NUMERICAL INVESTIGATION OF STATOR SHROUD LEAKAGE EFFECTS IN A 1.5-STAGE LOW-SPEED AXIAL COMPRESSOR

Gaps and leakage mass flows are always occurring between steady and rotating parts in turbomachines. Losses occur due to entropy generation in mixing processes of lowmomentum leakage flows and the main flow. These loss-inducing mixing processes are responsible for a significant amount of compressor performance degradation. This paper describes the numerical investigation of shroud leakage effects in a 1.5-stage low-speed compressor using tandem stator vanes. The aim is to investigate the influence of the leakage mass flow on loss generation in tandem stator rows. The focus is on the relation of leakage mass flow, efficiency degradation, and operating range. An analysis of the flow field within the cavity is conducted. Moreover, emphasis is put on the interaction of the leakage flow with the development of three-dimensional blockage in the tandem endwall region.