Numerical investigation of bubble growth and formation under quasi-static conditions

Abstract Bubble growth and formation process directly determines the bubble size, which is crucial for gas-liquid flow systems. Understanding the behaviors of bubble growth and formation in detail is crucial for predicting bubble diameter. This study investigated the effects of orifice parameters ( e.g. , orifice size, contact angle), fluid properties ( e.g. , liquid viscosity, density, surface tension coefficient), and operating conditions ( e.g. , gas inlet velocity, gravitational acceleration) on bubble growth and detachment characteristics ( e.g. , bubble shape, detached diameter, time) under quasi-static conditions using Coupled Level-Set/Volume-of-Fluid method. Empirical correlations of bubble detachment diameter, shape, bubble rising velocity, and bubble-induced liquid velocity at relatively low gas flow rates were proposed to understand the bubble growth mechanism. The mechanism of bubble formation under different orifice wettability conditions was revealed by establishing the relationship between critical and static contact angles. Finally, a new bubble diameter model was developed by considering the effects of a broad range of fluid properties, orifice size, contact angle, and inlet gas velocity. The new model significantly extends the applicability of the traditional bubble formation theoretical model derived from the simple buoyancy force and surface tension force balance, individually decreasing the deviations of predicted bubble diameter at the contact angles of 52 and 105° from 47.3 and 10.47 %–5.41 and 8.14 % and providing some theoretical basis for bubble formation and the reasonable closure of interphase force models based on bubble morphology.