Investigation on film cooling heat transfer for double row dust-pan shaped holes

Film cooling heat transfer for injection from single row and double row dust-pan shaped holes has been investigated experimentally. Distributions of heat transfer coefficients at downstream holes were measured. The effects on average heat transfer coefficient ratio by distribution of heat transfer coefficients, blowing ratio, Reynolds number of jet flow and distance between rows were analyzed. The Reynolds numbers of jet flow were between 5000 and 15000, the blowing ratios from 0.5 to 2.0, and the distances between rows were 5D, 10D and 15D. The results indicate that the heat transfer downstream the double row film cooling holes is enhanced and the distributions are more uniform as compared with the case of the flow injection from single row holes. The heat transfer coefficient ratio increases firstly and then decreases with the increase of blowing ratio; the lowest value is at the blowing ratio of 1.0. The heat transfer enhancement increases and then decreases with the increase of the distance between rows, and is highest when the distance between rows is 10D.