Cluster Formation and Particle-Induced Instability of Gas-Solid Flows. Numerical Simulation of Flow in Vertical Channel using the DSMC Method.

Abstract

A numerical simulation is performed on dispersed gas-solid flow in a vertical channel. Flow of the solid phase is determined by calculating individual particle motion, i. e. by the Lagrangian method, while the gas flow is determined by solving the equations of inviscid fluid. The Direct Simulation Monte Carlo (DSMC) metod is used to take account of particle-to-particle collisions. Attention is paid to the case of low gas velocities and high solid loading, for which the solid phase strongly affects the gas flow field. The flow fields of gas and solid are accordingly solved simultaneously, taking the interaction between both phases into consideration. It is found that the flow becomes unstable and inhomogeneous as the gas velocity decreases and the solid loading increases. Further-more effects of parameters such as the channel width and physical properties of particles on the instability and cluster formation are investigated.