Effects of blowing ratio on turbine vane suction side film cooling under different turbulence intensity conditions

The effects of blowing ratio on turbine vane film cooling under different mainstream turbulence intensity conditions were studied using the transient heat transfer measurement technique with narrow-band thermochromic liquid crystal in the whole region. The spatial distributions of film cooling effectiveness of cylindrical holes on the suction side of a turbine vane and surface heat transfer coefficient ratio in whole region were obtained. The results showed that the mixing effect and interaction intensity of film jets and mainstream changed with the mainstream turbulence intensity, so the effects of blowing ratio on the film cooling effectiveness and surface heat transfer coefficient ratio were different under different mainstream turbulence intensities. In experimental conditions, when the mainstream turbulence intensity was small, the film coverage and cooling effectiveness rapidly deteriorated with the increase of blowing ratio. However, the change of blowing ratio had relatively weaker effect under large mainstream turbulence intensity, especially in the far downstream region. Under the same mainstream turbulence intensity conditions, the increase of blowing ratio can enhance the surface heat transfer coefficient. However, the enhancement effect was relatively small under large mainstream turbulence intensity. Under the same blowing ratio, the surface heat transfer coefficient was relatively small when the turbulence intensity was high.