ANALYSIS OF PARTICLE MOTION IN A VERY SHALLOW FLUIDIZED-BED

It is well known that heat transfer characteristics can be improved by immersing the heat exchanger tubes into a fluidized bed. However, con ventional fluidized beds are rather unstable and the comparatively lar ge bed height causes a high pressure drop. To address this problem, on e of the authors developed a very shallow fluidized bed heat exchanger which is composed of a horizontal array of tubes and a special design ed multislit distributer that produces several two-phase jets. The sol id particles carried in the jet impinge against the tubes and cause co ntinuous defrosting by abrading ice formation. Here we shall present t heoretical predictions for the flow properties within the jet, the imp ingement rate against the tube and calculations of the granular flow o f particles on the inclined bottom chute that feeds the solids back in to the jet. The theoretical models are based on experimental observati ons and data which we also present here. (C) 1997 Elsevier Science Ltd .