Fluid mechanics and heat transfer in a fluidized counter current bed

The transfer of heat to a fluidized bed from larger and/or denser particles passed continuously downwards through the bed and removed from below was investigated. The research focuses on the mass holdup of the descending particles and the maximum attainable flow rates of these particles. An experimental apparatus was designed and constructed to obtain mass holdup and limiting flow rate data for several pairs of particles. The effects of the air flow rate, and of the feed rate, diameter and density of the descending particles on their holdup was investigated. The limiting feed rate for the descending particles was also determined and fitted by an empirical equation. Experiments were conducted in a two dimensional test bed to elucidate the mechanism of descent and the interaction between bubbles and the descending particles.