Experimental Investigations of a Comb-Like Film Cooling Scheme

The performance of a simple slot is perfect, but it does not have structural integrity. A new advanced cooling scheme with perfect performance and practical structural integrity is presented. Based on the crucial effect of the counter-rotating vortex pair (CRVP) on the film cooling effectiveness (η), the new scheme is composed of a comb-like structure and a blind slot, in which the comb structure maintains the mechanical strength, and the blind slot is intended to eliminate the CRVP and produce a smooth coolant film. The new scheme is investigated experimentally with the transient thermochromic liquid crystal (TLC) technique. Two classic geometries, the cylindrical hole and the simple slot, were also measured. The agreement of their results with the published data validated the present experimental facilities. The experimental results of the Comb scheme demonstrated that, with practical structural integrity, the new scheme has perfect performance, which bears comparison with the simple slot. Consequently, the success of the Comb scheme proved the crucial CRVP effect on η.