Film cooling on a convex wall: Heat transfer and hydrodynamic measurements for full and partial coverage

Discrete-hole injection is widely used for turbine-blade cooling in high-efficiency turbine engines. Detailed measurements of the spanwise-averaged heat transfer and the local hydrodynamics of a film-cooled flow on a convex wall, for both full and partial coverage are reported. Hydrodynamic boundary-layer profiles were measured with a triple hot-wire probe. Three mean-velocity components and six turbulence quantities were simultaneously measured; inside the blown region strong three-dimensionality was observed. The flow field seems divided into two types of lanes: those with injection holes and lanes without. The flow in lanes with holes was strongly affected by injection, but in the lane without holes only small effects were observed. A prediction program, STAN-FC-CRV (combining STANCOOL and STANCURV), was tested for four representative cases. Comparison of predictions with experimental data shows reasonable agreement, but further modification is necessary for the injection model.