One-dimensional mass and heat transfer and their coupling

Abstract

Consideration is given to the steady-state transfer of mass and heat frcm a porous wall to a non-dissipative binary system or air-hydrogen in one case, and air-carbon dioxide in another. Hydrogen or helium is injected at a uniform rate through the porous wall into the system. The flow, temperature, and concentration fields are assumed to be functions of the distance from the wall only. According to the thermodynamics of irreversible processes, the fluxes of heat and mass are coupled. The effects of such coupling are shown to be small on the concentration field, appreciable on the temperature field and heat flux under certain conditions, and negligible on the heat-transfer coefficient when defined in terms of an “adiabatic wall temperature”. In general, the magnitude of the effects are much more pronounced for hydrogen injection than for carbon dioxide injection, and are in the opposite sense.