Investigation of collisional parameters for rough spheres in fluidized beds

The effect of normal restitution coefficient and friction coefficient on the hydrodynamics of a dense bubbling solid-gas fluidized bed is investigated using a two fluid model (TFM) based on our kinetic theory of granular flow (KTGF) for rotating frictional particles. A comparison between TFM simulations using the present KTGF model, and a simpler KTGF model for rapid flows of slightly frictional, nearly elastic spheres derived by Jenkins and Zhang [1], is carried out. The simulation results reveal that both the coefficient of normal restitution and friction coefficient play an important role in the homogeneity of the bubbling bed. The particle friction has a strong effect on the solids flow patterns and distribution, while the normal restitution coefficient has a relatively small effect on both. The present model also predicts a larger amount of energy dissipation caused by the inclusion of particle friction. The present KTGF model leads to better agreement with detailed discrete particle model (DPM) simulation results for the axial particle velocity profiles and solids volume fraction distribution.