The Establish Of Post-surge Model And Stability Control Of Turbofan Engine

The compressor instabilities, such as rotating stall and surge, play a large role in safe work of gasturbine engines. With the development of technologies such as vectoring nozzle, the ability ofsuper-maneuvering flight is highly demanded. The engine will face harsh conditions of the inlet. Inorder to study the control of engine in serious inlet distortion, the thesis focuses on the instability ofengine and its stability control and carries out the study of turbofan engine with post-stall model,anactive stability control technology based on the correlation measure of pressure,and high stabilitycontrol of engine in super-maneuvering flight.First, a turbofan engine with post-stall model was established. Calculate every part of the enginealong the gaspath. The post-stall model considers the volume effectiveness, the characteristic ofpost-stall of the fan and compressor, the combustors with rich fuel and lean fuel characteristic. Theinlet included the model of total temperature distortion, total pressure distortion, and the combinationof two kinds of distortion.At last the Runge-Kutta method is used to achieve the final solution.Secondly, founded on the post-stall model，an active stability control technology is presentedbased on the correlation measure of pressure. Correlation measure threshold crossing events increasesin magnitude and number as the compressor approaches the limit of stable operation. So the stallmargin can be got and the active stability control mode is established. The active stability controlbased on the method of correlation measure successfully makes the engine operate in the safeenvelope.Thirdly, the thesis carries out the study of high stability control. It aims at the high stabilitycontrol of engine while the aircraft is taking super-maneuvering flight. The estimation of surge marginuses the prediction algorithm of Artificial Neural Networks (ANN). The method establishs the mapfrom measured parameters to stall margin, and then completes the high stability control. Study thehigh stability control included distortion prediction system and the stability management system. Atlast the full digital simulation and semi-physical simulation is carried out.