On the influences of surface heat release and thermal radiation upon transport in catalytic porous microreactors—A novel porous-solid interface model

Abstract

A novel porous-solid interface model is put forward to analyse the distribution of heat generated by exothermic catalytic reactions on the inner walls of a porous microreactor. This builds upon a recent theoretical development on the local thermal non-equilibrium interface modelling and further advances that to include thermal radiation. The model is then utilised by an analytical investigation of transport phenomena in a parallel-plates, porous microreactor. Two-dimensional, closed form solutions are developed for the velocity, temperature and concentration fields and analytical expressions are derived for Nusselt and Sherwood number as well as local and total entropy generation. The results show that exothermic catalytic activities can significantly affect the transport processes in microreactor by modifying the values of Nusselt and Sherwood number. This can be highly intensified by an imbalance in the catalytic activities of microreactor surfaces. It is further shown that interactions of the surface heat release with thermal radiation and heat losses through the walls introduce a wealth of Nusselt and Sherwood number behaviours, which considerably differ from those of non-catalytic systems. These clearly demonstrate the importance of including surface heat release in non-equilibrium analyses of the catalytic porous microreactors in which catalysts are placed on the walls.