Numerical Investigation of Air Flow Distribution in a Swirling Fluidized Bed

Abstract

Swirling fluidized bed (SFB) is one of the recent technologies developed in fluidization to overcome various drawbacks in the conventional fluidized beds, particularly poor lateral mixing and relatively high distributor pressure drop. Though a number of beds operating with similar technique are commercially available, very little has been published on the subject, particularly on the distributor design. The distributor of the SFB is formed by an array of blades which are inclined to the horizontal, with a centre body in the middle of the bed. Air flow investigation was carried out on the empty bed via CFD approach. The study focused on the effects of number of blades and its inclination angle on the flow distribution and pressure drop, so as to arrive at an optimum choice of the distributor design. The findings indicate that higher number of has lower open area which resulted higher jet velocity of air from the distributor. Blade inclination has significant effect on the flow distribution where lower blade inclination produces higher magnitude of tangential velocity that creates intense swirling but at an expense of higher pressure drop. In conclusion, the distributor with 30 blades and 15º inclination was found to meet the design criterion outlined.