Coupled radiation-gasdynamic solution method for hypersonic shock layers in thermochemical nonequilibrium

The purpose of this research was to develop a highly accurate computational method for calculating the nonequilibrium radiative heat transfer within reentry shock layers. The nonequilibrium state of the flowfield was obtained by using the multispecies multitemperature nonequilibrium flow solver NH7AIR which is capable of separately tracking the vibrational energy of each diatomic species and the energy of the free and bound electrons. The calculation of radiative heat transfer was performed by utilizing the detailed line-by-line spectral radiation solver SPRADIAN. Two radiative transport schemes were implemented in this coupled code. The first scheme was based on a straightforward application of the standard tangent slab solution method. The second scheme was based on the conservation of radiative energy and resulted in a finite volume method for radiative heat transfer (FVMR). Data from the FIRE II flight experiment were used to validate the coupled radiation-gasdynamic solver. Coupled results exhibited a high degree of agreement with experimental data. The utility of the FVMR scheme was also examined in an uncoupled implementation and shows promise for future implementation in a coupled setting. Together, the enhancement of the nonequilibrium thermal modeling, the use of a highly accurate spectral radiation solver and the development of a conservative scheme for radiative transport constitute a significant improvement in current capabilities available for modeling the radiating nonequilibrium shock layers which accompany reentry flight.