Voidage and particle velocity profiles in a spout-fluid bed

Detailed hydodynamic measurements have been obtained for fully cylindrical spout-fluid beds of 1.3 mm; 1.8 mm and 2.5 mm glass beads in a fully cylind rical column of diameter 152 mm using three different types of optical fibr e probes. The reallocation of up to 43% of the air to auxiliary air introdu ced through the conical base caused some decrease in spout voidages, but re markably little change in spout diameter compared with spouted beds where t here was no auxiliary air addition. Auxiliary air led also to same decrease in particle velocities in the spout and to a modest decrease in the net so lids circulation rate.