MODELING OF THE DROPLET ENTRAINMENT FRACTION IN ADIABATIC GAS-LIQUID ANNULAR FLOW

Abstract Many studies have been conducted on droplet entrainment in an annular flow regime, but little is known about droplet entrainment caused by nucleate boiling. In this report, visualization results of droplet entrainment caused by nucleate boiling are described. We observed two processes of droplet entrainment. The first one causes bubble bursting at a water surface. The second one causes filament breakup which occurs when the vapor bubble reaches and collapses at the interface between air and liquid. From comparison of the phenomena for the two processes, we found that the diameters of the droplets and vapor bubbles were considerably different. Using the results of this research allows the effect of forced convection to be taken into account. In the future, we plan to expand the amount of data and develop a boiling entrainment model under forced convection conditions.

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Generalization of droplet entrainment rate correlation for annular flow considering disturbance wave properties

Chemical Engineering Science ◽

10.1016/j.ces.2017.02.023 ◽

2017 ◽

Vol 164 ◽

pp. 279-291 ◽

Cited By ~ 15

Author(s):

Li Liu ◽

Bofeng Bai

Keyword(s):

Annular Flow ◽

Entrainment Rate ◽

Disturbance Wave ◽

Droplet Entrainment ◽

Rate Correlation ◽

Wave Properties

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A probability model for fully developed annular flow in vertical pipes: Prediction of the droplet entrainment

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2014.12.077 ◽

2015 ◽

Vol 84 ◽

pp. 225-236 ◽

Cited By ~ 12

Author(s):

Ri Zhang ◽

Haixiao Liu ◽

Mingyang Liu

Keyword(s):

Annular Flow ◽

Probability Model ◽

Droplet Entrainment

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Effect of Heat Flux on Droplet Entrainment Using Annular Flow Dryout Model

2010 14th International Heat Transfer Conference, Volume 1 ◽

10.1115/ihtc14-22866 ◽

2010 ◽

Cited By ~ 4

Author(s):

Masroor Ahmad ◽

Evgeniy Burlutskiy ◽

Simon P. Walker ◽

Geoffrey F. Hewitt

Keyword(s):

Experimental Data ◽

Heat Flux ◽

High Pressure ◽

Liquid Film ◽

Annular Flow ◽

High Pressures ◽

Droplet Entrainment ◽

Annular Film ◽

Low Pressures ◽

Flow Experiments

Annular film dryout depends upon the competition of entrainment, deposition and evaporation processes between the droplet-laden core and wall liquid film. In this paper, effect of heat flux on droplet entrainment is analyzed by modeling different low and high pressure diabatic annular flow experiments numerically using an annular flow dryout model (AFM). Overall, the AFM predicted the experimental data reasonably accurately. It is concluded that at high pressures increasing heat flux may enhance net entrainment considerably but this effect diminishes at low pressures.

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