Film Cooling Effectiveness for Injection from Multirow Holes

Experimental results are presented for film cooling effectiveness with injection from both a single row and multiple rows of holes with spanwise hole-to-hole spacings of three hole diameters. In the multi-row cases, the injection holes were arranged in staggered patterns with streamwise row-to-row spacings of five or ten hole diameters. Adiabatic wall temperature distributions near and downstream of injection holes were well visualized using a scanning infrared camera. The effect of mainstream pressure gradient was partially included. The additive nature of multi-row film cooling was demonstrated experimentally, in agreement with the Sellers superposition model.