Coalescence of two droplets in a plane Poiseuille flow

Abstract

The displacement and coalescence of multiple identical droplets in a plane Poiseuille flow was investigated. Three-dimensional lattice Boltzmann method with the multicomponent multiphase model of Shan and Chen was applied. For generalization, we utilized several non-dimensional numbers including capillary number (Ca) and Reynolds number (Re). The effects of the distance between two droplets were investigated. At the same Reynolds number, capillary number was controlled by adjusting surface tension of the droplets. The results indicated that the effect of Reynolds number is much weaker than that of capillary number. Therefore, capillary number was found to be the most important factor in the coalescence between two droplets. The shapes of the droplets were independent of Reynolds number, but strongly dependent on capillary number. And, the results showed that the moving distance of droplets up to the point of coalescence was determined by capillary number and a gap between two droplets.