Patent ID: 7997866

Claim:
A gas turbine airfoil comprising: a pressure sidewall and a suction sidewall defining and extending from a root to a tip and from a leading edge region to a trailing edge; at least one cooling passage between the pressure sidewall and the suction sidewall configured and arranged to permit cooling air to pass through and cool the airfoil from within; wherein at least one of the at least one cooling passage extends along the leading edge of the airfoil; a plurality of film cooling holes extending from the at least one cooling passage along the leading edge region to the outer surface of the leading edge region, the plurality of film cooling holes each having a shape that is diffused in a radial outward direction of the leading edge of the airfoil at least over a part of the length of the film cooling hole; wherein the plurality of film cooling holes each comprise a principal axis and a shape that is asymmetrically diffused, said shape being diffused in the radial outward direction from the principal axis along a forward inclination axis, and additionally diffused in a second lateral direction from the principal axis along a lateral inclination axis; and wherein the shape is diffused cylindrically in the radial outward direction along the forward inclination axis and in the second lateral direction along a lateral inclination axis.