Abstract: The premixed pilot nozzle includes axially elongated tubes defined within a plenum between an outer shroud and a first shroud disposed radially inward of the outer shroud. The tubes extend between tube inlets defined through a forward face and tube outlets defined through an aft face. A second shroud is disposed radially inward of the first shroud, thereby defining a fuel plenum between the first shroud and the second shroud, and the fuel plenum is in communication with a gaseous fuel supply. A fuel injection port, which is positioned between the tube inlet and the tube outlet of each tube, is in fluid communication with the fuel plenum. An air supply configured to fluidly communicate with the tube inlet of each tube. The second shroud defines a second plenum therein, the second plenum being coupled to a source of a non-combustible fluid.

Abstract: An injection assembly for a gas turbine combustor having a liner defining a combustion zone and a secondary combustion zone and a forward casing circumferentially surrounding at least a portion of the liner is provided. The injection assembly includes a thimble assembly and an injector unit. The thimble assembly, which is mounted to the liner, includes a thimble that extends through a thimble aperture in the liner. The injector unit, which is mounted to and extends through the forward casing, includes an injector blade that extends into the thimble. The injection assembly introduces a flow of fuel into a flow of air flowing through the thimble, such that fuel and air are injected into the secondary combustion zone in a direction transverse to a flow of combustion products from the primary combustion zone.

Abstract: A gas turbine combustor includes: a head end comprising a primary fuel nozzle; a liner defining a primary combustion zone proximate the head end and a downstream secondary combustion zone; a forward casing radially outward of and surrounding at least a portion of the liner; and an axial fuel staging system. The axial fuel staging system includes a plurality of fuel injection assemblies. Each fuel injection assembly includes a thimble assembly mounted to the liner, and an injector unit attached to the forward casing. A thimble of the thimble assembly extends through a thimble aperture in the liner. The injector unit extends through the forward casing, such that a portion of the injector unit is disposed within the thimble, and a fuel line fitting is disposed outward of the forward casing. The injector unit introduces fuel into air flowing through the thimble for injection into the secondary combustion zone.

Abstract: A thimble assembly, which directs fluid flow through a combustor liner, includes a thimble boss and a thimble. The thimble boss is mounted an outer surface of the liner and surrounds a liner opening, thus defining a thimble boss passage. The thimble is disposed through the passage and the liner opening. The thimble wall extends from an inlet portion to an outlet of the thimble. The inlet portion has a greater diameter than the outlet and defines an inlet plane and a parallel intermediate plane. A terminal plane, parallel to the intermediate plane, includes an array of points most distant from a corresponding array of points defining the intermediate plane. The thimble wall has a non-uniform length, such that the outlet of the thimble is oriented at an oblique angle relative to the terminal plane. The thimble wall may have an arcuate shape defined as one-fourth of an ellipse.

Abstract: A premix pilot nozzle is disclosed herein. The premix pilot nozzle includes a nozzle body. The nozzle body includes a forward wall, an aft wall, an outer band that extends between the forward wall and the aft wall and a tip portion that extends axially downstream from the aft wall. The nozzle body further defines a fuel inlet plenum that extends coaxially within the nozzle body, a fuel distribution plenum that is defined within the nozzle body radially outwardly from and in fluid communication with the fuel inlet plenum, a plurality of premix passages that extend helically around the fuel inlet plenum within the fuel distribution plenum and a plurality of air passages annularly arranged around the plurality of premix passages. One or more premix passages of the plurality of premix passages are in fluid communication with the fuel distribution plenum.

Abstract: A fuel nozzle includes an inner wall defining a central passage extending in an axial direction of the fuel nozzle, a hub wall surrounding the inner wall and defining a first annular passage, an outer wall surrounding the hub wall and defining a second annular passage, and a shroud surrounding the outer wall and defining a third annular passage. A swirler may receive air and direct the air into the first annular passage. The swirler includes at least one swirl vane extending from the shroud to the hub wall that has an air passage extending between the shroud and the hub wall. The air passage is coupled to the first annular passage and has a first width adjacent the shroud and a second width adjacent the hub wall. The second width is larger than the first width defining a diverging outlet into the first annular passage.

Abstract: The premixed pilot nozzle includes axially elongated tubes defined within a plenum between an outer shroud and a first shroud disposed radially inward of the outer shroud. The tubes extend between tube inlets defined through a forward face and tube outlets defined through an aft face. A second shroud is disposed radially inward of the first shroud, thereby defining a fuel plenum between the first shroud and the second shroud, and the fuel plenum is in communication with a gaseous fuel supply. A fuel injection port, which is positioned between the tube inlet and the tube outlet of each tube, is in fluid communication with the fuel plenum. An air supply configured to fluidly communicate with the tube inlet of each tube. The second shroud defines a second plenum therein, the second plenum being coupled to a source of a non-combustible fluid.

Abstract: A gas turbine combustor includes: a head end comprising a primary fuel nozzle; a liner defining a primary combustion zone proximate the head end and a downstream secondary combustion zone; a forward casing radially outward of and surrounding at least a portion of the liner; and an axial fuel staging system. The axial fuel staging system includes a plurality of fuel injection assemblies. Each fuel injection assembly includes a thimble assembly mounted to the liner, and an injector unit attached to the forward casing. A thimble of the thimble assembly extends through a thimble aperture in the liner. The injector unit extends through the forward casing, such that a portion of the injector unit is disposed within the thimble, and a fuel line fitting is disposed outward of the forward casing. The injector unit introduces fuel into air flowing through the thimble for injection into the secondary combustion zone.

Abstract: A thimble assembly, which directs fluid flow through a combustor liner, includes a thimble boss and a thimble. The thimble boss is mounted an outer surface of the liner and surrounds a liner opening, thus defining a thimble boss passage. The thimble is disposed through the passage and the liner opening. The thimble wall extends from an inlet portion to an outlet of the thimble. The inlet portion has a greater diameter than the outlet and defines an inlet plane and a parallel intermediate plane. A terminal plane, parallel to the intermediate plane, includes an array of points most distant from a corresponding array of points defining the intermediate plane. The thimble wall has a non-uniform length, such that the outlet of the thimble is oriented at an oblique angle relative to the terminal plane. The thimble wall may have an arcuate shape defined as one-fourth of an ellipse.

Abstract: An injection assembly for a gas turbine combustor having a liner defining a combustion zone and a secondary combustion zone and a forward casing circumferentially surrounding at least a portion of the liner is provided. The injection assembly includes a thimble assembly and an injector unit. The thimble assembly, which is mounted to the liner, includes a thimble that extends through a thimble aperture in the liner. The injector unit, which is mounted to and extends through the forward casing, includes an injector blade that extends into the thimble. The injection assembly introduces a flow of fuel into a flow of air flowing through the thimble, such that fuel and air are injected into the secondary combustion zone in a direction transverse to a flow of combustion products from the primary combustion zone.

Abstract: A combustor cap assembly includes an impingement plate coupled to an annular shroud and a cap plate which is coupled to the impingement plate and forms an impingement air plenum therebetween. The cap assembly further includes a flow conditioning plate which is coupled to a forward end portion of the shroud. The flow conditioning plate includes an inner band portion, an outer band portion and an annular portion which extends radially therebetween. The annular portion includes upstream side, a downstream side and a plurality of flow conditioning passages which provide for fluid communication through the upstream and downstream sides. The inner band portion of the flow conditioning plate at least partially defines an exhaust channel. The exhaust channel is in fluid communication with the impingement air plenum and an exhaust outlet. The exhaust outlet is positioned to route cooling air from the impingement air plenum into an annular flow passage defined within a combustor.

Abstract: A premix pilot nozzle and fuel nozzle assembly are disclosed herein. The premix pilot nozzle includes a nozzle body having a forward wall axially spaced from an aft wall and an outer band that extends axially between the forward wall and the aft wall. An air tube extends coaxially within the nozzle body and defines a cooling air plenum within the nozzle body. A fuel tube extends coaxially within the nozzle body and circumferentially surrounds the air tube so as to define a fuel inlet plenum therebetween. A fuel distribution plenum is defined within the nozzle body and is in fluid communication with the fuel inlet plenum. The nozzle body further includes a plurality of premix tubes. Each premix tube extends helically around the fuel tube within the fuel distribution plenum. One or more of the premix tubes is in fluid communication with the fuel distribution plenum.

Abstract: A premix pilot nozzle is disclosed herein. The premix pilot nozzle includes a nozzle body. The nozzle body includes a forward wall, an aft wall, an outer band that extends between the forward wall and the aft wall and a tip portion that extends axially downstream from the aft wall. The nozzle body further defines a fuel inlet plenum that extends coaxially within the nozzle body, a fuel distribution plenum that is defined within the nozzle body radially outwardly from and in fluid communication with the fuel inlet plenum, a plurality of premix passages that extend helically around the fuel inlet plenum within the fuel distribution plenum and a plurality of air passages annularly arranged around the plurality of premix passages. One or more premix passages of the plurality of premix passages are in fluid communication with the fuel distribution plenum.

Abstract: A system for utilizing cooling air within a combustor includes a fuel nozzle having an axially extending center body, a burner tube that circumferentially surrounds at least a portion of the center body and a premix passage defined between the center body and the burner tube. The system further includes a combustor cap assembly having a first cooling air plenum defined between a cap plate and a first partitioning plate, a second cooling air plenum defined upstream from the first cooling air plenum between a second partitioning plate and the first partitioning plate, and a tube that provides for fluid communication from the first cooling air plenum, through the second cooling air plenum and through the second partitioning plate. The system provides a method for utilizing the cooling air within the combustor.

Abstract: The present application provides a fuel nozzle for use with a flow of air and a flow of fuel in a gas turbine engine. The fuel nozzle may include a plenum, a mixing tube element positioned within the plenum, and an enhanced mixing feature positioned within the mixing tube element so as to promote mixing of the flow of air and the flow of fuel. The enhanced mixing feature may include a turbulated mixing zone.

Abstract: The present application provides a fuel nozzle for use with a flow of air and a flow of fuel in a gas turbine engine. The fuel nozzle may include a plenum, a mixing tube element positioned within the plenum, and an enhanced mixing feature positioned within the mixing tube element so as to promote mixing of the flow of air and the flow of fuel. The enhanced mixing feature may include a continuous thread.

Abstract: The present application provides a fuel nozzle for use with a flow of air and a flow of fuel in a gas turbine engine. The fuel nozzle may include a plenum, a mixing tube element positioned within the plenum, and an enhanced mixing feature positioned within the mixing tube element so as to promote mixing of the flow of air and the flow of fuel. The enhanced mixing feature may include a swirler.

Abstract: A system for utilizing cooling air within a combustor includes a fuel nozzle having an axially extending center body, a burner tube that circumferentially surrounds at least a portion of the center body and a premix passage defined between the center body and the burner tube. The system further includes a combustor cap assembly having a first cooling air plenum defined between a cap plate and a first partitioning plate, a second cooling air plenum defined upstream from the first cooling air plenum between a second partitioning plate and the first partitioning plate, and a tube that provides for fluid communication from the first cooling air plenum, through the second cooling air plenum and through the second partitioning plate. The system provides a method for utilizing the cooling air within the combustor.

Abstract: A fuel nozzle includes an inner wall defining a central passage extending in an axial direction of the fuel nozzle, a hub wall surrounding the inner wall and defining a first annular passage, an outer wall surrounding the hub wall and defining a second annular passage, and a shroud surrounding the outer wall and defining a third annular passage. A swirler may receive air and direct the air into the first annular passage. The swirler includes at least one swirl vane extending from the shroud to the hub wall that has an air passage extending between the shroud and the hub wall. The air passage is coupled to the first annular passage and has a first width adjacent the shroud and a second width adjacent the hub wall. The second width is larger than the first width defining a diverging outlet into the first annular passage.

Abstract: A fuel nozzle includes an inner wall defining a central passage extending in an axial direction of the fuel nozzle, a hub wall surrounding the inner wall and defining a first annular passage, an outer wall surrounding the hub wall and defining a second annular passage, and a shroud surrounding the outer wall and defining a third annular passage. A swirler may receive air and direct the air into the first annular passage. The swirler includes at least one swirl vane extending from the shroud to the hub wall that has an air passage extending between the shroud and the hub wall. The air passage is coupled to the first annular passage and has a first width adjacent the shroud and a second width adjacent the hub wall. The second width is larger than the first width defining a diverging outlet into the first annular passage.