Experimental investigation on heat transfer characteristics of film cooling using parallel-inlet holes

Experimental investigations on the film cooling characteristics of parallel-inlet film holes are carried out. There are four kinds of film hole arrangements: one-row, two-row(staggered arrangement), two-row(aligned arrangement) and three-row arrangement. Experimental results show that film hole arrangement and blowing ratios have great effects on film cooling effectiveness and heat transfer coefficient(HTC). Film cooling effectiveness is increased with the increase of blowing ratios, but the HTC is decreased with the increment of blowing ratio. The film cooling effectiveness of single-row film hole(d = 7 mm) is the best of all test pieces. As for staggered arrangement design, its HTC is larger than that of aligned arrangement at the same position. In addition, the HTC is increased with the decrement diameter of film hole for all kinds of film hole arrangement patterns. For film cooling, a smaller HTC means a better film cooling effectiveness.

► Cooling characteristics of parallel-inlet film holes are experimentally investigated.
► Film cooling effectiveness increased with an increase of the blowing ratios.
► Heat transfer coefficient of film cooling is greatly affected by hole geometry.
► HTC of staggered arrangement design is larger than that aligned arrangement.