Echanges thérmiques en fluidisation gazeuse III—Etude theorique du mécanisme de l'échange

Abstract

The experimental study of the heat exchange between an agitated fluidized bed and a wall shows that an appropriate mechanical agitation of the medium makes possible a substantial increase in the intensity of the exchange. At constant speed of rotation ω of the stirrer, the variations of the exchange coefficient as a function of the flow of air are represented by rising curves for small values of ω and by decreasing curves for high values. The interpretation of this result leads to a proposed new description of the mechanism of heat exchange. Two factors intervene; the degree of emptyness ε in the dense phase of the bed and the residence time τ of the whole of the particles in the vicinity of the wall.