Wärme‐ und Stoffübertragung in der Wirbelschicht

Heat and mass transfer in fluidized beds. Methods of calculation are presented which enable reasonably accurate prediction of heat and mass transfer coefficients in fluidized beds. Some well established equations already given in the literature could be used for estimating the range of existence of the fluidized bed and for calculating maximum fluidization velocities, bed expansion, and particle-to-fluid heat and mass transfer. However, a new model had to be developed for the wall-to-bed heat transfer from solid surfaces immersed in fluidized beds. This model makes use of some basic ideas adopted from the kinetic theory of gases in order to describe the mechanism of energy transfer through the moving particles. Predictions with this new model are in good agreement with most of the experimental observations, particularly regarding the effects of particle diameter, temperature, pressure, physical properties of gas and particles, and gas velocity.