Abstract: Chemical nonequilibrium effect on aeroheating environment of hypersonic vehicles is numerically investigated.First,three gas models are considered for comparing chemical nonequilibrium effect on aerodynamic and aeroheating characteristics over a 2D cylinder-blunt body.Then,a 3D sphere-blunt body is taken to further investigate chemical nonequilibrium effect,especially wall catalysis effect on aeroheating environment.It indicates that chemical nonequilibrium effect does not affect pressure significantly,but reduces shock-standoff distance remarkably and, more importantly, post-shock temperature, and hence affects aeroheating environment significantly.Moreover,wall catalysis effect affects aeroheating environment significantly,and thus effective control of this process reduces wall heat transfer considerably.It is concluded that understanding and accurate prediction of chemical nonequilibrium effect are of decisive importance for the design of thermal protection systems (TPS) of hypersonic vehicles.

Key words: chemical nonequilibrium, wall catalysis, aeroheating, hypersonic, TPS