Population balance model for gas-liquid flows: Influence of bubble coalescence and breakup models

In dispersed gas-liquid flows, the bubble size distribution plays an important role in the phase structure and the interphase forces, which, in turn, determine the multiphase hydrodynamic behaviors, including the spatial profiles of the gas fraction, gas and liquid velocities, and mixing and mass-transfer behaviors. The population balance model (PBM) is an effective method to simulate the bubble size distribution. The bubble coalescence and breakup models have a distinct influence on the prediction ability of the PBM. This work compares several typical bubble coalescence and breakup models. The results show that the bubble size distributions predicted by the PBM are quite different when different bubble coalescence and breakup models are used. By using proper bubble coalescence and breakup models, the bubble size distribution and regime transition can be reasonably predicted. The results also show that it is necessary to take into account bubble coalescence and breakup due to different mechanisms.