(380ak) Hydrodynamics and Mixing in a Pseudo-2D Rectangular Spouted Bed

Hydrodynamics and mixing behavior of polydispersed particles in a pseudo-2D rectangular spouted bed has been investigated using coupled CFD-DEM technique. Eulerian method (computational fluid dynamics, CFD) has been used to solve the Navier-Stokes equation for the gaseous phase and Lagrangian method (discrete element method, DEM) for particle phase. k-ε two-equation turbulence model has been used to incorporate the gas phase turbulence effect. In the present work, the minimum spouting velocity is predicted numerically for a fixed bed height of polydispersed glass beads. Hysteresis in time-averaged mean pressure drop and bed expansion have been observed. Solid velocity and mixing pattern have been studied for different superficial gas velocities in three different regions of the bed i.e. at annulus, spout, and fountain zones. The effect of particle phase restitution coefficient and gas velocity on the temporal evolution of particle mixing are analyzed. We observe a double recirculation pattern in the fountain region, where particle axial velocity is insignificantly influenced by the particle restitution coefficient. But in the spout zone, the particle velocity increases with a decrease in the restitution coefficient. Solid mixing improves with increasing superficial gas velocity due to the combined effect of convective and shear-induced mixing.