An experimental investigation of film cooling performance of louver scheme

An experimental investigation of the film cooling performance of louver schemes using Thermochromic Liquid Crystal technique is presented in this paper. The louver scheme allows the cooling flow to pass through a bend and encroach with the blade material (impingement effect), then exit to the outer surface of the aerofoil through the film cooling hole. The cooling performance of the louver scheme was analyzed for blowing ratios ranging from 0.5 to 1.5 and for a density ratio of 0.94. The results showed that the louver scheme enhances the local and the average film cooling effectiveness, and the net heat flux reduction better than other published film hole configurations. The louver scheme also provides a wide extensive spread of the secondary flow over the outer surface, thus enhancing the lateral film cooling performance over the downstream surface area. Moreover, the louver scheme produces a lower heat transfer ratio than other film hole geometries at low and high blowing ratios. As a result, the louver scheme is expected to reduce the gas turbine airfoil’s outer surface temperature by provide superior cooling performance than other film cooling schemes hence increasing the airfoil life time.