Numerical prediction of convective and radiative heating of Scramjet combustion chamber with hydrocarbon fuels

Flow and combustion of a hydrocarbon-air mixture in a channel modeling a section of a supersonic combustion ramjet (scramjet) are considered. Fields of concentrations, pressure, and temperature are calculated with the use of two-dimensional computational model based on non-stationary system of NavierStokes equations, energy conservation and diffusion equations together with system of chemical kinetic equations. Based on them, the fields of spectral optical properties and thermal radiation of the gas mixture within a scramjet combustor are computed. The density of the radiative heat flux to the chamber wall is computed by an approximation of the plane layer. Several fuels and corresponding chemical kinetics models are considered. These are: H2, CH4, C2H6, kerosene. Combustion of H2-air mixture is considered with the purpose of comparisons with calculation data of H.F.Nelson (Nelson, H.F., “Radiative Heating in Scramjet combustor,” J. Thermophysics and Heat Transfer, Vol. 11, No.1, 1997) and I.Boid et al. (Crow A., Boyd I., Terrapon V., “Radiation Modeling of a Hydrogen-Fueled Scramjet,” AIAA 2011-3769. 2011. 15 p.). It has been shown that some regimes of burning are non-stationary, and the radiative heat flux contributes significantly to the total heating of the combustor wall. Comparison of radiation heat fluxes for different initial conditions are presented.