EFFECT OF SLIP BOUNDARY CONDITIONS ON NONEQUILIBRIUM REACTING AIR FLOWS

A BSTRACT : We study the effect of slip boundary conditions on the kinetics, dynamics, and heat transfer in a strongly nonequilibrium flow with coupled vibrational relaxation, state-specific gas-phase and surface reactions. Two types of kinetic boundary conditions are introduced: whereas one ensures number flux conservation, the second conserves the mass flux. Both kinetic boundary conditions are suitable for state-to-state flow simulations and take into account gain and loss of particles on the surface due to recombination and excitation/deactivation of vibrational states. On the basis of the proposed kinetic conditions, the velocity slip, temperature jump and species normal mass fluxes on the surface are derived. The models are used for numerical simulations of a five-component air mixture along stagnation line. The effects of kinetic boundary condition, diffusion model, accommodation coefficients are evaluated for different rarefaction degree. Important effect of diffusion model and temperature jump on the fluid-dynamic variables and heat flux is shown.