Effect of endwall passage vortex generator on corner stall of a tandem compressor cascade

Abstract

The control mechanism of endwall passage vortex generator (EVG) on corner stall was investigated in a highly-loaded tandem cascade. Results show that utilizing EVG can reduce corner stall efficiently. The optimal EVG scheme in this study was located at 8% axial chord and 3.7 mm (14% of tandem cascade pitch) away from suction surface, which achieved a maximum loss coefficient reduction of 33.7%. The control mechanism was that the high-circulation fluid of the EVG induced vortex (EVGV) helped the corner stall fluid to move toward another direction, thus escaping from the streamwise adverse pressure gradient. As the location of the EVG moved downstream, the control effectiveness on corner stall was enhanced due to the fact that the flow separation at downstream of the EVG was reduced with the decrease of intersection angle between the flow and the EVG. As the location of the EVG moved toward pressure surface, the loss coefficient showed a tendency of first increasing and then decreasing; the increasing loss coefficient of P2S1 scheme was caused by the weaker contracted flow in the front blade passage and the enlarged corner separation in the rear blade passage; the corner stall could be effectively reduced with the EVG even it was far from the suction surface, which was due to the contracted flow passage between the EVG and the suction surface. The control effectiveness of the EVG was also numerically investigated, which showed that the EVG reduced the corner stall and loss coefficient in a wide range of incidence angle.