自 适 应 循 环 推 进 系 统 总 体 性 能 优 化 方 法

Adaptive cycle engine possesses strong airflow adjustment capability,which can decrease inlet outflow drag and improve propulsion system performance by remaining airflow. And realizing the promotion on propulsion sys⁃ tem performance is closely related to integrated optimization and design between engine and inlet/exhaust system. However,in early stages of engine overall scheme demonstration,optimization design is often carried out on the en⁃ gine itself,neglecting the impact of the inlet/exhaust system on the engine’s matching condition. And the consistency of optimal conditions between propulsion system and engine is hard to be ensured,which determines model complex⁃ ity and optimization priority during design process. Based on these problems,research on overall performance optimi⁃ zation method of propulsion system is carried out and adaptive cycle engine that has multiple control variables and working modes is taken as research object. Firstly,overall performance calculation model and installation performance calculation model of adaptive cycle engine are established. Secondly,the impact of key design parameters on installa⁃ tion loss of inlet/exhaust system and installation performance estimation are developed by using different configurations of inlets and nozzles. The optimal configurations and suitable parameters of inlets and nozzles are chosen. Finally, optimization method of propulsion system overall performance based on random search algorithm and regression analysis is developed. And two fast optimization methods to gain propulsion system performance are established：one is optimizing engine performance and then calculating installation performance,the other is directly optimizing installa⁃ tion performance. The comparisons of optimal performance between two optimization methods are conducted in the cruise throttling conditions and velocity-altitude characteristic conditions. By regression fitting precision analysis and co⁃ incidence comparison of optimal throttling characteristics in cruise conditions and maximum thrust characteristics in dif⁃ ferent velocities and altitudes,the maximum root mean square error is about 0. 01 in cruise conditions,and 0 in velocity-altitude characteristic conditions,which means that optimal working conditions of engine can represent optimal working conditions of propulsion system. Therefore,during the scheme demonstration stage,it is unnecessary to con⁃ sider the effect on inlet/exhaust system to ensure the optimality of the propulsion system,greatly simplifying the model complexity of the scheme design. This design method is suitable for different configurations of adaptive cycle engines to conduct fast optimization design of propulsion system performance,which has strong engineering guidance signifi⁃ cance and application value.