Improvements of performance and stability of a single-stage transonic axial compressor using a combined flow control approach

Abstract

The performance and the stability of axial compressors are seriously concerned as it's widely used in aero-engines and power machines. A new combined flow control approach was developed previously using blade slot and vortex generator, which was used to reduce flow loss and improve flow stability. The approach was experimentally proved to be very effective in linear compressor cascades. To further evaluate its availability in actual compressors, the new approach is implemented in a single-stage transonic compressor, which introduces a part-span slot into the rotor while a full-span slot and a vortex generator into the stator. CFD simulations are performed to evaluate the gains of compressor performance, and flow structures are analyzed to explain the corresponding mechanisms. Results show great improvements of performance and stability of the compressor. The averaged total pressure ratio and isentropic efficiency improve by 1.82% and 0.88% respectively due to the great reduction of separations in both the rotor and the stator. Because the compressor instability is initiated by the stator corner stall, the delay of the corner separations leads to a great increase of the stable mass-flow range by 26.1%. The compressor flow structures are also well improved because the detrimental backflows and large-scale vortices are mostly removed by the combined approach.