The flow properties of fluidized solids

Abstract

Experimental measurements of the non-Newtonian flow properties of a 200-μm-diam. sand fluidized at 1.5 – 3 U mf in open channel flow are reported. Asymmetry in the velocity profile was found to change with change in the experimental conditions, but it is thought primarily to be a consequence of air maldistribution which is partly generated by the bed flow in the experimental rig. There was evidence of varying degrees of drag across the distributor, from conditions of slip giving rise to a semi-plug flow profile at higher fluidizing velocities and bed flow rates, to conditions where the drag exacted across the distributor at lower solids flow rates exceeds that at the vertical channel walls. Bed flow properties deteriorate as the bed depth increases. This is a consequence of the deleterious effect of bubble growth within the bed. Reasonable agreement was obtained between velocity profiles predicted following Wheeler and Wissler and those measured under conditions where the drag across the distributor and the vertical channel walls was of similar magnitude. Some estimate was made of the relative effects of power law index, channel aspect ratio and slip on the solids flow.