Numerical Analysis of the Influence of Material Catalytic Differences and Deformation on the Aerothermal Environment of a Flexible Reentry Vehicle

Inflatable flexible reentry vehicles face intense high-temperature gas non-equilibrium effects during atmospheric reentry, where O 2 and N 2 in the flowfield undergo significant dissociation and ionization. The wall catalytic effect causes atomic and ionic components to release large compositional diffusion heat fluxes at the surface. Due to structural characteristics, the catalytic differences between the rigid thermal protection base and the flexible surface materials can exacerbate local thermal environments. Additionally, hypersonic flow alters the flexible surface aerodynamic shape, changing its heat flux distribution. This study employs the NNW-HyFLOW software with a two-temperature, 11-component thermo-chemical non-equilibrium model to numerically simulate the aerothermal environment of an inflatable reentry vehicle. The heat flux distributions under different thermal protection materials and deformation shapes are analyzed. Results show: The catalytic differences between the rigid base and flexible surface cause local heat flux change; the larger the catalytic coefficient difference, the more pronounced the change. Among GreyC-9, TABI, and PCC materials, GreyC-9 and TABI exhibit higher surface heat flux values at the material interface regions, with increases of 8.5% and 10.6%, respectively. Surface shape deformation intensifies the thermal environment, shifting peak heat flux locations. Greater deformation leads to more fluctuations in surface heat flux. The sp20 deformed shape results in a peak heat flux of 750 kW/m 2 , a 68% increase compared to a smooth shape, with a local heat flux difference of 620 kW/m 2 .