Experimental Investigation of Applying the Novel Bean-Shaped Hole Geometry for the Film Cooling

Shape of the jet hole highly affects the film cooling effectiveness of the gas turbine blades, which must be designed in such a way that creates proper distribution of the coolant over the surface to remove the hot spots. The present study investigates the cooling performance of the novel Bean-shaped hole geometry design for the jet hole experimentally using an infrared thermography method. The tests are performed at the main flow Reynolds number of 10,000 (based on the hole equivalent diameter) over a test plate at injection angle of 30 degrees relative to the surface. The measurements were carried out at the mainstream speed of 27 m/s and four blowing ratios of, 0.4, 0.5, 0.7 and 0.8. The obtained results show that the geometry of the Bean-shaped holes lead to an increase in the film cooling effectiveness in comparison to the cylindrical holes. The highest cooling effectiveness is obtained at blowing ratio of 0.5 and the lowest effectiveness is obtained over the surface at blowing ratio of 0.4. In the case of Bean-shaped hole geometry, the full area averaged cooling effectiveness increases by 45.4% to 207.4%.