Experimental Study on the Film Cooling Performance of Odd-Shaped Film Holes with Large Inclination Angle under High Turbulence Intensity

In order to obtain the film cooling characteristics of odd-shaped film holes with large inclination angle under high mainstream turbulence intensity, three film hole configurations with an inclination angle of 60°, including cylindrical hole, water-drop hole and curved dustpan hole, were studied under the mainstream turbulence intensity of 11.82% using transient liquid crystal measurement technique. At a blowing ratio of 0.5, the film attachment behavior on the wall is good for all the three hole configurations, and the film cooling efficiency in upstream region is higher than that in downstream region. At a blowing ratio of 1.0, the film jets lift off from the wall for the cylindrical hole and water-drop hole, resulting in lower film cooling efficiency in upstream region. With further increase of blowing ratio, the film jets of the curved dustpan hole also lift off from the wall. The increase of blowing ratio will obviously enhance the heat transfer intensity for all the three hole configurations. The heat transfer coefficient ratio of the cylindrical hole and water-drop hole decreases gradually along the streamwise direction. And the heat transfer coefficient ratio of the curved dustpan hole is lower than that of the cylindrical hole and water-drop hole under all blowing ratios, and has an undulation feature at large blowing ratios. The above results indicate that the film cooling performance of the curved dustpan hole is better than that of the cylindrical hole and water-drop hole under all blowing ratios, but the film cooling performance of the cylindrical hole and water-drop hole with large inclination angles is close to each other.