MECHANICS OF PARTICLE MOTION IN 3-PHASE FLOW

Flow behavior of three-phase flow was studied using a two-dimensional draft-tube fluidized bed operating with air, water and alginate partic les (d(s) = 2.5 mm, rho(s) = 1040 kg/m(3)). Momentum transfer between a particle and three-phase flow was assessed from settling velocities of tracer particles with diameters of 2.5 and 5 mm, and densities 1100 -2500 kg/m(3). The settling velocities of tracer particles were system atically lower than the corresponding free-settling velocities, as a r esult of additional momentum transfer with air bubbles and fluidized b ed particles. These effects were separated by comparative studies of p article settling in two-phase and three-phase how. Mechanics of partic le motion in three-phase flow was modeled in terms of the effective pa rticle buoyancy and the effective drag coefficients.