Research on the Hole Length Ratio of Fan-Shaped Holes in Flat Plate Film Cooling

Abstract

To study the influence of different hole length ratios on the flow structure and film cooling efficiency, a calculation model of fan-shaped hole was constructed and numerically studied. The effect of different hole length ratios on the cooling efficiency under different blowing ratios was compared and analyzed. The results showed that as the blowing ratio increases, the overall average efficiency of most of the hole length ratio cases first increases and then decreases. Only in the case with a cylindrical part length/total length ratio of 0.5 did the efficiency continue to increase. When the blowing ratio is small, the spanwise average efficiency of each hole length ratio case is closer, but the flow structure and efficiency distribution are quite different. For the medium blowing ratio, the overall average efficiency of the small hole length ratio case is higher, and the efficiency decreases as the hole length ratio increases. When the cylindrical part length/total length ratio is further increased to 1, the cooling efficiency region basically converges into a spanwise narrow region. For larger blowing ratio conditions, after 10D after the hole outlet, the case with a cylindrical part length/total length of 0.5 is more efficient.

Film-cooling hole optimization and experimental validation considering the lateral pressure gradient

“…It is usually difficult to study the film cooling performance considering the real flow environment due to its high complexity. Therefore, most studies only consider a single influencing factor on the cooling performance from the real environment, as shown in Zhou et al (2018), Chen et al (2019), and Zhou et al (2021). Among various turbine structures, the endwall of turbine blades suffers from high thermal load, and the flow environment is extremely complex (as depicted in Wang et al (1997)), making the analysis of cooling performance more challenging.…”