Study of Film Cooling on a Cascade Using Infrared Thermography

This paper studies the effect of two given free-stream turbulence intensities on film cooling at different blowing ratios on one cascade, made up of five blades. Experiments on the suction side were done at three different blowing ratios 0.5,1.0 and 1.5; those on the pressure side were done at four different blowing ratios, 0.5,0.75,1.5 and 1.75. The two given free stream turbulence intensities are 0.5% and 5% respectively. In these experiments, we adopted infrared thermography to capture the images of temperature distributions on blade surface. According to the experimental results, the turbulence acts on the effectiveness distributions differently on the pressure side and suction side due to the existence of blade curvature. Bigger turbulence intensity can worsen the cooling effect on both the suction side and the pressure side.