Patent ID: 7374401

Claim:
A turbine airfoil having an external surface defining a curvature, comprising: (a) a leading edge and an axially spaced-apart trailing edge, the leading edge having an axially-extending aerodynamic external surface curvature; (b) a root and a tip spaced-apart along a radially-extending span axis; (c) a pressure sidewall and a laterally-spaced-apart suction sidewall; (d) a cooling circuit positioned between the pressure sidewall and the suction sidewall for channeling a fluid flow for cooling the airfoil; (e) a plurality of cooling holes formed in the external surface of the airfoil in fluid communication with the cooling circuit, at least some of the plurality of cooling holes comprising: (i) a metering section downstream of the cooling circuit; (ii) a diffuser section downstream of the metering section and upstream of the external surface of the airfoil, the diffuser section having at least a bottom wall and opposed side walls defining an exit opening on the external surface for exiting a cooling film, the bottom wall having a downstream diverging, non-planar surface extending between the opposed side walls that defines a convex curvature in the direction of the span axis at the exit opening.