Airfoil row wake interactions in a high speed axial compressor

Abstract

Experiments are performed to study and quantify the time-varying characteristics of inlet guide vane (IGV) wakes interacting with the exit flowfield of a downstream high-speed rotor. Data define the IGV wake pressure and velocity fields across two vane passages and time resolved over one rotor blade passing period. Results show that the interaction of the rotor wake with the IGV wake has a significant effect on both the IGV and rotor wakes. When the rotor wakes are in phase with the IGV wakes, the IGV wake velocity deficit, semiwake width, and total pressure losses increase. The maximum and minimum velocity and total pressure envelopes over one rotor blade passing period decrease with distance from the rotor due to the decay of the rotor wake. More importantly, the differences between the velocity and total pressure maximum and minimum are smaller in the IGV wake regions; therefore, the rotor wakes have reduced fluctuations. The position of the IGV wake centerline moves under the influence of the rotor cutting action and exit flowfield. The IGV vortical and potential harmonic gust forcing functions downstream of the rotor are determined by a vortical/potential gust splitting analysis. The first harmonic vortical and potential gust magnitudes have two maximums over one rotor blade passing period that occur before and after the IGV and rotor wakes are in phase. Also, the higher harmonics of the temporally averaged instantaneous vortical and potential gusts decay at a very slow rate as they propagate.