mission capab ility as well as the exhaust signature are more important issues. At the least, soot emissions represent avai lable energy that is not utilized. Beyond that, the impact of thermal radiation from soot on engine components must be mitigated as part of the performance improvements needed to further explo it the attractive characteristics of gas turbines. In particular, the life of combus tor liners is strongly influenced by radiative exchange with soot produced in the flame. Soot production is enhanc ed at the higher temperatures and pressures expected in new designs. At thes e conditions the size and concentra tion of soot particles allows them to radiate as black bodies in the infrared an d this is the predominant heat load. The measure currently taken to control this effect involves additional film cooling ove r what otherwise might be required. This approach has a deleterious impact on engine performance by compromising temperature pattern factor, low power combustion efficiency and exhaust pollutants such as carbon monoxide and unburned hydrocarbons [8, 9]. Recent investigations of the soot formati on mechanism generally resolve it into four phases. These are nucleation, co agulation, surface reactions an d agglomeration. The source of carbon in the process involves both vapor-phase reactions and liqui d-phase pyrolysis. All of the phases are affected by local temperature, pressure and oxygen concentration, as well as fuel type. Research suggests that in regard to local temperature, soot bu rnout ceases below approximately 1300 K and soot formation requires appr oximately 1600 K for nucleation [10].

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18 The effect of molecular oxygen may, at high temperature, increase radical species and actually promote soot formation, rather than ox idation [11]. Further, soot volume fraction has been observed to be approximately proportional to a power of the absolute pressure with the exponent displaying variability depending on pressure regime [12-15]. Researchers have also been examining th e impact of high temperature combustion air with and without reduced oxygen concentration as well as more typical air temperatures and reduced oxygen concentration on combustion and flame characteristics. These studies generally involve near-atmospheric pressu res and preheat ranging from 540 R to 3600 R, with the goal of efficiency increases accompanied by reduced si ze and pollution for industrial boilers and furnaces. Observations of the effect of reducin g oxygen concentration, through dilution with recirculated exhaust or inert ga ses, include a reduction in soot production, with its accompanying flame luminosity, C2 species, CO, unburned hydrocarbons and NOx. When N2 is used as the diluent however, NOx reduction is dependent on conditions. As preheat temperatures increase in concert with dilution, temperature gradients are s een to diminish as the reaction zone becomes more distributed. When temperatures approach maximum and O2 concentration is reduced below 15% to a minimum of about 2%, the flame color may transform to blue, blue-green or become colorless, with combustion being nearly homogeneous and fully distributed throughout the combustion chamber [16-21]. This behavior has been referred to as Flame less or Mild combustion in the literature. Although the peak flame temperature is reduced, th e volumetric energy release tends to be higher since the reaction zone is distributed throughout the combustion chamber rather than having a peak near the point of fuel introduction.

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19 Thus, a higher mean temperature can be maintained without exceeding material limits. This is somewhat analogous to the temperature pattern factor in gas turbines. These furnace experiments did not addre ss how the soot formation mechanism was modified by operating conditions, only methods by which it might be accomplished. Similarly, the present study was an evaluati on of practical means by which one or more of the phases of soot formation could be interrupted and thus reduce or eliminate soot formation in the combustion zone of a gas turbine. This was accomplished by introducing cooled combustion products into the combustion air stream as a diluent and preheating the mixture by exhaust heat recuperation. Quantitative information on soot volume fraction and temperature behavior in the combustion zone was obtained using infrared ab sorbsion gas analysis and two color pyrometry via a spectrometer viewing the combustion fl ame through a sapphire window. The purpose of this investigation was to develop design tools making it possible to predict and control soot formation and extend the performance capability of gas turbine technology.

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20 CHAPTER 2 EXPERIMENTAL APPARATUS Test Engine The experim ental combustion rig used for this investigation is the High Pressure Recuperative Turbine Engine, (HPRTE) (Fig. 31), developed by the University of Florida Energy & Gasdynamic Systems Laboratory. The engi ne is augmented with a vapor absorbsion refrigeration system and can be operated with below ambient inlet temperature in what is referred to as the PoWER cycle. It is an independent twin spool, turbo shaft engine with recuperation and the capability to recirculate exhaust gas cooled by chilled water and vapor absorbsion refrigeration. This allows opera tion in a semi-closed cycle configuration. An abbreviated description of capabilities and operation of the HPRTE is given here. Detailed construction and capabilities of the HPRTE has been documented by Howell [27]. The core or high pressure section of the HPTRE is a Rover, model 1S-60, 60 hp, turbo shaft engine with a design mass flow rate of 1.33 lbs/s and a pressure ratio of 2.8. Th is engine was produced in the mid-twentieth century as pa rt of an educational package. It consisted of the Rover engine and a water-brake dynamometer, manufactured by Heenan & Froude, on a common frame with a stand alone fuel delivery system. Mechanical instrumentation provi ded data for operating performance evaluation. In order to investigate the pe rformance of a pressurized, semi-closed cycle, this package was augmented or upgr aded with electronic analog and digital instrumentation to provide more accurate and detailed information on the many components of the system. An additional fuel tank and fuel heat exchanger (FC) has also been added to allow testing of multiple fuels at controlled temperature.

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21 The external flow path has been modified considerably to accom modate a Garret GT 4294731376-1 turbocharger used in the low pressure s ection, as well as ducting between various heat exchangers and flow controls, to facilitate recirculation of e xhaust gases. Internally, the High Pressure Compressor (HPC) discharge has been changed to redirect flow to a specially constructed recuperator (RECUP). Also, the combustor liner has been modified by welding 18 ga, perforated stainless steel restrictor plates, having strai ght pattern 0.125 holes on a 0.25 pitch, over the dilution flow passages. There were two reasons for this. The return duct from the RECUP discharged over one of the passages causi ng an asymmetric temperature distribution at the high pressure turbine (HPT) exit. A single restrictor plate improved this condition. Three more plates were attached over the remaining pa ssages for this research. It was reasoned that higher primary zone flow, resulting from the add ition of these plates, w ould extend the level of recirculation that could be tolerated, without extinguishing the flame due to reduced oxygen concentration. In operation, the HPT discharges into the RE CUP where thermal energy is transferred to the combustor (Bnr) inlet gas stream. Exhaust gas ma y discharged to the stack, or be diverted to the low pressure turbine (LPT) and/or the recircul ation path. Recirculated gas is cooled by three custom heat exchangers in series. The first is the Hot Gas Cooler (HGC), which rejects heat to the Vapor Absorbsion Refrigeration System (VAR S) and generates refrigerant vapor for that process. The second, designated as the Warm Gas Cooler (WGC), rejects heat to the local Process Chilled Water (PCW) supply. The third is the VARS evaporator or Cold Gas Cooler (CGC) where additional heat is re jected providing the capability to cool the recirculated gases below ambient temperature.

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22 Recirculated exhaust gas is mixed with fres h air from the Main Air Inlet (MAI) and the Low Pressure Compressor inlet (LPCI) ahead of the HPC inlet. Discharge from the HPC is preheated in the RECUP be fore entering the Bnr. The HPRTE may be operated in open cycle, with air supplied thr ough the MAI and LPCI (in high pressure mode) with all exhaust sent to the stack. In semi-closed cycle mode, the recirculation control valve (VR) is opened, allowing cooled exha ust gas to flow to the mixing junction just up stream of the HPC inlet. This provides a parallel flow path and reduces MAI flow simultaneously. Once VR is fully opened, the amount of recirculation flow may be increased, within limits, by throttling the MAI valve (VMAI). The mass Recirculation ratio Rm, defined as the mass of recirculated gas flow di vided by the mass of ambient air flow was limited to a maximum of ~ 1.0 when throttling VMAI, after fully opening VR. The capability to pressurize the core engine was not exploited in this invest igation. To do so, with or without recirculation, the boost control valve (VB) would be throttled to divert e xhaust flow to the LPT. As flow through the LPC increases, so does recirculation flow due to the higher supply pressure from the throttled exhaust. Both VR and VB must be operated in unis on in order to control Rm. As the pressure ratio of the LPC approaches 1.0, VMAI must also be throttled and eventually closed to prevent reverse flow. In the cu rrent configuration, the LPC can achieve a maximum pressure ratio of ~ 1.4. The WGC chilled water flow is generally unrestricted when the HPRTE is in operation, however the VARS performance must be matched to heat load as recirculation gas flow changes in order to maintain stable behavior and desired HPC inlet temperature. Vapor Absorbsion Refrigeration System (Vars) The VARS i s a single effect, continuous ope ration, ammonia absorbsion refrigeration system, designed, built and installed by Energy Concepts of Annapolis Maryland. The VARS has a design performance of 19 tons re frigeration with a COP of 0.85.

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23 This system removes heat from the recirc ulated exhaust gases via the ammonia vapor generator and evaporator disc ussed above as the HGC and CGC respectively. VARS process heat is rejected to the PCW system. Recuperator And Warm Gas Cooler The RECUP and W GC heat exchangers were bo th custom built by Elanco Inc. of Newark Delaware. They are both she ll and tube designs with an effectiveness of 0.51 and 0.85 respectively. Instrumentation During test runs of the HPRTE data is reco rded in two ways, m anually and digitally. The manual instruments, including thermometers, mano meters and pressure gages, are generally redundant and are used to monitor parameters critical to the research and system health. This makes it possible to be aware of performance ch anges not being viewed at the moment on the digital system and also as a back-up in the even t of data file corruption. The various instruments used for measurement are discussed here. Optical Measurement The engine com bustion chamber has been modi fied by the addition of a 0.94 inch view diameter CeramTec sapphire windo w, P/N 17105-02-W. This allows observation of the flame in the primary combustion zone for video record ing and the collection of data with the spectrometer. All spectrometry hardware was supplied by Ocean Optics of Dunedin Florida, with the exception of one optical fiber assembly. The system is comprised of an optical fiber assembly and a S2000 spectrometer having a 500-770 nm bandwidth, equipped with a 1200 line grating blazed at 750 nm, a coated array, an L2 lens a nd a 10 m slit. This unit relies on a 2000 pixel, Charged Coupled Device array (CCD ) to measure emission intensity.

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24 During the test program, two optical fiber assemblies were used. The first was damaged and replaced with a P600-5-VIS/NIR assembly. Specifications for the first fiber were not available, however calibration data was taken fo r both to account for performance differences. The spectral data samples were recorded us ing a laptop computer running Ocean Optics Spectrasuite software. The emissions from the flam e were recorded in arbitrary units of total count, which is measured over a specific period defined as integration time. This time was chosen for each data point to prevent CCD satura tion. Saturation occurs at slightly less than 4000 counts and the integration time sel ected during data acquisition, kept the total at 50-80% of that level to maximize signal to noise ratio. To convert the data to an absolute intensity needed for analysis, calibration curves were generated using an LS-1-CAL tungsten halogen standard. Gas Analysis The gas analyzer used in this investigation was a COSA model 1600-IR. The device utilizes infrared absorb sion to measure CO, CO2 and unburned hydrocarbons as CH4, and electrochemical cells for NO and O2. Exhaust gas is sampled just prior to exiting the stack and passes through a x 18 stainles s steel probe and 6 of neoprene hose to a condensate trap at the analyzer inlet. Data is recorded as actual percent or ppm concentration, which is to say neither on a wet or dry basis. Storage capac ity is 50 data points which can be displayed on an LCD screen for transcription to a perman ent record. The analyzer was calibrated using certified gas mixtures, of a typi cal concentration expected to be measured, based on previous testing with the HPRTE.

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25 Load Measurement Dynamometer As stated in the engine de scription, shaft power is abso rbed with a H eenan & Froude Dyna mometer, equipped with a load cell on the moment arm. Documentation was no longer available for the load cell. Condensed water Condensed water was removed from the WGC a nd CGC using three peristaltic pumps. The pumps discharge into a reservoir supporte d by a load cell having a 72 pound capacity from Omega Engineering of Stamford CT. Engine Speed Measurement Shaft speed was m easured at the dynamome ter output flange using an ROS-W optical sensor and ACT-3 panel tachometer from Monarch Instruments of Amherst NH. Flow Measurement Air and Recirculation Fresh air flow for the HPC (the LPC was not utilized) was m easured using the MAI, original equipment bell mouth, pr ovided with the system. The throat diameter is 4.41 inches. Recirculated exhaust gas flow was measured with a ventur i (RCV), P/N V962900-CSI from Flow-Dyne of Fort Worth TX, having a throat di ameter of 2.900 inches and a beta ratio of 0.4936. Factory calibration data was used fo r discharge coeffi cient calculations. Fuel A turbine flow m eter, model number MF1/2X70B from Hoffer Flow C ontrols of Elizabeth City, NC was used to measure fuel flow in ga llons per hour. This data was corrected for fuel density variations due to temperature in mass flow calculations.

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26 Temperature Measurement For the dry bulb tem perature (Tdb) and we t bulb temperature (Twb) a psychrometer, catalog number 22010, from Industrial Instruments & Supplies of Southampton, PA was utilized. The percent RH was calculated during a run for e ach data point using the nomographic calculator supplied with the psychrometer. Combined with lo cal barometric pressure, this information was used to determine the molecular weight, specific gas constant and density of the fresh air supply to the engine. The remaining temperatures used in analysis were for the MAI, WGC exit/RCV inlet, HPR exit/Bnr inlet and the HPC inle t. All of these were type J thermocouples, of a length appropriate for each location, from Omega Engineering of Stamford CT. Pressure Measurement Pressure data was acquired with a selec tion of instrum ents and methods. Ambient barometric pressure was taken from data publishe d by the University of Florida Department of Physics Weather Station on an hourly basis. Both current and archival data can be found at the web site http://www.phys.ufl.edu/weather/ The v alue used for analysis was an average of measurements taken during the time of day for each test run. Three styles of manometer were utilized for data recordi ng. The MAI bell mouth was an inclined manometer, with a fluid SG of 1.91. The RCV P was measured with a U-Tube style, having a fluid SG 0.827 and the third was a column manometer with a fluid SG of 1.75 for the Bnr P. For all manometers, fluid specific gravity was corrected for variation with temperature to obtain actual P. The MAI inclined manometer was scal ed for direct readout in inches of H2O, which required the additional step of conversi on to inches of fluid before the temperature correction.

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27 Two other instruments were used for pressure data. The Bnr inlet was measured with a Bourdon Tube mechanical gauge and the RCV inlet was measured using a PX138 series pressure transducer from Omega Engineering. Digital Acquisition System (Daq) Signal conditioning National Instrum ents Corp. of Austin, Texas products were used for signal conditioning and processing software. The hardware chassis was a four slot model SCXI-1000 which could be configured with a selection of modules depending on research need s. In this investigation, an SCXI-1100, two SCXI-1102s and an SCXI-1126 were needed. The SCXI-1100 module was utilized for pressure transducer load cell and the engine tach ometer signals and was equipped with an SCXI-1300, general purpos e terminal block. All thermocouples for the engine proper were segregated on one of the SCXI-1102 modules. Thermocouples to monitor VARS performance were on the second SCXI-1102 module. Both were terminated using isothermal, cold junction compensated SCXI-1303 terminal blocks. The SCXI-1126 accepts frequency input from the fuel and PCW flow meters. It was co mplimented with an SCXI-1327 terminal block for extended voltage th reshold level. Operator interface terminal Real tim e and post-processing of the data wa s accomplished with a Dell Optiplex 150 desk top computer operating at 1200 MHz with 256 Mb of RAM. Real time processing utilized LabVIEW 7.1 software from Nationa l Instruments. This version of LabVIEW saved the data in a two column .xls file. A sample of this output is shown in Appendix C. The first column was an index and the second was the data value. In the current confi guration, the DAQ is continuously recording 63 parameters with an average scan rate of 1.3 seconds.

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28 Figure 3-1. Block diagram of HPRTE. HPC RE GG HPT LPT Stack Stack VMAI LPC CGC RECUP HGC WGC VB VR FC Fuel RCV MAI LPCI Bell mouth Bell mouth Bnr

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29 CHAPTER 3 THEORETICAL BASIS FOR DATA ANALYSIS Two-Color Pyrometry The application of two-color pyrom etry was introduced by Ho ttel and Broughton who utilized colored glass screens a nd an optical pyrometer [22]. Si nce that time there have been many advancements in instrumentation and data processing capability. However, the technique and results of their work are still in common use. The approach allows th e calculation of soot temperature and volume fraction and has been util ized by many researchers. One example is the work of Zhao and Ladommatos [23] where the met hod is presented in detail. A brief description is shown here for convenience. Soot Temperature Calculation W ith a blackbody having an emission intensity Ib, known at its surface, the temperature can be calculated at two wave lengths using Plancks equation for monochromatic emissive power and solving for T 1 and T 2. 1e C IT/C 5 1 ,b2 (3-1) Cl = 3.7418 x 10-16 W-m2 and C2 = 1.4388 x l0-2 m-K. In two-color pyrometry it is convenient to define the Apparent Temperature Ta, where Ib, (Ta) = I(T). Ib, (Ta) is the emission of a blackbody at Ta, equal to the intensity of a real emitter I(T), at the actual temperature T. Then the monochromatic emissivity is given by Equation 3-2. TI TI,b a,b (3-2) Combining 3-1 and 3-2 yields Equation 3-3.

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30 1e 1ea2 2T/C T/C (3-3) Monochromatic emissivity for a flame is of ten estimated by the empirical relationship developed by Hottel and Broughton: /LKexte1 (3-4) Equations 3-3 and 3-4 may be combined giving Equation 3-5. 1e 1e 1lnLKa2 2T/C T/C ext (3-5) Writing 3-5 for two wavelengths and setti ng both cases equal gives Equation 3-6. 2 2a22 22 1 1a12 121e 1e 1 1e 1e 1T/C T/C T/C T/C (3-6) where is an optical properties parameter typi cally chosen as 1.39 for soot at visible wavelengths. K is an absorption co efficient proportional to the number density of soot particles and L is the geometric thickness of the flame along the optical path of de tection. Equation 6 is solved for T = Tsoot with Ta1 and Ta2 from Equation 3-1. Then Equation 3-5 can be solved for KL. Soot Volume Fraction From Rayleigh theory, Kext = NCext and for an absorbing particle Cabs >> Cscat so that Cext ~ Cabs. Therefore Kext can be expressed as in Equation 3-7. ext ext 2 2 3 2 0 absKNCdddP 2m 1m IMNNC (3-7)

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31 In Equation 3-7, N = Particle density, Cext = particle extinction cross section, Cabs = particle absorption cross section, Cscat = particle scattering cross section, Kext = extinction coefficient, = d/ d = Particle diameter, = wavelength, m = n ik, the comp lex refractive index and P(d) is a particle size distribution func tion. The soot volume fraction can be expressed as in Equation 38. 0 3 vdddPd 6 N F (3-8) Solving 7 and 8 for 0 3dddPd, setting both terms equal and solving for Fv gives Equation 3-9. 2m 1m IM6 K F2 2 ext v (3-9) Having Tsoot and the optical path length L, the quantity Kext is known from 3-5. From the work of Chang & Charlampopoulos [24], m can be found where; n = 1.811+0.1263ln +0.027ln2 +0.0417ln3 (3-10) k = 0.5821+0.1213ln +0.2309ln2 -0.01ln3 (3-11) Use of the Rayleigh approximation require s that the particle size parameter = d/ <<1. Soot particles are generally believed to range in diameter from 10-60 nm [25, 26]. Since measurements are being taken through a window in the mid re gion of the combustion zone, a diameter of ~ 35nm is assumed. This gives ~ 0.21 which is reasonable, particularly since data is presented as a volume fraction ratio. To im plement solution of th ese relationships, the spectrometer must be calibrated for absolute irra diance with a standard source and the data must be corrected for sensing distance, view port transmission and optical fiber acceptance angle.

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32 For the calculation of Kext, the size of the flame must be assu med or measured to determine the optical path length L. Gas Composition Inlet Air Composition Manual data is taken for the air ambient pressure, Pamb, dry bulb temperature, Tdb and wet bulb temperature, Twb. From this, the percent relative humid ity (%RH) is known. A dry total air pressure can then be calculated. O2H amb dryPPP (3-12) The partial pressure of H2O, PH2O, is found from %RH and the H2O saturation pressure at Tdb. sat O2HP 100 RH% P (3-13) Assuming dry air is 21% O2 and 79% N2, the dry partial pressure of each is calculated based on Pdry. 76.4 P Pdry 2O (3-14) 2O 2NP76.3P (3-15) Dividing the partial Pressures by Pamb gives the volume or mole fraction, i, of the inlet air constituents. amb O2H O2HP P (3-16) amb 2O 2OP P (3-17) amb 2N 2NP P (3-18)

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33 Given the mole fractions and molecular weights of the constituents, the inlet air molecular weight, MWMAI, can be found. i MAIMW MW (3-19) With this and the universal gas constant, the specific gas constant for the inlet air is known for flow calculations. Rlbm lbfft MW 1545 Rair MAI (3-20) Recirculation Gas Compositio n From Exhaust Analysis The exhaust gas must be cooled pr ior to analyzer sampling. Only CH4, CO, CO2, NO and O2 are measured directly. Ther efore an unknown quantity of water may condense changing the species concentration. The recirculated gases ar e cooled further before mixing with the ambient air at the compressor inlet, re sulting in additional water conde nsation. As a result, only the relative concentration of measured species can be known for the re circulation flow from exhaust gas analyzer data. The actual composition of the exhaust gases is calculated through stoichiometry. The reaction equation 3-21 is used. 2N 2OH2O NO 2 CO CO4 CH 2OH2N2O yxNnOHnOnNOn COnCOnCHnOHNOAHC2 2 2 2 4 2 2 2 (3-21) In Equation 3-21, A is the known molar ambi ent air inlet flow pe r mole of fuel, ni is the exhaust species moles per mole of fuel and i is the inlet air constituent mole fraction. From exhaust gas analysis, species volume per cent and thus the molar ratio, expressed as Ki, is known for the constituents in Equations 3-22 through 3-26. 2CO4CH1n/nK (3-22) 2CO CO2n/nK (3-23) 1n/nK2CO2CO3 (3-24)

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34 2CO NO 4n/nK (3-25) 2CO2O5n/nK (3-26) The unknown mole ratios are K6 and K7. 2COO2H6n/nK (3-27) 2CO2N7n/nK (3-28) Atomic balances for carbon, hydrogen and ni trogen can be written in terms of nCO2, i and Ki as shown with Equations 3-29, 3-30 and 3-31 re spectively. These can be solved for nCO2, K6 and K7 given x and y for a known fuel. 3212COKKKnx (3-29) 6 12CO O2HK2K4nA2y (3-30) 7 42CO2NK2KnA2 (3-31) From test point data, the amount of water condens ed from the recirculated exhaust gas is known, as is the fuel flow. Therefore the moles of wate r condensed per mole of fuel can be calculated. The moles of water in the exhaust ga s per mole of fuel are known from K6. 62CO O2HKnn (3-32) The moles of water condensed are subtracted from the moles of water in the exhaust, which then allows calculation of species mole fraction in the recirculated gas. n ni i (3-33) Given the constituent mole fractions and molecu lar weights, the recirculated gas molecular weight, MWrec can be found using Equation 3-34. i recMW MW (3-34)

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35 With this and the universal gas constant, the sp ecific gas constant for recirculation gas, Rrec is known for flow calculations. Rlbm lbfft MW 1545 Rrec rec (3-35) Oxidizer (Air + Recirculation Mixture) From the test data, inlet pressure, temperature and p are known for the fresh air intake bell mouth and the recirculation gas path venturi. With the specific gas constants, the density can be calculated for both recirculation gas and ambi ent air intake using the ideal gas law where RT/P (3-36). For the fresh air intake bell mouth, Bernoulli s equation can be appl ied to find the flow velocity at the throat. Assuming constant densit y and elevation, the equa tion can be solved for velocity. throat amb cPP g2 V (3-37) The area of the bell mouth throat is known, therefore ambient air intake mass flow, MAIm can be solved for. MAI MAIVA m (3-38) For the recirculation venturi, the flow velocity is slightly more complex due to losses and geometric constraints. These are accounted for with the discharge coefficient, Cd, which is published by the manufacturer along with the physic al dimensions of the venturi. Velocity is then calculated. 4 c d1 Pg2 CV (3-39)

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36 Here is the contraction ratio equal to the throat diameter divided by the entrance diameter. The area of the venturi throat is known, therefore recirc ulated gas mass flow,recm, can be solved for. rec recVA m (3-40) With this information the mass basis recirculation ratio, Rm, is known. MAI rec mm m R (3-41) Given the MW of the mixtures, a mo le basis recirculation ratio, Rn can be calculated. rec air mnMW MW RR (3-42) The MW for the air/recirculation mixture or oxidizer, can then be found for use in equivalence ratio calculations. n rec nairR1 MWRMW MWox (3-43) Equivalence Ratio F/A Mass Ratio (Fuel/ Ai r-Recirculation Mix) If total oxidizer and fuel mass flow is known, it is necessary to determine the portion of oxidizer flowing to the primary zone in order to calculate This was investigated in two ways. Test data was available for the gas turbine in an unmodified cond ition while operating at maximum design power. Assuming a of 1, the primary air mass flow could be calculated by balancing the reaction equation. 2 2 2 2N2O yxNDOHCCOBNOAHC2 2 (3-44)

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37 The fuel molecular formula was assumed to be that of n-Dodecane, C12H26, with a molecular weight, MW, of 170.341. Fuel and ai r volumetric flow and density were known, allowing the calculation of flow on a mass and molar basis. So lving Equation 3-44 for A the moles of air per mole of fuel and multiplying by th e molar flow of fuel gave the flow of air on a mole basis. This was multiplied by the MW of dry air, 28.85, giving air mass flow into the primary zone. Dividing this valu e by the total inlet flow gave the primary flow fraction. In the second method all air passages in the combustor liner were measured and the flow areas apportioned to primary or d ilution flow according to their location. Both methods agreed within 0.1% indicating that, on av erage, the passages had similar flow coefficients. The primary flow fraction was 0.241-0.242 of the total. For this research, orifice plates were welded over the dilution flow passages to change flow distribution. This reduced the total flow area and increased the portion allotted to the primary zone, resulting in a primary flow fraction of 0.428. The fuel flow V was measured volumetrically during th e test runs. Fuel mass flow rate, fuelm, is calculated using fuel de nsity corrected according to te mperature with the following relation developed by the American Petroleum Institute: 0 fuel 0 fuel1TT002.0 (3-45), where T0 is the temperature at which the baseline density, 0 was measured. Fuel mass flow rate was then found with Equation 3-46. fuel fuelVm (3-46) The mass flow of the inlet ai r/recirculation gas mixture, oxm, is equal to, the sum of MAIm and recm.

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38 rec MAI oxmmm (3-47) The fuelair ratio can then be determined. ox fuelm428.0 m A/F (3-48) Stoichiometric F/A Mass Ratio (Fuel/ Air-Recirculation Mix) Given the molecular weight, species mole fr actions and mole recirculation ratio, Rn, of the air mixture with the formula and molecular weight of the fuel, the stoichiometric fuel-oxidizer ratio, F/Astoic, can be found. Beginning with the combustion equation, 2 2 2 2O2H22O NO22CO CO44CH n MAI 2O2H22N22O YxNDOHCCOB OHONO CO CO CH R OHNO AHC (3-49) Atomic balances can then be written for carbon, hydrogen and oxygen in Equations 3-50, 3-51 and 3-52 respectively. BCO CO CH ARxrec 22CO CO44CHn (3-50) C2OH2CH4AROHAyrec 2O2H 44CHn MAI 2O2H (3-51) CB2OHO2NO CO2COAROHO2Arec 2O2H22O NO22CO COn MAI 2O2H22O (3-52) Combining these equations allows solving for A, the stoichiometric moles of ambient air per mole of fuel. rec 22O NO CO44CH n MAI 2O2H22OO2NO CO CH4ROHO2 y2/1x2 A (3-53) The stoichiometric moles of oxidizer per mo le of fuel is found with Equation 3-54. n oxR1An (3-54) The stoichiometric fuel -oxidizer ratio is found with Equation 3-55.

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39 ox ox fuel stoicMWn MW)1( A/F (3-55) Lastly the equivalence ratio, can be calculated. STOIC ACTA/F A/F (3-56)

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40 CHAPTER 4 EXPERIMENTAL METHOD The HPRTE is a com plex system and optimally requires eight individuals for the tasks of gas analysis, DAQ operation, pressure data reco rding, temperature recording, VARS operation and data recording, engine room watch data, opera tor panel data and test run oversight. In order to accomplish the goals of this research, consis tent setup, operation and data acquisition was essential. With the exception of test run oversig ht, specific procedures and/ or data recording sheets were written for each task. In addition, a test plan and re quired data matrix was necessary for the overall program of testing as well as the individual test runs. In the case of test run oversight, a senior individual had the responsibility to monitor the health of the test rig and progress of the test This was accomplished by examining critical data as it was taken by others and evaluating whether the test run needed to be modified in real time. Each individual taking data ha d the responsibility of making the overseer aware of potential problems developing. Examples of possible action by the overseer would be emergency shutdown due to high turbin e inlet temperature transients or re ducing data points for the test due to limited available fuel. Pre-Test Setup Before the start of the test program, thermo couples, pressure transducers and manometers were checked for calibration. Thermocouples we re checked using a boilin g water bath and an insulated ice water bath. Pressure transducers an d manometers were calibrated using an Ametek portable pressure tester, model CPS-200. Once the test program had begun, the system was set up the evening before each test to minimize de lays from minor issues Engine preparations included filling the fuel tank, ch ecking lubricating oil level, se tting flow control valves and verifying battery charge for the starter and ignition systems.

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41 Instrumentation and audio/video systems were checked for proper operation and left on overnight. This was particularly important to stabilize cabinet temperature for the DAQ cold junction temperature compensati on. Any systems that could not remain on overnight were activated the morning of the test. This included the gas analyzer, which was battery powered and had internal heaters to maintain a consistent operating temperature for the IR bench. PCW flow to heat exchangers and the VARS were also started in the morning to avoid excessive condensation of ambient water va por in the laboratory. While th e spectrometer was set up the night before the test runs, baseli ne data was taken the morning of a test, with no light input, to record signal noise. Also, data was recorded with th e optical fiber in the te st position, to quantify any ambient light circumventing the light sh ields of the mounting system. Typical set-up procedures are illustrated in Appendix A. Start-Up, Operation And Shut-Down After checking communications and instrumentat ion for proper operation, recording offsets and ambient conditions, the start-up sequence was init iated. This involved verifying the status of a number of electrical pa nel switches and the fuel system as well as starting condensate pumps. When the electric starter was engaged, no fuel was allowed to flow until a 300 rpm minimum speed was achieved. This greatly reduced fuel build up in the combustion chamber prior to ignition. For the same reason, fuel rate was th rottled to approximately 50% of governor demand until the engine was self sustaining at about 2600 rp m. At that point, fuel rate was increased until unrestricted and the engine fuel rate was controlled by the gover nor at minimum load condition. During warm-up, dynamometer water flow was set at its operating level of 5 gpm, for the remainder of the run.

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42 Once the engine was considered to be running at a stable equilibrium, indicated by a steady recuperator exit temperature, da ta acquisition could begin or ad justments made to reach the required test point. System shut-down was esse ntially the reverse of start-up and a typical example of the procedure is shown in Appendix A. Data Acquisition Low load data points, defined by the run test plan, were approached by gradually increasing the load on the engine, either with the dynamometer or by throttling VMAI, in the case of high recirculation points. This was necessary because at low loads, insufficient heat is available to the VARS vapor generator and it would remain in standby mode. Under these circumstances, the HPCI temperature could appr oach design limits. As the load was increased and sufficient heat became available, the VARS would switch into operating mode and cool the recirculated gases flowing to the compressor. Once this occurred, transitions between data points could be accomplished more quickly. In general, data points were approached by se tting a shaft load with the dynamometer and then opening VR to increase RCV dp. Each data point in the test matrix represented a 0.5 change in dp, at the same load, or a 25% increas e in shaft load at the same dp. Recirculation could be increased by opening VR up to about 4.0 dp across RCV, with both VR and VMAI fully open. To reach higher recirculation ratios, VMAI would be throttled to increase RCV dp, again in 0.5 increments. Once run point adjustments were made, time was allowed for the recuperator exit temperature to stabilize before taking da ta. This was augmented with a stable HPCI temperature when the VARS was in operating mode As stated previously, data was recorded continuously by the DAQ, within scan rate limits, and also manually by personnel on station. At the end of each run, measurements from the gas analyzer were transcribed to a data sheet which was collected along with all manual instrument data sheets.

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43 Data from the spectrometer and DAQ were c opied and stored el ectronically for postprocessing. Examples of test plan s, test data matrix and the manual data recording sheets are in Appendix B.

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44 CHAPTER 5 DATA REDUCTION AND ANALYSIS For data red uction, an Excel spreadsheet was created to calculate the results needed for analysis in this investigation. Pertinent data from the manual data sheets, including gas analysis, was transferred directly into the spread sheet while spectral and DAQ data required postprocessing. Equations from Chap ter 3 and noted here were inco rporated into the analysis spreadsheet. Data Post-Processing Spectrometer Spectrometer data was used to calculate soot temperature and volume fraction. To do so, absolute monochromatic emission intensity at each data point had to be known. The recorded data was in arbitrary units of counts requiring conversion to in tensity. This was accomplished by taking data from a standard source of known em ission intensity over the same integration time used for each test data point. The arbitrary units were equated to the known intensity of the standard provided by the manufacturer a nd a conversion factor was calculated. In practice, emission intensity of the source was supplied by the manufacturer for discrete wavelengths at 10, 20, 25 and 50 nm interv als in tabulated form and having units of W/cm2/nm. These values were converted to W/m2/m for convenience in subseque nt calculations. The values were then plotted and a 4th order least squares polynomial curv e fit was found giving the absolute intensity of the standard as a function of wavelength. Data was then recorded with the spectrometer, measuring the output of the source. Dividing the known absolu te intensity of the source in W/m2/m by the counts recorded by the spectrome ter gave a correction factor for each wavelength in W/m2/m/count.

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45 Multiplying these factors by the test data at each run point gave the measured monochromatic emission intensity at the optical fiber sampling location in W/m2/m. This information was then entered into the data analysis spread sheet. Data Acquisition System The LabView software stores recorded data in two columns of an .xls file. The first is an index and the second is the data va lue. Post-processing was required to transfer the data to a file where all data was segregated into indivi dual columns for each parameter. This was accomplished using a MatLab algorithm edecimate developed by Howell [27]. The data was then copied to an Excel spreadsheet, deve loped by the ECGDL providing data headers, incorporation of offsets, performance calculations and plots of interest. Along with test parameters, the DAQ recorded the elapsed time (ET), in seconds, since recording was initiated. The ECGDL spread sheet included plots of forty nine different system parameters versus ET. An instability existed, which may be unique to this hardware/software combination, which advanced the recorded time by a number of seconds, typically in the range of 50 to 100 seconds, between two data scans. Th is ET anomaly did not always occur, but when it did, it was observable in the parameter vs. time plots and could happen more than once in a test run. Plots of the data were examined during post-processing and the ET corrected by subtracting the time advance from all subsequent data recordings and adding the average scan time between the two points where the anomaly occurred. As an example, consider two adjacent data points with a recorded ET of 945.9 sec. and 1019.7 sec. If the average scan time was 1.3 seconds, the ET for the second data point should have been 9 47.2 seconds. To implement the correction, the ET for the second and all subsequent data poi nts would be reduced by (1019.7-947.2) or 72.5 seconds.

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46 A second issue was signal noise. This was a random occurrence which caused stray data points with vastly different values than adjacent points taken one scan before or after. Again by examining the plots, these points were identif ied and the values corr ected by averaging the adjacent point values. Data Analysis The total number of data points taken during th is investigation was sixty five, with nine eliminated from consideration due to high or low spectrometer signals and one due to questionable gas analysis. For each of the remaining data points, extensive calculations were needed to ascertain the values pertinent to this research. To accomplish this task an Excel spread sheet was utilized to find the soot volume fractio n, soot temperature, gas composition, constants and flow rate, mass and molar recirculation ratio, mass fuel flow, equivale nce ratio and adiabatic flame temperature. It was also necessary to de velop correlations for wa ter vapor pressure and density as well as bell mouth and venturi performance. In the case of soot data, corrections were necessary due to physical constraints of the samp ling method. All data wa s transcribed directly into the analysis spread sheet from post-p rocessing files or the manual data sheets. Soot Temperature And Volume Fraction Soot emission values from the post-processing f ile had to be corrected to account for three sampling method constraints. These were, signa l attenuation by the sa pphire window, intensity reduction proportional to the square of the distance from the flame, and a sample area correction due to the acceptance angle of the optical fiber. With these corrections, the soot volume fraction and temperature were calculated according to the methods discussed in chapter 2. Sapphire window transmission Baseline spectral data was taken, with an arbi trary light source to determine the degree to which transparency might change during a run.

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47 A transmission fraction was calculated for the window when clean and just after a run at both wavelengths of interest. It was assumed that contaminant buildup on the window during a run would change this fraction. The transmission fraction was found to be 0.739 at both 525.03 nm and 675.01 nm with a clean window and 0.577 at the end of a typical run. The window wa s cleaned periodically during the test program in an attempt to maintain a somewhat consistent transmission performance run to run. Visual observations through the window during engine startup suggested that the majority of contamination build-up occurred at that time. However it is likely that some additional deposition continued throughout the run. There was no method to quantify the buildup rate in real time and so an average value for transmission factor of 0.66 was used for all data. Over the full range of transmission, soot temper ature and soot volume fraction ratio varied by +/0.25% compared to the average value. The emi ssion intensity was corrected by dividing the postprocessed value by the average transmission factor. Sampling distance The sampling plane of the optical fiber a ssembly was located 7.59 inches from the combustor centerline. The sampling distance corr ection was an inverse sq uare relationship and required an estimate of the distance from the co mbustor centerline to the flame perimeter. The combustor liner inside diameter was known to be 4.6 inches. The fuel injector had a 90 degree cone angle and the distance from the injector face to the center of the sapphire window was known to be 1.36 inches, resulting in a nominal sp ray cone diameter of 2.72 inches at that location. The liner shape in the combustion zo ne approximated a sphe re and the flame was considered to be essentially the same shape. No expedient method was available to verify the diameter of the flame so it was taken as the averag e of the fuel spray cone diameter and the liner inside diameter or 3.66 inches which is al so taken to be the optical path length L.

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48 The distance from centerline was one half th is dimension or 1.83 inches. The distance correction factor was therefore e qual to the square of the rati o 7.59/1.83 or 17.2. The emission intensity was corrected by multiplying the post-processed value by the correction factor. Optical fiber acceptance angle The acceptance angle represents the field of view of an optical fiber. A light ray approaching the fiber at an angle greater than the acceptance angle will not be propagated. When calibrating for absolute emission in tensity, the full field of view of the fiber is exposed to the standard light source. When sampling an emission source through an aperture that is smaller than the field of view, a correction must be made fo r this reduction in area. The sampling geometry for the spectral data was such that the sapphire window functioned as an aperture. The fiber assembly used in this investigation had an acceptance angle of 24.8 degrees, giving a conical field of view with a base diameter of 1.62 inch es at the plane of the window. The view diameter of the window however is 0.94 inches. These diam eters were projected onto spheres intersecting the plane of the window and the surface areas calculated as 2 rh. The ratio of these areas was 2.088/0.704 or 2.966. The emission intensity was corrected by multiplying the post-processed value by this ratio. The geometry of interest for distance and accepta nce angle correction is illustrated in Figure 5-1. With the corrected emission intensity at the perimeter of the flame, Equation 3-1 was solved for Ta1 and Ta2. Using Equation 3-6, Tsoot was found iteratively with the solver utility in Excel by setting the difference between the left and right side of Equation 3-6 equal to zero. KextL was then calculated with Equation 3-5 and the soot volume fraction, Fv, from Equation 3-9. For all runs, the maximum Fv, defined as Fvmax, occurred at minimum load with no recirculation of exhaust gases.

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49 The soot volume fraction, at a ny data point, was divided by Fvmax to establish a nondimensional soot volume fraction ratio, FvR, for investigating correlations between soot production and other parameters. Gas Analysis Exhaust gas analysis produced the informati on needed to calculate the constituent mole fractions, specific gas constant, molecular weight, density and mass flow rate of the recirculated gases. Combined with similar calculations for the ambient air intake, the composition of the mixture at the HPCI was known as well as the re circulation ratio on both a mass and mole basis. With this information, it was possible to determine the equivalence ratio and the adiabatic flame temperature. Ambient air, Tdb, %RH and Pamb were taken from the manual data and entered into the analysis spread sheet. Equations 3-12 through 3-20 and 3-36, 3-37 and 3-38 were applied giving the properties of interest and the ambient air intake flow. Fo r expedience, a correlation for Psat of H2O versus Tdb, having an accuracy of 0.19%, was develo ped from tabulated data [28] where 5432P2.02311()1.0899()2.2627()3.5465()1.917sat db db db dbETETETETE 4()3.8202dbTE (5-1) Exhaust gas sample data for the percent by volume for CH4, CO, CO2, NO (ppm) and O2 was entered into the spread sh eet as input for Equations 3-22 through 3-35. This provided the properties of interest to calcul ate the recirculation gas flow us ing Equations 3-36, 3-39 and 3-40. Also for expedience, a correlation was developed for Cd versus P/P, having an accuracy of 0.032%, from the recirculation venturi manufacturers calibration data where 2 3 4 5 64689.96772.58774.19187.2 P P E P P E P P E P P E Cd 1744.9 754.42007.9 E P P P P E (5-2)

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50 Lastly, Rm, Rn and MWox were found utilizing Equations 3-41, 3-42 and 3-43. Equivalence Ratio The fuel was assumed to be comparable to n-Dodecane having a molecular formula of C12H26 and a molecular weight of 170.341. The baseline density 0, was measured as 52.702 lb/ft3 at a baseline temperature T0, of 74o F. Volumetric fuel flow data, from the DAQ, was utilized along with Equations 3-45 and 346 to calculatefuelm. Combined with the results from gas analysis and Equations 3-47 and 3-48, the nominal F/A ratio was found. Given x and y from the fuel formula, air and recirculation gas mole fractions and Rn from gas analysis, F/Astoic was found from Equations 3-53, 3-54 and 3-55. Equivalence ratio could then be calculated with Equation 3-56. Adiabatic Flame Temperature From gas analysis, the mass flow rate, constitu ent mole fractions and molecular weight of the air and recirculation gas were known. Similarly, the mass flow and molecular weight of the fuel were known. Given the molecular weight of the air and recirculati on constituents and the primary flow fraction, the gas constituent fl ow on a molar basis, into the primary zone, in, was calculated. MW m 428.ni i i (5-3) The mole basis fuel flow was calculated in the same way. fuel fuel fuelMW m n (5-4)

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51 The initial temperature and pressu re of the reactants were need ed to calculate the adiabatic flame temperature. The inlet temperature was taken at the HPRE duct just upstream of the combustor. The combustion pressure was not measured directly.The gage pressure PHPRE was known at the same location as the HPRE temper ature. Also known was th e pressure drop across the combustor liner, P BNR, and Pamb. The absolute combustion pressure, Pcomb, was therefore equal to amb BNR HPRE combPPPP (5-61) With the quantity of all reactants entering the combustion zone known along with initial conditions, the adiabatic flame temperature was found using NASA CEA2 software. This program was available from the NASA web site http://www.grc.nasa.gov/WWW/CEAWeb/ The software has a W indows compatible graphical user interface for convenient data entry. It should be noted that the units of input and output data for the software are a mixture of SI and English. The inputs required for CEA2 in this analys is were pressure, temperature, moles and chemical formula of the reactants. The fuel enth alpy of formation was also needed and was taken to be -292.162 kJ/gmole. The results were transcri bed to the analysis spr eadsheet for subsequent examination and plotting.

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52 Figure 5-1. Geometry and dimensions used to correct emission intensity for sampling distance and optical fiber acceptance angle

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53 CHAPTER 6 RESULTS AND DISCUSSION The test program acquired data at fifty-five stead y-state operating points, taken over nine test runs. Mass basis recirculat ion ratio ranged from 0 to 1.04, equivalence ratio ranged from 0.42 to 0.64, reactant oxygen concentration range d from 15.4 to 20.7% and combustion pressure ranged from 33.1 to 36.1 psia. Soot Temperature and soot volume fraction ratio, calculated from spectral measurements, ranged from 3100 to 3720 Rankine and 0.01 to 1.00 respectively. The mean molecular weight of the in let air, recirculated gas and exhaust gas was found to be 28.60 +/0.11, 28.58 +/0.24 and 28.59 +/0.12 respectiv ely. The goal of this investigation was to determine what relationship existed between s oot volume fraction and oxygen concentration, equivalence ratio, combustion pressure and local temp erature, these being the primary variables in the combustion zone. All data anal ysis is based on a control volume about the combustor. With the combustor as the control volume in a semi-closed cycle gas turbine, defining an operating point must include combustor inlet and O2 percent for a constant speed machine. This is because each is a function of recirculation ratio and load. As recirculation ratio is increased and load is held constant, will increase and O2 percent will be reduced owing to the greater portion of exhaust gas in the reactants The same is true when load is increased and recirculation ratio is held c onstant since at higher load th e concentration of oxygen in the recirculated exhaust is reduced. At a specific load and recircul ation ratio, there will be a particular pair of values for these parameters. It was assumed that soot formation would be affected by oxygen concentration combustion pressure and local temperature according to resu lts by other investigators. Further, it seemed reasonable that the amount of fuel in the combus tion zone should also have a direct impact on Fv and that would be reflected by a O2 percent pair.

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54 Because of this, the impact of soot temperature, Tsoot, and adiabatic flame temperature, Tad, were both examined as a surrogate for local te mperature. As previously stated, the maximum soot volume fraction, Fv was observed at minimum load a nd no recirculation of exhaust gas diluent. With a small increase in load, Fv quickly reduced to a minimu m and then increased with load. This behavior was attributed to re duced fuel demand caused by the addition of a recuperator. The engine fuel in jector was not modified from th e original design and the lower fuel demand resulted in less than optimal fu el atomization. All soot volume fraction data presented was normalized with this maximum to give the soot vol ume fraction ratio, FvR, used for plotting and correlation. In all cases Fv and FvR followed the same relationships. Combustion Zone Parameters In Figure 6-1 FvR was plotted against combustor inlet O2%, accompanied with a least squares fit power curve trend line, and a rela tionship was clear. However, the high level of scatter suggested the impact of other parameters was significant. Figure 6-2 and 6-3 reflect the behavior of emi ssivity as oxygen concentration changes. The emissivity is calculated using Equation 3-4 a nd all quantities are cons tant at each wavelength except Kext. As Kext becomes small so does emissivity. Note the similarity to Figure 1. This is to be expected since as soot volume fraction diminishes so does the number of particles or their absorbsion cross section or both. Thus Kext, equal to NCabs, would be reduced. Figure 6-4 illustrates a similar, a lthough mirrored relationship between FvR and combustor inlet Again, a least squares fit power curv e trend line is shown for comparison. A plot of FvR vs. Primary zone absolute pressure, Pcomb, is presented in Figure 6-5. No trend was apparent but the pressure changes were very small, between 33.1 and 36.1 psia, due to the near constant speed, and therefore pressure rati o, of the machine. The main contribution to pressure change was from MAI throttling to increase exhaust recirculation flow.

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55 It was of interest whether fuel atomizati on might have an obvious impact on the soot volume fraction ratio versus oxygen concentration relationship. Fi gure 6-6 shows data for which the fuel mass flow rate was between 91 and 98% of maximum. As can be seen, data points with nearly the same oxygen concentration can differ by a factor of almost 5 in their soot volume fraction ratios and there is no obviou s trend. This suggests that, at least at high fuel flow rate conditions, fuel atomization was not a significant driver of soot formation. Having said this, it should be borne in mind that in this test engine fuel flow, air flow and therefore equivalence ratio cannot be independently contro lled. As oxygen percent decreases, is increasing. The ability to hold constant might present different results. Figures 6-7 and 6-8, plot FvR vs. Tsoot calculated from spectral measurements, or Tad calculated with NASA CEA2. As in Figure 6-6, no di rect relationship is apparent. For a specific machine and fuel, Tsoot was expected to correlate with O2 percent, Pcomb and In Figures 6-9, 610 and 6-11, Tsoot was plotted vs. these parameters Again no obvious relationship was discernable. Adiabatic flame temperature was examined in the same way in Figures 6-12 through 6-14. Results demonstrated the same lack of a distin ct correlation. It was of interest whether a relationship existed between Tsoot and Tad. A temperature ratio was calculated as Tratio = Tsoot/Tad. Tratio was plotted vs. O2 percent, Pcomb and In Figures 6-15 through 6-17, Tratio was generally increasing with O2 percent and Pcomb while decreasing with A linear least squares trend line was shown to illustrate this behavior. Over all, the data Tsoot was 3410 +/310 degrees R with and average of 3450 degrees R. Tad was 2900 +/170 degrees R with an average of 2930 degrees R and Tratio was 1.17 +/0.13 with an average of 1.18.

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56 A multi-variant least squares exponen tial regression was performed for Tsoot and Tad on percent O2 and Pcomb with and without to determine the impact of each parameter and develop a correlation. The regression equatio n was the form of Equation 6-1. *M*M*bY2 1X 2 X 1 (6-1) Table 6-1 shows the resulting equation coefficients for each case. In Figure 6-18 both the regres sion and data values of Tsoot vs. O2 percent were plotted with linear trend lines for comparison. The trends we re nearly identical a lthough the data values displayed much greater scatter. Both regression e quations had essentially the same average error. With included in the regression, the average error was 0.046%, without the average error was 0.047% demonstrating a good correlation and also that was not important to Tsoot within the range of testing. The same comparison was examined in Figure 6-19 for Tad. Here the impact of was clearly evident. When was included in the regression the values followed data much more closely having an average error of 0.002%. When was not included the results were comparable to the Tsoot correlations with an average error of 0.045% Regression Analysis Of Fvr Based On Combustion Zone Parameters An exponential regression was carried out on FvR using O2%, Pcomb and Tsoot or Tad as variables. The results of the Tsoot regression suggested the model could be simplified, for the HPRTE at least, and Tsoot was considered by proxy through O2% and Pcomb. However, a better fit to the data was achieved when Tsoot was included in the regression directly and 6-1 implemented with four parameters for FvR. Values for the coefficients are presented in Table 6-2. The results of the analysis are shown in Figures 6-20 and 6-21 where actual FvR and the regression FvR was plotted vs. % O2 in the reactant gas.

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57 Input for the regression equation was the values for O2%, Pcomb and Tsoot or Tad measured or calculated from test data. Trend lines for both data and regression values of FvR are a least squares fit for a power curve. While the Tad correlation displayed a better curve fit, the average error was found to be 48% compared to 20% when Tsoot was used for the temperature parameter. In Figures 6-22 through 6-25 the pressure e ffects predicted by the regression were examined with values of 0.4 and 0.65 and Pcomb varied from 30 to 40 psia. Temperatures were calculated as, Tsoot = f (O2%, Pcomb) and Tad = f (O2%, Pcomb, ) for the calculation of FvR. Here the regression reflected an inverse power relationship between FvR and Pcomb at any or O2% with the pressure exponent ranging from -1.93 to -4.70. Other investig ations, [12-15], involving methane or ethylene, have shown a direct scalin g with pressure and exponents of 1.2 at high pressure (290-580 psia) to 2 at low pressure (72-290 psia). Note that when Tsoot is used as the temperature parameter, the pressu re exponent is not a function of Noting the trends illustrated in Figures 6-1, 6-4 and 6-22 through 25, two extreme synthetic data sets were calculated for FvR using Tsoot and Tad to determine if the run points from the test data would fall between the minimum an d maximum curves predicted by the regression. Using values from test data for minimum Pcomb = 33.1 psia and = 0.42, a maximum FvR set was generated. In the same way using maximum Pcomb = 36.1 psia and = 0.64, a minimum FvR set was generated. In Figure 6-26 and 6-27 these data se ts are plotted along with the actual test data. The synthetic curves using Tsoot for the temper ature parameter follow the run data quite well with 70% of the test points inside the bounde d area and the remaining points following the curves closely. For the regression using Tad, onl y 50% of the data points plotted inside the boundary.

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58 A similar Min/Max case was develo ped for FvR as a function of For the minimum case, O2% was 15.4%, and Pcomb was 36.1 psia. For the maximum case, O2% was 20.7%, and Pcomb was 33.1 psia. The results were plotted in Figure 6-28 and 6-29 along with the test data. While a few test points lie outside the bracketed region, they remain very near to the predicted limits when Tsoot was used as the temperature parameter in Figure 6-28. In Figure 6-29 the regression is less convincing with more data points lying farther outside the curves. The regression equation requires values for O2%, Pcomb and T to calculate FvR. From the trends illustrated in Figures 6-20, 6-21 and 6-26 through 6-29, the Tsoot was selected as the more relevant temperature parameter compared to Tad. It was desired to calcul ate synthetic values for FvR and examine the predicted soot fo rmation behavior as a function of and O2% only. To accomplish this, appropriate values for Pcomb and temperature were needed that were comparable to actual run conditions. Examining a ll the test points, the average Pcomb was found to be 34.8 psia. A constant value of 35 psia was therefore selected for Pcomb. To obtain values for temperature, Equation 6-1 was used with the coe fficients in Table 6-1, along with the chosen values for O2% and Pcomb as input variables for Tsoot. Synthetic FvR data was then generated with ranging from 0.40 to 0.65, O2% ranging from 15 to 21%, Pcomb = 35 psia and Tsoot = f (O2%, Pcomb ). The results were plotted in Figure 6-30. The regression equation predicted that reducing O2% would diminish FvR at any equivalence ratio. However, this effect was much less pronounced at high where FvR approaches a linear relationship with O2%. While the prediction of lower FvR with increasing seemed counterintuitive, only four of the data points were at zero recirculation. Theref ore, the test points were heavily weighted with reduced O2% operating conditions.

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59 As stated previously, combustor inlet is a function of both load and O2%. A reduction in O2% increases without an increase in load and diminishes FvR. This behavior, illustrated in Figure 6-2 was reflected by the regression. That FvR would continue to increase with O2% was also predicted. Obviously this investigation was limited to the ambient O2% and soot formation beha vior as lean blowout conditions are approached may not follow this model with certainty. Similarly the regression suggests a minimum for FvR at low O2%. However, at any load, decreasing O2% would drive toward 1.0 and beyond. Soot formation behavior would be expected to change under those conditions. With a maximum of 0.64 for this investigation, extrapolation of the mode l would not be useful. In Figures 6-31 and 6-32 the behavior of the Tsoot regression was examined by holding Pcomb = 35 psia in 6-31 and O2% = 18% in 6-32. The independent e ffects can be seen as a linear relationship for Tsoot vs. O2% and Tsoot vs. Pcomb respectively. Measurement Error Analysis The method of two-color pyrometry has been employed to study soot since the early 1900s. The usefulness of the method depends on knowi ng the optical properties of soot particles such as the optical properties parameter, and th e complex refractive index. Values found by different researchers vary widely and can affect results for soot temperature by +/25 K and results for soot volume fraction, Fv, by 20%-75% as demonstrated by di Stasio and Massoli [29]. The primary source of variability in the spectral data recorded in this research was related to the measured intensity correction due to the assu med optical fiber position, flame diameter and sapphire window transmission. In the case of Tsoot this would affect results by an additional +/3 K. Regarding soot vol ume fraction ratio, FvR, the uncertainty was increased by +/0.02.

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60 It is important to note that all soot volu me fraction calculations utilized the same assumptions for the optical properties and the physical configuration for data acquisition. Therefore the error quoted above for soot volume fraction, Fv, would largely cancel out when expressing the results as the soot volume fraction ratio FvR. The quantities percent oxygen, equivalence ratio and combustion pressure were calculated using data from the non-optical test facility instrumentation. The value of the combustion pressure, Pcomb, is dependent on measurements from a Bourdon gage and two manometers. Since the gage performance is the overw helming contributor to the inaccu racy of the calculated value, the uncertainty of the Pcomb calculation is considered to be on the order of +/0.8 psi, using a 100 psi gage rated with an accuracy of +/0.75% of full scale. In the same way, the overwhelming contributor to the inaccuracy of percent oxygen and equivalence ratio calculations was the gas analyzer. All species measurements had an accuracy of either +/5% or much less than 1%. A simple root of the sum of the squares operati on was performed using the accuracy for each gas constituent used in the calculations. The result was an uncertainty value of +/7% for both and O2%. These results are summarized in Table 63. The method of calcu lation can be found in Appendix C.

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61 Table 6-1. Regression equati on coefficients for soot temp erature and adiabatic flame temperature Parameter X1 = % O2 X2 = PcombX3 = Y b M1 M2 M3 Tsoot 2585.549 1.003 1.007 Tsoot 3010.405 1.000 1.006 0.893 Tad 3992.361 1.006 0.988 Tad 1004.149 1.034 0.998 2.795 Table 6-2. Regression e quation coefficients for s oot volume fraction ratio Parameter X1 = % O2 X2 = PcombX3 = X4 = T Y b M1 M2 M3 M4 FvR = f(Tsoot) 1.464E+07 1.825 1.102 1.112E-04 9.919E-01 FvR = f(Tad) 1.302E-06 7.111E+017.513E-01 4.948E+459.635E-01 Table 6-3. Data uncertainty for major parameters Parameter Uncertainty FvR +/0.02 Tsoot +/28 K Pcomb +/0.8 psi +/7% of value O2% +/7% of value

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62 y = 5.019E-19x1.390E+010.000 0.200 0.400 0.600 0.800 1.000 1.200 15.016.017.018.019.020.021.0 O2%FvR Figure 6-1. Soot volume fracti on ratio vs. combustor inlet O2%

PAGE 63

63 y = 5.927E-19x1.332E+010.00 0.05 0.10 0.15 0.20 0.25 15.016.017.018.019.020.021.022.0 % O2Monochromatic Emissivity Figure 6-2. Emissivity at 525.03 nm vs. % O2

PAGE 64

64 y = 3.385E-19x1.339E+010.00 0.05 0.10 0.15 0.20 0.25 15 16 17 18 19 20 21 22 % O2Monochromatic Emissivity Figure 6-3. Emissivity at 675.01 nm vs. % O2

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65 y = 1.725E-04x-9.856E+000.00 0.20 0.40 0.60 0.80 1.00 1.20 0.40 0.45 0.50 0.55 0.60 0.65 0.70 PhiFvR Figure 6-4. Soot volume fraction ratio vs. combustor inlet equivalence ratio

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66 0.00 0.20 0.40 0.60 0.80 1.00 1.20 32.533.033.534.034.535.035.536.036.5 Pcomb psiaFvR Figure 6-5. Soot volume fracti on ratio vs. combustion pressure

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67 0.000 0.050 0.100 0.150 0.200 0.250 0.300 15.015.516.016.517.017.518.018.519.0 % O2FvR Figure 6-6. Soot volume fr action ratio vs. oxygen concentr ation at high fuel flow

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68 0.00 0.20 0.40 0.60 0.80 1.00 1.20 3200 3300 3400 3500 3600 3700 3800 Tsoot deg. RFvR Figure 6-7. Soot volume fracti on ratio vs. soot temperature

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69 0.00 0.20 0.40 0.60 0.80 1.00 1.20 270027502800285029002950300030503100 Tad deg. RFvR Figure 6-8. Soot volume fraction ra tio vs. adiabatic flame temperature

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70 3200 3300 3400 3500 3600 3700 3800 15 16 17 18 19 20 21 %O2Tsoot deg. R Figure 6-9. Soot temperature vs combustor inle t percent oxygen

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71 3200 3300 3400 3500 3600 3700 3800 33 33 34 34 35 35 36 36 37 Pcomb psiaTsoot deg. R Figure 6-10. Soot temperature vs absolute combustion pressure

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72 3000 3100 3200 3300 3400 3500 3600 3700 3800 0 40 50 50 60 60 70 7 PhiTsoot deg. R Figure 6-11. Soot temperature vs. combustor inlet e quivalence ratio

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73 2700 2750 2800 2850 2900 2950 3000 3050 3100 15 16 17 18 19 20 21 % O2Tad deg. R Figure 6-12. Adiabatic flame temperat ure vs. combustor in let percent oxygen

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74 2700 2750 2800 2850 2900 2950 3000 3050 3100 32.533.033.534.034.535.035.536.036.5 Pcomb psiaTad deg. R Figure 6-13. Adiabatic flame temp erature vs. combustion pressure

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75 2700 2750 2800 2850 2900 2950 3000 3050 3100 0.40 0.45 0.50 0.55 0.60 0.65 0.70 PhiTad deg. R Figure 6-14. Adiabatic flame temperatur e vs. combustor inle t equivalence ratio

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76 0.8 0.9 1.0 1.1 1.2 1.3 1.4 15 16 17 18 19 20 21 22 % O2Tratio Figure 6-15. Soot temperature/adiabatic flame temperature vs. combustor inlet % O2

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77 0.8 0.9 1.0 1.1 1.2 1.3 1.4 32.533.033.534.034.535.035.536.036.5 Pcomb psiaTratio Figure 6-16. Soot temperature/adiabatic flame temperature vs. combustion pressure

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78 0.8 0.9 1.0 1.1 1.2 1.3 1.4 0 40 50 50 60 60 70 7 PhiTratio Figure 6-17. Soot temperature/adiabatic flame temperature vs. equivalence ratio

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79 3200 3300 3400 3500 3600 3700 3800 15161718192021 O2 %Tsoot deg. R Data Tsoot Regr. Tsoot no Phi Regr. Tsoot with Phi Figure 6-18. Regression and data soot te mperature vs. combusto r inlet percent oxygen

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80 2700 2750 2800 2850 2900 2950 3000 3050 3100 3150 15 16 17 18 19 20 21 % O2Tad deg. R Data Tad Regr. Tad No Phi Regr. Tad With Phi Figure 6-19. Regression and data adiabatic flame temperature vs. combustor inlet percent

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81 y = 5.019E-19x1.390E+01y = 1.073E-18x1.363E+010.0 0.2 0.4 0.6 0.8 1.0 1.2 15 16 17 18 19 20 21 % O2FvR Act Regr Figure 6-20. Run data and regression Fvr vs. combustor inlet % O2 using Tsoot for the temperature parameter

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82 y = 1.459E-18x1.352E+01y = 1.157E-18x1.360E+010.0 0.2 0.4 0.6 0.8 1.0 1.2 15.0 16.0 17.0 18.0 19.0 20.0 21.0 % O2FvR Act Regr Figure 6-21. Run data and regression Fvr vs. combustor inlet % O2 using Tad for the temperature parameter

PAGE 83

83 y = 7288.1x-3.2264y = 138207x-3.32390.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 3031323334353637383940 Pcomb psiaFvR20 % O2 15 % O2 Figure 6-22. Synthetic FvR vs. Pcomb, = 0.4 with 15% and 20% O2 using Tsoot

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84 y = 14193x-3.3239y = 748.43x-3.22640.000 0.020 0.040 0.060 0.080 0.100 0.120 0.140 0.160 0.180 0.200 3031323334353637383940 Pcomb psiaFvR15 % O2 20 % O2 Figure 6-23. Synthetic FvR vs. Pcomb, = 0.65 with 15% and 20% combustor inlet O2 using Tsoot

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85 y = 514743x-3.7419y = 82311x-4.70120.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 3031323334353637383940 Pcomb psiaFvR20 % O2 15 % O2 Figure 6-24. Synthetic FvR vs. Pcomb, = 0.4 with 15% and 20% combustor inlet O2 using Tad

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86 y = 12.795x-1.925y = 617.33x-3.16550.000 0.002 0.004 0.006 0.008 0.010 0.012 0.014 0.016 0.018 0.020 3031323334353637383940 Pcomb psiaFvR 15 % O2 20 % O2 Figure 6-25. Synthetic FvR vs. Pcomb, = 0.65 with 15% and 20% combustor inlet O2 using Tad

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87 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 15 16 17 18 19 20 21 O2 %FvR Max Min Act Figure 6-26. Run data and extreme case synthetic FvR vs. combustor inlet % O2 using Tsoot

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88 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 15 16 17 18 19 20 21 O2 %FvR Max Min Act Figure 6-27. Run data and extreme case synthetic FvR vs. combustor inlet % O2 using Tad

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89 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 0.40 0.45 0.50 0.55 0.60 0.65 0.70 PhiFvR Test Min Max Figure 6-28. Run data and extreme case synthetic FvR vs. combustor inle t equivalence ratio using Tsoot

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90 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 0.40 0.45 0.50 0.55 0.60 0.65 0.70 PhiFvR Max Min Act Figure 6-29. Run data and extreme case synthetic FvR vs. combustor inle t equivalence ratio using Tad

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91 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 15 16 17 18 19 20 21 O2 %FvR Phi = 0.4 Phi = 0.45 Phi = 0.5 Phi = 0.55 Phi = 0.6 Phi = 0.65 Figure 6-30. Synthetic FvR vs. combustor inlet % O2 with variable combustor inlet

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92 y = 1.02E+01x + 3.28E+03 3420 3430 3440 3450 3460 3470 3480 3490 3500 15 16 17 18 19 20 21 % O2Tsoot deg. R Figure 6-31. Synthetic Tsoot vs. combustor inlet % O2 with constant Pcomb

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93 y = 2.36E+01x + 2.64E+03 3300 3350 3400 3450 3500 3550 3600 3031323334353637383940 psiaTsoot deg. R Figure 6-32. Synthetic Tsoot vs. Pcomb with constant combustor inlet % O2

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94 CHAPTER 7 CONCLUSIONS A test prog ram was completed with the High Pressure Recuperated Turbine Engine at the University of Florida Energy & Gasdynamic Sy stems Laboratory where soot volume fraction was measured in the combustion zone while changing inlet oxyge n concentration. A trend of increasing soot formation with increasing oxyge n concentration was observed. This trend approximately follows a power relationship. A trend of decreasing soot formation with increasing equivalence ratio was also observed and was approximated by a power relationship. A regression analysis was perf ormed on soot temperature as a function of percent reactant oxygen and absolute combustion pressure. This re lation demonstrated good agreement with test data and predicted a linear dependence on both pe rcent reactant oxygen and absolute combustion pressure. A regression analysis was pe rformed on soot volume fraction as a function of equivalence ratio, percent reactant oxygen, absolute combustion pressure a nd soot temperature. Synthetic data generated from the regression re flected trends nearly identical to test data and at extremes of test parameters almost fully bounds the test da ta. The regression reflec ted the inverse power relationship between soot volume fraction and absolute combustion pressure at any equivalence ratio or reactant oxygen percent and showed that soot formation diminishes with decreasing reactant oxygen and increasing equivalence ratio. When oxygen c oncentration was reduced from ambient to 17.5%, soot formation decreased by an order of magnitude. The test engine operation points ranged between an equivalence ratio of 0.42 and 0.64 and an oxygen concentration between 15.4 and 20.7%. If operating points approached more lean or rich conditions, soot beha vior would be expected to deviate from the models.

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95 As an example, if the equivalence ratio appr oached or exceeded 1.0, clearly the soot and adiabatic flame temperatures woul d be expected to diminish a nd soot volume fraction increase. This is not predicted and theref ore the models should not be extr apolated to hi gher equivalence ratios. For low equivalence ratios, as combustion ap proaches lean blowout, flame instability would be expected to have an impact and was not studied in this research. Therefore the models should not be extrapolated to lower equivalence ratios. The limitations to the range of operation and the model are, in part, attributed to the fixed geometry of the combustor liner and perfor mance of engine components. The method of restricting the liner dilution holes to divert flow to the primary zone did so at the cost of greater pressure drop as well as increased film cooling flow. The effectiv eness of the recuperator limited the temperature of the reactants entering the co mbustion zone. Both of these conditions likely increased the minimum oxygen concentration the engine would tolerate. This research has demonstrated the signifi cant effect of oxygen concentration on soot formation within a gas turbine. The regression e quations developed from this work are useful design tools for circumstances where diluti on of combustion air is being considered.

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96 CHAPTER 8 RECOMMENDATIONS The m odels developed in this work were useful in predicting behavior of the HPRTE at the University of Florida Energy & Gasdynamic Systems Laboratory. Additional testing with a different semi-closed cycle gas turbine would be warranted in order to investigate the general applicability of the techniques utilized here. Also while the model coefficients may change with each machine, it may be possible to correlate these with basic design parameters, allowing investigative studies prior to testing. The data collected in this research did not include operating po ints approaching or exceeding an equivalence ratio of 1.0. It would be expected to observe increasing soot volume fraction under those conditions a nd the model does not predict th is. Additional testing should be conducted to examine whether a single model is sufficient and if not, whether a boundary exists beyond which a second model can be applied. The data collected in this research also did not include operating points below ~15% oxygen concentration. It would be expected to observe increas ing soot volume fraction under those conditions and th e model does not predict this. Additi onal testing should be conducted to examine whether a single model is sufficient and if not, whether a boundary exists beyond which a second model can be applied. When the HPRTE was operated at minimum load with no recirculation, an increase in soot volume fraction was observed and attributed to p oor atomization. A smaller injector orifice should be evaluated with additional testi ng to verify whether this is the case. At the time this investigation was undertaken, two issues were unres olved related to gas analysis. The first concerned the gas analyzer itself. The manufacturer representatives were unsure whether the data collected was on a wet or dry basis.

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97 Ultimately the answer was neither. Analysis was based on actual concentration at the device without correction for wate r vapor or condensation. As a result, much more complicated calculations were necessary to determine the co mposition of the recirculated gases, based on exhaust analysis. Gas analysis data was also take n from a point in the flow path after the mixing of ambient air and recirculati on gas, which would have given direct measurement of species concentration at the combustor in let. The measurement basis was one of the reasons this data could not be exploited. The second issue was that the seal design used for duct flanges in the recirculation path was inadequate. This allowed introduction of ambient air which could not be accounted for in the measurement of recirculation flow. The si gnificance of the leakage also could not be determined and was the second reason that gas an alysis data from the post mixing flow was not utilized. Both of these issues have now been resolved. A limited test program to acquire verification data should be executed in order to evaluate the im pact on the model coefficients presented. Test program requirements included video record ings of the flame to examine changes in observable characteristics. When th e optical fiber used to collect spectral data was in position to take data, the view of the camera was obscured. This necessitated a flexible mount so the fiber could be removed and replaced. Further, the fi ber was in the vicinity of high temperature components and had to be repositioned to avoid heat damage during transitions between data points. While great care was taken to position the fiber consistently, minor variation was unavoidable. The mounting system for the optical fibe r should be redesigned to facilitate precise placement whenever repositioning is needed. The incorporation of a cooling feature or heat shielding would also be advantageous.

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98 Calculation of the soot volume fraction and te mperature rely on assumptions relating to the transmission characteristics of the sapphire window and the extin ction coefficient of the soot component in the flame. Installation of a second window would allow both of these characteristics to be more directly quantifie d by taking transmission da ta using a laser or calibrated light source. If a thir d widow was feasible, then scattering measurements would also be possible. This would facilitate a more direct measurement of the soot volume fraction as well as future investigations into soot particle characteristics. Fuel flow is measured volumetrically during ope ration of the facility. The fuel flow on a mass basis is needed for various analysis calc ulations. This is accomp lished with known fuel density corrected for fuel temperature. The fuel flows through a small diameter line exposed to ambient conditions and for this i nvestigation the fuel temperature was assumed to be equal to the ambient temperature at each data point. Over al l testing, the fuel dens ity variation was only ~3% and much less for any single test run. While the potential error is small using this temperature assumption, the fuel temperature should be meas ured directly upstream of the flow meter to eliminate the need.

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99 APPENDIX A OPERATING PROCEDURES The HPRTE Setup Procedure, Rev. 8/14/07 HPRTE Soot Investigation Test Run #10: Dated 8/1407 OPERATORS NAME Support Systems: Site Chill Water: 1. Slowly open the source and retu rn overhead isolation valves. Cooler Chill Water: 1. Connect the process water hoses to the cooler. 2. Supply water to the cooler by opening isolation valves. 3. Verify main cooler flow by listening for flow noise. 4. Record minor leaks for later resolution. ARU Chill Water: 1. Connect the process water hoses to the ARU. 2. Supply water to the cooler by opening all isolation valves. 3. Verify water flow by checking the ARU flow meter. 4. Record minor leaks for later resolution Boost Control Valve and Waste Gate Control Air: 1. Set supply air regulator by the South door to 40 psig. 2. Verify the Supply Air Pressure at the control panel is at least 30 psig by adjusting the South door regulator in 1. Above.

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100 3. Close the Fisher boost Contro l Valve by reducing the controll er air pressure to 5 psig. Verify full closing by the valve stem flag. 4. Open the Fisher boost Control Valve by increas ing the controller air pressure to 15 psig. Verify full open by the valve stem flag. 12 Volt Battery Check 1. Unplug the battery charge r and store the charger. 2. ___ Throw the isolation switch. 3. Verify each start battery has a cold reading of 13.2 volts minimum. This ensures that the batteries are fully char ged. Record Voltage: N VDC, S VDC 4. Verify each ignition battery has a cold reading of 12.6 volts minimum. This ensures that the batteries are sufficiently charged. Record Voltage: N VDC, S VDC Fuel Supply 1. Verify Gravity and speed trim lines to engi ne skid. Open the ROVER side of the gravity system. 2. ___ Unscrew, remove and replace the fuel Pump accumulator to charge with air. 3. Plug in the fuel transfer pump and verify operation. 4. Check fuel level by sight glass, minimum full. Fill as necessary. 5. ___ Fill the seven gallon tank unde r the fuel cabinet, if required. 6. Check the entire fuel cabinet and hoses for leaks. 7. ___ Fill and place on station, auxili ary fuel containers, as required. 8. ___ Dry and position the skid drip pan and the fuel drain drip pan.

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101 Oil Levels 1. ___ Verify Rover engine oil leve l. Refill with single viscosity 10 W oil as necessary up to half way between the high and low mark ings. Record any amount added. 2. ___ Safety wire the dipstick. Oil added __________________ Dynamometer Setup and Oil Cooler Process Water 1. ___ Route system drain lines ou tside under the main overhead door. 2.___ Adjust Froude Dyno inlet a nd outlet valve to full open. 3. ___ Fully open the water supply to the Dyno. Purge Dyno. 4. ___ Verify the in-line Rota meter is reading ~ 7 gpm. 5. ___ Verify the water brake is fully unloaded, that is, the geared handle is full to the CCW position. 6. ___ Verify the gear lock remains disengaged. 7. ___ Visually confirm gland leakage. 8. ___ Confirm discharge flow from three drain lines. They are; 1.)The Rover oil cooler, 2.) The dyno, 3.) The dyno drip pan. Water Recovery 1. ___ Hang the Water Recovery Bucket on the load cell. 2. ___ Route AC extension cord to the dr ain pumps. Switch on/off to verify rotation Inlet, Recirculation and Exhaust Start-up Check 1. ___ Check the exhaust system to ensure all pe netrations are covered and joints are tight. 2. ___ Verify that the Rover Inle t Isolation Valve is fully open

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102 3. ___ Verify the Rover Recirculation Valve is fully shut. Engine room Preparation Room Ventilation: 1. Open the main bay door about five feet (to marked line). 2. Turn on the lab ventilation fan and the compressor room fan. 3. ___ Set up Psychrometer. Lab Over-watch: 1. Check the lab area for debris that could be ingested into th e engine or present a tripping hazard. Remove as necessary. 2. Attach the Safety Chain at the hall outside the Lab. 3. Move fire extinguishers to areas in th e lab where they are readily accessible. ARU Setup 1. Refer to the ARU set up procedure, separate from this document. Video and Audio Recording 1. ___ Turn on the control room VCR, channel A. Run the cables to the control room to the video monitor. 2. ___ Set up the microphone (plug in the power supply) to record the communications loop. Hook this into the VCR sound input and radio receiver.

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103 3. ___ Synchronize VCR time and date with the DAQ. 4. ___ Insert a new VCR tape for the days activ ity. Ensure tape is recording on E.P. (extended play). 5. ___ Synchronize Camera time and date with the DAQ. 6. ___ Complete a system check to be sure the monitoring and recording systems are working correctly. This system is used to ve rify the data set switch points and aids in improving subsequent runs through lessons learned. 7. Check all the communication gear. Change batteries as warranted. All units should be on the same channel and in Push-To-Talk (PTT) mode. All units should be on TX, not INT. Use channel A. Personnel Safety Equipment and Communications 1. ___ All personnel should wear appropriate clothing for an environment where high temperature piping, heavy equipment and high speed rotating equipment exist. i.e., long sleeve shirt, long pants, closed toe and heel shoes, and no loose fitting items or jewelry. 2. ___ TURN OFF CELL PHONES. 3. ___ All personnel and visitors should have hear ing protection, either communication sets or ear muffs. 4. ___ All personnel and visitors should have eye protection. 5. ___ Visitor Policy: all visitors should be check ed in, briefed, and supplied with safety equipment before the run set-up begins. Optim ally, all visitors should be supplied with Listen-Only communication head gear. No la te or unannounced visitors are allowed. The VARS Operating Procedure Rev. 8/13/07

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104 Set upfor Stand by 1. Check if the solution receiver is at least half full. If it is lower than 1/2, see Controlled Start-up step one. 2. If the solution receiver is empt y or very close (level < ~2), notify the Team Leader and review the instructions for transferring fluid from the Rectifier to the Solution Receiver. 3. Connect the Power Cord. 4. Open V2 (TXV isolation valve). 5. Open V14 (pump discharge valve) 6. Open V25 (absorber isolation valve) 7. Set V15 at 3-1/2 turn open (column feed). 8. Set V26 for process chilled water to the condens er at 1.2 to 2 gpm fo r water temperatures between 44F and 60 F. 9. Set V27 for absorber process chilled water at 1-1/2 turns open. 10. Turn power switch on. Panel lights should go from Red to Yellow. When the Heat Recovery Vapor Generator (HRVG) inlet air becomes hot, the solution pump will start, the solenoid valves will open and the Green light will come on. Control during Start-up: 1. Observe the Solution Receiver level as the unit comes online. If the fluid level drops below 50%, open V13 1-2 turns until the level begi ns to rise. As the level approaches 7580%, begin closing the valve until the so lution flow rate is 3.2 gpm again. 2. Expedite the Start-up phase by throttling V13 such that the Ammonia Receiver pressure follows the pump discharge pressure. Control during Normal Operation: Note that the two primary Faults that will s hut down the unit, are when the Solution Receiver Pressure reaches 120 psi or the Ammonia Receiver Pressure reaches 250 psi. Most of your actions will be taken to maintain these at acceptable levels.

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105 TXV: This is an expansion valve c ontrolling liquid NH3 to the evaporator with two feedback mechanisms: a mercury vapor bulb on the evapor ator return line, and a pressure feedback from the same. It is intended to keep the evaporator exit vapor a few degrees superheated, but generally, the evaporator exit temperature (T4) oscillates periodically, until the TXV has fully opened. This valve has an operating range that can be adjusted by removing the stem cap and raising or lifting the stem with a wrench. Consu lt the valve literature fo r instructions on this adjustment. Note that the wrong literature was provided by EC for this valve. Its not a Danfoss, it is believed to be Sporlan. V3: This is the TXV bypass valve, and is invaluable as a manual cont rol for refrigerant flow when the TXV isnt opening sufficiently to carry the ev aporator (Cold Gas Cooler, CGC) heat load. It is a needle valve suitable for fine adjustment and establishing a baseline refrigerant flow while the TXV modulates above this level. If the Solution Receiver pressure is exceeding 110psig, it is most sensitive to the TXV/V3 positions If V3 is open at all, close it in 1 to 2 turn increments, waiting 5 to 10 seconds between adjustments, until the pressure returns to an acceptable value. Note that the CGC exit temper ature on the refrigerant side (T4) will be increasing. If unsuccessful, you can still manua lly adjust the operating range of the TXV and eventually succeed, but again, youre reducing refrigerant flow to the evaporator and increasing the superheat of the refrigerant. V15: This is a control valve used to regulate the temperature of the vapor leaving the rectifier (hot side) and proceeding to the condenser (COND). Ideally, this temperature (T1) should be around 110F to 125F for moderate heat load s (<23 TR on the HRVG) and NH3 receiver pressures (200-220). For more extreme heat loads (>25 TR on the HRVG) and high-side pressures (240-250), try to keep this temp ar ound 150F to 160F, for reasonable performance. If it creeps up to 180F, thats probably okay, but th ere will likely be lots of water carrying over into the NH3 receiver and evaporator, resulting in higher evaporator temperatures (T14). In general, open to turns as necessary. While opening this valve increases the RECT cold

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106 side flow, it simultaneously takes flow away fr om the HRVG, increasing T10. Thus, there are two effects competing against one another. Ho wever, observation of the solution flow meter (FM on the schematic) has indicated that the fi rst several turns (be yond 3.5 open) opening V15 doesnt detract appreciably from the HRVG flow Open it slowly. Watch the flow meter. Watch T1 and T10. T10 is best maintained below 270F. It has run as high as 310F, but the system performance was likely degraded. Try to keep it closer to 220F to 230F. V23: This control valve bypasses the float valve. It is almost always clos ed, and should be opened only when the float valves float chamber is too full (above full in the sight glass). V26: This valve throttles the flow of Process Chilled Water (PCW) to the condenser and is probably the most useful control valve. Decr easing the flow rais es the Ammonia (NH3) Receiver pressure (NH3 receiver gauge), and increasing th e flow lowers the pressure. NH3 receiver pressure is extremely sensitive to the PCW flow rate and temperature, so use very small turns, and wait for the flow meter to update. If the pres sure is approaching th e 250 psi limit, and V26 is wide open, and T7 < 85F, then close V27, turn. Consider also somewhat rest ricting flow to the warm gas cooler (WGC) if WGC exit temperatures arent t oo excessive. If this is successful, you are running close to limits. If not successful, the unit is approachi ng a fault condition and the HRVG heat load must be reduced. Inform the Team Leader. V27: This valve throttles PCW flow to the absorber. Only open this valve, beyond its initial position, during operation if absolu tely necessary, as it robs flow from the condenser and the north PCW header (warm gas cooler supply). Things that may necessitate this action: a) If you see the pump exit temperature (T7) sl owly climbing past 90F, open in turn increments until stable at ~85F. This onl y happens when the ARU is getting a severe workout or there is a problem or both.

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107 b) If the low-side pressure (solution receiver press. gauge) is climbi ng past 105 psig, open in half turn increments. Watch the high-si de pressure. Youre taking flow from the condenser. Youll probably n eed to simultaneously add flow through V26. Note: Adding to the absorber flow actually has very little effect on the lo w side pressure; this is a last ditch effort, and then only if you have the flow to spare on the south PCW header. Planned Shut Down: A controlled shut down of the THERMOCHARGER is generally uneventful, even if there is an emergency shut down of the turbine. As the heat load decreases and pressures and temperatures drop, the various adjustments can be returned to their Stand-by settings When the heat load drops sufficiently, the unit will return to Stand-by mode and can then be shut down at the switch panel. The primary goal is to leave the Solution R eceiver 75-80 % full. If it is already at or below this level, do not wait for stand-by mo de; turn off the system and close V2, V14 and V25. If it is above this level, continue to r un and allow the pump to bring the level down. Remember that in stand-by mode, the pump is off, but the level will continue to drop slowly if the valves are still open. When shutting down the test facility, unplug the power cord. Unplanned (Fault) Shut Down: This will occur when you are operating at the lim its of the system and is generally due to exceeding maximum pressure. The turbine is usually at a high power level and action must be taken immediately!! The High Pressure Compressor Inlet Temperature will climb rapidly. Potentially, the rotor may experience a structural failure. Notify everyone repeatedly and with exuberance of this condition unt il you get confirmation, so an Emergency Turbine Shut down will be initiated. Remember you are not ending a test, you are saving the facility. When shutting down the test facility, unplug the power cord. Transferring Fluid from the Rectif ier to the Solution Receiver: Two people required. The primary operator must be wearing a chemical viso r. The secondary (spray tank) operator must be wearing full safety glasses. This operation takes about one hour.

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108 To verify the solution is in the Rectifier, check the R ectifier Float Valve sight glass, it should be full. With all valves in shut-down position, proceed as follows; 1. Turn on the exhaust fans. 2. Verify that V 13 and V 14 are closed. 3. Bring both water sprayers to the vicinity. 4. Check that both water sprayers are full of water, then pressurize. (Note there is a pressure bleed on the tank.) When making or breaking any connection, i rrigate with a continuous spray of water. All valves tend to leak and all hoses are probably charged with ammonia. 5. Connect a hose from V 20 at the Rectif ier to V 7 at the solution Receiver. 6. Connect the ammonia tank (upright) to V 21 on the SHX (recuperative heat exchanger). 7. Open the tank valve to pressurize the line. 8. Crack open the hose fitting connection to V 21, allowing air to purge from the line, then re-seal. 9. Open V 7 then V 20 to allow the fluid to transfer. 10. Open V 21 to pressurize the circuit with ammonia vapor. 11. Continue fluid transfer until the solution rece iver is ~ full. On the sight glass this would be a reading of ~ 7. The transfer cause s oscillation in the sight glass reading. As the level approaches 7, stop transfer occasiona lly to be sure what the level actually is. 12. Before disconnecting the ammonia tank hose from V 21, de-pressurize the hose by opening the pressure relief ball valve at the tank end. Ammonia will bleed out of the line into a water bucket through the relief line. Do not allow water to draw back into the line as pressure drops. Lab Data Acquisition System Procedure Rev. 8/5/07 HPRTE Soot Investigation Test Run #10: Dated 8/10/07 OPERATORS NAME Date System Set-up: Record Barometric pressure in Hg This information can be obtained from http://www.phys.ufl.edu/weather/

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109 1. Switch on the National Instruments unit at least one hour before the run. 2. Turn on the monitor and computer. 3. ___ Turn on the Fluke VOM for fuel flow rate readout. 4. ___ Turn on the Pressure Trans ducer regulated power supply. 5. ___ Switch on the thermal couple readouts (c ontrol panel below the selectors). 6. ___ Switch on the surge protected powe r strip behind the control panel. 7. The computer password is, lear2005 8. On the desktop, open the Rover data acquisition folder. 9. Double click the latest program version, currently Rover5enomod4. vi; this will open the LabView data panel. 10. Click the Continuous Run button and wait for the Not Recording light to begin blinking. 11. Verify that all thermocouples are readi ng properly by both the analog and digital data acquisition systems. Confirm agreement with the instrumentation map. This should be completed a day in advance of the run. 12. Verify that all pressure taps are reading properly by both the an alog and digital data acquisition systems. Confirm agreement with the instrumentation map. This should be completed a day in advance of the run. 13. Verify the analog pressure, temperature, and manometer reading legends are clearly displayed on the panel near the instruments. 14. Observe the readouts for a sufficient period of time to deduce an average, then enter the offsets for the following: a) On the Rover Vitals tab; 1) HP Comp exit Press. 2) Prvci, (recirc. venturi inlet pressure) 3) HP Comp inlet Press. 4) Seal Tip Pressure b) On the LP Spool tab, Comp. exit Pressure 15. On the Rover Vitals tab, press the Write Data toggle, on command of the test manager, during the start-up sequence.

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110 16. At the end of the run, stop data recordi ng by pressing the Write Data toggle again. The readouts are still active and can be monitored during cool-down. Data Post Processing: 1. The data is recorded in C:\Rover\day,date,yea r.xls, e.g. Thursday, March 02, 2006.xls. It is in two columns. The first is the index, the second is the data value. Each scan of the DAQ is recorded sequentially, so the inform ation must be put into a spreadsheet as follows. 2. Open Matlab and run MatLab program Edeci mate(filename), the filename being todays run file. It is easie st to copy the filename as text and paste it between the apostrophes to insure correctness. 3. Press Enter and wait for the post-processed data file to be written. Its location is C:\Old_Rover_Data\filename. 4. The Excel data template is now required a nd the easiest way to get one is to open a previous run. 5. Save the previous run in a folder created for the current test program. 6. On the All Data worksheet, delete the data only in the first 64 (currently) columns. This is the data template. 7. Open the new data in the C:\Old_Rover_Data\filename location. 8. Copy the data, paste it in the data fiel d of the template and save the file. 9. Change the source data of the plots to incl ude data from start-up to shut-down of the current run. 10. Examine the plots for stray data points cause d by signal noise. Find these data points in the data columns and replace them with an av erage of the five previous or subsequent data points. 11. The lead-in cells on thePresDat worksheet, st ill contain the range from the old run data you have deleted to get the template. Change this by going to the AllData worksheet and finding the cell containing the ET recorded at Engine Start Solenoid Engaged. Now go to the PresDat worksheet and copy the row number of the cell. Copy the row number of this cell address (e.g. 144 for cell A144) into each of the l ead-in cells, such that they are the second input into each of the AVERAGE functions. For example, if the correct

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111 ET at Engine Start Solenoid Engaged is in cell A144 of the AllData worksheet, then AVERAGE(TU3,TU190) would be come AVERAGE(TU3,TU144). The lead in data is now averaged over the proper time period for the new run. This time range may also be deduced by examining the plots and choosing, as your ET, the time just before temperature excursions indicate engine start. 12. The LabView and operating system combination has a Bug that causes jumps in the ET clock. When this occurs a blank region is obs erved in the plots where data seems to stop then begin again many seconds later. This may occur more than once during a run. Handle each occurrence in sequence. Repair the problem as in the following example. (1) Determine the amount of time "lost", e.g. ET = 3997, 3999, 4001, 4003, 4005 4055 4057, 4059 about 50 seconds (2) Determine the average delta-t preceding the time loss, in the above, it's two seconds (3) Subtract the delta-t from the time lost, in this example, 48 seconds (4) Create a new column at the end of the spreadsheet, beginning with the first row following the time loss. That is, the same row as ET = 4055 in the above example. This column will replace the corrupted ET column, by subtracting 48 seconds from every ET, e.g. 4055-48, 4057-48, 4059-48 etc to the end of the data. (5) Select the partial column with the new ET's, from where you started it, e.g. 405548 and cut it (ctrl + x). (6) Select the cell where the time loss begins, the cell with the 4055 in the above example, and right click. (7) Select the "Paste Special" opt ion; a dialog box will appear. (8) Select the "Values" radio bu tton, and press "Okay". (9) Check out the plots to ensure success. (10) Repeat this process for any additiona l time gaps farther into the run. 13. Post processing is now complete. Copy the pos t-processed spreadsheet to the flash drive provided.

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112 Spectrometer Operating Procedure Rev., 7/22/07 HPRTE Soot Investigation Test Run #10: Dated 8/10/07 OPERATORS NAME This document defines the operating procedure for the Ocean Optics spectrometer system available from Dr. David W. Hahn at the Laser La b in the MAE A lower level. It consists of a laptop computer, mouse, 500-770nm S2000 spectro meter, SAD 500 signal conditioner, fiber optic cable, a magnetic base with holder a nd shield, signal cable, laptop power supply and spectrometer power supply. Note th at the spectrometer is a precisi on instrument; take care not to damage it or the optical fiber cable. Use large radius loops when handlin g the cable, sharp bends will break it. Set-up: 1. Connect the laptop mouse and power supply and turn on the computer. 2. At the prompt, press ctrl-alt-del and enter the password lab. 3. Synchronize the date and time with the control room DAQ computer. 4. Verify the spectrometer is the correct 500-770 nm range. 5. Connect the signal cable between the laptop and the SAD500. 6. Connect the spectrometer power supply. 7. Create a folder on the Desktop named Run # mm/dd/yy. 8. On the Desktop, double click the OOIBase32 Icon. 9. Set Integration time to 100ms. 10. Set Average to 20. 11. Set Boxcar to 0. 12. The X axis scale should read 500 to 760, if it does not; a) Open the Spectrometer menu. b) Open Spectrometer Configuration c) Go to C:\program files\ocean optics\OOIBase32 d) Double click 500-770.spec e) At the prompt click yes for default configuration 13. Mount the magnetic base/fiber holder/inner light shield asse mbly approximately at the location marked on the Rover inlet duct. Be sure the V of the mag base is fully seated

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113 on the duct. The holder shield must be centered and co-axial in the viewport light shield. There should be 5/8 axial clearance between the cable holder and the viewport light shield. These should also be parallel. 14. Remove the blue fiber cable protector and connect the cable to the S2000 spectrometer. The cable nut must be fully engaged, finger tight is sufficient. Data Acquisition: 1. Grasp the other end of the fiber optic cable with the protector still in place, fully shrouded, in the palm of your hand. 2. Take a data point and save in the run folder with the filename Dark Signal. 3. Remove the black cable protector and insta ll the cable into the magnetic base holder, finger tight. 4. Take a data point and save in the run fo lder with the filename Stray Light. 5. When taking test data points during the run, the goal is to use maximum signal integration time for each data point without saturating the Spectrometer CCD. The table shows acceptable combinations. Integration Time and Signal Averaging Table Integration Time13 15 20 304050100 Averaging 15013010070504020 6. Saturation is indicated by a horizontal line on the screen where there should be a continuous smooth curve. If the curve peak is off the screen, use Spectrum Auto scale to view the entire curve. 7. If saturation is not occurring, increase the Integration time until it does, then choose the next lower Integration Time and Averagi ng from the table before taking the data. 8. Save all additional data points, taken when called for by the team leader, in the run folder, use filenames DP1 DP2 etc. 9. At the end of the run, close the program. 10. Remove the mouse from the USB port a nd install the flash drive provided. 11. Copy the run data folder and paste it to the flash drive. 12. Shut down the system, disconnect the hardware and return it to the storage location.

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114 The COSA 1600 IR Gas Analyzer Operating Procedure Rev., 5/9/07 1. Remove the analyzer from their storage case and re-locate to the control room counter top. Disconnect the sampling wand from th e rubber sample tube, if attached. 2. Remove the battery from the analyzer ca rry case and connect it to the charger. 3. Install the charged battery into the analyzer carry case and connect it to the analyzer. 4. The screen will prompt with start-up and cal ibration date information. Press Enter at each prompt until the Warming up sequence begins. Warm up will take ~ 4 minutes and the suction pump will start. 5. When warm up completes, and the screen wi ll prompt Set to zero please wait. Zeroing takes about 1 minute. 6. When zeroing completes, the screen will change to the menu. 7. Select Settings and Clock. 8. Synchronize the Analyzer cl ock to the Lab DAQ computer. 9. Connect the sampling hose to the sample diverter valve port. 10. Press Enter to begin sampling for measurement. The memory location number will be in the upper right corner of the screen. 11. Allow the analyzer to stabilize for on e and one half minute (90 sec.). 12. To record gas composition data, press Enter. 13. The unit will immediately begin sampling for the next measurement. 14. At the end of the run, press Off to put the unit in Standby mode. Notes: 1. The condensate trap must always be ve rtical, drain and dry after each run. 2. Always put the unit in standby mode befo re the battery is disconnected, otherwise the data will be lost. 3. It should be assumed that fully charged batt eries go dead within 3 days of non-use. The battery for each run must be on charge overnight before the run. 4. The unit must re-zero from time to time duri ng the run, usually when you are trying to record a measurement. The screen notifies you and instructs you to disconnect, wait for

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115 zero and reconnect the sample hose. Do not di sconnect the hose, simply remove the lower cap of the condensate trap. 5. If the screen returns to the mode menu, the da ta point was recorded. Press Enter to begin sampling. If the screen returns to data readout, the data poi nt was not recorded (check the memory location on the screen). In this case wa it for stable readings (1min.) and record. Stored data retrieval 1. The unit must warm up and zero before retrieval can begin. 2. At the opening menu, move the curser to Stored Data with the up/down arrow buttons. 3. Press Enter. 4. With the left/right arrow buttons select the data point 1-50. 5. Starting at data point 1, press the up or down arrow and the stored data for that point will be displayed. 6. Subsequent data points are selected with the left/right arrow buttons. 7. Transcribe all data to the Gas Analysis Run Data Sheet file. 8. To return to the main menu, press Enter. 9. To clear memory, select Stored Data then press the print button. The options are return, print actual, send data and Del all Data 10. Scroll to Del all Data and press the Enter bu tton. The screen will return to the Place 1 memory location. Note that once deleted, the memory is not recoverable. Double check that you have accurately transcribe d the data before executing steps 9. and 10. 11. Press Enter to begin taking Measurements again. 12. Press the Off button to end the session, conf irm at the yes prompt by pressing the Enter button to put the unit in standby mode. 13. To completely shut down the unit, disconnect the battery. 14. Distribute the Gas Analysis Run Data Sheet file as instructed.

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116 Digital Camera Set-up Procedure Rev. 7/22/07 Setting up for a test run: 1. Set up the tri-pod with the legs fully extended and locked. If applicable, lock the tri-pod central support. 2. Attach the tri-pod ad aptor to the camera and mount the camera to the tri-pod. 3. Connect the power supply adapter to the camera. Note that th e cord is at the top when installed. 4. Connect the power supply adapte r cord to the power supply. 5. Connect the AC power cord to the power supply. 6. Plug the AC power cord into a receptacle. 7. Open the AV jack cover at th e right rear of the camera. 8. Plug the AV jack into the AV receptacle (top one, yellow). 9. Connect the yellow and white AV, RCA jacks into the overhead AV cables. 10. Turn on the camera. The switch is at the top, rear of the camera. 11. Open the camera view screen. 12. Synchronize your timepiece to the Contro l room DAQ system. If you dont have a timepiece and/or dont know how to synchroni ze it, find someone who has these assets and ask them to finish setting up while you go do something else. 13. Press the menu button at the back of the camera. 14. Using the central grey button on the mode dial, Select Basic 15. Using the central grey button on the mode dial, Select Clock set 16. Using the central grey button on the mode dial, Select Yes 17. Press the central grey button on the mode dial, to bring up the time and date display. 18. Set the time and date using your synchronized timepiece. 19. Press the menu button to exit. 20. Aim the camera at the rig and adjust the z oom for maximum picture with both the fuel pressure gage and the combus tion chamber viewport visible. 21. To record on the internal tape, press the silver record button at the back of the camera. Note: It is not necessary to record interna lly to record on the control room VHS deck.

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117 To rewind the internal tape: 1. Turn the mode dial to the green arrow with the green border. 2. Select rewind (left) with the centr al grey button on the mode dial.

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118 APPENDIX B DATA SHEETS Test Matrix Bill Ellis, Rev. 5/30/07 RCV Dynamometer Net Load (lbf) P 9 15 25 35 45 0 Run 1, DP1 Run 1, DP2 Run 1, DP3Run 1, DP4 Run 6, DP13 .5 Run 6, DP1,12 Run 1, DP5 Run 6, DP11 1.0 Run 6, DP2 Run 1, DP6 Run 6, DP10 1.5 Run 6, DP3 Run 1, DP7 Run 6, DP4 2.0 Run 5, DP12 Run 1, DP8 Run 6, DP5 2.5 Run 5, DP11 Run 1, DP9 Run 6, DP6 3.0 Run 2, DP1 Run 1, DP10 Run 6, DP7 3.5 Run 2, DP2 Run 3, DP1 Run 1, DP11 Run 6, DP8 4.0 Run 2, DP3 Run 4, DP1 Run 1, DP12 Run 6, DP9 4.5 Run 2, DP4 Run 4, DP2 Run 1, DP13 Run 7, DP1 5.0 Run 2, DP5 Run 4, DP3 Run 5, DP10 Run 7, DP2 6.0 Run 2, DP6 Run 4, DP4Run 5, DP9 Run 7, DP3 7.0 Run 2, DP7 Run 5, DP1Run 5, DP8 Run 7, DP4

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119 HPRTE Soot Investigation Test Run #7: Dated 8/10/07 Rev. 8/2/07 OPERATORS NAME Note: The AC vent blows on the table in front of the ARU/VARS unit. Locate the Ps ychrometer where it is not affected by AC airflow. Calculate RH % before handing in the data sheet please !!! Engine room Watch Data Sheet Data Point WET Bulb (F) DRY Bulb (F) RH (%) NH3 Rec Press. (PSIG) Sol. Pump Press. (PSIG) Sol. Rcvr Press. (PSIG) Sol. Flow Rate (GPM) Cond Flow Rate (GPM) NH3 Level (inch) Sol. Level (inch) 1 2 3 4 5 6 7 8 9

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120 HPRTE Soot Investigation Test Run #7: Dated 8/10/07 Rev. 8/2/07 OPERATORS NAME Switch Position A: High Compressor Exit Switch Position B: High Turbine Exit Gas Analysis Data Pt Sw. Pos. Mem Loc. time Ch4 % CO % CO2 % NO ppm O2 % A 1 1 B 2 A 3 2 B 4 A 5 3 B 6 A 7 4 B 8 A 9 5 B 10 A 11 6 B 12 A 13 7 B 14 A 15 8 B 16 A 17 9 B 18 10 A 19

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121 HPRTE Soot Investigation Test Run #7: Dated 8/10/07 Please take care that all entries a re legible and fill in the page #s Rev. 8/5/07 OPERATORS NAME ENGINE START: AM/PM ENGINE STOP: AM/PM Operators Panel Data Sheet Data Point Instrument 1 2 3 4 5 6 STRAIN DYNO LOAD (LBf) FUEL FUEL LEVEL GAGE FUEL PRESSURE (PSIG) ENG. OIL P PRESSURE (PSIG) ENG. OIL T TEMPERATURE(0C) DYNO PRESSURE DYNO INLET PRESSUE (PSIG) DYNO FLOW TOTAL DYNO INLET FLOW (GPM) MAI VALVE POSITION RECIRC VALVE POSITION ROTAMETER FUEL FLOW (g/s) RPM ENGINE SPEED J11 HPCI (0F) K5 (1150 max) HPTX (0F)

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122 HPRTE Soot Investigation Test Run #7: Dated 8/10/07 Please take care that all entries a re legible and fill in the page #s Rev. 8/2/07 OPERATORS NAME Pressure Data Sheet Data Point Instrument 1 2 3 4 5 6 M0BRNR DP (S.G. 1.75) M4 RECRC DP (S.G. .827) M9 MAI (S.G. 1.91) M12 EVAP (S.G. 1.00) G5 HPCX (PSIG) G7 Seal P (PSIG) G8 HPRI (PSIG) G2-2 BRNR IN (PSIG) G1-1 HPTI (PSIG) G2-1 HPCI (in Hg Vac.)

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123 HPRTE Soot Investigation Test Run #7: Dated 8/10/07 Please take care that all entries are legible Rev. 4/29/07 OPERATORS NAME Temperature Data Sheet Data Point Instrument 1 2 3 4 5 6 T1 ARU-T14 T2 NCWS T4 SCWS T11 ARU-T9 T12 ARU-T10 T16 ARU-T4 J2 HPCX J5 WGCE J11 HPCI (W) J12 HPCI (E) K2 HPTX (t,e) K3 HPTI K4 HPTX (b,e) K5 HPTX (t,w) K12 HPTX (b,w) Ambient Thermometer

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124 HPRTE Soot Investigation Test Run #10: Dated 8/10/07 Please take care that all entries a re legible and fill in the page #s Rev. 5/30/07 OPERATORS NAME Record the beginning and ending time for each data point. Timekeeper Data Sheet Computer Clock Time (h/m) Computer ET (h/m/s) Brief Description of occurrence Engine Start Solenoid Engaged Engine Ignition, Solenoid fuel valve on

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125 Test Plan Shakedown Run HPRTE Soot Investigation Dated 03/22/07 Bill Ellis, Rev. 3/16/07 The Soot Investigation shakedown run will be the first time the HPRTE has been in operation for several months. Some personnel who will assist in the run have no previous experience with HPRTE operation. This document de fines the goals for this run. There are two primary goals: The first is to provide an opportunity for ever yone on the team to observe the test rig in operation, become familiar with procedures, our methods of data acquisition, gain confidence with the controls and acquire an understanding of rig response to control changes. Considering the time elapsed since the last run, even the experienced operators will benefit from the initial run in this regard. The desired result is an increased proficiency of the team that will enhance our ability to complete future data runs in a timely and economical manner. The second primary goal is more closely related to data acquisition. The operating limits we will approach are not yet clearly define d for the proposed conditions. It will be necessary to establish these. Specifically; (see Soot Investigation Test Plan) 1. The minimum dynamometer load for data points 1-11. 2. The dynamometer load possible at maximum turb ine inlet temperature for data points 5666. 3. The maximum recirculation venturi Dp possible before restricting the boost control valve. 4. The maximum optical radiation intensity the spec trometer is expected to encounter is at data point 66. The spectrometer integration time may need to be reduced to avoid CCD saturation. 5. Flame transition can be expected at high recirc ulation ratios. Well find it at some point and avoid it in subsequent runs. The data will be taken in three runs after the shakedown. Knowledge gain ed on control positions will allow the rig to be brought up from star t to the next test point more quickly. To accomplish these goals four data points will be attempted on the shakedown run. These are 1, 66, 56 and 11, in that order. Since these are at the extremes of the matr ix, encountering one of the above limitations is likely. This will begin to define the performance characteristics of the current configuration combustion liner.

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126 APPENDIX C RELEVANT DATA Table C-1. Processed data Data Point FvR Rm Tsoot Deg. R Tad Deg. R % O2 Pcomb psia 1 1.000 0.4270.0003559 2864 20.71 36.17 2 0.904 0.4170.0003590 2841 20.72 36.08 3 0.805 0.4390.0003587 2923 20.73 36.10 4 0.684 0.4630.0003582 3012 20.58 35.96 5 0.677 0.4780.1323511 2977 19.64 35.94 6 0.637 0.4690.2013514 2904 19.21 35.66 7 0.574 0.4760.2443468 2906 19.01 35.74 8 0.571 0.4740.2793491 2893 18.82 35.83 9 0.581 0.4820.3203489 2901 18.64 35.87 10 0.571 0.4850.3613462 2893 18.43 35.99 11 0.452 0.4830.3943491 2864 18.21 35.88 12 0.156 0.4870.4323472 2871 18.15 35.94 13 0.115 0.4970.4713472 2881 17.90 35.81 14 0.302 0.4920.4283309 2893 18.24 35.41 15 0.304 0.5140.4643317 2966 18.36 35.31 16 0.253 0.5410.4973309 3050 18.39 35.11 17 0.241 0.5500.5423306 3058 18.18 34.91 18 0.147 0.5370.6053307 2976 17.78 34.77 19 0.131 0.5740.6853303 3067 17.67 34.58 20 0.131 0.5810.7773297 3058 17.36 34.30 21 0.160 0.5970.8533294 3011 16.34 34.13 22 0.193 0.5850.8973261 2960 16.16 33.85 23 0.143 0.6391.0383228 3060 15.74 33.45 24 0.687 0.5000.4153323 2920 18.17 34.04 25 0.526 0.4770.4873356 2789 17.79 35.15 26 0.193 0.4770.5083400 2776 17.62 35.11 27 0.191 0.4810.5483408 2788 17.64 34.80 28 0.163 0.4960.6143381 2794 17.15 34.53 29 0.125 0.5250.7173387 2851 16.81 34.18 30 0.091 0.5410.8143393 2860 16.36 33.71 31 0.088 0.5670.8853373 2907 16.05 33.10 32 0.120 0.5000.6803383 2794 17.01 34.80 33 0.081 0.5100.7533389 2795 16.71 34.70 34 0.024 0.5240.8403473 2814 16.45 34.50 35 0.027 0.5350.8983434 2820 16.14 34.30 36 0.028 0.5930.9223411 2952 15.69 34.20 37 0.009 0.5750.8603554 2944 16.07 34.50 38 0.008 0.5520.7773569 2925 16.56 34.60 39 0.006 0.5350.6943648 2939 17.22 34.80

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127 Table C-1. Continued. Data Point FvR Rm Tsoot Deg. R Tad Deg. R % O2 Pcomb psia 40 0.027 0.5250.6243477 2923 17.38 35.00 41 0.066 0.5560.5383396 3074 18.04 35.20 42 0.607 0.5230.3193453 3067 19.04 35.20 43 0.547 0.5000.2913404 3009 19.15 35.10 44 0.186 0.4230.1273623 2797 19.57 35.12 45 0.704 0.4300.1913469 2787 19.12 34.76 46 0.659 0.4240.2713454 2737 18.78 34.89 47 0.144 0.5120.2413470 3035 18.70 34.93 48 0.129 0.5040.2843421 2979 18.42 35.07 49 0.068 0.5020.3463434 2937 18.07 35.11 50 0.074 0.5090.3723426 2950 18.00 34.74 51 0.052 0.5150.4213462 2948 17.80 34.88 52 0.007 0.5260.4703692 2961 17.54 34.72 53 0.097 0.5020.2033475 3026 18.90 34.46 54 0.251 0.5030.1523490 3063 19.21 34.29 55 0.660 0.4250.1463463 2797 19.37 34.03 56 0.528 0.4710.0003548 3052 20.34 33.77 57 0.007 0.5530.5173721 3030 17.48 34.86 58 0.007 0.5580.5523682 3019 17.19 34.76 59 0.006 0.5630.6303693 2999 16.87 34.36 60 0.006 0.5720.7073685 2978 16.47 34.26 61 0.011 0.5900.8663562 2959 15.74 33.82 62 0.074 0.6110.9063426 2955 15.39 34.48

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128 Table C-2. Sample Labview Output 0 0 1 79.40388 2 1649.221 3 77.6002 4 78.30279 5 62.4443 6 61.94059 7 75.00613 8 77.82876 9 76.79381 10 76.94235 11 80.43185 12 78.13914 13 81.17278 14 79.61881 15 81.75643 16 -0.42701 17 -0.11914 18 0.043567 19 2.665943 20 0.150181 21 4.906085 22 1.580672 23 -0.41621 24 0.036023 25 -0.78179 26 -0.22353 27 3.19627 28 -3.59566 29 0.136194 30 2.724582 31 2600.127 32 19.58565 33 12.17088 34 -0.51699 35 78.25413 36 78.96556 37 78.76843 38 76.83228 39 0.041883 40 46.49488 41 19.03054 42 61.63222

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129 Table C-2. Continued. 43 61.6227 44 0.025831 45 77.00661 46 74.11941 47 75.82267 48 70.80216 49 70.24372 50 68.22599 51 67.36043 52 77.67521 53 75.27425 54 78.36711 55 77.45163 56 77.55927 57 77.75253 58 75.5365 59 73.61412 60 74.46709 61 62.07341 62 63.19882 63 80.846 Measurement Error Analysis Values for Tsoot and FvR are directly related to the emi ssion intensity, measured with the spectrometer, after correcting for distance and set-up assumptions. Th e values of interest are the physical location of the optical fiber in its hold er, the assumed radius of the flame and signal attenuation by the sapphire window. The average for these values was used to obtain the results presented in this work. The location of the optical fiber was known within +/0.12 of its mean, the radius of the flame was known within +/0. 5 and the window transmissibility was known within +/0.08. A minimum and maximum corre cted signal intensit y was calculated using extreme values for these variables al ong with the corresponding values for Tsoot and FvR. These were compared to the results of this research. One half of the range wa s considered to be the measurement uncertainty.

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130 Combustion pressure, Pcomb, was measured using a bourdon tube mechanical gage with a 100 psi range and a 60 inch u-tube manometer. Th e accuracy of the gage was quoted to be +/0.75 % of full scale or 0.75 psi. The accuracy of the manometer was quoted to be +/0.04 psi. The contribution to uncertainty by the manometer was much less than the gage. Therefore the overall uncertainty was determined by rounding o ff the gage specification and presented as +/0.8 psi. Values for O2 % and were dependent on the accuracy of fuel, humidity and exhaust gas measurements. The instrumentation for fuel a nd humidity measurements had a quoted accuracy of 1 %. For the exhaust gas analyzer, measurement accuracy for CO and CO2 was +/5 % and for oxygen it was +/0.2 %. Uncertainty was calculated as follows. 2/1 2 2 2 2 2%2.0%5%5%1%1%2.7

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131 LIST OF REFERENCES 1. IPCC, 1995. Climate Change 1995. Intergovernmental P anel on Climate Change. Cambridge Univ. Press, London (1995). 2. Haywood, J.M., and Shine, K.P., Quart. J. R. Meteorol. Soc.123:1907 (1997). 3. Seinfeld, J. H., Nature, 391:837 (1998). 4. Shine, K. P., and M. de F. Forster, Piers, Global and Planetary Change 20:205, (1999). 5. Kirkeva, A., Iversen,T., and Arne, D., Atmospheric Environment 33:2621-2635 (1999). 6. American Lung Association, Selected Key Studies on Par ticulate Matter and Health: 1997 2001, New York (2001). 7. Gupta, A.K., Energy Convers. Mgmt. 38:10-13:1311-1318, (1997). 8. Lefebvre, H., Int. J. Heat Mass Transfer. 27:9:1493-1510, (1984). 9. Moss, J.B., and Stewart,C..D., Experimental Thermal and Fluid Science 28:575-583, (2004) 10. Frenklach, M., Phys. Chem. Chem. Phys., 4:2028, (2002). 11. Glassman, I., Combustion, 3d ed., Academic Press, New York, 1996 12. Thomson, K. A., Glder, L., Weckman, E. J., Fraser, R. A., Smallwood, G. J., and Snelling, D. R., Combustion and Flame 140:222 (2005). 13. Roditcheva, V. X., and Bai, S., Chemosphere 42:811-821, (2001). 14. McCrain, L. L., and Roberts, W. L., Combustion and Flame 140:60-69, (2005). 15. Brooks, S. J., and Moss, J. B., Combustion and Flame 116:49-61, (1999). 16. Gollahalli, S.R., and Puri, R., Energy Convers. Mgmt. 38:10-13:1073-1081, (1997) 17. Konishi, N., Kitagawa, K., Ar ai, N., and Gupta, A. K., Journal of Propulsion and Power, 18:1, (2002) 18. Shimo, N., and Fujisou, A., Second International Symposium on High Temperature Air Combustion and Gasification, Kaohsuing, Taiwan, 1999, pp B6 19. Weber, R., Verlaan, A. L., Orsino, S., and Lallemant, N., Second International Symposium on High Temperature Air Combustion and Gasification, Kaohsuing, Taiwan, 1999, pp C2

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132 20. Gupta, A. K., and Hasegawa, T., Second International Symposium on High Temperature Air Combustion and Gasification, Kaohsuing, Taiwan, 1999, pp A4 21. Caveliere, M. de Joannon, and Ragucci, R., Second International Symposium on High Temperature Air Combustion and Gasification, Kaohsuing, Taiwan, 1999, pp B4 22. Hottel, H. C. and Broughton, F. P., Industrial and Engineering Chemistry, Analytical Edition, Vol. 4, No. 2, (1932) 23. Zhao H., and Ladommatos, N., Prog. Energy Combust. Sci. 24:221-255, (1998). 24. Chang, H., and Charalampopoulos, T. T., Proc. R. Soc. Lond. A, 430:577-591 (1990). 25. Choi, M. Y., Hammins, A., Mulholla nd, G. W., and Kashiwagi, T., Combustion and Flame, 99:174-186 (1994). 26. Jenkins, T. P., and Hanson, R. K., Combustion and Flame, 126:1669-1679 (2001). 27. Howell, E. B., Masters Thesis, University of Florida Gainesvill e, Department of Mechanical Engineering, 2007. 28. Sonntag, R. E., and Van Wylen, G. J., In troduction to Thermodynamics: Classical and Statistical, John Wiley & S ons, Inc., New York, 1971. 29. di Stasio, S. and Massoli, P., Meas. Sci. Technol., 5:1453-1465, (1994).

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133 BIOGRAPHICAL SKETCH W illiam J. Ellis, Jr. was born in West Palm Beach Florida. His primary education was completed in Fort Lauderdale Florida. He grad uated in the top 10% of his class in 1970. Early undergraduate work was undertaken at Broward Junior Colleg e (Davie, Florida) and the University of South Florida (Tampa) where he received an Associate of Arts degree. After transferring to the University of South Carolina at Clemson in 1977, he graduated with a Bachelor of Science in mechanical engineeri ng in 1979 with honors. After a career spanning 27 years, he enrolled for graduate studies at the University of Florida in Gainesville Florida and received a Master of Science in mechanical engineering in 2008.