High Density Circulating Fluidized Bed Riser: Influence of Drag Model, Kinetic Theory and Wall Slip Conditions

Abstract

High density circulating fluidized bed (HDCFB) modeling has been performed by Computational Fluid Dynamics (CFD). The influence of three crucial modeling parameters was studied; the drag model (the Wen Yu, Gidaspow and EMMS models were assessed), the use of kinetic theory of granular flow (KTGF) and the wall slip condition (influence of slip, no slip and partially slip boundary conditions were investigated). Comparison of numerical results with experimental ones reported in literature for a laboratory planar riser allowed pointing out the impact of each one of the three modeling parameters on flow behavior, concluding that the drag model has a crucial role on the prediction of solid output flow and solid vertical profile. On the other hand, KTGF and the no-slip wall condition showed to be crucial to guaranty the numerical stability.