Effects of liquid velocity and particle size on the individual heat transfer resistances in the heater and fluidized bulk zone have been determined.
A two-resistance model is proposed for heat transfer between a coaxially mounted immersed heater and the bulk zone in liquid-fluidized beds. The optimum bed porosity at which the maximum heat transfer coefficient occured coincides with the bed porosity at which the boundary layer thickness around the heater attained the minimum value.
The heat transfer in the heater zone was found to be the rate controlling step in the liquid-fluidized bed and the overall heat transfer resistance has been represented by a modified Stanton and Peclet numbers based on the heat transfer resistances in the heater zone and in the fluidized bulk zone in series.