Rarefied gas–surface interaction under multi-incidence parameter coupling conditions: A molecular dynamics simulation

An effective gas–surface interaction model is crucial for accurately predicting the aerodynamic thermal properties of hypersonic vehicles. However, the applicability of classical interface models has been severely challenged under hypersonic conditions since the boundary properties predicted by different gas-surface interaction models vary greatly, which seriously threatens the flight safety. Therefore, in order to accurately describe gas–surface interaction under hypersonic conditions, we analyzed the reflection behavior of the gas on a silicon-based surface through molecular dynamics simulations and presented a modified Maxwell model. Furthermore, the dependence of model parameters on incident energy, angle, and gas type was also obtained. By analyzing gas–surface interaction time and potential well depth, the endogenous mechanism of the accommodation coefficient variation under multi-incidence parameter coupling conditions is revealed. These results not only elucidate the microscopic mechanism of gas–surface interaction but also provide an important basis for establishing accurate boundary conditions for larger-scale simulations.