EXPERIMENTAL INVESTIGATION OF INLET STAGNATION PRESSURE DISTORTION EFFECTS ON A TRANSONIC AXIAL COMPRESSOR ROTOR

This work shows the results of an experimental investigation of a transonic axial compressor subjected to a 120 degrees circumferential inlet distortion. The goal of the investigation was to determine the rotor performance when exposed to a circumferentially non-uniform inlet stagnation pressure. The upstream grid was rotated with respect to the fixed instrumentation to provide high resolution information around the annulus. The resulting rotor performance characteristics are shown for 70% and 100% corrected speeds. The results showed that the distorted and undistorted rotor performance differed significantly from the uniform inlet rotor performance. The undistorted compressor performance saw higher maximum inlet Mach numbers than the corresponding uniform characteristic. The distorted compressor performance had stable operating conditions at lower inlet Mach numbers and higher stagnation pressure ratios than the uniform characteristic. The rotor performance orbits were hypothesized to be related to the pre-swirl and counter-swirl created by the inlet circumferential static pressure gradient.