Nonlinear Distributed Modeling, Control, and Simulation of Rotating Stall and Surge in Transonic Compressors

Aerodynamic instabilities that will limit the operating range, performance, and reliability of gas turbine engines include rotating stall and surge. These aerodynamic instabilities occur in the compressor at low flow rates. Enabling technologies that have been used to demonstrate the stabilization of compression systems and operating range extension by means of active feedback control include the manipulation of compressor flow field with inlet guide vanes, bleed valves, and air injection. A potential application of the performance improvement associated with active feedback control is to reduce the weight of an aircraft engine. The number of compressor stages required to achieve the same overall pressure rise can be reduced by using active feedback control to extend the operating range of a compressor with steep speed-lines. And since the compressor makes up a large percent of the weight of an aircraft engine, reducing the number of compressor stages will reduce the engine weight thus increasing its thrust to weight ratio. This paper presents a full state nonlinear distributed model of rotating stall and surge with an air injection actuation system, a nonlinear controller design, and a closed loop simulation architecture that can be used for evaluating different control algorithms. The full state nonlinear distributed model was validated with stall inception data from a transonic compressor, and a sliding mode nonlinear controller was designed using the validated nonlinear distributed model. The closed loop simulation setup was then used to compare the performance of existing baseline linear controllers with the nonlinear controller model presented in this paper. The simulation results showed that more operation range extension can be obtained with robustness to compressor disturbances by using single-sided sliding mode control law.