Fuel injection assembly for turbomachinery

Abstract

To provide a fuel injection assembly and a combustor.SOLUTION: A fuel injection assembly (200) includes a fuel injector (202) having a first annular wall (214) that is centered on an axial centerline (216) and extends from a primary inlet (220) disposed at a first end (222) to a primary outlet (224) disposed at a second end (226). A second annular wall (230) surrounds the first annular wall (214). A fuel plenum (232) is defined between the first annular wall (214) and the second annular wall (230). A fuel duct (208) extends from a fuel outlet (240) defined in the second annular wall (230) to a fuel inlet (242). The fuel duct (208) is in fluid communication with the fuel plenum (232). The fuel duct (208) includes a polygonal segment (244) and a cylindrical inlet segment (246). The polygonal segment (244) extends from the fuel outlet (240) to the cylindrical inlet segment (246).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates generally to fuel injectors for turbomachine combustors, and more particularly to fuel injectors for use with axial fuel staging (AFS) systems associated with such combustors. [Background technology]

[0002] Turbomachines are utilized in various industries and applications for the purpose of energy transfer. For example, a gas turbine engine typically includes a compressor section, a combustion section, a turbine section, and an exhaust section. The compressor section gradually increases the pressure of a working fluid entering the gas turbine engine and supplies the compressed working fluid to the combustion section. The compressed working fluid and fuel (e.g., natural gas) are mixed in the combustion section and combusted in a combustion chamber to generate high-pressure and high-temperature combustion gases. The combustion gases flow from the combustion section to the turbine section, where they expand to produce work. For example, the expansion of the combustion gases in the turbine section can rotate a rotor shaft connected to, for example, a generator, to generate electricity. The combustion gases then exit the gas turbine through the exhaust section.

[0003] In some combustors, combustion gases are generated in two axially spaced stages. Such combustors are referred to herein as including an “axial fuel staging” (AFS) system, which delivers fuel and oxidizer to one or more fuel injectors downstream from the head end of the combustor. In combustors with an AFS system, primary fuel nozzles at the upstream end of the combustor inject fuel and air (or a fuel / air mixture) axially into a primary combustion zone, and AFS fuel injectors located downstream from the primary fuel nozzles inject fuel and air (or a second fuel / air mixture) in a crossflow into a secondary combustion zone downstream from the primary combustion zone.

[0004] AFS injectors are often constructed using additive manufacturing systems, which allow for complex structural geometries and internal circuitry within the injector that, in some cases, cannot be manufactured. However, various features of AFS fuel injectors can be difficult and / or impossible to additively manufacture without utilizing numerous temporary supports. While temporary supports prevent certain features of the fuel injector from collapsing during the additive manufacturing process, they are often expensive and must be removed through post-fabrication processes, increasing overall manufacturing time.

[0005] Therefore, there is a need in the art for an improved AFS fuel injector having features that minimize the number of temporary supports required during fabrication, thereby reducing the amount of post-processing to the fuel injector. Summary of the Invention

[0006] Aspects and advantages of the fuel injection assembly and combustor according to the present disclosure will be set forth in part in the description which follows, or will be obvious from the description, or may be learned by practice of the present teachings.

[0007] According to one embodiment, a fuel injection assembly is provided. The fuel injection assembly includes a fuel injector having a first annular wall centered about an axial centerline and extending from a primary inlet disposed at a first end to a primary outlet disposed at a second end. A second annular wall surrounds the first annular wall. A fuel plenum is defined between the first and second annular walls. A fuel duct extends from a fuel outlet defined in the second annular wall to the fuel inlet, the fuel duct being in fluid communication with the fuel plenum. The fuel duct includes a polygonal segment and a cylindrical inlet segment. The polygonal segment extends from the fuel outlet to the cylindrical inlet segment.

[0008] According to another embodiment, a combustor is provided. The combustor includes a primary fuel nozzle and a combustion liner. The combustion liner extends radially between an inner liner segment and an outer liner segment. The combustion liner includes a forward end portion, an aft end portion, a first sidewall, and a second sidewall. The combustion liner defines a cavity extending between the first sidewall and the second sidewall. The combustor further includes a fuel injection assembly positioned downstream of the primary fuel nozzle. The fuel injection assembly includes a fuel injector centered on an axial centerline and having a first annular wall extending from a primary inlet disposed at a first end to a primary outlet disposed at a second end. A second annular wall surrounds the first annular wall. A fuel plenum is defined between the first annular wall and the second annular wall. A fuel duct extends from a fuel outlet defined in the second annular wall to a fuel inlet, the fuel duct being in fluid communication with the fuel plenum. The fuel duct includes a polygonal segment and a cylindrical inlet segment, the polygonal segment extending from the fuel outlet to the cylindrical inlet segment.

[0009] These and other features, aspects, and advantages of the present fuel injection assembly and combustor will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present technology and, together with the description, serve to explain the principles of the technology.

[0010] A full and enabling disclosure of the present fuel injection assembly and combustor, including the best mode of making and using the present systems and methods, directed to one of ordinary skill in the art, is set forth in this specification, which makes reference to the accompanying drawings. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a turbomachine according to an embodiment of the present disclosure; [Figure 2] 1 is an upstream view of an exemplary combustion section of a turbomachine according to an embodiment of the present disclosure. [Figure 3] 1 is a perspective view of an integrated combustor nozzle from a first side according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is a perspective view of an integrated combustor nozzle from a second side according to an embodiment of the present disclosure. [Figure 5] FIG. 1 is a perspective view of an integrated combustor nozzle showing four fuel injection assemblies exploded according to an embodiment of the present disclosure. [Figure 6] FIG. 1 is a perspective view of two fuel injection assemblies according to an embodiment of the present disclosure. [Figure 7] FIG. 2 is an enlarged perspective view of a fuel injection assembly according to an embodiment of the present disclosure. [Figure 8] 1 is a cross-sectional view of a fuel injector according to an embodiment of the present disclosure. [Figure 9] 1 is a cross-sectional view of a fuel injector according to an embodiment of the present disclosure. [Figure 10] 1 is a cross-sectional view of a fuel injector according to an embodiment of the present disclosure. [Figure 11] 2 is a cross-sectional view of a polygonal segment of a fuel duct of a fuel injector according to an embodiment of the present disclosure. FIG. [Figure 12] 2 is a cross-sectional view of a polygonal segment of a fuel duct of a fuel injector according to an embodiment of the present disclosure. FIG. [Figure 13] 2 is a cross-sectional view of a polygonal segment of a fuel duct of a fuel injector according to an embodiment of the present disclosure. FIG. [Figure 14] 2 is a cross-sectional view of a polygonal segment of a fuel duct of a fuel injector according to an embodiment of the present disclosure. FIG. [Figure 15] 2 is a cross-sectional view of a polygonal segment of a fuel duct of a fuel injector according to an embodiment of the present disclosure. FIG. [Figure 16] 2 is a cross-sectional view of a polygonal segment of a fuel duct of a fuel injector according to an embodiment of the present disclosure. FIG. [Figure 17] FIG. 2 is an enlarged perspective view of a fuel duct of a downstream fuel injector according to an embodiment of the present disclosure. [Figure 18] FIG. 2 is an enlarged perspective view of a fuel duct of an upstream fuel injector according to an embodiment of the present disclosure. [Figure 19] FIG. 2 is an enlarged perspective view of a fuel duct of a downstream fuel injector according to an embodiment of the present disclosure. [Figure 20] FIG. 2 is an enlarged perspective view of a fuel duct of an upstream fuel injector according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Reference will now be made in detail to the embodiments of the present assembly, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the present technology, not as a limitation thereof. Indeed, it will be apparent to those skilled in the art that modifications and variations can be made in the present technology without departing from the scope or spirit of the claimed technology. For example, features illustrated or described as part of one embodiment can be used in another embodiment to yield yet a further embodiment. Accordingly, the present disclosure is intended to cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0013] The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description are used to refer to like or similar parts of the invention. As used herein, the terms "first," "second," and "third" can be used interchangeably to distinguish one component from another and are not intended to denote the location or importance of individual components.

[0014] As used herein, the terms "upstream" (or "forward") and "downstream" (or "aft") refer to relative directions with respect to fluid flow in a fluid pathway. For example, "upstream" refers to the direction from which fluid flows, and "downstream" refers to the direction from which fluid flows. The term "radially" refers to a relative direction substantially perpendicular to the axial centerline of a particular component, the term "axially" refers to a relative direction substantially parallel and / or coaxially aligned with the axial centerline of a particular component, and the term "circumferentially" refers to a relative direction extending around the axial centerline of a particular component. Approximate terms such as "generally," "substantially," "approximately," or "about" include values ​​within plus or minus 10% of the stated value. When used in the context of an angle or direction, such terms include a range of plus or minus 10 degrees from the stated angle or direction. For example, "generally perpendicular" includes any direction, e.g., clockwise or counterclockwise, within 10 degrees of perpendicular.

[0015] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will be further understood that the terms "comprise" and / or "comprising," as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or sets thereof.

[0016] As described below, exemplary embodiments of the present subject matter involve the use of an additive manufacturing machine or method. As used herein, the terms "additively manufactured" or "additive manufacturing technique or process" generally refer to a manufacturing process in which successive layers of material are provided on top of each other to "build up" a three-dimensional component, layer by layer. The successive layers generally fuse together to form a monolithic component that may have various integral subcomponents.

[0017] Although additive manufacturing techniques are described herein as enabling the fabrication of complex objects by building the object point by point, typically in a vertical direction, layer by layer, other fabrication methods are possible and are within the scope of the present subject matter. For example, while the description herein refers to the addition of material to form successive layers, one skilled in the art will understand that the methods and structures disclosed herein can be practiced using any additive manufacturing technique or technology. For example, embodiments of the present invention may use a layer-additive process, a layer-removal process, or a hybrid process.

[0018] Suitable additive manufacturing techniques according to the present disclosure include, for example, fused deposition modeling (FDM), selective laser sintering (SLS), 3D printing such as inkjet and laser jet, stereolithography (SLA), direct selective laser sintering (DSLS), electron beam sintering (EBS), electron beam melting (EBM), laser engineered net shaping (LENS), laser net shape manufacturing (LNSM), direct metal deposition (DMD), digital light processing (DLP), direct selective laser melting (DSLM), selective laser melting (SLM), direct metal laser melting (DMLM), as well as other known processes.

[0019] In addition to using a direct metal laser sintering (DMLS) or direct metal laser melting (DMLM) process that uses an energy source to selectively sinter or melt portions of a powder layer, it should be understood that, according to alternative embodiments, the additive manufacturing process may be a “binder jetting” process. In this regard, binder jetting involves sequentially depositing layers of additive powder in a manner similar to that described above. However, instead of using an energy source to generate an energy beam to selectively melt or fuse the additive powder, binder jetting involves selectively depositing a liquid binder onto each powder layer. The liquid binder may be, for example, a photocurable polymer or another liquid binder. Other suitable additive manufacturing methods and variations are intended to be within the scope of the present subject matter.

[0020] Referring now to the drawings, Figure 1 shows a schematic diagram of one embodiment of a turbomachine, which in the illustrated embodiment is a gas turbine 10. Although an industrial or land-based gas turbine is shown and described herein, the present disclosure is not limited to land-based and / or industrial gas turbines unless otherwise stated in the claims. For example, the invention described herein may be used with any type of turbomachine, including, but not limited to, a steam turbine, an aircraft gas turbine, or a marine gas turbine.

[0021] As shown, the gas turbine 10 generally includes an inlet section 12, a compressor 14 disposed downstream from the inlet section 12, a combustion section 16 disposed downstream from the compressor 14, a turbine 18 disposed downstream from the combustion section 16, and an exhaust section 20 disposed downstream from the turbine 18. Additionally, the gas turbine 10 may include one or more shafts 22 coupling the compressor 14 to the turbine 18.

[0022] During operation, air 24 flows through the inlet section 12 to the compressor 14, where the air 24 is progressively compressed, thereby providing compressed air 26 to the combustion section 16. At least a portion of the compressed air 26 is mixed with fuel 28 in the combustion section 16 and combusted to generate combustion gases 30. The combustion gases 30 flow from the combustion section 16 to the turbine 18, where energy (kinetic and / or thermal) is transferred from the combustion gases 30 to rotor blades (not shown), causing the shaft 22 to rotate. The mechanical rotational energy may then be used for various purposes, such as powering the compressor 14 and / or generating electricity. The combustion gases 30 exiting the turbine 18 may then be exhausted from the gas turbine 10 via the exhaust section 20.

[0023] FIG. 2 illustrates an upstream view of the combustion section 16 according to various embodiments of the present disclosure. As shown in FIG. 2, the combustion section 16 may be at least partially surrounded by an outer casing or compressor discharge casing 32. The compressor discharge casing 32 may at least partially define a high-pressure plenum 34 that at least partially surrounds various components of the combustor 16. The high-pressure plenum 34 is in fluid communication with the compressor 14 ( FIG. 1 ) and may receive compressed air 26 therefrom. In various embodiments, as shown in FIG. 2, the combustion section 16 includes a segmented annular combustion system 36 that includes several combustors or integral combustor nozzles 100 arranged circumferentially around an axial centerline 38 of the gas turbine 10, which may coincide with the gas turbine shaft 22.

[0024] FIG. 3 illustrates a perspective view of the integrated combustor nozzle 100 from a first side. Similarly, FIG. 4 illustrates a perspective view of the integrated combustor nozzle 100 from a second side in accordance with an embodiment of the present disclosure. As collectively illustrated in FIGS. 2, 3, and 4, the segmented annular combustion system 36 includes a plurality of the integrated combustor nozzles 100. As described further herein, each combustor nozzle 100 includes a first sidewall 116 and a second sidewall 118. In certain embodiments, the first sidewall is a pressure sidewall and the second sidewall is a suction sidewall based on the integration of the sidewalls with the corresponding pressure and suction sides of a downstream turbine nozzle 120. It should be understood that references made herein to a pressure sidewall and a suction sidewall represent certain embodiments, and such references are made for ease of description, and such references are not intended to limit the scope of any embodiment unless the particular context dictates otherwise.

[0025] 3 and 4 , each circumferentially adjacent pair of combustor nozzles 100 defines a respective primary combustion zone 102 and a respective secondary combustion zone 104 therebetween, thereby forming an annular array of primary combustion zones 102 and secondary combustion zones 104. The primary combustion zones 102 and secondary combustion zones 104 are circumferentially separated or fluidly isolated from adjacent primary combustion zones 102 and secondary combustion zones 104, respectively, by combustion liners 110.

[0026] 3 and 4 , each combustor nozzle 100 includes an inner liner segment 106, an outer liner segment 108, and a hollow or semi-hollow combustion liner 110 extending between the inner liner segment 106 and the outer liner segment 108. It is contemplated that multiple (e.g., two, three, four, or more) combustion liners 110 may be positioned between the inner liner segment 106 and the outer liner segment 108, thereby reducing the number of joints between adjacent liner segments that require sealing. For ease of description herein, reference will be made to a unitary combustor nozzle 100 having a single combustion liner 110 between each inner and outer liner segment 106, 108, although the liner segment to combustion liner ratio need not be 2:1. As shown in Figures 3 and 4, each combustion liner 110 includes a leading or upstream end portion 112, an aft or downstream end portion 114, a first sidewall 116, which is the pressure sidewall in the particular exemplary embodiment shown in Figure 3, and a second sidewall 118, which is the suction sidewall in the particular exemplary embodiment shown in Figure 4.

[0027] The segmented annular combustion system 36 further includes a fuel injection module 117. In the illustrated exemplary embodiment, the fuel injection module 117 includes a plurality of fuel nozzles. The fuel injection module 117 is configured to be installed in the forward end portion 112 of each combustion liner 110. For purposes of description herein, the fuel injection module 117 including a plurality of fuel nozzles may be referred to as a "bundle-tube fuel nozzle." However, the fuel injection module 117 may include or comprise any type of fuel nozzle or burner (such as a swirl fuel nozzle or a swozzle), and the claims should not be limited to a bundle-tube fuel nozzle unless otherwise specified.

[0028] Each fuel injection module 117 may extend at least partially circumferentially between two circumferentially adjacent combustion liners 110 of the respective combustor nozzle 100 and / or at least partially radially between the respective inner liner segment 106 and outer liner segment 108. During axial-staged fuel injection operation, the fuel injection modules 117 provide a flow of premixed fuel and air (i.e., first combustible mixture) to the respective primary combustion zone 102.

[0029] 3 and 4 , one or more downstream end portions 114 of the combustion liner 110 transition to a generally airfoil-shaped turbine nozzle 120 that directs and accelerates the flow of combustion products toward the turbine blades. Thus, the downstream end portion 114 of each combustion liner 110 can be considered an airfoil without a leading edge. When the integrated combustor nozzle 100 is installed within the combustion section 16, the turbine nozzle 120 can be positioned immediately upstream of a stage of turbine rotor blades of the turbine 18.

[0030] As used herein, the term "integral combustor nozzle" refers to a seamless structure that includes a combustion liner 110, a turbine nozzle 120 downstream from the combustion liner, an inner liner segment 106 (embodied by the turbine nozzle 120) that extends from the forward end 112 to the aft end 114 of the combustion liner 110, and an outer liner segment 108 (embodied by the turbine nozzle 120) that extends from the forward end 112 to the aft end 114 of the combustion liner 110. In at least one embodiment, the turbine nozzle 120 of the integral combustor nozzle 100 functions as a first stage turbine nozzle and is positioned upstream of the first stage of turbine rotor blades.

[0031] As described above, one or more of the integral combustor nozzles 100 are formed as a unitary or unitary structure or body including the inner liner segment 106, the outer liner segment 108, the combustion liner 110, and the turbine nozzle 120. The integral combustor nozzle 100 may be fabricated as a unitary or seamless component via casting, additive manufacturing (such as 3D printing), or other manufacturing techniques. Forming the combustor nozzle 100 as a single or unitary component may reduce or eliminate the need for seals between various features of the combustor nozzle 100, reduce part count and costs, and simplify or eliminate assembly steps. In other embodiments, the combustor nozzle 100 may be fabricated, such as by welding, or formed from different manufacturing techniques, with components fabricated by one technique joined to components fabricated by the same or another technique.

[0032] In certain embodiments, at least a portion or all of each integral combustor nozzle 100 may be formed from a ceramic matrix composite (CMC) or other composite material. In other embodiments, a portion or all of each integral combustor nozzle 100, and more specifically, the turbine nozzle 120 or its trailing edge, may be made from or coated with a material that is highly resistant to oxidation (e.g., coated with a thermal barrier coating).

[0033] In another embodiment (not shown), at least one of the combustion liners 110 may be tapered at a trailing edge aligned with the longitudinal (axial) axis of the combustion liner 110. That is, the combustion liners 110 may not be integrated with the turbine nozzles 120. In these embodiments, it may be desirable to have an uneven number of combustion liners 110 and turbine nozzles 120. Tapered combustion liners 110 (i.e., those without integrated turbine nozzles 120) may be used alternating with combustion liners 110 with integrated turbine nozzles 120 (i.e., integrated combustor nozzles 100) or in some other pattern.

[0034] At least one of the combustion liners 110 may include at least one cross-fire tube 122 extending through respective openings in the pressure sidewall 116 and the suction sidewall 118 of the respective combustion liner 110. The cross-fire tubes 122 facilitate flame propagation and ignition of circumferentially adjacent primary combustion zones 102 between circumferentially adjacent integral combustor nozzles 100.

[0035] In many embodiments, as shown in FIG. 3 , each combustion liner 110 may include a plurality of radially spaced-apart pressure side injection outlets 164 defined along the pressure sidewall 116, through which the pressure side fuel injectors 202, 204 may extend. As shown in FIG. 4 , each combustion liner 110 may include a plurality of radially spaced-apart suction side injection outlets 165 defined along the suction sidewall 118, through which the suction side fuel injectors 202, 204 may extend. Each respective primary combustion zone 102 is defined upstream of the corresponding pressure side injection outlets 164 and / or suction side injection outlets 165 of a pair of circumferentially adjacent integrated combustor nozzles 100. Each secondary combustion zone 104 is defined downstream of the corresponding pressure side injection outlets 164 and / or suction side injection outlets 165 of a pair of circumferentially adjacent integrated combustor nozzles 100. Although the multiple pressure side injection outlets 164 are illustrated in FIG. 2 as being in a common radial or injection plane relative to the axial centerline of the integrated combustor nozzle 100 or at a common axial distance from the downstream end portion 114 of the fuel injection panel 110, in certain embodiments, one or more of the pressure side injection outlets 164 may be axially staggered relative to a radially adjacent pressure side injection outlet 164, thereby offsetting the axial distance of the pressure side injection outlet 164 relative to the downstream end portion 114 of a particular pressure side injection outlet 164. Similarly, while FIG. 4 illustrates the multiple suction side injection outlets 165 in a common radial or injection plane or at a common axial distance from the downstream end portion 114 of the fuel injection panel 110, in certain embodiments, one or more of the suction side injection outlets 165 may be axially staggered relative to a radially adjacent suction side injection outlet 165, thereby offsetting the axial distance of the suction side injection outlet 165 relative to the downstream end portion 114 of a particular suction side injection outlet 165.

[0036] 5 illustrates a perspective view of the integrated combustor nozzle 100 with four fuel injection assemblies 200 shown exploded, in accordance with an embodiment of the present disclosure. As shown, the integrated combustor nozzle 100 includes two fuel injection assemblies 200 oriented to inject a fuel and air mixture into the pressure side of the integrated combustor nozzle 100 and two fuel injection assemblies 200 oriented to inject a fuel and air mixture into the suction side of the integrated combustor nozzle 100.

[0037] In many embodiments, an interior portion of each combustion liner 110 may be defined between the pressure side wall 116 and the suction side wall 118 and may be partitioned into various air passages or cavities 124, 126, 127 by one or more ribs 128, 129. In certain embodiments, the air cavities 124, 126, 127 may receive air from the compressor discharge casing 32 or other cooling source. The ribs or partitions 128, 129 may extend within the interior portion of the combustion liner 110 and at least partially form or separate the multiple air cavities 124, 126, 127. In certain embodiments, some or all of the ribs 128, 129 may provide structural support to the pressure side wall 116 and / or the suction side wall 118 of the combustion liner 110.

[0038] In certain embodiments, each of four fuel injection assemblies 200 may be positioned within the central air cavity 126, for example, between the forward air cavity 124 and the aft air cavity 127. Each of the fuel injector assemblies 200 may be in fluid communication with both the high-pressure plenum 34 and the fuel supply 130 to provide a secondary fuel-air mixture to the secondary combustion zone 104. The fuel supply 130 may be fluidly coupled to each of the fuel injection assemblies 200 via conduit fittings 132. The conduit fittings 132 may mechanically fasten each of the fuel injection assemblies to the fuel supply 130.

[0039] 6 illustrates two fuel injection assemblies 200 isolated from various other components of the integrated combustor nozzle 100. In various embodiments, the fuel injection assemblies 200 illustrated in FIG. 6 may be either suction side or pressure side fuel injection assemblies, i.e., operable to deliver a secondary mixture of fuel and air to the secondary combustion zone 104 through either the pressure side wall 116 or the suction side wall 118. In many embodiments, as shown, each fuel injection assembly 200 may include a first or upstream fuel injector 202 and a second or downstream fuel injector 204 with respect to the direction of fuel flow through the fuel injection assembly 200. In certain embodiments, each of the fuel injector assemblies 200 may further include a fluid.

[0040] As shown in FIG. 6 , each of the fuel injectors 202, 204 includes a body 206 and a fuel duct 208 extending from the body 206. In many embodiments, the fuel duct 208 of the upstream fuel injector 202 may be coupled to both a fluid supply conduit 210 and a connecting conduit 212. The fluid supply conduit 210 may extend between the conduit fitting 132 and the fuel duct 208 of the upstream fuel injector 202 to fluidly couple the upstream fuel injector 202 to the fuel supply source 130. In various embodiments, the connecting conduit 212 may couple the fuel duct 208 of the upstream fuel injector 202 to a fuel duct of the downstream fuel injector 204. While the embodiment shown in FIG. 6 includes a fuel injection assembly having two fuel injectors 202, 204 fluidly coupled via the connecting conduit 212, other embodiments may include three, four, five, six, or more fuel injectors coupled to each other via multiple connecting conduits.

[0041] FIG. 7 illustrates an enlarged perspective view of a fuel injection assembly 200 according to an embodiment of the present disclosure, and FIGS. 8-10 illustrate different cross-sectional views of fuel injectors 202, 204 according to an embodiment of the present disclosure. As collectively shown in FIGS. 7-10, the body 206 of each of the fuel injectors 202, 204 includes a first annular wall 214 that extends about an axial centerline 216 of the fuel injector 202, 204 ( FIGS. 9 and 10 ). In many embodiments, the first annular wall 214 of the fuel injector 202, 204 extends axially, e.g., along the axial centerline 216, from a primary inlet 220 located at a first end 222 to a primary outlet 224 located at a second end 226. For example, the first annular wall 214 may define a premix passage 218 shaped as a geometric stadium, e.g., a rectangle with rounded ends, which advantageously allows the fuel injectors 202, 204 to deliver the fuel-air mixture over a greater axial distance relative to the axial centerline of the gas turbine 10. As shown, the primary outlet 224 of the first injector 202 and the primary outlet 224 of the second injector 204 are disposed in the first sidewall 116 of the combustion liner 110. In an exemplary embodiment, the first annular wall 214 of each fuel injector 202, 204 may extend through a respective injection outlet 164, 165 defined in one of the pressure sidewall 116 or the suction sidewall 118 of the combustion liner 110 to provide the fuel-air mixture to the secondary combustion zone 104.

[0042] In many embodiments, a second annular wall 230 may be spaced apart from and surround the first annular wall 214 of the fuel injectors 202, 204 such that a fuel plenum 232 is defined therebetween. For example, the fuel plenum 232 may be annularly defined between the first annular wall 214 and the second annular wall 230 such that it extends around the inner surface of the fuel injectors 202, 204. The second annular wall 230 may include a first end wall 234 and a second end wall 236 spaced apart from the first end wall 234, and a side wall 238 may extend between the first end wall 234 and the second end wall 236. In various embodiments, the first end wall 234 and the second end wall 236 may be generally perpendicular to the side wall 238 such that the second annular wall 230 has a rectangular cross-sectional shape. For example, as shown in FIGS. 9 and 10, the side walls 238 may extend generally parallel to one another and may be longer than the first end wall 234 and the second end wall 236 .

[0043] 8 , the first annular wall 214 and the second annular wall 230 may be joined to each other at opposite ends to define forward and aft boundaries of the fuel plenum relative to the direction of fuel and air within the fuel injector 202. For example, at the first end of the fuel injector 202, the first annular wall 214 may converge toward and join the second annular wall 230 such that the forward boundary of the fuel plenum 232 is defined at the intersection of the two walls 214 and 230. In other words, the first annular wall 214 may diverge away from the axial centerline 216 of the fuel injector 202 and join to the second annular wall 230 at the first end of the fuel injector 202. Similarly, between the first and second ends of fuel injector 202, second annular wall 230 may converge toward and join first annular wall 214 such that an aft boundary of fuel plenum 232 is defined at the intersection of the two walls 214 and 230. In other words, second annular wall 230 may converge toward axial centerline 216 of fuel injector 202 and join first annular wall 214 between the first and second ends of fuel injector 202.

[0044] 7-10 , each of the plurality of secondary conduits 288 may extend from a secondary inlet 290 defined in the second annular wall 230, through the fuel plenum 232, to a secondary outlet 292 defined in the first annular wall 214. More specifically, each of the plurality of secondary conduits 288 may extend from a secondary inlet 290 defined in one of the side walls 238 of the second annular wall 230, through the fuel plenum 232, to a secondary outlet 292 defined in the first annular wall 214. As shown in FIG. 9 , each of the plurality of secondary conduits 288 may define one or more fuel ports 294 in fluid communication with the fuel plenum 232. In this manner, each of the secondary conduits 288 may provide an individual flow of fuel and air to the premix passage 218 for mixing prior to introduction into the secondary combustion zone 104.

[0045] 7-10 , the fuel duct 208 may extend from a fuel outlet 240 defined in the second annular wall 230 to a fuel inlet 242. In various embodiments, the fuel duct 208 may extend away from the second annular wall 230 of the body 206 of the fuel injector 202, 204. More specifically, the fuel duct 208 may extend generally perpendicular to a first end wall of the second annular wall of the body 206. In an exemplary embodiment, the fuel duct 208 may be in fluid communication with both the fuel supply 130 and the fuel plenum 232.

[0046] 7-10 , fuel duct 208 of upstream fuel injector 202 and downstream fuel injector 204 may include a polygonal segment 244 and a cylindrical inlet segment 246. In an exemplary embodiment, polygonal segment 244 may extend from fuel outlet 240 to cylindrical inlet segment 246, which may extend from polygonal segment 244 to fuel inlet 242 of fuel duct 208. Polygonal segment 244 may have a cross-section shaped as a polygon having at least three straight sides that extend from and form angles with one another, which advantageously allows the fuel duct to be additively manufactured with minimal or no temporary supports, thereby reducing manufacturing time and costs.

[0047] In many embodiments, upstream fuel injector 202 may include a cylindrical outlet segment 268 positioned opposite cylindrical inlet segment 246. In this manner, fuel duct 208 of upstream fuel injector 202 acts as a junction point for fuel received by fuel source 130. For example, fuel received by fuel duct 208 of upstream fuel injector 202 may be split between the polygonal segment of the fuel duct and cylindrical outlet segment 268 for use by another fuel injector, such as downstream fuel injector 204.

[0048] As best shown in FIG. 9 , the cylindrical inlet segment 246 may include a diameter 284 that is larger than the diameter 286 of the cylindrical inlet segment 268, which may advantageously ensure that sufficient fuel is divided between the polygonal segment 244 and the cylindrical outlet segment 268 of the upstream fuel injector 202 for use by the downstream fuel injector 204.

[0049] In the exemplary embodiment, fluid supply conduit 210 may fluidly couple a cylindrical inlet segment 246 of upstream fuel injector 202 to fuel supply 130. Connecting conduit 212 may fluidly couple a cylindrical outlet section 268 of upstream fuel injector 202 to a cylindrical inlet segment 246 of downstream fuel injector 204. As shown in FIG. 6 , connecting conduit 212 may be a generally straight tube / pipe shaped as a hollow cylinder, which advantageously reduces manufacturing time and costs for fuel injection assembly 200 by not requiring special fabrication and / or bends to connecting conduit 212.

[0050] In many embodiments, both the cylindrical inlet segment 246 and the cylindrical outlet segment 268 can be molded as hollow cylinders that extend generally straight, i.e., without bends or curves. Unlike the polygonal segment 244 of the fuel duct 208, the cylindrical segments 246, 268 may require one or more temporary supports during the additive manufacturing process to achieve their geometric shape. However, because the cylindrical segments 246, 268 extend straight, i.e., without bends or curves, the temporary supports can be removed using cost-effective, conventional removal means, such as drilling or milling. Additionally, the cylindrical segment 246 allows for coupling to conventional tubing / piping, for example, instead of specialized piping, reducing the overall cost of the fuel injection assembly 200. For example, the connecting conduit 212 can be a generally straight tube / pipe that does not require bending or fabrication, thus reducing the overall manufacturing time and cost of the fuel injection assembly 200.

[0051] 11-17 each illustrate a cross section of a polygonal segment 244 of a fuel duct 208 in accordance with an embodiment of the present disclosure. As shown, the polygonal segment 244 of the fuel duct 208 may include a centerline 248 that extends through the center of the cross section and is generally parallel to the axial centerline 216 of the fuel injectors 202, 204. In various embodiments, the centerline 248 may be generally parallel to one or both of the sidewalls 252, 254. In many embodiments, the polygonal segment 244 of the fuel duct 208 may include at least one sloped end wall 250 that is sloped or angled relative to the centerline 248 of the polygonal segment 244.

[0052] For example, in some embodiments, the angled end wall 250 may form an angle 256 with the centerline 248 of the polygonal segment 244 that is between about 10° and about 80°. In other embodiments, the angled end wall 250 may form an angle 256 with the centerline 248 of the polygonal segment 244 that is between about 20° and about 70°. In various embodiments, the angled end wall 250 may form an angle 256 with the centerline 248 of the polygonal segment 244 that is between about 30° and about 60°. In certain embodiments, the angled end wall 250 may form an angle 256 with the centerline 248 of the polygonal segment 244 that is between about 40° and about 50°. The angle 256 of the angled end wall 250 advantageously allows the polygonal segment 244 of the fuel duct 208 to be fabricated using an additive manufacturing process with minimal or no temporary supports. For example, the structure of polygonal segment 244 does not require additively manufactured temporary supports and / or additional structures, and therefore does not require post-processing to remove such supports, thereby saving both manufacturing time and costs.

[0053] In many embodiments, the polygonal segment 244 of the fuel duct 208 may include a vertical end wall 266, a first side wall 252, and a second side wall 254. In the embodiment shown in FIGS. 11-12 , the vertical end wall 266 may be axially spaced from the one or more angled end walls 250 relative to the centerline 248 of the polygonal segment. In such embodiments, the vertical end wall 266 may extend between the first side wall 252 and the second side wall 254. In the exemplary embodiment, the vertical end wall 266 may be generally perpendicular to both the side walls 252, 254 and the centerline 248 of the polygonal segment 244.

[0054] In various embodiments, the first side wall 252 and the second side wall 254 can extend between the vertical end wall 266 and the angled end wall 250, as shown in Figures 11, 12, and 16. In other embodiments, the polygonal segment 244 can include only one side wall 252 that extends directly between the vertical end wall 266 and the angled end wall 250, as shown in Figure 13. In yet other embodiments, the polygonal segment 244 can not include any side walls, such that the vertical wall 266 extends directly between the first angled wall 258 and the second angled wall 260, as shown in Figure 14.

[0055] 11 and 14, the angled end wall 250 may be a first angled end wall 258, and the polygonal segment of the fuel duct may further include a second angled end wall 260 disposed opposite the first angled end wall 258. In other embodiments, as shown in FIGS. 15 and 16, the polygonal segment 244 may include a third angled end wall 262 and a fourth angled end wall 264 such that no vertical end walls are present.

[0056] FIG. 17 shows an enlarged perspective view of the fuel duct 208 of the downstream fuel injector 204, and FIG. 18 shows an enlarged perspective view of the fuel duct 208 of the upstream fuel injector 202. As shown in FIGS. 17 and 18 , each of the fuel ducts 208 of the fuel injectors 202, 204 can seamlessly transition between the polygonal segment 244 and the cylindrical segment 246, 268. For example, the fuel duct 208 can transition between the polygonal segment 244 and the cylindrical segment 246, 268 such that the entire fuel duct 208 is a single, continuous piece of metal. In this manner, the fuel duct 208 may advantageously include fewer subcomponents and may advantageously include no joints. Additionally, a fuel duct 208 with a seamless transition advantageously prevents leaks and improves overall performance.

[0057] FIG. 19 illustrates an enlarged perspective view of an alternative embodiment of the fuel duct 208 for the downstream fuel injector 204, and FIG. 20 illustrates an enlarged perspective view of an alternative embodiment of the fuel duct 208 for the upstream fuel injector 202. As shown in FIGS. 19 and 20 , in some embodiments, the polygonal segment 244 of the fuel duct 208 can include a first portion 270 and a second portion 272 that extend continuously with one another. The first portion can extend generally perpendicularly away from the body 206, and the second portion can curve and extend toward the primary outlet 224 of the fuel injector 202. In this manner, the second portion 272 of the polygonal segment 244 can extend axially relative to the axial centerline 248 of the fuel injectors 202, 204 beyond where the second annular wall 230 is coupled to the first annular wall 214. In many embodiments, as shown in FIG. 19 , the fuel duct 208 of the upstream fuel injector 202 may include a conical ceiling 274, which advantageously allows the fuel duct 208 to be additively manufactured with minimal or no temporary supports, thereby reducing manufacturing time and costs.

[0058] 20 , in some embodiments, the fuel duct 208 may include a transition piece 276 extending from the polygonal segment 244 of the fuel duct 208. More specifically, the transition piece 276 may extend from the second portion 272 of the polygonal segment 244 of the fuel duct 208. The transition piece 276 may include a tapered ceiling portion 278 extending between a cylindrical inlet segment 280 and a cylindrical outlet segment 282. The tapered ceiling portion 278 may advantageously be additively manufactured without temporary support structures, thereby reducing the overall manufacturing time and associated costs associated with manufacturing the fuel injector 204.

[0059] This written description uses examples to disclose the invention, including the best mode, and to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they contain structural elements that do not differ from the literal language of the claims, or equivalent structural elements that do not differ substantially from the literal language of the claims. [Explanation of symbols]

[0060] 10. Gas turbine 12 Entrance Section 14 Compressor 16 Combustion section, combustor 18 Turbine 20 Exhaust Section 22 Gas turbine shaft 24 Air 26 Compressed air 28 Fuel 30 Combustion Gas 32 Compressor discharge casing 34 High-Pressure Plenum 36 Annular Combustion System 38 Axial centerline 100 Integrated combustor nozzle, integrated combustion nozzle 102 Primary Combustion Zone 104 Secondary Combustion Zone 106 Inner liner segment 108 Outer liner segment 110 Combustion liner, fuel injection panel 112 Front end, upstream end 114 Rear end section, downstream end section 116 first side wall, pressure side wall 117 Fuel injection module 118 second side wall, negative pressure side wall 120 Integral turbine nozzle, downstream turbine nozzle 122 Cross-fire tube 124 Air cavity, forward air cavity 126 Air Cavity 127 Rear air cavity 128 Ribs, bulkheads 129 Ribs, bulkheads 130 Fuel Source 132 Pipe fittings 164 positive pressure side injection outlet 165 Negative pressure side injection outlet 200 Fuel injection assembly, fuel injector assembly 202 Negative pressure side fuel injector, positive pressure side fuel injector, first injector, upstream fuel injector 204 Negative pressure side fuel injector, positive pressure side fuel injector, second injector, downstream fuel injector 206 Main Unit 208 Fuel Duct 210 Fluid supply conduit 212 Connecting conduit 214 First Circular Wall, Wall 216 Axial centerline 218 Premix passage 220 Primary entrance 222 first end 224 Primary exit 226 Second End 230 Second Circular Wall 232 Fuel Plenum 234 First End Wall 236 Second End Wall 238 Side wall 240 fuel outlet 242 Fuel inlet 244 polygon segments 246 Cylindrical inlet segment, cylindrical segment 248 Center line, axial center line 250 Inclined End Wall 252 First Side Wall 254 Second Side Wall 256 angle 258 First inclined wall, first inclined end wall 260 Second inclined wall, second inclined end wall 262 Third Sloping End Wall 264 Fourth Sloping End Wall 266 Vertical walls, vertical end walls, end walls 268 Cylindrical outlet section, cylindrical inlet segment, cylindrical outlet segment, cylindrical segment 270 First Part 272 Second Part 274 Conical Ceiling 276 Transition Piece 278 Tapered ceiling section 280 Cylindrical Inlet Segment 282 Cylindrical Exit Segment 284 diameter 286 diameter 288 Secondary conduit 290 Secondary entrance 292 Secondary exit 294 fuel port

Claims

1. A fuel injection assembly (200) comprising a fuel injector (202), the fuel injector (202) having a body (206) and a fuel duct (208), the body (206) comprising: a first annular wall (214) extending about an axial centerline (216), the first annular wall (214) extending from a primary inlet (220) located at a first end (222) to a primary outlet (224) located at a second end (226); a second annular wall (230) surrounding the first annular wall (214); a fuel plenum (232) defined between the first annular wall (214) and the second annular wall (230); It is equipped with the fuel duct (208) extends from a fuel inlet (242) to a fuel outlet (240) defined in the second annular wall (230), the fuel outlet (240) being in fluid communication with the fuel plenum (232), the fuel duct (208) comprising a polygonal segment (244) and a cylindrical inlet segment (246), the polygonal segment (244) extending from the fuel outlet (240) to the cylindrical inlet segment (246); the polygonal segment of the fuel duct has an angled end wall relative to a centerline of the polygonal segment, the angled end wall further comprising a first angled end wall and a second angled end wall extending from the first angled end wall, the centerline of the polygonal segment being perpendicular to a direction of fluid flow through the fuel duct, and the second angled end wall being disposed opposite the first angled end wall and joining the first angled end wall; The polygonal segment (244) of the fuel duct (208) further comprises a first sidewall (252), a second sidewall (254), and a vertical end wall (266) perpendicular to the first and second sidewalls (252), (254), and the centerline (248) of the polygonal segment (244), wherein the first angled end wall (258) extends between the second sidewall (254) and the second angled end wall (260), and the second sidewall (254) is perpendicular to the first sidewall (252) and the first angled end wall (260). a first sidewall (252) and a second sidewall (254) extending between the first sidewall (252) and the second sidewall (254), the first sidewall (252) being axially spaced from the second sidewall (254) relative to the centerline (248) of the polygonal segment (244), the first sidewall (252) being axially spaced from ... second sidewall (254) being axially spaced from the first sidewall (252) and the second sidewall (254), the first sidewall (252) being axially spaced from the first sidewall (252) and the second sidewall (254), the second sidewall (254) being axially spaced from the first sidewall (252) and the second sidewall (254), the first sidewall (252) being axially spaced from the second sidewall (254) relative to the centerline (248) of the polygonal segment (244).

2. The fuel injection assembly (200) of any preceding claim, wherein the fuel duct (208) seamlessly transitions from the polygonal segment (244) to the cylindrical inlet segment (246) at a transition zone (276).

3. 2. The fuel injection assembly of claim 1, wherein the second annular wall comprises a first end wall, a second end wall spaced from the first end wall, and a side wall extending between the first end wall and the second end wall, and the fuel duct extends from the first end wall.

4. 2. The fuel injection assembly of claim 1, wherein the fuel injector is a first fuel injector, the fuel duct of the first fuel injector includes a cylindrical outlet segment, a fluid supply conduit fluidly couples the cylindrical inlet segment of the first fuel injector to a fuel supply source, and a connecting conduit fluidly couples the cylindrical outlet segment of the first fuel injector to the cylindrical inlet segment of a second fuel injector.

5. The fuel injection assembly (200) of claim 4, wherein the connecting conduit (212) is shaped as a straight hollow cylinder.

6. The fuel injector (202) is a first fuel injector (202), and the fuel injection assembly (200) further includes a second fuel injector (204) coupled to the first fuel injector (202) via a connecting conduit (212), the second fuel injector (204) having a body (206) and a fuel duct (208), the body (206) of the second fuel injector (204) being aligned with an axial centerline (216) of the second fuel injector (204). a first annular wall (214) extending around the second fuel injector (204) from a primary inlet (220) disposed at a first end (222) to a primary outlet (224) disposed at a second end (226); and a second annular wall (230) surrounding the first annular wall (214) of the second fuel injector (204), wherein a fuel plenum (232) is formed between the first annular wall (214) of the second fuel injector (204) and the second annular wall (230). a second annular wall (230) between the fuel injector (204) and the fuel duct (208) of the second fuel injector (204) extending from a fuel outlet (240) defined in the second annular wall (230) of the second fuel injector (204) to a fuel inlet (242), the fuel duct (208) of the second fuel injector (204) being in fluid communication with the fuel plenum (232) of the second fuel injector (204), 2. The fuel injection assembly of claim 1, wherein the fuel duct of a fuel injector comprises a polygonal segment and a cylindrical inlet segment, and the polygonal segment of the second fuel injector extends from the fuel outlet of the second fuel injector to the cylindrical inlet segment of the second fuel injector.

7. a primary fuel nozzle; a combustion liner (110) extending radially between an inner liner segment (106) and an outer liner segment (108), the combustion liner (110) including a forward end portion (112), an aft end portion (114), a first sidewall (116) of the combustion liner (110), and a second sidewall (118) of the combustion liner (110), the combustion liner (110) defining a cavity (124, 126, 127) extending between the first sidewall (116) of the combustion liner (110) and the second sidewall (118) of the combustion liner (110); a fuel injection assembly (200) according to any one of claims 1 to 6 positioned downstream of the primary fuel nozzle; A combustor comprising:

Images