The Influence of Real Gas Effects and Thermochemical Reactions on the Characteristic Parameters of Flow in Shock Tunnel

The real gas effect will change the thermal properties of the gas, and the thermochemical reaction will affect the state behind the shock wave, which will jointly affect the characteristic parameters of the shock wave wind tunnel flow field. Based on the state equation of real gas and the hypothesis of thermochemical equilibrium, a fast calculation method of real gas thermophysical properties and after-wave parameters is established, and the change of real gas thermochemical reaction on the after-wave parameters is studied. The influence of real gas effects and thermochemical reactions on the spatiotemporal structure of flow in shock tunnel and the flow parameters in the stagnation zone are investigated by quasi-one-dimensional numerical simulation considering the effects of real gas and thermochemical non-equilibrium combined with theoretical analysis. It is found that the sound speed, enthalpy, entropy and other thermophysical properties are significantly differences compared with real gas and ideal gas. All deviations increase with the increase of pressure. The thermochemical reactions induce the temperature and pressure behind the shock lower and higher than that of the fixed specific heat ratio gas respectively. The states behind incident and reflected shock both close to thermochemical equilibrium. The real gas effect increases the propagation speed of the expanding wave head and decreases the Mach number of the incident shock wave, which affects the space-time structure of the wind tunnel flow field and may lead to a decrease in the effective experiment time. © 2024 Chinese Society of Astronautics. All rights reserved.