Heat transfer characteristic of a fully cooled turbine vane

Abstract

To evaluate the heat transfer performance of a fully cooled turbine vane, an experiment was conducted in the low-speed wind tunnel using transient liquid crystal technology. The test vane was fabricated with 18 rows of cylindrical holes, which were supplied by two plenums. In these experiments, three mass flow ratios of 5.5%, 8.4%, and 12.5%, three turbulence intensities of 2%, 9%, and 15%, three Reynolds numbers of 300000, 400000, and 500000, two density ratios of 1.0 and 1.5 were tested. The results show that the heat transfer coefficient in the leading edge is much higher than the pressure and suction side due to the direct impact of the mainstream and the severe mainstream and injection mixing. The increased mass flow ratio significantly increases the heat transfer coefficient over the entire vane surface by 3.6%–71.3%, and the elevated turbulence intensity enhances the heat transfer coefficient by 5%–45% on the suction side and the rear half of the pressure side. The higher Reynolds number causes the thinner boundary layer and the higher velocity near the wall, which results in the Nusselt number increases by 52% in the case of increasing the Reynolds number from 300000 to 500000. Additionally, the heavier coolant leads to a slightly reduced heat transfer coefficient because of the lower injection penetration.