Determination of the effective probabilities of the heterogeneous recombination of atoms when heat flow is influenced by gas-phase reactions

Results are presented from experimental and numerical studies of nonequilibrium heat exchange between a subsonic high-enthalpy ($20$ MJ/kg) nitrogen jet from a induction-type plasmotron and the flat end surface of a model within a broad range of degrees of nonequilibrium in the dissociated boundary layer – from near-frozen to near-equilibrium. An analysis is made of literature data on the kinetics of the gas-phase reaction $\rm N + \rm N \rightleftarrows \rm N_2$ from the viewpoint of the best agreement between theoretical values of heat flux to the neutral surface and experimental data for low-catalytic molybdenum. Consistent experimental and theoretical data on heat flux at the critical point of the model is used to obtain new data on the probability of the heterogeneous recombination of nitrogen atoms $\gamma_w$ on beryllium $(T_w = 300$ K$)$ and quartz $(T_w = 300$–$1500$ K$)$ within the pressure range $0.1$–$0.9$ atm. Some results are presented from determination of $\gamma_w$ on thermally protective coatings on the orbital craft “Buran” for high surface temperatures.