Average circulatory motion of particles in fluidized beds

Abstract

Average circulatory motion of solid particles in fluidized bed affects the processes of heat and mass transfer in the bed. The primary circulatory motion is described by a solution of the averaged dynamic equations of multiphase flow as applied to a cylindrical bed in the absence of bubbles. Either of the cases of particles AWDC (ascending near the wall and descending at the center) and ACDW may arise, depending on the parameters of phase interactions. The direction of circulation is not necessarily affected by the depth of the bed but is influenced by the sign of (average terminal velocity of particles in the dense phase — average interstitial velocity): > O for ACDW, < O for A WDC, although the stability of the AWDC mode is affected by the bed height. Validity is supported by the results of an independent experimental study.