Patent ID: 8328517

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 section extending from an inner surface of the outer wall into the outer wall, a second section extending the first section and terminating before an outer surface of the outer wall, and a third section extending from the second section and at the outer surface of the outer wall; wherein at least one surface defining the second section extends outwardly from an intersection of the first and second sections towards the third section such that the at least one surface is angled way from a longitudinal axis of the at least one diffusion film cooling hole thereby increasing a size of a cross-sectional area of the second section; where at least one surface defining the third section extends outwardly from an intersection of the second and third sections towards the outer surface of the outer wall such that the at least one surface is angled way from the longitudinal axis more than the at least one surface forming the second section thereby increasing a size of a cross-sectional area of the third section; wherein the second and third sections are conical; and wherein the first, second and third sections are concentric with each section sharing the same longitudinal axis.