Abstract
The apparent buoyancy force acting on lead spheres is measured at various locations in the fluidized bed of different size particles by changing the particle size ratio and the mixing ratio of coarse and fine particles. In the case of particles with a similar size, the apparent buoyancy in the center of the fluidized bed is larger than that near the wall, indicating the existence of a circulating particle flow, i. e., the particles are rising in the center and falling down in the vicinity of wall. When the difference in particle size is large, the apparent buoyancy in the center is smaller than that near the wall. Most of the coarse particles exist near the wall at the bottom of the bed and the bubbles are frequently generated. A complicated particle flow occurs in this case, and the distribution of apparent buoyancy is markedly different from that in the bed of particles with a similar size.
