Evaluation of interfacial area transport models for horizontal bubbly flow

This paper presents evaluation results of interfacial area transport equation (IATE) for horizontal air-water bubbly flow. The steady-state one-dimensional, one-group IATE for adiabatic air-water bubbly flow developed by Talley [1] is employed in the current evaluation study. The models evaluated include: (a) drift-flux-based closure relations for void-weighted bubble velocity and void fraction; (b) frictional pressure drop model based on the Lockhart-Martinelli approach; (c) bubble interaction mechanisms; and (d) covariance associated with asymmetric bubble distribution in horizontal two-phase flow. In order to evaluate the models, a local two-phase flow database obtained by the four-sensor conductivity probe in fourteen different test conditions is employed, which covers a wide range of flow conditions in horizontal bubbly flow regime, with superficial liquid and gas velocities ranging from 3.50-6.00 m/s and 0.09-1.00m/s, respectively. It is demonstrated that both the void weighted bubble velocity and void fraction are predicted well with an average percent difference of ±2.7%. The fictional pressure loss can be predicted with an average percent difference of ±1.12%. The covariance parameters calculated from the modeling approach generally compare well with those calculated from experimental data within ±20% difference. It is found that the IATE generally predicts the measured interfacial area concentration with an average percent difference of ±5.7%. Furthermore, the effect of liquid velocity on individual bubble interaction mechanisms is investigated. It is found that both the contributions of random collision and turbulent impact decrease as liquid velocity decreases.