Investigation Of Real Gas Effects On Flow Separation/Attach At High Mach Number And Low Reynolds Number

With the accelerating progress of time and technology, the hypersonic vehicle flying is developing from fixed path (such as reentry capsule, shuttle, ballistic missile, etc.) towards high maneuverability which makes the configuration of hypersonic vehicle becomes more and more complex. A few complex flow phenomena, such as shock/boundary layer interactions, shock/shock interactions and flow separation and reattachment, occur around the compression corners generated by deflected control surfaces or engine inlet on hypersonic vehicles. These phenomena influence the local distribution of pressure, frictional drag and heat flux. The influence on heat flux is especially important because aerodynamic heating occur around the reattachment point, and the value and position of heat flux peak are both the key parameters during designing thermal protection system.A critical problem of developing a high maneuver hypersonic vehicle is to design the control surfaces reasonably, which is crucially important for the control and stability of hypersonic vehicle. When the vehicle flies at high Mach number, the temperature of air behind the shock wave become very high because of the strongly compression of shock wave and the viscosity, the degrees of freedom within the air molecules will be excited, dissociation and ionization reactions will occur. This phenomenon is called real gas effects. Real gas not only affects the aerodynamic characteristics and heat load of vehicle directly, but also has significant impact on the local flow separation and reattachment phenomena which caused by the complex configuration. Therefore, real gas effects should be considered during designing the control surfaces and other important parts of hypersonic vehicle.The thesis includes six chapters. Chapter 1 is the introduction, which introduces the research background, the domestic and foreign research progress about real gas effects, and summarizes the influence of real gas effects on the local complex flow phenomena. Chapter 2 and chapter 3 describe the numerical methods applied in the calculation of equilibrium gas and chemical nonequilibrium gas. Chapter 4 verifies the computer program by some numerical simulations of typical state. Chapter 5 carries out the calculation research of lifting body with control surfaces deflected under different conditions by calorically perfect gas, equilibrium gas and chemical nonequilibrium gas model. The effects of real gas on the local flow separation of lifting body control surfaces and the aerodynamic characteristics of lifting body are analyzed. Chapter 6 is conclusion, in which the work of this paper is summarized and the direction of future work is pointed out.