Numerical simulation of flow behavior of particles in a gas-solid stirred fluidized bed

Abstract

Flow behavior of particles is simulated by means of two-fluid model combining with kinetic theory of granular flow in a gas-solid stirred fluidized bed with a frame impeller. The Huilin-Gidaspow drag model is used to obtain the interphase interaction of gas and solids phases. The moving reference frame is used to simulate the rotation of numerical domain. Simulated results are compared with experimental data measured by Jiajun Wang et al. (2013) in a gas-solid stirred fluidized bed. The comparisons show that the present model can capture the gas-solid flow with mechanical agitation. The distributions of bed pressure drop, standard deviations of the differential pressure between different bed heights, particle velocity vectors and solids volume fraction are predicted. The effects of agitation speed and particle density on flow behavior of particles are analyzed. Simulations indicate the bed expansion ratio is increased, and then decreased with an increase of agitation speed. Increasing the mechanical agitation, the movements of particles are intensified, especially, the lateral movements of particles according to the distribution of particle velocity vectors. Moreover, the granular temperatures are increased with an increase of agitation speed and a decrease of particle density. Present investigations provide the detailed hydrodynamic characteristics of gas and particles and bed expansion with different agitation speeds and particle densities in a stirred fluidized bed.