Dynamic similarity rules: Validity check for bubbling and slugging fluidized beds

Abstract

An experimental verification is reported on the validity of scale-up rules for fluidized beds, which were proposed and discussed previously [6]. Five different gas-solid systems were investigated: three of them dynamically similar, the fourth one characterized by non-spherical particles, and the last one completely out of scale. The minimum fluidizing velocity, as well as the bed expansion and the instantaneous pressure fluctuations inside the bed, were measured at different gas flow rates. The analysis of the experimental data confirms the applicability of the scaling rules when the fluidized beds exhibit bubbling behaviour. However, for increased aspect ratio, so that the slugging regime prevails, all the dimensionless values of the frequency and standard deviation of the pressure signal differ significantly.