A Novel CFD Scheme for Collision of Micro-bubbles in Turbulent Flow

Abstract — A numerical scheme for bubble trajectories including their collisions is developed. An Eulerian-Lagrangian computational scheme is used to study the bubble trajectories. The 2D averaged Navier stokes equations are solved. The SIMPLEC algorithm is used to relate the pressure to velocity. A one-way coupling is assumed and the effects of the bubbles on carrier flow are neglected. The bubble equation of motion includes the drag, buoyancy, pressure gradient, Saffman lift and bubble volume change forces. The variation of the bubble radius is modelled using the Rayleigh-Plesset equation. The Kraichnan model is used to simulate the instantaneous turbulence fluctuation velocities. The hard sphere collision model is used to model the bubble collisions and the effects of bubble rotations are neglected. Trajectories of micro-bubbles in the near wall region are investigated, and the rate of collisions and bubble settling are studied. The results are compared with other simulations and good agreement is observed. Index Terms—CFD, Two phase flow, Bubble, Collision. I.