This paper presents experimental demonstration of surge stabilization in an axial compressor rig with a feedback linearizing controller. The controller design approach is model-based, and hence a nonlinear surge model for the facility is first validated. The surge model is a modification of the classic one-dimensional incompressible fluid surge model, with an effective length function incorporated, to account for the increased path-length of the fluid in the compressor due to the imparted tangential forces of the blade. This model, which adequately describes the observed surge dynamics both in terms of amplitude and frequency of oscillation, is then used to develop the feedback control law. The feedback linearizing control input implicitly linearizes the dynamics between the system input, throttle area parameter, and the system output, inlet dynamic pressure. A linear state feedback control input, implemented on the feedback linearized system thus ensures stabilization of the surge dynamics in the original nonlinear model. Finally, the nonlinear based observer is included in closed loop implementation to enhance the tracking of the system output, and also to minimize the adverse effect of measurement noise, thereby improving closed loop system performance.

This content is only available via PDF.