Computational Analysis of Radiative Heat Loading on Hypervelocity Reentry Vehicles

Abstract

Space exploration missions may include atmospheric entries at very high velocities (for example, sample return or entries from hyperbolic orbits) or into an atmosphere with highly radiative constituents (for example, Mars or Titan). The effects of gas radiation in the shock layer and wake flows may become significant at such flight conditions; hence, an accurate computational fluid dynamics analysis of these flows requires adequate modeling of the local absorption and emission properties and the energy transport by radiation. The wide range of numerical techniques for the integration of radiation in entry vehicle simulations includes Monte Carlo models, which enable accurate and computationally efficient predictions of radiative energy transport in participating (absorbing and emitting) media for complex geometries. Reentry type flow properties are characterized by a large variation of local absorption and emission properties in the spectral range. Therefore, and due to the absence of general averaging rules, a fine spectral discretization is needed for practical computations. Here, binning methods offer the potential to reduce the required resolution while maintaining a high level of accuracy. The application of a Monte Carlo radiation transport code using high spectral resolution and a loose coupling approach with the applied flow solver was found to give good agreement with the available heating rate measurements of the Second Flight Investigation of Reentry Environment flight experiment.