变循环发动机模态转换建模及控制规律设计方法研究

为了实现变循环发动机快速可靠的模态转换，本文发展了变循环发动机模态转换过渡态模型及控制规律设计方法。在变循环发动机动态数值仿真程序的基础上，针对模态选择阀与涵道引射器这两个模态转换过程中的关键变几何部件，建立了高精度的气流突扩局部损失模型。首次提出了可考虑模态选择阀堵塞对发动机性能影响的模态选择阀堵塞模型，消除了由于模型不精确造成的模态转换参数波动。在建立的变循环发动机数学模型的基础上，提出了基于直接推力控制技术的模态转换控制规律设计方法，考虑了变循环发动机的8个可调参数，采用差分进化算法对模态转换过程进行了优化。结果表明，本文提出的模态转换控制规律设计方法可以实现变循环发动机快速平稳的模态转换，双外涵转单外涵的参数变化规律与单外涵转双外涵的参数变化规律基本类似，推力在0.6秒就稳定在目标推力值，其余参数大多在1.4秒之后才趋于稳定。本文提出的变循环发动机模态转换控制规律设计方法还可应用于常规航空发动机的加/减速过渡态控制规律设计中。

Mode Transition Modeling and Control Law Design Method of Variable Cycle Engine

In order to realize the rapid and reliable mode transition of variable cycle engine, the mode transition model and control law design method of variable cycle engine were developed. A high-precision model of airflow sudden expansion local loss for mode select valve and the bypass injector was added to the dynamic numerical simulation program of variable cycle engine. A model that can consider the effect of mode selection valve blocking on engine performance was proposed for the first time, eliminating the fluctuation of mode transition parameters caused by model inaccuracy. Using variable cycle engine mathematical model, a design method of mode transition control law based on direct thrust control technology was proposed. Considering the eight variable parameters of variable cycle engine, the differential evolution algorithm was used to optimize the mode transition process. The results show that the mode transition control law design method proposed in this paper can realize the fast and smooth mode transition of variable cycle engine. The variation law of parameters of double to single bypass mode is basically similar to that of single to double bypass mode. The thrust stabilizes at the target thrust value in 0.6 seconds, while most of the other parameters stabilize after 1.4 seconds. The mode transition control law design method proposed in this paper can also be applied to the design of acceleration and deceleration control law of conventional aero-engine.