Discrete Particle Simulation of the Gas-Solid Flow in a Circulating Fluidized Bed

This paper presents a numerical study of the gas-solid flow in a three-dimensional Circulating Fluidized Bed (CFB) by means of Combined Continuum and Discrete Method (CCDM) in which the motion of discrete particles is described by Discrete Particle Method (DPM) on the basis of Newton’s laws of motion applied to individual particles and the flow of continuum fluid by the traditional Computational Fluid Dynamics (CFD) based on the local averaged Navier-Stokes equations. The simulation is achieved by incorporating DPM codes into the commercial CFD software package Fluent. It is shown that the discrete particle simulation can capture the key flow features in CFB such as core-annulus structure, axial solid segregation and S-shaped axial solid concentration. The numerical results also show the effect of the pulsation arising from the expansion of the fluidized bed on the performance of the cyclone separator. The gas-solid, particle-wall and particle-particle interactions are analysed to understand the underlying mechanisms of CFB systems