Two-phase gas-liquid flow

2000

Letters

to the Editors 1967, Chisholm D., A theoretical basis for the Lockhart-Martinelli correlation for two phase flow. Int. .I. Heat Mass Transfer 10 1767-l 778. Hewitt G. F. and Roberts D. N., 1969, Studies of two phase flow patterns by simultaneous X-ray and flash photograph. AERE Report M2 159. Taitel Y., Barnea D. and Dukler A. E., 1980, Modelling flow pattern transition for steady upward gas-liquid flow in vertical tubes. A.1.Ch.E. J. 26 345-354. Troniewski L. and Ulbrich R., 1984, Two-phase gas-liquid flow in rectangular channels. Chem. Engng Sci. 39 75 l-765.

Subscripts

air : L T

V W

I&d turbulent viscous water

REFERENCES Chen J. J. J., 1984, Unpublished work.

CkmicrrlEng*uerwScknce,Vol. 40,No. IO,pp. ZOOO-2002. 1985. Printed

in Great

000%2509185 S3.00+0.00 Pergamon F’ress Ltd.

Britain.

Two-phase

gas-liquid (Received

flow: authors’ reply

4 February

Dear Sirs, The flow regime map of two-phase gas-liquid flow in a vertical pipe (Fig. 3), presented by the authors of [ 11, has been worked out on the basis of the statistical analysis of a large number of flow pattern maps cited in the literature and only in this sense the authors regard this map as general. Some further information on the analysis of flow regime maps can be found in [2] by Troniewski and Ulbrich. In the proposed flow regime map (Fig. 3) the boundary lines wGsz const are valid for the range w Ls < 2 m/s. Table 1 presents some

1985)

examples confirming the permissibility ofadoption of such an assumption; also given is the maximum value of the liquid velocity wLsmax for which the assumption wGs z const is admissible. As regards the calculation of pressure drop, some attention should be paid to the fact that the method used for calculating the values of S#I~or 4L [relationship (5)], proposed in [l] refers to pipes and it has only been used in the further part of the paper for computing the pressure drop in flow through rectangular channels.

Table 1. Boundaries between two-phase flow regimes in vertical pipe with wGSz const according to various authors NO

Ref.

Boundary

Comment

WGS

1

c31

F-A

14

2

c43

E-P P-F F-A

0.25

3.5

3 1

air-water steam-water air-water

2 12

0.3

D = 25.4 mm

3

c51

P-F F-A

1.45 13

1 10

air-water, D = 25 mm theoretical models

4

C61

B-F F-A

0.06

0.3

10

0.5

air-water rod bundle

13

0.4

air-water solution of sugar

5

c71

F-A

6

PI

E;

0.065 2.5

0.1 0.7

air-water D = 50.7 mm

7

c91

B-P

0.065

0.1

P-F F-A

2.0

0.1

air-water, D = 25.4 mm theoretical models

8

Cl01

P-F P-F

11 1.5 1.0

0.8 1 0.8

air-water, D = 38.8 mm air-flocculated kaolin slurries (non-Newtonian)