Energy transfer processes in a partially ionized, two-temperature gas

The elementary situation of convective energy transfer between parallel plates at different temperatures is analyzed for partially ionized, nonreacting, monatomic hydrogen wherein the electrons may be at a temperature different from that of the heavier species. The gas conditions considered are such that an ion sheath, less than a mean free path in spatial extent, forms on the fully catalytic colder surface. The numerical results obtained indicate that 1) the gross features of the continuum solution are rather insensitive to the models of sheath and transition regions employed; 2) the energy transfer between ions and electrons due to the electric field external to the sheath is appreciable, particularly in its effect of reducing electron temperature; 3) thermal nonequilibrium effects on total heat transfer are not as great as might be anticipated because of the energy transfer between species by electric fields and the contribution of diffusional processes; and 4) magnetic field effects on total heat transfer are less than the effect on electronic thermal conductivity would indicate and are further lessened by thermal non equilibrium effects.