ESTIMATION OF PARTICLE RENEWAL RATES ALONG THE WALL IN A MECHANICALLY STIRRED GRANULAR BED

In indirectly heated mechanically stirred vessels for granular solids, the particle flow characteristics, especially in the immediate vicinity of the heated surface, are important in evaluating the surface-to-bed heat transfer rate. This study presents for the first time experimentally observed particle flow patterns along the wall in a vessel stirred by paddle-type blades. The effects of solids flowability, bed height, blade rotational speed, blade height, wall-to-blade clearance, air flow rate and vessel diameter on the particle movement patterns are examined in this paper. Estimation of the particle renewal rates along the heated wall from the measured information on particle movement is discussed. © 1990.