Multiscale Modeling of Gas-Solid Surface Interactions Under High-Temperature Gas Effect

The high-temperature gas effect is critical to the design of high-speed aircraft in terms of the thermal protection at their surfaces. However, studies on this topic are challenging for both experiments and numerical simulation. To cope with the breakdown of continuum methods and the extremely high cost of molecular methods, a multiscale model and simulation method for flow, diffusion, adsorption/desorption, reaction, and heat transfer is developed to understand the gas effect based on hard-sphere/pseudo-particle modeling (HS-PPM). The model was first used to describe the catalytic reactions of high-temperature gas without flow on the surface of copper, tungsten, platinum, nickel, silicon dioxide, etcetera. The recombination coefficients of oxygen and nitrogen atoms obtained at different temperatures are in good agreement with the existing simulation and experimental results, which verified the effectiveness and accuracy of the approach. The approach is also capable of simulating the complex physical and chemical processes in the gas flow near the silicon dioxide surface, with the critical flow velocity slip and temperature jump reasonably reproduced. These studies demonstrated that HS-PPM can be a comprehensive virtual experimental tool for the study of surface catalytic characteristics of thermal protection materials in a hypersonic environment and accurate prediction of the aerodynamic thermal behavior there.