Experimental investigation of leading edge film cooling heat transfer with a row of film cooling holes

Heat transfer coefficient on leading edge with one row of holes was a studied experimentally. The model was a blunt body with a half cylinder leading edge and two flat plates. One row of holes was located at 2 hole diameter away from the stagnation line. Foreign gas injection was used to obtain a density of approximately 1.5. High turbulence intensity was produced by a passive grid. Momentum ratios were varied from 0.5 to 4 for both air and CO₂ injections. The results indicate that heat transfer coefficients increase with increasing momentum flux ratio. High turbulence has pronounced influence on the heat transfer without secondary injection, but this effect is very weak with secondary injection. Various density ratios have little influence on heat transfer. In the case of high turbulence, heat transfer coefficients decreases along the flow direction and in the case of low turbulence and peak enhanced factor occurs at the x/d=4.5.