Leading edge cooling channel for airfoil
Methods and systems of cooling airfoils are provided. The present invention provides systems and methods for providing cooling channels located within walls of a turbine airfoil. These cooling channels include micro-circuits that taper in various directions along the length and width of the airfoil. In addition, these cooling channels have a variety of shapes and areas to facilitate convective heat transfer between the surrounding air and the airfoil.
1. An airfoil for a gas turbine having a leading edge and a trailing edge, the airfoil comprising:
an airfoil wall having a pressure side wall and a suction side wall, wherein the pressure side wall has a pressure side inner surface and a pressure side outer surface, wherein the suction side wall has a suction side inner surface and a suction side outer surface, wherein the pressure side outer surface and the suction side outer surface together define an airfoil wall outer surface, wherein the pressure side inner surface and the suction side inner surface together define an airfoil wall inner surface, and wherein the airfoil wall forms an airfoil chamber at least partially enclosed by the airfoil wall inner surface; and
a plurality of airfoil passages formed at the leading edge and extending to the suction side wall and the pressure side wall, each of the plurality of airfoil passages comprising:
a first opening in the pressure side outer surface,
a second opening in the suction side outer surface, and
a channel extending from the first opening and the second opening to a third opening in the airfoil wall inner surface, the channel tapering in at least one of a radial direction and an axial direction such that a first cross-sectional area of the first opening and a second cross-sectional area of the second opening is smaller than a third cross-sectional area of the channel at the third opening, wherein the third opening provides fluid communication between the channel and the airfoil chamber, and wherein the channel is a wave-like shape.
2. The airfoil of claim 1 , wherein a ratio of the third cross-sectional area to at least one of the first cross-sectional area and the second cross-sectional area is between 1.1:1 and 10:1.
3. The airfoil of claim 1 , wherein for each of the plurality of airfoil passages, the channel tapers in both the radial direction and the axial direction.
4. The airfoil of claim 1 , wherein each of the plurality of airfoil passages has rounded corners.
5. The airfoil of claim 1 , wherein each of the plurality of airfoil passages has sharp-edged corners.
6. The airfoil of claim 1 , wherein the third opening is located adjacent a calculated leading edge stagnation point.
7. The airfoil of claim 1 , wherein the plurality of airfoil passages are formed using additive manufacturing.
8. A gas turbine assembly, the assembly comprising:
a plurality of airfoils, wherein each of the plurality of airfoils comprises:
an airfoil wall having a pressure side wall and a suction side wall, wherein the pressure side wall has a pressure side inner surface and a pressure side outer surface, wherein the suction side wall has a suction side inner surface and a suction side outer surface, wherein the pressure side outer surface and the suction side outer surface together define an airfoil wall outer surface, wherein the pressure side inner surface and the suction side inner surface together define an airfoil wall inner surface, and wherein the airfoil wall forms an airfoil chamber at least partially enclosed by the airfoil wall inner surface; and
an airfoil passage formed in a leading edge of the airfoil wall and extending to the pressure side wall and the suction side wall, wherein the airfoil passage comprises:
a first opening in the pressure side outer surface,
a second opening in the suction side outer surface, and
a channel extending from the first opening and the second opening to a third opening in the airfoil wall inner surface, the channel tapering in at least one of a radial direction and an axial direction such that a first cross-sectional area of the first opening and a second cross-sectional area of the second opening is smaller than a third cross-sectional area of the channel at the third opening, wherein the third opening provides fluid communication between the channel and the airfoil chamber, and wherein the channel is a wave-like shape.
9. The assembly of claim 8 , wherein the airfoil passage further comprises a plurality of flow turbulators.
10. The assembly of claim 9 , wherein the plurality of flow turbulators are arrayed in a linear or a non-linear pattern along a length of the airfoil passage.
11. The assembly of claim 8 , wherein the airfoil passage internal equivalent surface roughness is at least 400 micro-inches.
12. The assembly of claim 8 , wherein a ratio of the third cross-sectional area to the first cross-sectional area and the second cross-sectional area is between 1.1:1 and 10:1.
13. A method of manufacturing airfoils, the method comprising:
providing an airfoil having an airfoil wall comprising a pressure side wall and a suction side wall, wherein the pressure side wall includes a pressure side inner surface and a pressure side outer surface, wherein the suction side wall includes a suction side inner surface and a suction side outer surface, wherein the pressure side outer surface and the suction side outer surface together define an airfoil wall outer surface, wherein the pressure side inner surface and the suction side inner surface together define an airfoil wall inner surface, and wherein the airfoil wall forms an airfoil chamber at least partially enclosed by the airfoil wall inner surface; and
forming a plurality of airfoil passages within a leading edge of the airfoil wall and extending to the pressure side wall and the suction side wall, each of the plurality of airfoil passages comprising:
a first opening in the pressure side outer surface,
a second opening in the suction side outer surface, and
a channel extending from the first opening and the second opening to a third opening in the airfoil wall inner surface, the channel tapering in at least one of a radial direction and an axial direction such that a first cross-sectional area of the first opening and a second cross-sectional area of the second opening is smaller than a third cross-sectional area of the channel at the third opening, wherein the third opening provides fluid communication between the channel and the airfoil chamber, and wherein the channel is a wave-like shape.
14. The method of claim 13 , wherein the plurality of airfoil passages are formed using additive manufacturing.