Aerodynamic behavior of a transonic axial flow compressor stage with self-recirculating casing treatment

Abstract

In this manuscript, a new discrete type of passive Self-Recirculating Casing Treatment (RCT) is designed for a transonic axial compressor stage, fabricated, and tested for its performance. Parametric evaluation of the casing flush-mounted RCT for injection skew angle is studied experimentally and numerically to achieve considerable stall margin improvements. Detailed flow investigations are carried out for the RCT configurations and baseline solid casing behavior at different flow conditions using steady and unsteady measurements. The unsteadiness in the flow and the rotating stall signatures are captured through Kulite pressure sensors. Results indicate improvements in the stall margin and other overall compressor performance parameters for the investigated speeds. Improvements of stall margin in axial compressor stage with self-recirculating casing treatment are found to be because of the RCT by investing the already worked high-pressure fluid is able to overcome losses associated with the tip leakage flow. There is a delay in the onset of rotating stall instability with casing treatment which plays a role in the enhanced performance improvements.