Effect of steady-state pressure distortion on inlet flow to a high-bypass-ratio turbofan engine

Abstract : Experiments were conducted to determine the effects of steady-state circumferential-pressure distortion on inlet flow and internal engine performance of a high-bypass-ratio turbofan engine. To measure these effects, flow-angle, static-pressure, and total-pressure instrumentation was placed between the rotatable distortion-generator assembly and the engine inlet. In addition, both static-pressure and total-pressure were recorded at the fan exit and compressor inlet and exit. Three circumferential screens were separately mounted on the rotatable assembly. For all configurations data were recorded at each of twelve 30 deg increments of assembly rotation. Experiments were conducted with fan speeds (corrected to station 2 temperature) of 80 or 90 percent of rated condition (7005 rpm) and Reynolds number indices of 0.2 or 0.5. Yaw angle increased between the distortion-generating assembly and the engine inlet. A change in Reynolds number index (RNI) has only a slight effect and a change in speed had no effect on yaw angle distribution. The flow angle was largest in the hub region of the engine inlet.