Numerical Simulation of the Effect of Wall Temperatures on Hypersonic Thermochemical Nonequilibrium Flow

Hypersonic vehicle travels at high speeds and in thin gas environment with high temperatures and heat fluxes. To accurately predict the flow field, the nonequilibrium Navier-Stokes equation was employed to account for the nonequilibrium thermochemical reactions. The characteristics of the flow field, including shock standoff distance, heat flux distribution, particle number distribution, and aerodynamic forces were analyzed by varying the wall temperature. The findings demonstrate that a low-temperature wall (T_w/T_i=4) fails to sufficiently expand the gas within the shock boundary layer, resulting in minimal shock standoff distance. As the wall temperature increaseing, there is an expansion of gas within this boundary layer. Consequently, both temperature and pressure rise sharply within the shock layer, leading to variations in particle ionization distribution influenced by shock wave position. It is observed that as wall temperature increaseing so does particle ionization degree. Axial pressure exhibits a positive correlation with shock standoff distance and displays an increasing trend with rising wall temperature. These research outcomes provide a theoretical foundation for developing aerothermodynamic protection systems and prediction models for hypersonic vehicles.