Measurement of heat transfer on turbine blade endwall with upstream wakes at different relative positions

The cooling system design based on heat transfer analysis of turbine hot components, such as vanes and blades, is necessary to protect hot components operated under high temperature conditions. Especially, in turbine blade endwall, various vortices such as horseshoe vortex, passage vortex, corner vortex, etc. are generated and complex flow characteristics appear. In addition, the wakes generated from vane trailing edge affect endwall periodically due to the rotation of blade. The complex heat transfer characteristics are exhibited on the endwall due to the effects of vortices and wakes, and accurate heat transfer measurement of endwall is required. Therefore, in this study, experiments were conducted to investigate the effect of wake on endwall heat transfer. The naphthalene sublimation method was used to measure the heat/mass transfer on endwall. This study measured and compared the heat/mass transfer distributions affected by wakes generated at different relative positions. The wake from the front of the blade leading edge had a low effect on the passage vortex, but the wake between the blade and the blade interrupted the passage vortex. As a result, high heat/mass transfer distribution caused by the passage vortex was broken and the heat/mass transfer was decreased due to the wake.