Experimental investigation on the overall cooling effectiveness of t-type impinging-film cooling

This paper presents an experimental investigation of impinging-film cooling concerning the effects of various factors on overall cooling effectiveness eta. The factors include blowing ratio M (0.31 <= M <= 1.84), non-dimensional jet-to-plate pitch Zn/d (1 <= Zn/d <= 2), non-dimensional spacing of jet holes Yn/d (1.6 <= Yn/d <= 2.4) and diameter of jet hole. The results show that overall cooling effectiveness invariably increases with a raise in blowing ratio. As non-dimensional jet-to-plate pitch increases, the cooling performs better. The decline of non-dimensional spacing of jet holes improves the overall cooling effectiveness at higher blowing ratios (M >= 0.91), which was not observed in cases with low blowing ratios (M <= 0.61). The variation of hole diameter (1.0-1.8 mm) has little influence on cooling performance. (c) 2017 Elsevier Ltd. All rights reserved.