Mixing and segregation of binary mixtures of particles in liquid–solid fluidized beds

The effects of size, shape, and density of tracer particles on mixing and segregation in liquid–solid fluidized beds were studied. A collision technique was used to define a new mixing index. Collisions between tracer particles and probes were found at 16 locations inside the fluidized bed simultaneously. The collision frequency of particles on probes was considered to be proportional to their local concentration inside the fluidized bed. Glass beads (3 and 5 mm in diameter) were used to study the effect of size on mixing. Graphite beads and cylindrical aluminum beads were introduced into a bed of spherical glass beads to investigate the density and shape effects, respectively. Smaller bed heights enhanced the mixing of particles lighter than the bed particles. Particle density had a greater effect on segregation than size and shape.