Effect of vane/blade relative position on heat transfer characteristics in a stationary turbine blade: Part 2. Blade surface

This study was carried out to investigate local heat/mass transfer characteristics on the stationary blade near-tip surface for various relative positions of the blade. A low speed wind tunnel with a stationary annular turbine cascade was used. The test section has a single turbine stage composed of sixteen guide plates and sixteen blades. The chord length of the blade is 150 mm and the mean tip clearance of the blade is 2.5% of the blade chord. Detailed mass transfer measurements were conducted for the stationary blade fixed at six different relative blade positions in a single pitch using a naphthalene sublimation method. The Reynolds number based on the blade inlet velocity and the chord length ranges between 1.0×105 and 2.3×105 and mean turbulence intensity is about 3%. The change in blade position, which causes a different interaction between vane and blade, changes the incoming flow condition. As a result, significantly different patterns are observed on the blade surface, especially near the blade tip due to the variation in tip leakage flow.