Solid flow transition in liquid and three-phase fluidized beds

Abstract

Flow transition of solids in liquid and three-phase fluidized beds of Newtonian and non-Newtonian fluids have been studied in a pyrex glass column. The relations between the fluid flow rate and the bed porosity in three-phase fluidized beds have been determined in terms of effective volumetric flux of fluid phases from modification of the Richardson and Zaki equation. The modified particle Reynolds number exhibited its maximum value with the variation of bed porosity in liquid and three-phase fluidized beds. The drag coefficient changed its slope apparently at the bed porosity where the maximum value of the modified particle Reynolds number could be attained. At the flow transition condition, the continuity wave velocity, energy dissipation rate, and continuity shock wave velocity have their maximum values. The immersed heater-to-bed and wall-to-bed heat transfer coefficients, wall-to-bed mass transfer coefficient, liquid radial mixing coefficient and solid particle diffusivity in the literature data have maximum values at the transition condition of liquid and three-phase fluidized beds.