Mean Velocity and Density Distribution of Solids

FIGRUE 9.9 Solids mean dynamic behavior (circumferentially averaged) in a cylindrical fluidized bed for 500-pm glass particles at ujumf = 2 (a) recirculation pattern, (b) mean velocity vector field, and (c) density distribution 

The foregoing observations can be interpreted in terms of the bubble behavior in fluidized beds. Werther and Molerus (1973) reported that very close to the distributor region, intensified bubble activity exists in an annular region near the wall. As bubbles detach and rise, they tend to move toward the center. If the bed is sufficiently deep, they will eventually merge at the center. Because the solids are carried upward in the wake of the bubbles, they basically move along the bubble tracks. Therefore, the solids would 

FIGURE 9.10 Effect of superficial velocity on solids circulation patterns in a cylindrical fluidized bed for 500-mm glass particles at (a) ujumf = 1.5, (b) Jumj=2, (c) u,/um/ = 4 

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