Numerical Simulation of Influence of Adsorption on Surface Heterogeneous Catalysis Process of Hypersonic Vehicles

Abstract

In view of the issue that surface catalysis has a significant influence on aerodynamic heating of hypersonic vehicle heatshield and is difficult to accurately predict, a four-step surface heterogeneous catalytic model including physisorption, chemisorption, Eley-Rideal (ER) recombination, and Langmuir-Hinshelwood (LH) recombination was established by combining theoretical analysis and numerical simulation. Based on the model, the nonequilibrium flow and the aerodynamic heat around a two-dimensional cylinder were simulated. The influence of the fraction of occupied physisorption and chemisorption sites on the catalysis rate and the aerodynamic heat was analyzed. The results show that the established model can improve the prediction accuracy of the aerodynamic heat. The surface adsorption has a nonlinear influence on the aerodynamic heat due to the competing and promoting between different reaction pathways. Based on the real physicochemical process, the model can reflect the catalytic properties of different materials and further provides theoretical support for the lightweight and low redundancy design of the thermal protection system.

Keywords

• surface catalysis
• chemical nonequilibrium
• physisorption
• aerodynamic heat
• hypersonic
• interface physics