Interfacial area concentration in gas-liquid bubbly to churn-turbulent flow regime

There are very few established correlations to predict the interfacial area concentration beyond the bubbly flow regime in cap-slug and churn-turbulent flow regimes. Present study shows a systematic approach to estimate the interfacial area concentration in bubbly, cap-slug and churn-turbulent flow regimes. Ishii and Mishima's (1980) formulation and the two group approach for categorizing bubbles (Group-1: spherical or distorted bubble, Group-2: cap bubble) are used to estimate the interfacial area concentration. The key parameters in this framework are the estimation of Group-1 bubble size and the amount of void in the liquid slug, which is a function of Group-1 void fraction. Hibiki and Ishii's (2002) correlation is utilized to predict the size of the Group-1 bubbles. A correlation is developed to estimate the Group-1 void fraction. The developed model for the estimation of interfacial area concentration is compared with the three existing datasets. These are data for air-water flow taken in annular geometry and round tube and also for air-NaOH solution taken in round tube. The estimation accuracies for these data sets are +/- 36.4%, +/- 26.5% and +/- 37.4%, respectively. These datasets cover a wide range of flow regimes and different physical properties. (C) 2012 Elsevier Inc. All rights reserved.