Study on the real gas effect on the windward side of an inflatable reentry capsule

In this paper, the reentry flow field of an inflatable reentry capsule was numerically simulated using the air 9-component chemical nonequilibrium model and the ideal gas hypothesis model. The difference in the calculation results of the two methods was investigated, the manifestation of the real gas effect was studied, and the reasons for the difference between the real gas effect of the inflatable reentry capsule and the real gas effect of the rigid reentry capsule were explored. The results show that compared with the ideal gas hypothesis, the real gas effect makes the shock wave position closer to the wall, the air temperature after the shock wave decreases, and the wall heat flux density decreases; at 83 km, the specific heat ratio of the gas after the shock wave is higher than 1.4, and the air undergoes a dissociation reaction, while at 73 km, the real gas effect is weaker, the specific heat ratio of the air after the shock wave remains at 1.4, and the air still exists in the form of molecules; the main reason for the difference in the strength of the real gas between the inflatable reentry capsule and the rigid reentry capsule in the same altitude range is that the drag-to-weight ratio of the inflatable reentry capsule is larger than that of the rigid reentry capsule, and the speed decreases faster after entering the atmosphere, and the speed is lower at the same altitude.