Abstract
The present study aims to investigate the effect of an upstream wake on the convective transport phenomena over a turbine blade with shower-head film cooling. A naphthalene sublimation technique was implemented to obtain the detailed mass transfer distributions on both suction and pressure surfaces of the test blade. All mass transfer runs were conducted on a blowing-type wind tunnel with a six-blade linear cascade. The leading edge of the test blade was drilled with three rows of equally spaced injection holes. The upstream wake was simulated by a circular bar with the same diameter as that of the trailing edge of the test blade.The test condition was fixed at Re = 397,000, M = 0.8, and Tu = 0.4% and upstream wakes were generated at four different locations ahead of the blade cascade. Measured results show that there is a difference in mass transfer rate from the case without upstream wake. This difference is greater on the suction side than on the pressure side. The difference results from the interaction between the wake flow that is induced by the upstream wake and the injection flows that are ejected from the multi-rows of injection holes on the test blade. It was also found that the location of upstream wake generation significantly affects the mass transfer distributions on both surfaces of test blade.