HEAT-TRANSFER IN GAS-FLUIDIZED BEDS .1.

The scope of this paper involves the prediction of maximum heat transfer coefficients in bubbling fluidized beds, which properly takes into account the thermal and fluid-dynamic properties of the particulate material and the fluidizing agent. The present analysis suggests that heat transfer between heating or cooling surfaces and bubbling fluidized beds mainly shows itself as a particular manifestation of the otherwise widely accepted general rules of convective heat transfer. The only additional feature consists in an appropriate modelling of the particle convective component, and this leads to the definition of a two-phase Prandtl number.