A theoretical model for coalescence efficiency in collisions induced by the wake entrainment of a spherical‐cap bubble

Bubble coalescence induced by wake entrainment of large bubbles is common in multiphase systems, whereas a physically grounded mechanistic model remains lacking. Therefore, this study aims to develop a theoretical model for predicting the coalescence efficiency in bubble collisions induced by the wake entrainment of a spherical‐cap bubble. The model integrates the liquid film drainage mechanism with conservation laws of mass, momentum, and energy to derive analytical expressions for bubble contact time and film drainage time, incorporating the effects of curvature‐dependent film geometry and wake‐induced bubble interaction dynamics. The contact time is determined by analyzing the conversion between kinetic and surface energies during collision, while the drainage time is obtained by applying conservation laws to the film drainage process. Additionally, the proposed modeling approach offers a physically based methodology that can be extended to predict coalescence efficiency in other collision systems involving curved liquid films.