A numerical study of the effects of injection velocity on stability improvement in high-speed compressors

Abstract

The current paper presents numerical simulations for a high-speed axial-flow compressor rotor, NASA Rotor-67, with continuous air injection upstream of the rotor. A parametric study relating injection velocity to compressor stability is undertaken. The effects of injector exit velocity on blade loading and flow field are investigated and discussed. Results indicate that the injection velocity has major effects on compressor stability. The injector effectiveness is found to be maximized when the injector exit Mach number is equivalent to unity. Significant range extension in terms of reduction in stalling flow coefficient equivalent to 13.23 per cent is obtained for the case of choked injector, whereas the injection mass flow is only a small percentage of the main flowrate.