Patent ID: 7246992

Claim:
A turbine airfoil having an external surface defining a curvature, comprising: (a) a leading edge and an axially spaced-part 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 and disposed in fluid communication with the cooling circuit, each of the plurality of cooling holes having a diffuser section communicating with the external surface, and having opposed walls defining a generally quadralinear exit opening on the external surface, the diffuser section being angled upwardly about 15 degrees relative to the radial axis of the airfoil for discharging the cooling airflow radially upwardly towards the tip of the airfoil; and (f) at least one of the diffuserwalls having a convex curvature that approximately matches the external surface curvature of the airfoil local to the cooling hole whereby fluid flow from the fan hole exit Is evenly dispersed and spread along land portions of the external surface of the airfoil adjacent to the cooling holes.