Patent ID: 8092176

Claim:
A turbine airfoil, comprising: a generally elongated airfoil having a leading edge, a trailing edge and at least one cavity forming a cooling system in the airfoil; an outer wall forming the generally elongated airfoil and having at least one diffusion film cooling hole positioned in the outer wall and providing a cooling fluid pathway between the at least one cavity forming the cooling system and an environment outside of the airfoil; wherein the at least one diffusion film cooling hole includes a first sidewall having a first radius of curvature about an axis generally orthogonal to a centerline of cooling fluid flow through the at least one diffusion film cooling hole and a second sidewall having a second radius of curvature about an axis generally orthogonal to the centerline of cooling fluid flow through the at least one diffusion film cooling hole; and wherein the radii of curvature of the first and second sidewalls are different and wherein the radius of curvature of the first sidewall is less than the radius of curvature of the second sidewall, which is downstream from the first sidewall.