Modeling multiple gas jet interactions during fluidization in a pseudo-2D bed

The hydrodynamics of fluidized beds involving gas and particle interactions are very complex, and must be carefully considered when modeling such a system using computational fluid dynamics (CFD). One of the issues is the interaction of multiple jets developing above the distributor plate, which affects the uniformity of fluidization. To model the distributor plate, one approach is to use a uniform velocity at the inlet and the other is to model the distributor holes and specify the jet velocity. To predict and examine the hydrodynamics of interacting jets, a multi-fluid Eulerian-Eulerian CFD model was employed. In the present work, simulations of a pseudo-two-dimensional (2D) fluidized bed were compared to a corresponding experiment designed to examine multiple jet interactions for two distributor plate configurations with 9 and 5 holes. Two-dimensional and three-dimensional simulations of the pseudo-2D bed were used to investigate fluidization characteristics, volume fractions and solids velocity distributions. The deadzones formed due to multiple jet configurations of the distributor were quantified and their distributions over the plate were analyzed. It was found that three-dimensional simulations captured the effect of multiple jets and provided more accurate predictions of pressure, particle velocity and particle distribution. It was shown that increasing the number of holes along the gas inlet plane changed the fluidization characteristics, whereby fewer holes restricted the amount of particles that fluidized, irrespective of inlet velocity. When the number of holes increased, more material fluidized with increasing velocity. It was also found that although the reactor geometry is effectively two-dimensional, using two-dimensional simulations did not always capture all aspects of the flow, especially, the particle velocity. (C) 2017 Elsevier B.V. All rights reserved.