Influence of cooling-air injection from leading edge on the aerodynamic performance of rectangular turbine cascade with large turning angle

Measurements of flow passage inside a rectangular turbine cascade with large turning angle while cooling-air injection upstream from three different rows at leading edge were performed. Experimental results show that the static pressure distributions are changed due to the coolant air. The cooling-air injections form different rows have different effects on the passage vortex and end-wall boundary layer; the amount of loss increase differs from each other in three cases due to the different mechanism of loss increase.