Mathematical modeling of nitrogen flow around hypersonic bodies

Research results related to the study of physicochemical processes in the near-wall boundary layer occurring during the flow of nitrogen around a graphite specimen is presented. The influence of the catalytic wall on the heat flux is considered. The main attention is paid to the analysis of the distribution of chemical components concentrations across the boundary layer thickness of high-speed aircraft, based on a detailed account of the flow mechanism of heterogeneous catalytic reactions under conditions of surface mass transfer. It is shown that, oxygen is an important component of air (from the point of view of heat transfer and heating of the surface), since its recombination proceeds mainly in the low-temperature zone near the surface. Non-catalyticity appears most strongly in the frozen boundary layer when a sufficient number of non-recombined atoms appears at the surface. The diffusion of atoms from the flow to the wall will be weakened and the transfer of chemical energy will be small compared with the molecular thermal conductivity. It is interpreted that the amount of heat released during recombination can be reduced by selecting a surface with low catalytic activity. The distribution of chemical components concentrations over the boundary layer thickness at the critical point of blunt graphite body for a specific section of the flight trajectory is given.