Combustor head end section with integrated cooling system

1 . A combustor head end section with an integrated cooling system, the combustor head end section comprising:

a bundled tube fuel nozzle assembly for a gas turbine combustor, the bundled tube fuel nozzle assembly comprising: a forward plate facing a head end air plenum, an aft plate facing a combustion chamber, a first plurality of premixing tubes extending from the forward plate to the aft plate, and a side wall extending circumferentially around the first plurality of premixing tubes and extending axially from the forward plate to the aft plate;

wherein the forward plate, the aft plate, and the side wall define a fuel plenum, and each premixing tube of the first plurality of premixing tubes includes at least one fuel injection hole therethrough in fluid communication with the fuel plenum;

wherein the first plurality of premixing tubes comprises a radially outer group of premixing tubes in fluid communication with the fuel plenum;

wherein a second plurality of premixing tubes extends between the forward plate and the aft plate in a center region of the bundled tube fuel nozzle assembly;

wherein the second plurality of premixing tubes is a radially inner group of premixing tubes;

wherein the radially inner group of premixing tubes and the radially outer group of premixing tubes are separated by a partition that defines a center fuel plenum and that separates the fuel plenum from the center fuel plenum;

wherein the partition comprises a plurality of boundary premixing tubes, each of the plurality of boundary premixing tubes defining a plurality of boundary fuel injection holes;

wherein a first boundary fuel injection hole of the plurality of boundary fuel injection holes is fluidly connected to the fuel plenum;

wherein a second boundary fuel injection hole of the plurality of boundary fuel injection holes is fluidly connected to the center fuel plenum;

wherein the head end air plenum is in fluid communication with the combustion chamber, via inlet ends of the first plurality of premixing tubes;

wherein the integrated cooling system comprises at least one air flow passage integral with an exterior surface of a respective premixing tube and extending from the forward plate to an air outlet on the aft plate;

wherein the partition further comprises connecting walls that each connect adjacent premixing tubes of the plurality of boundary premixing tubes; and

wherein the plurality of boundary premixing tubes and connecting walls form an outermost boundary of the center fuel plenum.

2 . The combustor head end section of claim 1 , wherein the at least one air flow passage has an inlet defined in the forward plate and in fluid communication with the head end air plenum.

3 . The combustor head end section of claim 2 , wherein the air outlet of the at least one air flow passage is fluidly coupled to at least one cooling channel defined in the aft plate; wherein each cooling channel of the at least one cooling channel terminates in a swirl funnel, the swirl funnel being in fluid communication with the combustion chamber for delivering a swirling flow of air to the combustion chamber.

4 . The combustor head end section of claim 3 , wherein each cooling channel of the at least one cooling channel intersects the swirl funnel in a tangential direction to promote delivery of the swirling flow of air to the combustion chamber.

5 . The combustor head end section of claim 1 , wherein the integrated cooling system comprises one or two air flow passages integral with the exterior surface of the respective premixing tube.

6 . The combustor head end section of claim 1 , wherein the integrated cooling system comprises a plurality of air flow passages, one or two of which are integral with exterior surfaces of the first plurality of premixing tubes.

7 . The combustor head end section of claim 6 , wherein the integrated cooling system comprises a plurality of swirl funnels defined in the aft plate between premix outlets of the first plurality of premixing tubes and a plurality of cooling channels extending from the air outlet of the at least one air flow passage to the plurality of swirl funnels; and wherein the plurality of cooling channels provides convective cooling to the aft plate.

8 . The combustor head end section of claim 1 , wherein the connecting walls each defining a boundary air flow passage of a plurality of boundary air flow passages disposed between the adjacent premixing tubes of the plurality of boundary premixing tubes, the plurality of boundary air flow passages being in fluid communication with the head end air plenum.

9 . The combustor head end section of claim 8 , wherein at least one boundary air flow passage of the plurality of boundary air flow passages has a uniform cross-sectional shape from an inlet at the forward plate to an outlet defined in the aft plate; and wherein the outlet is fluidly coupled to one or more cooling channels defined in the aft plate.

10 . The combustor head end section of claim 1 , wherein the bundled tube fuel nozzle assembly comprises an exterior side wall disposed circumferentially about the side wall, such that an annular air plenum is defined therebetween.

11 . The combustor head end section of claim 10 , wherein a plurality of perimeter cooling channels is defined alongside a perimeter of the aft plate, each of the plurality of perimeter cooling channels being in fluid communication with the annular air plenum and with a respective swirl funnel in fluid communication with the combustion chamber.

12 . The combustor head end section of claim 1 , wherein the bundled tube fuel nozzle assembly comprises an additively manufactured body that spans an entire diameter of the combustor head end section of the gas turbine combustor; wherein the first and second plurality of premixing tubes and the plurality of boundary premixing tubes are integrally connected to the forward plate and the aft plate; and wherein the integrated cooling system is integrally formed with the additively manufactured body.

13 . The combustor head end section of claim 8 , wherein the plurality of air flow passages define a first cross-sectional shape, wherein the plurality of boundary air flow passages each define a second cross-sectional shape, and wherein the first cross-sectional shape is different than the second cross-sectional shape.

14 . The combustor head end section of claim 1 , wherein the bundled tube fuel nozzle assembly includes fuel delivery chutes that are arranged around a perimeter of the bundled tube fuel nozzle, the fuel delivery chutes disposed tangentially relative to a radius of the bundled tube fuel nozzle assembly and oriented to direct fuel between adjacent rows of the radially outer group of premixing tubes.