Simulation Of Thermal Environment Calculation And Thermal Protection Structure Analysis For Hypersonic Vehicles

Aerodynamic-heating of hypersonic vehicles is one of the key techniques demanding prompt solution. Severely aerodynamic heating will greatly affect the aircraft structure, payload in cabin, flight performance and security. This thesis presented a rapid and accurate calculation method to predict the hypersonic aerodynamic heating based on the engineering and numerical calculation method. The method was applied for analyzing the thermal protection structures of a hypersonic-glide vehicle.Simulation analysis of the outer edge boundary layer of the hypersonic vehicle was studied. Models of air specific heat coefficient and specific heat ratio coefficient changing with temperature were formed. The temperature-air attribute model was built up. The engineering calculation model of outer edge boundary layer parameters was established based on both perfect air model and chemical balanced air model. Inviscid theory based outer edge boundary parameters numerical calculation model was constructed according to the temperature-air attribute model. The outer edge boundary parameters of blunt double-cone model and the hypersonic-glide vehicle were calculated using engineering and numerical methods, separately. The simulation results were compered to validate the better performance of the inviscid numerical method than the engineering method. The inviscid numerical method obtained higher accuracy.Simulation analysis of the hypersonic vehicle thermal environment near the wall was studied. The streamline on the wall of hypersonic vehicle based on outer edge boundary layer parameters was deduced. The laminar and turbulent flow aerodynamic heating model of classified components were built up based on the reference enthalpy theory. The aerodynamic thermal of the blunt double-cone model was calculated. Results of(aerodynamic thermal of) hypersonic-glide vehicle calculated by simply numerical method were compared with the method presented in this thesis. The biggest difference of the heat flux of per square meter was 31.5%. The engineering and numerical combined method had a better accuracy. The aerodynamic heating environment of the hypersonicglide vehicle flying along the trajectory was calculated, which laid the foundation of the thermal structure design and analysis.Thermal protection structural design and analysis of hypersonic-glide vehicle were worked on. The implicit finite difference equation was deduced based on the energy balance principle and the Fourier heat conduction equation. Based on the heat flux of per square meter, the temperature distribution of aircraft warhead, equipment cabin, engines and tail section wall, structural layer and the interior cabin were calculated. The impact of treatment on the results of the wall conditions was analyzed. The results showed that the hot wall decrease a maximum percent of 44% than the colder wall in heat flux. In other words, if the heat flux was calculated according to the cold wall, heat-resistant layer design result was larger. In addition, the design of adding the nano-porous heat method airgel insulation materials, and optimized the protection structure with the Sequential Approximation Optimization method, decreased the temperature on equipment cabin of 43%, engines of 49%and tail section wall of 35%, the highest temperature is 375 K, which satisfied the temperature required. The research provided a reference for hypersonic-glide vehicle heat-protection structural design and analysis.The calculation method described herein had higher accuracy and computational efficiency which can meet the demand of fast and accuracy of engineering estimation on hypersonic vehicle design. The structure of thermal protection satisfied the demand of material temperature allowing, it can provide a certain reference in practical application.