A Numerical Research on Diverse Cratered Film Cooling Hole Geometries

The goal of this research is to investigate cratered hole geometries on film cooling performance. Five kinds of cratered holes, namely, the concentric crater, the circular crater, the downstream offset crater, the upstream offset crater, and the direct crater are being studied along with the conventional flush hole. All craters has the same depth of 0.5 hole diameter. Through numerical simulation with CFX at a single blowing ratio of 0.5 and Reynold number of 11000, we analyze and compare the performance and behavior of five kinds of cratered holes with the conventional cylindrical hole. The simulation employs k-ε turbulent model and wall function. Film cooling effectiveness is achieved for all cases. Among all cases, concentric cratered hole perform the best which increases averaged film cooling effectiveness by 64% at X/D=5.35. All cratered holes appear some performance improvement compared to the baseline case. For cratered holes, film lateral convergence and stream-wise attaching performance was both enhanced owing to the expansional configuration of the crater and the consequent backflow region.