Experimental Investigation of Aerodynamic Performance of a Turbine Cascade with Trailing-Edge Injection

Abstract

Trailing-edge mixing flows associated with coolant injection are complex and result in significant aerodynamics losses. A series of tests on a high-pressure turbine vane cascade with trailing-edge injection were conducted to study the effects of trailing-edge injection on the loss characteristics of the turbine profile. Wake traverses with a five-hole probe and tests of the static pressure distributions on the turbine profile were carried out for test Mach numbers of 0.7, 0.78, and 0.84 and injection mass-flow ratios of 0, 2, 3.6, and 5.5%. Wake total pressure losses and flow angles as well as pressure distributions on the turbine profile were compared with tests without trailing-edge injection, indicating a significant influence of trailing-edge injection on the profile wake development and its blockage effect on the vane passage flow. As the test Mach number increases, there are few variations in the flow angle downstream of the cascade without trailing-edge injection, but its circumferential unevenness is enhanced. Trailing-edge injection of 2% increases the static pressure value in the rear part of the vane suction side, and then reduces the vane loading, but causes increased wake losses at different test Mach numbers. However, the aerodynamic losses start to be reduced as the injection mass-flow ratio increases to 3.6%.