Abstract: Under the pressure of hypersonic inflow, the surface of an inflatable deceleration structure will deform on the wind-ward side, thereby changing the flow field. Based on the thermochemical non-equilibrium reaction model, simulations are conducted for the flow past an inflatable deceleration structure before and after surface deformation, analyzing the influence of surface deformation on the flow. The shape of inflatable deceleration structure is a blunt nosed cone with a radius of 2.4m and a half cone angle 60°, consisting of a rigid head face and 6 inflatable rings. The numerical model adopts a 5-component dual-temperature thermochemical reaction model, and the wall catalytic conditions include non-catalytic and fully catalytic. The influence of surface deformation on flow characteristics, heat flux, and pressure under different attack angles is investigated. The results show that surface deformation can lead to periodic temperature and pressure fluctuations in the shock layer of the inflatable deceleration structure, as well as non-uniform distribution of dissociated components. The influence of surface deformation on flow variables weakens as the attack angle increas-es. After the surface deformation, the change in velocity leads to increase in the heat flux and decrease in the pres-sure at inflatable rings, as well as decrease in the heat flux and increase in the pressure at the concavities between inflatable rings. The effect of surface deformation on the pressure is weaker than that on the heat flux. There is no significant change in the aerodynamic coefficients of the front face of the inflatable deceleration structure after defor-mation.

Key words: Inflatable deceleration, hypersonic flow, aerothermodynamics, nonequilibrium reaction, two-temperature model, numerical simulation