Effect of Catalytic Properties on the Thermal Loads and Radiation Characteristics for Re-entry Capsules

For the spectral characteristics of thermochemical nonequilibrium flow field gases and wall coating radiation, as well as the aerodynamic thermal loads of re-entry capsule Fire II, a finite-rate catalytic model combined with the multi-component chemical nonequilibrium N-S equation is developed. Based on this model, the effects of dissociation and recombination reactions of gas components on the wall coating temperature and heating flux are simulated. In addition, we investigate and analyze further the influence of the coating's catalytic properties on the radiation spectral characteristic of the high-temperature nonequilibrium flow field and the wall coating radiation. The results show that the catalytic properties intensify the non-homogeneous recombination and exothermic processes near the wall surface. It results in a significant decrease in the number of component particles contributing to the radiative spectral intensity near the wall, which slightly reduces the flow field gas spectral radiation intensity. Meanwhile, the catalytic properties also increase the wall temperature and heating flux, significantly increasing the intensity of the wall radiation spectral in the near-infrared region.