Effect of Components of the Thermal Conductivity Tensor of Heat-Protection Material on the Value of Heat Fluxes from the Gasdynamic Boundary Layer

Abstract

The effect of components of the thermal conductivity tensor of heat-protection material on heat fluxes from the gas to the body were studied based on the first obtained analytical solution of the problem of heat transfer in anisotropic composite material in conditions of a convective-conductive heat transfer flow around by a high-temperature gasdynamic boundary layer. Such an analysis made it possible to determine a considerable decrease in heat fluxes to the lateral surface of blunted anisotropic body with the use of a heat-protection material with a high degree of longitudinal anisotropy (e.g., pyrolytic graphites, the ratio between the longitudinal and transversal thermal conductivities of which may reach a hundred or more). The main contribution to the decrease in heat fluxes is made by the decrease in the temperature gradient on the gas-body boundary from the gas side at the expense of increased body temperature downstream. In addition, the increased gas temperature on the wall leads to increased dynamic viscosity and decreased density, which decreases the local Reynolds numbers and promotes a decrease in heat fluxes. The numeric results are analyzed.