Research on Dual-Loop Redundancy Control Method on Turbofan Engines

Comparing to traditional turbofan engines, new configuration engines with variable area fan nozzle (VAFN) have an additional control variable, making it a redundancy control. This paper studies the influence of the VAFN area, which is a redundant control variable, on the performance of the fan and the engine. Specifically, a controller including two variable control loops is designed for redundantly-controlled engines. An activation logic is designed for the redundant variable control loop, so that the redundant loop can be switched into control when necessary to improve the performance of the fan and the engine. After meeting the control goal, the control is deactivated and switched off, saving power consumption in the control process. Perform the same acceleration process on the same engine. The simulation show that, comparing to traditional single-variable control, Redundant control can significantly improve the performance of the fan and the engine, in which the fan efficiency is about 10% higher, the reserved surge margin is 15% lower, and the distribution of circle work between core and bypass duct is more reasonable. The fuel consumption of the engine is reduced by 3.7%, and the thrust and specific thrust are respectively higher by about 10% and 20%.