Computational Study of the Effect of Draft Plates on the Solid Behavior in a Spout-Fluid Bed

Using computational fluid dynamics coupled with the discrete element method (CFD-DEM), the gas–solid flow in the spout-fluid bed with or without draft plates is numerically simulated to quantify the effect of draft plates and plate length on the behavior of the solid phase. The mixing behavior, force, velocity, and dispersion of the solid phase in all three regions of the system are explored. The results demonstrate that the insertion of draft plates slows the mixing of the solid phase. Increasing the draft plate length leads to a lower fraction of particles in the spout and fountain regions, increases the solid cycle time, and the solid residence time in the annulus and fountain regions. Also, the collision force between particles is one order-of-magnitude larger than the fluid force. Moreover, increasing the draft plate length enhances the translational and rotational solid velocity, and the vertical solid dispersion in both the spout and fountain regions.