Effect of endwall vortex generator jets on flow separation control in a linear compressor cascade

Abstract

As a 50° camber angle compressor cascade being the object, the numerical investigations of the endwall vortex generator jets effect on flow separation control were conducted. The results show that the flow separation is significantly weakened and the maximum total pressure loss reduction is 9.5% at Mach number 0.23. When the cascade inlet Mach number is 0.71, more benefit is obtained and the total pressure loss is reduced by up to 14.8%. A primary streamwise vortex is produced by the interaction of endwall jet with the coming flow. This vortex could restrain the transverse movement of the endwall secondary flow and entrain high energy fluid of the mainstream to the corner region. Both of the aspects are of benefits for the flow momentum increasing in the corner region. Thus, the flow separation is suppressed efficiently. The location and intensity of the streamwise vortex are important to the performance of vortex generator jet. For the object investigated in this paper, the proper jet location is around 10% axial chord length before the cascade and meanwhile close to the suction surface. To avoid strong mixing losses, the intensity of the streamwise vortex is suggested be moderate.