Optimization design for scramjet and analysis of its operation performance

Flow field numerical simulation methods of scramjet introduced in this paper, include using CFD method to analyze the flow phenomenon in each component of scramjet, i.e. forebody/inlet, combustor and afterbody/nozzle. Design and optimization of a generic scramjet model are investigated based on the bilevel integrated system synthesis method. Analysis and design procedures of each component are treated as a black box in scramjet system design. Components of scramjet are designed and optimized at subsystem level in the first step, and then a system level optimization is performed for the whole scramjet. Multi-fidelity simulation models are developed and applied to analyze and design the scramjet model. According to the requirement of design, appropriate fidelity simulation models are adopted in design cycle under the limitation of time and budget. A design and optimization example is presented in which some parameters are chosen as scramjet system level variables by sensitivity analysis of all possible design parameters; other parameters become component level variables of forebody/inlet, combustor and afterbody/nozzle. The design of experiment method and genetic algorithm arc applied to explore design space and to obtain optimal or near optimal solution. Operation performance of scramjet is also analyzed in this paper, considering the interaction between scramjet and vehicle airframe.