ROTATING STALL CONTROL OF AN AXIAL-FLOW COMPRESSOR USING PULSED AIR INJECTION

This paper presents the use of pulsed air injection to control rotatin g stall in a low-speed, axial flow compressor. In the first part of th e paper the injection of air is modeled as an unsteady shift of the co mpressor characteristic, and incorporated into a low dimensional model of the compressor. By observing the change in the bifurcation behavio r of this model subject to nonlinear feedback, the viability of variou s air injection orientations is established. An orientation consistent with this analysis is then used for feedback control. By measuring th e unsteady pressures near the rotor face, a control algorithm determin es the magnitude and phase of the first mode of rotating stall and con trols the injection of air in the front of the rotor face. Experimenta l results show that this technique eliminates the hysteresis loop norm ally associated with rotating stall. A parametric study is used to det ermine the optimal control parameters for suppression of stall. The re sulting control strategy is also shown to suppress surge when a plenum is present. Using a high-fidelity model, the main features of the exp erimental results are duplicated via simulations.