Numerical Simulation of Catalytic Reaction on the Reentry Surface of Spacecraft

As human spaceflight technology continues to evolve, new requirements are emerging for extremely high speeds and long flight times for near-space vehicles. Gradual breakthroughs in major space projects such as lunar and deep space exploration. The re-entry velocity of aircraft will be higher than ever before, posing serious challenges to aircraft thermal protection systems. The molecular dynamics model of the cross-scale finite rate surface catalytic reaction is constructed according to the surface catalytic reaction theory and the underlying Direct Simulation Monte Carlo (DSMC) algorithm. The model includes chemisorption, physisorption, Eley-Rideal recombination reaction, Langmuir-Hinshelwood recombination reaction, and physical and chemical desorption. At the same time, the coupling effect of the five-component gas reaction and the surface catalysis reaction is considered. The influence of the surface catalysis model on the hypersonic re-entry process of spacecraft has been analysed by simulating typical examples. Compared with the Navier-Stokes Direct Simulation Monte Carlo (NS-DSMC) method developed by our team, the shock pressure, temperature and particle number density of the aircraft head show significant changes. The maximum surface heat flux is almost 30 % higher than without considering the surface catalytic model. This model is expected to solve the problem that it is difficult to characterise the thermochemical non-equilibrium surface effect in hypersonic flight, and further improve the ability to predict the aerodynamic heating of the vehicle shell.