Numerical and Experimental Investigations of Flow Control in Axial Compressors

T he increase of the thrust-to-weight ratio of modern gas-turbine engines results in higher loads and a reduced number of blades and stages for the compressor. The designer must ensure the acceptable performance of each compressor stage (efficiency and stable operating range) and control the rising risk of blade boundary layer separation. This can be obtained using passive or active control devices which act on the behavior of the tip leakage flows or the endwall corner stall when the operating point gets closer to the stall or surge limit (compressor). This study focuses on casing treatments, with axisymmetrical and non-axisymmetrical slots, on injection or recirculating grooves, which are efficient approaches to extend the stable operating range, especially by increasing the stall margin of a compressor system while the efficiency penalty must remain as small as possible. The hub corner stall is controlled by aspirated compressor and vortex generators.