Patent attributes
A film cooling hole for an air cooled turbine airfoil, the film cooling hole including an inlet metering section and a diffusion section that opens onto a surface of the airfoil and has a bean shaped cross section. The diffusion section has a 10×10×10 expansion on the side walls and the downstream wall, and the sides are smoothly and continuously contoured to be without sharp corners. The bottom wall includes a convex middle portion and two concave outer end portions that have the same radius of curvatures. The shape of the film cooling hole allows for the hole to be formed from a laser beam cutting process instead of the EDM electrode process. Because of the larger zones formed in the sides, vortex flow formation under the film stream is minimized to produce a more effective film with lower shear mixing of the hot gas vortices with the cooling air.
