单外涵变循环发动机变几何特性仿真

为了研究单外涵变循环发动机变几何性能收益，建立了一种单外涵变循环发动机总体性能仿真模型，并通过算例验证了仿真模型的计算精度。根据不同飞行状态的发动机控制规律和最优控制目标，模拟生成3种变几何方案最佳变几何参数以及最佳节流特性和高度-速度特性。结果表明：在设定的控制规律下，相对发动机常规变几何方案（方案1），尾喷管、混合器与低压涡轮导向器可调的变几何方案（方案3）使发动机地面节流状态耗油率降低1.7%～3.0%，超声速巡航推力增大14%～29%，亚声速巡航耗油率降低0.9%～3.1%，在3种变几何方案中性能收益最大；尾喷管与混合器可调的变几何方案（方案2）使发动机地面节流状态耗油率降低1.2%～2.2%，超声速巡航推力增大3%～17%，亚声速巡航耗油率降低0.9%～1.2%，在3种变几何方案中性能收益居中。发动机变几何方案的选择应综合考虑结构复杂度、可靠性、质量等方面的代价与基于特定任务需求的总体性能收益的平衡。

Simulation of Variable Geometry Characteristics of Single Bypass Variable Cycle Engine

To investigate the performance gain of the single bypass variable cycle engine, we established a simulation model and veri? fied its computational accuracy through examples. The simulation and generation of the best variable geometry parameters, throttling characteristics, and altitude-velocity characteristics for the three variable geometry schemes are based on the engine control laws and optimal control objectives for different flight states. The study indicates that Scheme 3, which employs a variable geometry scheme with adjustable tail nozzle, mixer, and low-pressure turbine guide, outperforms Scheme 1, the conventional engine variable geometry scheme. Scheme 3 reduces fuel consumption rate by 1.7% to 3.0% in ground throttling state, increases supersonic cruise thrust by 14% to 29%, and reduces fuel consumption rate by 0.9% to 3.1% in subsonic cruise. This represents the largest performance gain among the three variable geometry schemes. Scheme 2, the variable geometry scheme with an adjustable tail nozzle and mixer, can reduce fuel consumption rate by 1.2% to 2.2% in ground throttling state, increase supersonic cruise thrust by 3% to 17%, and reduce subsonic cruise fuel consumption rate by 0.9% to 1.2%. Among the three variable geometry schemes, Scheme 2 exhibits intermediate performance gains.When selecting engine geometry options, it is important to consider the balance between the costs of structural complexity, reliability, and mass, and the overall performance gains based on specific mission requirements.