Vortex Effects Resulting From Transverse Injection in Turbine Cascades, and Attempts at Their Reduction

A preliminary experimental investigation has been made of the effects of vortices in the approach stream on turbine blade row performance. The vortex regime has been simulated by stationary vortex generators. The net pressure losses within the following blade row were reduced by 23 and 12 percent when the vortex generators were placed in line, respectively, with the mid-passages and with the leading edges. Further, the discrete inlet vortices had virtually disappeared at the exit plane. In addition, methods have been tested for reducing the exit vortex, particularly when enhanced by transverse injection. The most effective scheme examined was a fence location on the suction surface near the endwall. However, there is a pressure loss penalty.