STALL INCEPTION IN SINGLE-STAGE, TRANSONIC COMPRESSORS WITH STRAIGHT AND SWEPT LEADING EDGES

Two single-stage, transonic compressor designs were tested for the presence of modal wave development in the process leading up to aerodynamic stall. The two rotors had similar design points (speed, pressure ratio, mass flow) and were tested in the same rig under the same operating conditions. The stalling process of both transonic rotors was associated with the growth of small amplitude rotating waves (modal waves) for all speeds tested. Prestall time of emergence of the waves is believed to be correlated with the shape of the stage characteristic (speed line). In cases where the speed line slopes of the two rotors were virtually identical, the swept rotor (R6) exhibited more stall warning time than the unswept design, suggesting that reduced shock strength due to backsweep may favor advanced detection of the modal waves. © 1995 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.