Experiment on effects of mainstream turbulence intensity on film cooling characteristics of turbine vane

The effect rules of mainstream turbulence intensity on film cooling characteristics of cylindrical holes on the suction side of turbine vane were studied using the transient heat transfer measurement technique with narrow-band thermochromic liquid crystal in the whole region. The results show that the mainstream turbulence intensity increase from 0.59% to 6.85% in experimental conditions can make film sticking the wall and expand the lateral coverage area in the upstream region to improve the film coverage performance. But when the mainstream turbulence intensity is very large, the film cooling performance will rapidly deteriorate. In the downstream region of film injection, film cooling efficiency decreases gradually with the mainstream turbulence intensity increasing. Heat transfer on the smooth vane surface without film cooling can be enhanced by increasing the mainstream turbulence intensity. Under the conditions with film cooling, the effects of the heat transfer enhancement of vane surface caused by the film injection have distinctive regional characteristics with the mainstream turbulence intensity increasing. The heat transfer coefficient ratio firstly increases and then decreases in the upstream region, gradually decreases in the midstream region, and slightly increases in the downstream region.