Research On Airframe/Engine Integration Issues And Multidisciplinary Design Optimization Methods For Airbreathing Hypersonic Vehicle

The airframe and engine highly integration nature of airbreathing hypersonic vehicle results in intense interactions among disciplines or subsystems, especially a strong coupling effect between propulsion system operation performance and airframe basic aerodynamic characteristics. Therefore, preliminary hypersonic vehicle design requires an integrated design process that includes aerodynamics, propulsion, aeroheating, cooling, weight and sizing, trajectory and overall performance, and can account for effects among disciplines simultaneously. Only by this way, global optimal design concept can be obtained. By introducing multidisciplinary design optimization (MDO), the airfirame/engine integration issues and hypersonic vehicle system design optimization methods are studied systematically and comprehensively in this dissertation by means of theoretical analysis, numerical simulation and experiment validation. The results attained are as follows.Integrated design methodology of scramjet-powered hypersonic vehicle is proposed and studied systemically. The coupled quantities among disciplines and design structure matrix of hypersonic vehicle are analyzed in detail, and the integrated design framework and optimization model of hypersonic vehicle are established.An airframe/engine integration performance analysis method of hypersonic vehicle is proposed. Three kinds of typical airframe/engine integration models are compared, and some rules of airframe/engine integration models selection are summarized. A new design parameter region classifying method is presented, and used to evaluate the influence degrees of design parameters on vehicle performance in a 5-level mode basing on parameter sensitivities. The reliability and fidelity of analysis methods and codes are validated by especially designed airframe/engine integrated model force tests in hypersonic wind tunnel.A parallel multiobjective hybrid genetic algorithm (PMOHGA), basing on fast elitist non-dominated sorting, crowding and multimethod parallel collaboration strategy, is developed. Airframe/engine integrated components multiobjective optimization designs are performed using PMOHGA. During this research, a two-dimensional scramjet inlet multi-level and multiobjective optimization design method and a two-dimensional scramjet nozzle multiobjective optimization design method are presented respectively. Scramjet combustor design optimization for a test scramjet model engine is conducted by employing genetic algorithms, and an optimal design much better than original design is obtained.An airframe/engine integrated cooling analysis model of hypersonic vehicle is presented. The coolant rates required for aeroheating parts and engine flowpath are examined under constant height trajectory and constant dynamic pressure trajectory respectively. The study shows that regenerative cooling can meet the airframe/engine integrated cooling requirements in the range of flight Mach numbers from 6 to 12, as fuel injection concept (injector locations and injection fuel mass flow) is set properly, and hydrogen temperature at the exit of cooling passage is allowed to be a relative higher value.A new cycle performance measure, called synthetically specific impulse, is defined, which can reflect the effects of aerodynamics, propulsion and weight on vehicle overall performance simultaneously. Various scramjet cycles are compared. Results show that expender cycle and fuel-rich gas generator cycle have higher synthetically specific impulse and propellant specific impulse, and have remarkably better performance than other cycles.A hypersonic cruise vehicle MDO model based on parametric method is established.D-Optimal design, Taguchi design and uniform design are employed to conduct hypersonic cruise vehicle MDO respectively via parallel computation in a local network, and near optimal designs better than baseline design are reached.A hypersonic cruise vehicle MDO model based on optimal algorithm is established. An optimization method, which combines patter search, Powell and genetic algorithm i...