Cooling circuit for a multi-wall blade

1. A cooling system for a multi-wall blade, the multi-wall blade including at least one central plenum and a first set of near wall cooling channels, comprising:

a forked passage cooling circuit, the forked passage cooling circuit including a first leg and a second leg; and

an air feed cavity for supplying cooling air to the first leg and the second leg of the forked passage cooling circuit;

wherein the first leg and the second leg of the forked cooling circuit are located at a radial position along the multi-wall blade that is closer to a tip area of the multi-wall blade than the at least one central plenum and the first set of near wall cooling channels, wherein the first leg of the forked passage cooling circuit extends radially outward from and at least partially over the at least one central plenum of the multi-wall blade, and wherein the second leg of the forked passage cooling circuit extends radially outward from and at least partially over the first set of near wall cooling channels in the multi-wall blade.

2. The cooling system of claim 1 , wherein the first leg and the second leg of the forked passage cooling circuit extend from the air feed cavity toward a trailing edge of the multi-wall blade.

3. The cooling system of claim 1 , wherein the first leg and the second leg of the forked passage cooling circuit extend from the air feed cavity toward a leading edge of the multi-wall blade.

4. The cooling system of claim 1 , wherein the first set of near wall cooling channels is located adjacent a pressure side of the multi-wall blade.

5. The cooling system of claim 1 , wherein the first leg of the forked passage cooling circuit extends over and at least partially over a second set of near wall cooling channels in the multi-wall blade, wherein the first leg of the forked cooling circuit is located at a radial position along the multi-wall blade that is closer to the tip area of the multi-wall blade than the second set of near wall cooling channels.

6. The cooling system of claim 5 , wherein the second set of near wall cooling channels is located adjacent a suction side of the multi-wall blade.

7. The cooling system of claim 1 , wherein at least one of the first leg or the second leg of the forked passage cooling circuit includes at least one tip film channel for directing the cooling air to a tip of the multi-wall blade to provide tip film.

8. The cooling system of claim 1 , wherein the second leg of the forked passage cooling circuit includes at least one pressure side film channel for directing the cooling air to a pressure side of the multi-wall blade to provide pressure side film.

9. The cooling system of claim 1 , wherein the cooling air is supplied to the air feed cavity from the at least one central plenum or the first set of near wall cooling channel of the multi-wall blade.

10. A multi-wall turbine blade, comprising:

a cooling system disposed within the multi-wall turbine blade, the multi-wall blade including at least one central plenum and a first set of near wall cooling channels, the cooling system including:

a forked passage cooling circuit, the forked passage cooling circuit including a first leg and a second leg; and

an air feed cavity for supplying cooling air to the first leg and the second leg of the forked passage cooling circuit;

wherein the first leg and the second leg of the forked cooling circuit are located at a radial position along the multi-wall blade that is closer to a tip area of the multi-wall blade than the at least one central plenum and the first set of near wall cooling channels, wherein the first leg of the forked passage cooling circuit extends radially outward from and at least partially over the at least one central plenum of the multi-wall blade, and wherein the second leg of the forked passage cooling circuit extends radially outward from and at least partially over the first set of near wall cooling channels in the multi-wall blade.

11. The multi-wall turbine blade of claim 10 , wherein the first leg and the second leg of the forked passage cooling circuit extend from the air feed cavity toward a trailing edge of the multi-wall blade.

12. The multi-wall turbine blade of claim 10 , wherein the first leg and the second leg of the forked passage cooling circuit extend from the air feed cavity toward a leading edge of the multi-wall blade.

13. The multi-wall turbine blade of claim 10 , wherein the first set of near wall cooling channels is located adjacent a pressure side of the multi-wall blade.

14. The multi-wall turbine blade of claim 10 , wherein the first leg of the forked passage cooling circuit extends over and at least partially over a second set of near wall cooling channels in the multi-wall blade, wherein the first leg of the forked cooling circuit is located at a radial position along the multi-wall blade that is closer to the tip area of the multi-wall blade than the second set of near wall cooling channels.

15. The multi-wall turbine blade of claim 14 , wherein the second set of near wall cooling channels is located adjacent a suction side of the multi-wall blade.

16. The multi-wall turbine blade of claim 10 , wherein at least one of the first leg or the second leg of the forked passage cooling circuit includes at least one tip film channel for directing the cooling air to a tip of the multi-wall blade to provide tip film.

17. The multi-wall turbine blade of claim 10 , wherein the second leg of the forked passage cooling circuit includes at least one pressure side film channel for directing the cooling air to a pressure side of the multi-wall blade to provide pressure side film.

18. The multi-wall turbine blade of claim 10 , wherein the cooling air is supplied to the air feed cavity from the at least one central plenum or the first set of near wall cooling channel of the multi-wall blade.

19. The multi-wall turbine blade of claim 10 , wherein the multi-wall turbine blade forms a portion of a turbine bucket, and wherein the turbine bucket includes a shank coupled to the multi-wall turbine blade.

20. A turbomachine, comprising:

a gas turbine system including a compressor component, a combustor component, and a turbine component, the turbine component including a plurality of turbine buckets, and wherein at least one of the turbine buckets includes a multi-wall blade; and

a cooling system disposed within the multi-wall blade, the multi-wall blade including at least one central plenum and a first set of near wall cooling channels, the cooling system including:

a forked passage cooling circuit, the forked passage cooling circuit including a first leg and a second leg; and

an air feed cavity for supplying cooling air to the first leg and the second leg of the forked passage cooling circuit;

wherein the first leg and the second leg of the forked cooling circuit are located at a radial position along the multi-wall blade that is closer to a tip area of the multi-wall blade than the at least one central plenum and the first set of near wall cooling channels, wherein the first leg of the forked passage cooling circuit extends radially outward from and at least partially over the at least one central plenum of the multi-wall blade, and wherein the second leg of the forked passage cooling circuit extends radially outward from and at least partially over the first set of near wall cooling channels in the multi-wall blade.