变循环发动机模态转换建模及控制规律设计方法研究

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 0.6s, while most of the other parameters stabilize after 1.4s. 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.