Influences of position of hole-rows on film cooling on leading edge of turbine blade

Film cooling effectiveness of hole-rows on leading edge of turbine blade has been studied experimentally. The model is a blunt body with a half-cylinder leading edge with two flat side-walls. Six rows of round holes are located at ±15°, ±40° and ±60° from stagnation on the half-cylinder leading edge. The holes in each row are spaced three hole-diameters apart and are angled 30° and 90° to the surface in the spanwise and streamwise directions respectively. The length of hole is four hole-diameter. The focus of this paper is the influences of holes-row position on film cooling effectiveness on leading edge of turbine blade. Measurement is carried out for mainstream Reynolds number (based on leading edge diameter) from 42000 to 127000 and blowing ratio (average secondary-to mainstream mass flux ratio) from 0.5 to 2.0. The results show that the better positions of single holes-row ordinarily are 60°, 40° and 15° and that the better positions of double holes-row are (40°, 60°). The results also show that there is no difference in using single or double or three film cooling holes-row with larger secondary flow flux, and that the better film cooling effect with smaller secondary flow flux can be taken in using three film cooling holes-row.