In this study, an investigation was carried out to clarify the mechanism of countercurrent flow limitation (CCFL) or flooding, that is, limitations in the falling water mass flux in countercurrent two-phase flow in vertical channels, and to identify the effects of predominant parameters regarding CCFL, adopting the criterion that the CCFL condition be given by an envelope of momentum equation applied for the entire length of the channel with respect to any void fraction. As a result, it was found that the analytical model proposed could adequately predict all existing experimental results investigated in this study. In the channel configuration, circular, rectangular, and annular or planar channels, channel dimensions of diameter, gap size, width or circumference, and length, interfacial and wall friction, water injection mode, and inlet water subcooling were dominant parameters. Therefore, both the mechanism and the quantitative effects of CCFL have been identified.

1.
Bharathan, D., Wallis, G. B., and Richter, H. J., 1979, “Air–Water Countercurrent Two-Phase Flow,” EPRI Rep. No. NP-1165.
2.
Chang
S. H.
,
Baek
W-P.
, and
Bae
T. M.
,
1991
, “
A Study of Critical Heat Flux for Low Flow of Water in Vertical Round Tubes Under Low Pressure
,”
Nuclear Eng. & Design
, Vol.
132
, pp.
225
237
.
3.
Cheng, L. Y., 1990, “Countercurrent Flow Limitation in Thin Rectangular Channels,” Proc. Int. Topical Mtg. on Safety Status and Future Non-commercial React. and lrradiat. Facilit., ANS, pp. 671–678.
4.
Collier, R. P., et al., 1978, “Steam-Water Mixing and System Hydrodynamics Program,” NUREG/CR-0526, BMI-2011.
5.
Crowley, C. J., and Block, J. A., 1975, “ECC Delivery Study, Experimental Results and Discussion,” Creare Technical Note, TN-217.
6.
Crowley, C. L, Block, J. A., and Rothe, P. H., 1976, “An Evaluation of Scaling Parameters for ECC Penetration Data,” Creare Technical Note, TN-217.
7.
El-Genk
M. S.
,
Haynes
S. L.
, and
Kim
S-H.
,
1988
, “
Experimental Studies of Critical Heat Flux for Low Flow of Water in Vertical Annuli at Near Atmospheric Pressure
,”
Int. J. Heat Mass Transf.
, Vol.
31-11
, pp.
2291
2304
.
8.
Frea, W. J., 1970, “Two-Phase Heat Transfer and Flooding in Countercurrent Flow,” presented at the 4th Int. Heat Transfer Conf., Paris, Vol. B5, No. 10.
9.
Graham, G., 1975, “Summary of Recent Thayer School Annulus Penetration Results, Memorandom,” Thayer School of Engineering, Dartmouth College, Hanover, NH
10.
Katto
Y.
, and
Hirao
T.
,
1991
, “
Critical Heat Flux of Counter-flow Boiling in a Uniformly Heated Vertical Tube With a Closed Bottom
,”
Int. J. Heat Mass Transf.
, Vol.
34–4/5
, pp.
993
1001
.
11.
Kusuda
H.
, and
Imura
H.
,
1974
, “
Stability of a Liquid Film in a Countercurrent Annular Two-Phase Flow
,”
Bulletin of the JSME
, Vol.
17–114
, pp.
1613
1618
.
12.
Mishima, K., 1984, “Boiling Burnout at Low Flow Rate and Low Pressure Conditions,” Ph.D. Thesis, Kyoto Univ., Japan.
13.
Motomura, T., Kurosawa, A., Otsuji, T., Mishima, K., Hibiki, T., and Nishihara, H., 1993, “Critical Heat Flux Experiment in a Narrow Vertical Rectangular Channel Heated From One-Side at Atmospheric Pressure,” presented at the 1993 Fall Mtg. of the AES of Japan, Paper No. A26.
14.
Osakabe
M.
, and
Kawasaki
Y.
,
1989
, “
Top Flooding in Thin Rectangular and Annular Passages
,”
Int. J. Multiphase Flow
, Vol.
15-5
, pp.
747
754
.
15.
Pushkina
O. L.
, and
Solokin
Y. L.
,
1969
, “
Breakdown of Liquid Film Motion in Vertical Tubes
,”
Heat Transf. Soviet Research
, Vol.
l–5
, pp.
56
64
.
16.
Richter, H. J., Wallis, G. B., and Speers, M. S., 1979, “Effect of Scale on Two-Phase Countercurrent Flow Flooding,” NUREG/CR-0312.
17.
Richter
H. J.
,
1981
, “
Flooding in Tubes and Annuli
,”
Int. J. Multiphase Flow
, Vol.
7
, pp.
647
658
.
18.
Sudo
Y.
, and
Kaminaga
M.
,
1989
, “
A CHF Characteristics for Downward Flow in a Narrow Vertical Rectangular Channel Heated From Both Sides
,”
Int. J. Multiphase Flow
, Vol.
15-5
, pp.
755
766
.
19.
Sudo
Y.
,
1984
, “
Parameter Effects of Downcomer Penetration of ECC Water in PWR-LOCA
,”
J. Nucl. Sci. Technol.
, Vol.
22-1
, pp.
32
41
.
20.
Sudo
Y.
, and
Ohnuki
A.
,
1984
, “
Mechanism of Falling Water Limitation Under Countercurrent Flow Through a Vertical Flow Path
,”
Bulletin of JSME
, Vol.
27–226
, pp.
708
716
.
21.
Sudo
Y.
,
Miyata
K.
,
lkawa
H.
,
Kaminaga
M.
, and
Ohkawara
M.
,
1985
, “
Experimental Study of Differences in DNB Heat Flux Between Upflow and Downflow in Vertical Rectangular Channel
,”
J. Nucl. Sci. Technol.
, Vol.
22-7
, pp.
604
618
.
22.
Sudo
Y.
,
Usui
T.
, and
Kaminaga
M.
,
1990
, “
Experimental Study of Falling Water Limitation Under a Countercurrent Flow in a Vertical Rectangular Channel (1st Report, Effect of Flow Channel Configuration and Introduction of CCFL Correlation)
,”
JSME Int. J., Ser. II
, Vol.
34-2
, pp.
169
174
.
23.
Wallis, G. R, 1969. One-Dimensional Two-Phase Flow, McGraw-Hill, New York, pp. 336–339.
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