Radiant heat transfer in nonisothermal gas with variable elemental composition

The spectrum-integrated characteristics of the radiation field of a planar gas layer in local thermal equilibrium as well as large temperature and chemical species gradients are modelled analytically. Attention is given to combined variations in the temperature and chemical species, with the pressure assumed to be constant, and their effect on the integrated radiant flux. The nonisothermal gas layer is divided into uniform layers and the spectral intensity of the radiation at any node of a finite difference grid is calculated as a function of the temperature, the concentration of chemical elements, and the geometric thickness of each layer. The expansion coefficients are calculated on the reference profiles while computing the radiant heat flux, and contain all data on the spectral composition and the angular dependence of the radiation. A binary diffusion model is formulated for the radiant heat transfer of a three element (O-N-C) hypersonic shock layer near the critical point of a blunt graphite body.