CPC F01D 25/12 (2013.01) [F01D 5/186 (2013.01); F01D 9/041 (2013.01); B33Y 80/00 (2014.12); F05D 2240/81 (2013.01); F05D 2260/202 (2013.01)] | 20 Claims |
1. A nozzle segment for a gas turbine, the nozzle segment comprising: an inner platform and an outer platform;
a plurality of airfoils arranged between the inner platform and the outer platform; wherein the inner platform, the outer platform and the plurality of airfoils are manufactured by additive manufacturing; wherein each airfoil comprises a leading edge, a trailing edge, a pressure side and a suction side; wherein a hot gas flow passage is formed between the inner platform, the outer platform and each pair of sequentially arranged airfoils of said plurality of airfoils;
a set of platform film cooling holes, including at least one platform film cooling hole on a surface of the inner platform or on the surface of the outer platform, facing said hot gas flow passage;
wherein the cooling holes are shaped cooling holes having a non-circular and non-elliptical diverging shape,
wherein a ratio between a distance in tangential direction of the platform film cooling hole from the pressure side of the respective airfoil and a width of the hot gas flow passage in tangential direction at the platform film cooling hole is comprised between 0 and 0.5,
wherein a stagger complementary angle of each said airfoil is equal to or less than 85°, and
wherein a ratio between a vane passage width and an axial chord of each said hot gas flow passage is comprised between 0 and 0.5.
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