Modeling of spout-fluidized beds and investigation of drag closures using OpenFOAM

The present work employs the open source package, OpenFOAM, for dynamic simulations of the intrinsically unsteady and nonhomogeneous gas-particle flows in spout fluidized beds using the discrete particle model (DPM) coupled with the computational fluid dynamics (CFD). Firstly, the effect of grid size on particle motion is investigated and a minimum ratio of grid size to particle diameter is suggested for gas-particle flow simulations. Secondly, the porosity calculation procedure is tested by the simulation of particle packing process. Finally, two cases of the single bubble behavior and the spout-fluidization regime in spout-fluidized beds are simulated and the effect of drag closures are investigated. The results show that the Plessis & Masliyah drag relation predicts an inappropriate gas-particle interaction especially in condition of low particulate volume fraction. The embedded drag relations from lattice-Boltzmann (LBM) simulations perform better than the Gidaspow relation especially for the spout-fluidization regime. The van der Hoef et al. drag relation is found more suitable for modeling spout-fluidized beds than the others in the present work. (C) 2016 Elsevier B.V. All rights reserved.