Investigation of film cooling effectiveness for double fan-shaped holes

This paper presents detail measurements of film cooling effectiveness in a flat plan for a row double fan-shaped holes. The streamwise angle of hole was 45° and the diameter of hole was d. The pitch-to-diameter ratio (p′/d) contained 2, 3 and 4. The momentum flux ratios varied from 1 to 4 and the turbulence level contained 0.4% and 8%. The result indicated that the double fan-shaped holes made significant improvement of film cooling effectiveness compared with the round holes. The variety of the p/d had great effects on film cooling effectiveness. Increasing the momentum flux ratio lead to large improvement of film cooling effectiveness at the p/d=2, while the momentum flux ratio had small effects on it at the p/d=4. The enhancement of turbulence level lead to obvious decrease in film cooling effectiveness when p/d is large and the momentum ratio is high.