Experimental Study of a High-Throughflow Transonic Axial Compressor Stage

Design information and experimental results are presented for a transonic axial compressor stage passing 40 lbs/s-ft/sup 2/ frontal area (195 Kg/s-m/sup 2/) with a pressure ratio of 1.95 at 1500 ft/s (457 m/s) tip speed. The design incorporates several unusual features that helped it achieve a peak isentropic efficiency over 88 percent at design speed. The compressor was evaluated at three rotor tip clearances and an optimum was found. Vortex generators placed upstream on the casing proved relatively ineffective in influencing stall margin. Vortex generators installed on the rotor did improve stall margin and also increased efficiency at speeds of 90 percent and below.