Dynamics of two bubbles colliding at high Reynolds numbers in water: Bubble rebound behavior study

Abstract

The collision between bubbles is essential to gas–liquid dispersion systems. When bubbles encounter each other, they may either rebound or coalesce. Yet, little is known about the rebound dynamics immediately after two bubbles collide. This work investigates such collision dynamics of two bubbles at high Reynolds numbers in water through experiment and simulation. The moving velocity, deformation, contact time during collision and restitution coefficient of bubbles are analyzed. Simulations reproduced quantitatively the bubble rebound behavior, revealing the evolution of various energies involved in collision. Simulation results show that over 70% of the system's initial mechanical energy (SME) could be converted into bubble surface energy (BSE) during the approach. In turn, the excess BSE is converted back into SME driving bubbles to rebound with significant dissipation. A mass-spring-damper model is developed, which describes the dynamic of bubble rebound well. This contribution enhances the understanding of bubble interactions in multiphase flow.