Miniaturized gas-solid fluidized beds

Fluidized beds are suspensions of grains by ascending fluids in tubes, and commonly used industry given their high rates mass heat transfers between the solids fluid. Although usually employed large scales (tube diameter order meter), fluidized have a great potential much smaller (order millimeter) for processes involving powder fluids. Of particular interest is pharmaceutical industry, which can take advantage mm-scale promoting diffusion species, classifying grains, or peeling individual particles. This paper reports experiments with gas-solid bed, consisted 0.5-mm-diameter glass particles suspended an air flow 3-mm-ID tube. We filmed bed high-speed camera processed images numerical code tracking both entire found that instabilities form alternating high- low-compactness regions (known respectively as plugs bubbles) appear fluctuating energy granular temperature) relatively low within plugs. Therefore, reduced agitation transfer when compared to m-scale counterparts. show also increasing velocity does not avoid appearance plugs, though temperature increases, mitigating problem. Our results shed light on detailed mechanisms taking place miniaturized providing insights chemical powders.