CFD-DEM investigation of the interaction between a particle swarm and a stationary bubble: Particle-bubble collision efficiency

Abstract

This study presents a Computational Fluid Dynamics–Discrete Element Method (CFD-DEM) model to simulate the interaction and approach of a particle swarm to a stationary bubble for various solid fractions (0.01 ≤ εp ≤ 0.25) and bubble Reynolds numbers (50 ≤ Reb ≤ 200). It was observed that the collision efficiency decreased with increasing the solid fraction until achieving a plateau value. This plateau was attributed to the increase in the lateral expansion of the swarm and particle velocities. The former effect decreased the collision by interception, while the latter increased the inertial effects. However, when the bubble Reynolds number increased, the particle swarm did not have enough time to accelerate or deform before reaching the bubble, and thus, the collision efficiency became insensitive to the solid fraction. The modelling approach presented provides a framework to manage the complexity of particle-bubble interactions in a multiple-particle system.