IMPROVED HYDRODYNAMIC MODEL OF TWO-PHASE SLUG FLOW IN VERTICAL TUBES

Merits of the Fernandes model(Fernandes et al.1983)for two-phase slug flow in verticaltubes are reviewed in this paper.While predicting many macroscopic parameters of slug flow in verti-cal tubes,it fails to present correctly the trend that the average voidage in liquid slugs increases asthe rising velocity of Taylor bubbles is increased.It is also desirable to extend its application toelectrolyte systems, and to churn flow conditions.Based on the diagnostic analysis,the model equa-tion for gas entrainment by falling liquid film is reformulated and the influence of surface tension isalso accounted for.Development of the falling liquid film is recognized in the revised model in or-der to suit the case of short Taylor bubbles as well.The modified model predicts the variation of av-erage voidage in liquid slugs in good agreement with available experimental data.

IMPROVED HYDRODYNAMIC MODEL OF TWO-PHASE SLUG FLOW IN VERTICAL TUBES

Merits of the Fernandes model (Fernandes et al. 1983) for two-phase slug flow in vertical tubes are reviewed in this paper. While predicting many macroscopic parameters of slug flow in vertical tubes, it fails to present correctly the trend that the average voidage in liquid slugs increases as the rising velocity of Taylor bubbles is increased. It is also desirable to extend its application to electrolyte systems, and to churn flow conditions. Based on the diagnostic analysis, the model equation for gas entrainment by falling liquid film is reformulated and the influence of surface tension is also accounted for. Development of the falling liquid film is recognized in the revised model in order to suit the case of short Taylor bubbles as well. The modified model predicts the variation of average voidage in liquid slugs in good agreement with available experimental data.