EXPERIMENTAL AND NUMERICAL INVESTIGATION OF A SHOWER HEAD ADVANCED JET IMPINGEMENT ON CONCAVE SURFACES

A novel configuration of jet impingement cooling for leading edge of a gas turbine blade is proposed in this paper. The new configuration is obtained by rearranging the jet impingement holes in a shower head fashion with a combination of circular and elliptic holes. The entire configuration is simulated by a jet impingement pipe (JIP) to experimentally investigate the improved performance of cooling of concave target surfaces. The central JIP has circular ends, remaining four neighboring JIP have 45 degrees chamfer at one of its ends facing target surface to ensure uniformity and extension in cooling coverage. The heat transfer characteristics of jet impingement were investigated both experimentally and numerically by varying jet Reynolds number and gap ratio. Simulations are also carried out for different curvature ratios to determine the relative surface curvature effect on jet impingement heat transfer. This is accomplished by varying diameter of concave surface. The augmentation in heat transfer by both the elliptic (chamfered JIP) and circular (whose all JIP ends are circular) shower head arrangements are compared.