Stagnation-point heating and ablation analysis of orbital re-entry experiment

Abstract

In this study, stagnation-point heating and ablation analysis of the orbital re-entry experiment (OREX) are performed including the air and ablation gas mixture. In gas-gas interactions, the ablation gas is ejected into the shock layer, and the interaction between the air and ablation gases is fully considered. The two-temperature model is employed to describe the thermochemical nonequilibrium flows of the OREX flight conditions. The state-of-art chemical-kinetic parameters of 19-species, including the air and carbon-related ablation gas species, are assessed and utilized to calculate the re-entry flows. In gas-surface interactions, three types of ablation models, the fully equilibrium model, Park model, and surface thermochemistry model of the Zhluktov-Abe and Prata models, are employed to describe the ablation on the surface of carbon-carbon composite CC material of the thermal protection system. For the selected trajectory points of the OREX flight conditions, quasi-one-dimensional thermochemical nonequilibrium flow calculations are carried out, and the results are analyzed in detail. From the calculated results of the re-entry flows, it was found that the production of CO, CO2, and CN is the dominant mechanism of the surface heating on the ablating surface. Heat loss by surface recession is relatively small in OREX flight conditions. The total amount of surface recession due to ablation is approximately 0.22-0.32 mm in the selected range of the OREX flight. Heat loss from surface radiation increases with the surface temperature, and the amount of heat loss is comparable to the amount of surface heating at the trajectory point of 7481.5 s in the OREX flight.