ANALYTICAL COMPARISON AND CRITERIA FOR HEAT AND MASS-TRANSFER MODELS IN METAL HYDRIDE PACKED-BEDS

This paper puts forward a mathematical model of transport processes in a metal hydride packed bed along with an analytical quantification of the frequently used assumptions. The complete model takes into accoun t heat transfer by conduction, convection, mass transfer, as well as r eaction kinetics and convective interactions between the fluid and sol id phases. By analyzing several frequently used assumptions, a system of useful and practical analytical criteria is obtained. The criteria reveal when simplifications of the model are possible. The sampled mod els obtained by reduction of the complete model can be effectively use d in describing transport processes in metal hydride beds within the l imits determined by a set of analytical criteria. Specifically, criter ia for the validity of local thermal equilibrium, steady-slate approxi mation, the frontal model approximation, and the filtration approximat ion are established analytically.