Interaction effects between the rotor wake and hub leakage flow in a multi-stage cantilevered compressor

Abstract

Abstract The cantilevered stator is a typical configuration for axial compressors. To gain insight into the effect of the hub leakage flow, unsteady simulations were performed in a multi-stage cantilevered compressor. The main goal is to gain a better understanding of the interaction between the upstream rotor wake and hub leakage flow, and the effect of the hub leakage flow on the downstream rotor performance. The results show that the upstream rotor wake affects the hub loading of the cantilevered stator periodically and thus changes the leakage flow characteristics, leading to an unsteady benefit in the vicinity of the hub. At the higher span region, the unsteady benefit depends on the reversible recovery and the wake-boundary layer interaction. The increased hub clearance not only causes performance degradation on the cantilevered stator but deteriorates the downstream rotor performance, especially for the absolute angle due to the mass flow redistribution. These results indicate great attention should be paid to the interaction between the upstream rotor wake and the hub leakage flow, and also the stage matching caused by the hub leakage flow in the design process of cantilevered compressors.