Simulation of the flow and segregation of particle mixtures in liquid fluidization

One interesting phenomenon called "layer inversion" is often observed in liquid fluidization for a binary mixture of particles. In the past macroscopic studies of physical experiments and theoretical models, it is difficult to obtain particle scale information which, however, is very important to develop understanding of "layer inversion" phenomenon. In this work, an approach of combined discrete particle simulation (DPS) for particle flow and computational fluid dynamics (CFD) for liquid flow is used to simulate this process. The general features of layer inversion obtained from the simulation are consistent with those observed in physical experiments. The occurrence of layer inversion is further analyzed in terms of force information, including particle-particle interaction force and particleliquid interaction force. The simulation results illustrate that DPS-CFD approach presents a promising method to identify the underlying mechanisms of layer inversion for a binary mixture of particles in liquid fluidization.