Analysis of bed voidage characteristic of a gas-liquid-solid fluidized bed by CFD simulation and experiment

Abstract

The bed expansion profile of a co-current three-phase fluidized bed have been studied using liquid as the continuous phase and gas as the discontinuous phase for different particle size and bed mass. Air, water and glass beads are used as the gas, liquid and solid phases respectively. The experiments were carried out in a 0.1m ID, 1.88m height vertical Plexiglas column. A two dimensional transient model has been developed to simulate the bed voidage behaviour of the mentioned gas–liquid–solid three-phase fluidized bed using the computational fluid dynamics (CFD) method. An Eulerian Granular Multiphase model has been used in the present study and simulations are carried out using the commercial CFD package Fluent 6.2.16. The bed voidage is found to increase with the liquid velocity significantly, but the increase in bed voidage with gas velocity is meagre. The bed voidage is found to decrease with particle size and static bed height. The CFD simulation predictions are compared with the experimental data. The simulation results are in good agreement with the experimental values. Finally empirical correlations have been developed to predict bed voidage behaviour.