Group Title: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings
Title: 2.6.3 - Comparison between Sonic and Supersonic Steam Jet
ALL VOLUMES CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00102023/00064
 Material Information
Title: 2.6.3 - Comparison between Sonic and Supersonic Steam Jet Multiphase Flows with Heat and Mass Transfer
Series Title: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings
Physical Description: Conference Papers
Creator: Li, W.J.
Yan, J.J.
Liu, G.Y.
Pan, D.D.
Publisher: International Conference on Multiphase Flow (ICMF)
Publication Date: June 4, 2010
 Subjects
Subject: sonic
supersonic
steam jet
 Notes
Abstract: In the present work, a contracting nozzle and a Laval nozzle were designed and investigated experimentally to find the difference between sonic and supersonic steam jet in subcooled water. Six different shapes of steam plume could be generated in supersonic steam jet, and they were called contraction, expansion-contraction, double expansion-contraction, double expansion-divergent, contraction-expansion-contraction, contraction-expansion-divergent shapes. But for the under-expanded sonic steam jet, only four shapes of plume were observed except contracting-expansive-contracting and contracting-expansive-divergent shapes. Under the same test condition, the dimensions penetration length of sonic steam jet was found to be always larger than that of supersonic steam jet. Considering the effect of nozzle configuration, a correlation was set up to predict the dimensionless penetration length of the steam plume, and the predicted errors were below ± 30%. Moreover, the flow characteristics were analyzed and the isothermal and isobar diagrams were drawn and discussed, and the fluctuation of pressure and temperature could confirm the existence of expansion and compression waves.
General Note: The International Conference on Multiphase Flow (ICMF) first was held in Tsukuba, Japan in 1991 and the second ICMF took place in Kyoto, Japan in 1995. During this conference, it was decided to establish an International Governing Board which oversees the major aspects of the conference and makes decisions about future conference locations. Due to the great importance of the field, it was furthermore decided to hold the conference every three years successively in Asia including Australia, Europe including Africa, Russia and the Near East and America. Hence, ICMF 1998 was held in Lyon, France, ICMF 2001 in New Orleans, USA, ICMF 2004 in Yokohama, Japan, and ICMF 2007 in Leipzig, Germany. ICMF-2010 is devoted to all aspects of Multiphase Flow. Researchers from all over the world gathered in order to introduce their recent advances in the field and thereby promote the exchange of new ideas, results and techniques. The conference is a key event in Multiphase Flow and supports the advancement of science in this very important field. The major research topics relevant for the conference are as follows: Bio-Fluid Dynamics; Boiling; Bubbly Flows; Cavitation; Colloidal and Suspension Dynamics; Collision, Agglomeration and Breakup; Computational Techniques for Multiphase Flows; Droplet Flows; Environmental and Geophysical Flows; Experimental Methods for Multiphase Flows; Fluidized and Circulating Fluidized Beds; Fluid Structure Interactions; Granular Media; Industrial Applications; Instabilities; Interfacial Flows; Micro and Nano-Scale Multiphase Flows; Microgravity in Two-Phase Flow; Multiphase Flows with Heat and Mass Transfer; Non-Newtonian Multiphase Flows; Particle-Laden Flows; Particle, Bubble and Drop Dynamics; Reactive Multiphase Flows
 Record Information
Bibliographic ID: UF00102023
Volume ID: VID00064
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: 263-Li-ICMF2010.pdf

Full Text

Paper No 7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010


Comparison between Sonic and Supersonic Steam Jet



Wenjun Li, Junjie Yan*, Guangyao Liu and Dongdong Pan

Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University,
Xi'an 710049, China
yanjj mail.xjtu.edu.cn


Keywords: sonic, supersonic, steam jet




Abstract

In the present work, a contracting nozzle and a Laval nozzle were designed and investigated experimentally to find the
difference between sonic and supersonic steam jet in subcooled water. Six different shapes of steam plume could be generated
in supersonic steam jet, and they were called contraction, expansion-contraction, double expansion-contraction, double
expansion-divergent, contraction-expansion-contraction, contraction-expansion-divergent shapes. But for the under-expanded
sonic steam jet, only four shapes of plume were observed except contracting-expansive-contracting and
contracting-expansive-divergent shapes. Under the same test condition, the dimensions penetration length of sonic steam jet
was found to be always larger than that of supersonic steam jet. Considering the effect of nozzle configuration, a correlation
was set up to predict the dimensionless penetration length of the steam plume, and the predicted errors were below + 30%.
Moreover, the flow characteristics were analyzed and the isothermal and isobar diagrams were drawn and discussed, and the
fluctuation of pressure and temperature could confirm the existence of expansion and compression waves.


Introduction

Steam-water direct-contact condensation is a common
event encountered in many two-phase systems. It is a
phenomenon of high importance in nuclear, chemical and
marine industry applications. The advantageous feature of
applying this phenomenon to various technical applications
is that heat transfer is greatly enhanced due to the
increased turbulence in the vicinity of the vapour-liquid
interface.
Many experimental and theoretical works on the
steam-jet condensation in subcooled water have been
reported. Empirical correlations of the steam jet length
were proposed by many researchers. Kerney et al. (1972)
experimentally investigated the parametric effects of steam
mass flux, liquid subcooling, and nozzle configurations on
the penetration length of vertically injected steam jets at
sonic speed. Weimer et al. (1973) investigated theoretically
the steam jet length and proposed simple models for
predicting the steam jet length.
Stanford et al. (1972) examined the steam jet profile
of both sonic and subsonic flow. Kudo et al. (1974)
observed the typical cone jet shape when the steam was
injected into the highly subcooled water at atmosphere
pressure. Furthermore, a turbulent diffusion model was
proposed, and the theoretical results corresponded to
experimental results. The internal and external boundaries
of two-phase region of the sonic jet were observed by
Kostyuk (1985), the cone jet shape occurred at high
subcooling, with decreasing subcooling the shape became


swollen in the middle. According to the observation, the
mechanism of condensation process of steam jet in a pool
was reported. Chun et al. (1996) experimentally studied the
steam jet and observed two shapes of steam plume (conical
and elliptical). Kim et al. (2001) also observed conical and
ellipsoidal shapes of steam jet in the experiment. Empirical
correlation for dimensionless penetration length of the
steam plume was established and the axial and radial
temperature distributions of the jet region were measured.
The supersonic steam jet in subcooled water was
experimentally studied (Wu et al., 2007). Six different
plume shapes were observed besides conical and elliptical
shapes, and the correlations to predict expansion ratio,
penetration length were given.
A number of experimental studies were performed to
establish the empirical correlations of heat transfer
coefficient for different steam mass flux and ambient water
temperature. Sonin (1984) tried to establish the heat
transfer coefficient correlation with the turbulent
intensities near the steam-water interface. Simpson and
Chan (1982) investigated the basic mechanism of subsonic
steam jet condensation. They observed that the dynamics
of subsonic steam jet were quite different from those of
sonic steam jet and the average heat transfer coefficients of
subsonic steam jets were lower than those of sonic steam
jets.
According to the above retrospect, almost all the
research on steam jet was for subsonic or sonic, and the
dynamics of subsonic steam jet were found to be quite
different form those of sonic steam jet. The present work






Paper No


deals with the experiments to find the difference between
the sonic and supersonic steam jet. A contracting nozzle
and a Laval nozzle (pressure ratio 0.175) were designed
and investigated experimentally over a wide range of
steam pressures and ambient water temperatures. Several
jet parameters were obtained and compared. Moreover, the
flow outside the nozzle was analyzed and the isothermal
and isobar diagrams were drawn and discussed.


Nomenclature


condensation driving potential
liquid specific heat (Jkg-'K 1)
diameter (mm)
steam mass flux (kgm 2s1)
heat of condensation (Jkg-1)
dimensionless penetration length
penetration length (mm)
Mach number
pressure (MPa)
mean transport modulus
temperature (K)


7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010

the range of 0.5-2K for different steam mass fluxes.
Based on the accuracy of the instruments and the
method of analyzing uncertainty given by Moffat (1988),
the maximum uncertainties relevant to the range of
parameters in the present experiment were obtained. The
uncertainty of temperature was 1K, and the uncertainties of
pressure and steam mass flux measurements were 2.0%
and 2.5%, respectively. Furthermore, the uncertainty in the
dimensionless penetration length calculated relevant to the
present results was 4.4%.
Tab. 1 Test conditions
Parameters Values
Po 0.20-0.60
Tw 293-343
Pb 0.102
dm 8
de 8, 10.4
e 0.577, 0.175
Ma 1, 1.82


Greek letters
e pressure ratio
y ratio of specific heats
p density (kgm 3)

Subsripts
0 stagnation state
b back pressure
e nozzle exit
m nozzle throat
p constant pressure state
w ambient water


Experimental Facility


Figure 1: Schematic diagram of experimental system


Axes


To investigate the sonic and supersonic steam jet, a
transparent experiment system was designed, which mainly
consisted of an electric steam generator, a surge tank, a
rectangular tank of 3000mmx 1000mmx 1200mm and some
valves, as shown in Fig. 1. The saturated steam supplied by
the steam generator with electric heaters of 330kW was
injected into the water tank through a nozzle fixed on the
wall of the tank by a flange. The test conditions are shown
in Table 1.
The steam flow rate was measured by a vortex type
steam flowmeter. The temperature of the flow field was
measured by 21 K-type thermocouples fixed on a mobile
test block, as shown in Fig.2. The pressure was measured
by 9 pitots fixed on another mobile test block, as shown in
Fig.3. When the steam jet was stable for a certain test
condition, a high-speed video camera was used to take
pictures of the steam plume. Then the test blocks were
moved by a stepper motor to measure the temperature and
pressure fields. The measurement was carried out every 5K,
and in a set of measurements, the temperature rise was in


Figure


Figure 3: Schematic diagram of pressure test block






Paper No


Results and Discussion

Steam plume shapes
In the previous investigations, the steam plume was
mainly observed by a high-speed camera. Two typical
plume shapes, including conical and ellipsoidal shapes for
sonic steam jet have been reported by Giovanni (1984),
Chun (1996) and Kim (2001). Six different plume shapes
for supersonic steam jet were observed besides conical and
elliptical shapes by Wu et al. (2007). In the present work,
four shapes of the steam plume were observed for sonic
steam jet as shown in Fig.4, but for supersonic steam jet,
another two shapes were observed as shown in Fig.5. They
were called contraction, expansion-contraction, double
expansion-contraction, double expansion-divergent,
contraction-expansion-contraction, contraction -expansion-
divergent shapes respectively, and the last two kinds of
plume were not observed for sonic steam jet.
A P-0.2MPa T K293K C P-0.5MPa T=333K

B P=0.5MPa T293K D 0.6MPa 343K


Figure 4: Steam plume shapes for sonic steam jet

P i0.3MPa T, 293K N T=323K

B Po0.6MPa T,=308K D Po0.6MPa T-343K F P=0.3MPa T,=338K


Figure 5: Steam plume shapes for supersonic steam jet

If shock wave occurred at the Laval nozzle exit, the
pressure lifting ratio could be calculated according to the
following expression:
P, / P=P, P/ Ma22y(y + 1) -1) /(y + 1)
The back pressure was 0.102MPa. The designed Mach
number and pressure ratio of the Laval nozzle was 1.82
and 0.175 respectively. For dry saturated steam, y was
1.135. So the pressure before the shock wave could be
calculated as follows:
P] = Pb (y+1) [2yMa2 -(y-1)] = 0.0296MPa
Total pressure:
P, = P, /0.175= 0.169MPa
During the experiment, the total pressure was in the
range of 0.2-0.6MPa, higher than 0.169MPa. Therefore, no
shock wave occurred in the nozzle region and the flow
after the throat was supersonic. Moreover, when the total
pressure was in the range of 0.2-0.5MPa, the steam was
over-expanded, namely the nozzle exit pressure was lower
than back pressure. When the total pressure was 0.6MPa,
the steam was under-expanded, namely the nozzle exit
pressure was higher than back pressure. But for the
contracting nozzle, the pressure at the nozzle exit was
always being equal to or greater than back pressure. In this
work, the total pressure was in the range of 0.2-0.6MPa,
and the back pressure was 0.102MPa, so the pressure ratio
was in the range of 0.17-0.51, lower than the critical
pressure ratio 0.577. Therefore, the steam could not fully
expand in the contracting nozzle, and the pressure at the
contracting nozzle exit was always higher than back
pressure in present work. So, the case of over-expand


7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010

might occur if and only if the nozzle was a Laval nozzle.
According to the observation, the shape of the steam
plume was mainly controlled by the nozzle exit pressure
and the subcooling of the ambient water. For
under-expanded steam jet as shown in Fig.6, expansion
waves would occur at the nozzle exit (broken lines
represented expansion waves, and real lines represented
compression waves), and they would intersect at point B.
After flowing through the expansion waves AB and A'B,
the steam in region 1 would turn aside from the axes, the
temperature decreased, and the pressure declined to back
pressure. After point B, if the steam in regions 2 and 3
maintained their flow direction, a wedge of empty space
would be formed. So, another two expansion waves BC
and BC' occurred. After that, the flow direction became
paralleled by the axes again in region 4 and the pressure
decreased further and became lower than back pressure. As
a result, the steam in region 4 began to be compressed, and
compression waves CD and C'D occurred at the
steam-water interface. Contrary to expansion waves, after
flowing through the compression waves CD and C'D, the
steam in region 4 would deflect towards the axes, the
temperature increased, and the pressure rise to back
pressure. But the steam in regions 5 and 6 was of different
flow direction, and they would encounter and compress
each other at point D to generate another two compression
waves DE and DE'. After that, the parameters of flow field
in region 1' turned back to those of region 1.
For over-expanded steam jet, compression waves
would occur at the nozzle exit. The steam was compressed
first, and section CC' could be considered as the nozzle
exit, and the flow outside the nozzle was similar to the
above. Neglecting the effect of viscosity and condensation,
the above phenomenon would appear periodically. But for
real gas, viscosity was inevitable, and those waves would
disappear when speed was below sonic. Moreover, the
steam would condense completely sooner or later. For
higher undercooling, the steam condensed immediately,
and contraction shape (shape A) was observed. With the
decrease of undercooling, two periods at most were
observed in present work. When the subcooling was lower
than 35K, the steam plume tended to be divergent.
Fb CF


P> FB


Figure 6: A sketch map for intersection and reflection of
expansion and compression waves

Consequently, six different shapes of steam plume
could be generated by supersonic steam jet. But due to the
under-expanded of steam in the contracting nozzle,
contraction-expansion-contraction, contraction -expansion-
divergent shapes could not be generated by sonic steam jet
and only four kinds of different plume were observed.

Dimensionless penetration length


3b
A'






Paper No


Dimensionless penetration length L, which was
defined as the ratio of the penetration length of the steam
plume 1 to the nozzle exit diameter de was calculated.
Steam mass flux determined the amount of steam for
condensation, so it played a significant role in the steam
plume dimensions. In the previous work, many researchers
found that the dimensionless penetration length increased
with the steam mass flux. For a single nozzle, the
dimensionless penetration length did increase with the
steam mass flux, because the penetration length increased
with the total pressure as shown in Fig.7, and the steam
mass flux also increased with the total pressure. But in the
present work, the trend was found to be not strictly
monotonous, but with fluctuation as shown in Fig.8, and
for different bath temperature, the trend was similar to each
other. Under the same test condition, the dimensionless
penetration length of sonic steam jet was found to be
always larger than that of supersonic steam jet as shown in
Fig.7. Therefore, configuration of the nozzle would have
an effect on the dimensionless penetration length.

SP0=0.2MPa **...... super sonic steam jet
14 Po=0.3MPa sonic steam jet
Po=0.4MPa
Po=0.5MPa
10 Po=0.6MPa


8 --- ----
6 -- -- -- --


7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010

flux at bath pressure, B= C)T/h was the condensation
driving potential, AT was the temperature difference
between both phases, S was the mean transport modulus
which was assumed to be a constant according to the
experiment data (Kerney et al., 1972).
Many researchers have proposed their dimensionless
correlations for the steam plume length according to
expression (1). Utilizing a variable density single fluid
model for the two-phase flow, a theoretical expression for
the steam penetration distance was developed by Weimer
et al. (1973) and this model was found to correlate the
experimental results over a wide range of operating
conditions and injector geometries. The expression was
given as
L=lld, = aB (p, pw)-(G / G,) 5 (2)
In this equation, the density ratio resulted from the
turbulent entrainment law, and Pe was the steam density
at nozzle exit, and p, was the density of ambient water.
By removing the theoretical restrictions on property
powers prior to least squares fitting, an improved data
correlation could be obtained as
L= 0.03B 16(p,e/ w) 13(CG/GJ)186 (3)
Expression (3) had a coefficient of multiple determination
of 0.967 with a maximum deviation between the measured
and predicted values of dimensionless penetration length
of 30% as shown in Fig.9.


14 /


4 --


290 300 310 320
Water Temperature T /K


29.5%


330 340


Figure 7: Comparison of dimensionless penetration length
for sonic and supersonic steam jet


T =293K
14- T=303K
ST=313K
12- T =323K
T =333K
10- T =343K


P=0.102MPa


0 2 4 6 8 10
Measured value of L
Figure 9: Comparison of predicted
dimensionless penetration length


12 14

and measured


6- .

4 -

2

200 300 400 500 600 700 800
Steam mass flux G / kg- (- s )1
Figure 8: Dimensionless penetration length at different
steam mass flux

Neglecting the effect of buoyant and assuming an
axially symmetric flow, the dimensionless penetration
length of the steam plume could be obtained by Kerney et
al. (1972)
L = / de = 0.5(Ge / Gt)' 5/(SB) (1)
where Gm was taken to be equal to the critical steam mass


Temperature and pressure distributions
According to the measured data, the temperature and
pressure fields for various test conditions were obtained.
Four typical isobar and isothermal diagrams were drawn as
shown in Fig.10. A, B and C of Fig. 10 were drawn based
on the data of sonic steam jet while D was drawn based on
the data of supersonic steam jet, and they corresponded
with contraction, expansion-contraction, double
expansion-contraction, contraction-expansion-contraction,
shapes respectively.
The flow outside the nozzle was analyzed based on
expansion and compression waves in section 3.1. The
fluctuation of pressure and temperature was evident due to
expansion and compression waves as shown if Fig.10.
After the expansion wave, pressure and temperature
decreased, as shown in the dark blue region in Fig. 10, and
the minimum pressure could be even lower than back


-27.6%


ii


/i






Paper No


pressure. On the contrary, the pressure and temperature
would increase after the compression wave, as shown in
the red region in Fig.10, and for higher subcooling of
ambient water the maximum pressure could be even higher
than the total pressure at nozzle inlet. Therefore, the isobar
and isothermal diagrams could confirm the existence of
these waves and the former had more persuasion.

EO

10 n


T/K 290 311 312 312 313 314 315 321 330 340 358 375 378


I x17m 1


T/K 290 302 312 322 335 352 359 363 364 369 375 378 401


on I


T/K 328 350 353 358 361 362 363 365 368 374 375 378 390


E
ED

-lot
00

T/K
Figure 10:
conditions


320 336 343 350 354 358 361 363 364 366 372 375 379
Pressure and temperature fields for various test


Conclusions


In the present work, a contracting nozzle and a Laval nozzle


7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010

(pressure ratio 0.175) were designed and investigated
experimentally to find the difference between sonic and
supersonic steam jet. The results could be summarized as
follows:
(1)Six different shapes of steam plume could be generated
by supersonic steam jet in present work, and they were
called contraction, expansion-contraction, double
expansion-contraction, double expansion-divergent,
contraction-expansion-contraction, contraction-
expansion-divergent shapes. But due to the under-expanded
of steam in the contracting nozzle,
contraction-expansion-contraction and contraction-
expansion-divergent plume could not be generated by sonic
steam jet and only four kinds of different plume were
observed.
(2)Under the same test condition, the dimensionless
penetration length of sonic steam jet was found to be always
larger than that of supersonic steam jet. Considering the
effect of nozzle configuration, a correlation was set up to
predict the dimensionless penetration length of the steam
plume. The correlation had a coefficient of multiple
determination of 0.967 with a maximum deviation between
the measured and predicted values of dimensionless
penetration length of 30%
(3)The flow outside the nozzle was analyzed and the isobar
and isothermal diagrams were drawn and discussed. The
isobar and isothermal diagrams could confirm the existence
of expansion and compression waves and the former had
more persuasion.

Acknowledgements

This work was supported by the National Natural Science
Foundation of China (No. 50676078) and Major State Basic
Research Development Program of China (973 Program)
(No. 2009CB219803)

References

Kerney, P.J. & Faeth, GM. & Olson, D.R., J. Penetration
Characteristics of a Submerged Steam Jet. American
Institute of Chemical Engineering, Vol. 18(3),
548-553(1972)

Weimer, J.C. & Faeth, GM. & Olson, D.R., J. Penetration of
Vapor Jets Submerged in Subcooled Liquids. American
Institute of Chemical Engineering, Vol. 19(3),
552-558(1973)

Kudo, A. & Egusa, T. & Toda, S., C. Basic Study on Vapor
Suppression. Proc. 5th International. Heat Ttransfer
Conference, Tokyo, Vol. 3, 221-225(1974)

Simpson, M.E. & Chan, C.K., J. Hydrodynamics of a
subsonic vapor jet in subcooled liquid. Journal of Heat
Transfer, Vol. 104, 271-278(1984)

Sonin, A.A., J. Suppression pool dynamics research at MIT.
NUREG/CP-0048, 400-421(1984)

Moffat, R.J., J. Describing the Uncertainties in
Experimental Results. Experimental Thermal and Fluid
Science, Vol. 1, 3-17(1988)





Paper No 7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010


Liang, K.S. & Griffith, P., J. Experimental and Analytical
Study of Direct Contact Condensation of Steam in Water.
Nuclear Engineer and Design, Vol. 147, 425-435(1994)

Chun, H. & Kim, Y.K. & Park, J.W, J. An Investigation of
Direct Condensation of Steam Jet in Subcooled Water.
International Communications in Heat and Mass Transfer,
Vol. 23(7), 947-958(1996)

Eden, T.J. & Miller, T.F. & Jacobs, H.R., J. The Centerline
Pressure and Cavity Shape of Horizontal Plane Choked
Vapor Jets with Low Condensation Potential. Journal of
Heat Transfer, Vol. 120(11), 999-1007(1998)

Kim, H.Y & Bae, YY. & Song, C.H. & Park, J.K. & Choi,
S.M., J. Experimental Study on Stable Steam Condensation
in a Quenching Tank. International Journal of Energy
Research, Vol. 25, 239-252(2001)

Kim, Y.S. & Park, J.W. & Song, C.H., J. Investigation of the
Steam-Water Direct Contact Condensation Heat Transfer
Coefficients Using Interfacial Transport Model.
International Communications in Heat and Mass Transfer,
Vol. 31(3), 397-408 (21.14)

Petrovic, A. & Calay, R.K. & de With, G, J. Three
-dimensional condensation regime diagram for direct
contact condensation of steam injected into water.
International Journal of Heat and Mass Transfer, Vol.
50(9-10), 1762-1770(2007)

Wu, X.Z. & Yan, J.J. & Shao, S.F. & Cao, Y & Liu, J.P, J.
Experimental study on the condensation of supersonic steam
jet submerged in quiescent subcooled water: steam plume
shape and heat transfer. International Journal of Multiphase
Flow, Vol. 33, 1296-1307(2007)




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs