A fluidized-bed heat transfer mechanism is proposed that assumes that the chief resistance to heat exchange between a confining wall and a fluidized bed is in the laminar film at the vessel boundary. Heat flow through the film is by conduction. As the solids-particle velocity along the wall will modify film thickness, correlation of film coefficients in terms of particle velocities or the equivalent suggests itself. That heat transport from the boundary of the heating element to the fluidized core proceeds by way of turbulent solids mixing seems indicated by the considerable effect that the solids heat capacity appears to exert on over-all coefficients.

The resulting correlation is examined critically in relation to pertinent literature data. The effect of fluidized-bed parameters on heat transfer coefficients is considered, and applicability and limits of the correlation are ascertained.