Bundled tube fuel nozzle with internal cooling

A combustor comprising:

• an end cover coupled to an outer casing;
• a bundled tube fuel nozzle disposed within the outer casing and coupled to the end cover via one or more fluid conduits, wherein the bundled tube fuel nozzle comprises:
• a forward plate, a first intermediate plate, and an outer sleeve defining a fuel plenum therebetween, wherein the fuel plenum is in fluid communication with at least one fluid conduit of the one or more fluid conduits;
• a second intermediate plate axially spaced from the first intermediate plate, wherein the first intermediate plate, the second intermediate plate, and the outer sleeve define a purge air plenum therebetween;
• an aft plate axially spaced from the second intermediate plate, wherein the second intermediate plate, the aft plate, and the outer sleeve define a cooling air plenum therebetween, and wherein the outer sleeve defines one or more exhaust ports, the one or more exhaust ports providing fluid communication out of the cooling air plenum;
• a plurality of tubes that extends through the forward plate, the fuel plenum, the first intermediate plate, the purge air plenum, the second intermediate plate, the cooling air plenum, and the aft plate;
• an annular wall that extends from the second intermediate plate to the aft plate, the annular wall defining a cooling flow channel;
• and
• a plurality of apertures defined proximate to a cool side of the aft plate, wherein the plurality of apertures provides for fluid communication between the cooling flow channel and the cooling air plenum.

A combustor comprising:

• an end cover coupled to an outer casing;
• a plurality of bundled tube fuel nozzle assemblies disposed within the outer casing and annularly arranged about a center fuel nozzle of the combustor, wherein each bundled tube fuel nozzle assembly is coupled to the end cover, via at least one fluid conduit, and comprises:
• a forward plate, a first intermediate plate, and an outer sleeve defining a fuel plenum therebetween, wherein the fuel plenum is in fluid communication with the at least one fluid conduit;
• a second intermediate plate axially spaced from the first intermediate plate, wherein the first intermediate plate, the second intermediate plate, and the outer sleeve define a purge air plenum therebetween and wherein the second intermediate plate defines an opening therethrough;
• an aft plate axially spaced from the second intermediate plate, wherein the second intermediate plate, the aft plate, and the outer sleeve define a cooling air plenum therebetween;
• a plurality of tubes that extends through the forward plate, the fuel plenum, the first intermediate plate, the purge air plenum, the second intermediate plate, the cooling air plenum, and the aft plate, the plurality of tubes being disposed around the opening;
• an annular wall that extends from the opening in the second intermediate plate to the aft plate, the annular wall defining a cooling flow channel separate and independent from the plurality of tubes;
• and
• a plurality of apertures defined proximate to a cool side of the aft plate, wherein the plurality of apertures provides for fluid communication between the cooling flow channel and the cooling air plenum.