The aero-physics of space vehicles entering into atmosphere with orbital and super-orbital velocities is classified as aerothermodynamics which is based on thermally and chemically non-equilibrium gas dynamic models. Development of computational models and tools for description of aerothermodynamics of re-entry into earth atmosphere space vehicles or entry probes has been attempted in the past, as the result some codes have been developed and employed in both scientific and engineering sections. Nowadays numerical simulation of such flows is an integral part in the design process of reentry vehicles. The simulation of weakly ionized gases over reentry vehicles has been performed successfully for a large number of spacecraft, including RAM-C, FIRE, Apollo Command Module, Huygens and Mars Science Laboratory. Computational aerothermodynamics is being routinely used in aerospace community.One of the most important parameters for design is the heat transfer to the spacecraft, which is one of the most difficult to accurately calculate. The heat transfer is mainly composed of two parts: convective and radiative heating. For the stagnation point of a blunt body, the convective heat transfer is roughly proportional to ρ0.5u3.0/RN 0.5 where ρ is the freestream density, u is the freestream speed and RN is the nose radius. The radiative heat transfer is roughly proportional to ρ1.6u8.5RN. The convective heating is usually the largest component, but the previous expressions show that the radiative heating component becomes increasingly important as the size of the spacecraft grows. Because of the increased diameter of modern spacecrafts, there is a lot of interest in the radiative heating component. The FIRE-II flight experiment from the 1960’s is still one of the best set of data available for radiative and total heating measurements. It is commonly used as a validation test case for aerothermodynamics codes.In one of these validation studies, it was observed that two independent NASA codes, DPLR10 (developed at NASA Ames) and LAURA (developed at NASA Langley), showed good agreement for computed convective heating rates with the difference staying below 7% for 11-species air model simulations. That work also showed larger differences in the computed radiative heating rate, on the order of 17 to 25 %. The physical and numerical modeling used in these codes is complex and it is not known which model may be the cause for such differences. A sensitivity analysis may be performed to obtain information on the impact of modeling choices on the results and to explain the differences.This work takes place in the aerothermodynamic analysis of a reentry space vehicle with coupled radiation. The computational methods used in this work are based on the coupled computational fluid dynamics (CFD) and computational radiative heat transfer. The thermochemical nonequilibrium effects are taken into account for CFD, the radiative transfer equations are numerically solved by discrete ordinate method (DOM), in which the participate media are ionized emitter-absorber-scatter gases.

Computational Study on Radiative Aerothermodynamics of a Reentry Space Vehicle

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

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