Three-Dimensional Radiation Ray-Tracing for Shock-Layer Radiative Heating Simulations

A three-dimensional ray-tracing algorithm is developed for shock-layer radiative heating predictions. When coupled with a tangent slab approximate code, such as the HARA radiation code, this algorithm provides an efficient approach for computing the radiative heating and allows the commonly applied tangent slab approximation to be removed. Application to several Earth- and Mars-entry conditions show that the ray-tracing approach predicts up to 15% lower radiative heating values than the tangent slab approximation at the stagnation point, which is consistent with the results of previous studies. In the afterbody region of Mars entry vehicles, where radiative heating from the molecule may be larger than convective heating, a 70% reduction from the tangent-slab result is seen, indicating the inadequacy of the tangent slab approximation in such regions.