Improved fuel circuit for fuel injectors

Abstract

To provide a fuel injector that advantageously minimizes recirculation and flow vortices and that equalizes pressure drop along its entire length, thereby reducing the overall emissions of a gas turbine.SOLUTION: A fuel injector 200 includes a forward end wall 206 and an aft end wall 208. The fuel injector further includes side walls that extend between the forward end wall and the aft end wall. The forward end wall, the aft end wall and the side walls collectively define an opening 210 for passage of air. At least one fuel injection member is disposed within the opening and extends between the end walls. A fuel circuit is defined within the fuel injector. The fuel circuit includes an inlet plenum 252 defined within the forward end wall of the fuel injector. The fuel circuit further includes a fuel passage 254 that extends from, and is in fluid communication with, the inlet plenum. The fuel passage is defined within the at least one fuel injection member. The fuel passage has a cross-sectional area that varies along the length of the fuel injection member.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates generally to fuel injectors for combustors of gas turbines, and more particularly to fuel injectors for use in 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 and 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 gas generation occurs in two spaced-apart stages. Such combustors are referred to herein as combustors with an "axial fuel staging" (AFS) system, which delivers fuel and oxidizer to one or more fuel injectors downstream of the combustor's head end. In combustors with an AFS system, primary fuel nozzles at the upstream end of the combustor axially inject fuel and air (or a fuel / air mixture) into a primary combustion zone, and AFS fuel injectors located downstream of the primary fuel nozzles inject fuel and air (or a second fuel / air mixture) in a crossflow into a secondary combustion zone downstream of the primary combustion zone. The crossflow is generally transverse to the flow of combustion products from the primary combustion zone. In some cases, it is desirable to introduce the fuel and air as a mixture into the secondary combustion zone. Therefore, the mixing capabilities of the AFS injectors determine the efficiency and / or emissions of the gas turbine's overall operation.

[0004] Typically, an AFS injector includes a hollow injection member with multiple fuel outlets that inject fuel to be mixed with air prior to combustion in the secondary combustion zone. However, the use of hollow fuel injection members presents problems. For example, fuel recirculation in the hollow injection member and uneven pressure drop of the fuel at each of the multiple fuel outlets can result in uneven fuel distribution at the fuel injector. Both recirculation and uneven pressure drop at the fuel injection member can result in uneven mixing of fuel and air at the fuel injector, causing a loss in the overall operating efficiency of the gas turbine.

[0005] Therefore, there is a need in the art for an improved fuel injector that can distribute fuel evenly over its entire length, and in particular, a fuel injector that advantageously minimizes recirculation and flow vortices and equalizes pressure drop over its entire length, thereby reducing the overall emissions of the gas turbine. Summary of the Invention

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

[0007] According to one embodiment, a fuel injector is provided. The fuel injector includes a front end wall and a rear end wall disposed opposite the front end wall. The fuel injector further includes a side wall extending between the front end wall and the rear end wall. The front end wall, the rear end wall, and the side wall cooperatively define an opening for the passage of air. At least one fuel injection member is disposed in the opening and extends between the end walls. A fuel circuit is defined within the fuel injector. The fuel circuit includes an inlet plenum defined within the front end wall of the fuel injector. The fuel circuit further includes a fuel passage extending from the inlet plenum and in fluid communication with the inlet plenum. The fuel passage is defined within the at least one fuel injection member. The fuel passage has a cross-sectional area that varies along a length of the fuel injection member.

[0008] According to another embodiment, a combustor is provided. The combustor includes a head end portion having an end cover and at least one fuel nozzle extending from the end cover. A combustion liner extends between the head end portion and an aft frame and defines a combustion chamber. The combustor further includes a fuel injector disposed downstream from the at least one fuel nozzle and in fluid communication with the combustion chamber. The fuel injector includes a front end wall and an aft end wall disposed opposite the front end wall. The fuel injector further includes sidewalls extending between the front end wall and the aft end wall. The front end wall, the aft end wall, and the sidewalls cooperatively define an opening for the passage of air. At least one fuel injection member is disposed in the opening and extends between the end walls. A fuel circuit is defined within the fuel injector. The fuel circuit includes an inlet plenum defined within the front end wall of the fuel injector. The fuel circuit further includes a fuel passage extending from the inlet plenum and in fluid communication with the inlet plenum. A fuel passage is defined within the at least one fuel injector member, the fuel passage having a cross-sectional area that varies along the length of the fuel injector member.

[0009] These and other features, aspects, and advantages of the present fuel injector 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 injector and combustor, including the best mode of making and using the same, directed to one of ordinary skill in the art, is set forth in this specification, with 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 a cross-sectional schematic view of a combustor according to an embodiment of the present disclosure. [Figure 3] 1 illustrates a perspective view of a fuel injection assembly removed from a combustor according to an embodiment of the present disclosure. [Figure 4] 1 illustrates a cross-sectional plan view of a fuel injection assembly installed in a combustor according to an embodiment of the present disclosure. [Figure 5] 1 illustrates a partial cross-sectional plan view of a fuel injection assembly according to an embodiment of the present disclosure. [Figure 6] 1 illustrates a cross-sectional side view of a fuel injector according to an embodiment of the present disclosure. [Figure 7] 1 illustrates a cross-sectional side view of a fuel injector according to an embodiment of the present disclosure. [Figure 8] 1 illustrates a cross-sectional side view of a fuel injector according to an embodiment of the present disclosure. [Figure 9] 1 illustrates a cross-sectional plan view of a fuel injector according to an embodiment of the present disclosure. [Figure 10] 1 illustrates a cross-sectional plan view of a fuel injector according to an embodiment of the present disclosure. [Figure 11] 1 illustrates a cross-sectional plan view of a fuel injector according to an embodiment of the present disclosure. [Figure 12] 1 illustrates a cross-sectional plan view of a fuel injector according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Reference will now be made in detail to embodiments of the present fuel injector and combustor, one or more examples of which are illustrated in the drawings. Each example is provided to explain the present technology, not to limit it. 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 still a still 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] In the detailed description, numerical and letter designations are used 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 "radial" refers to relative directions that are substantially perpendicular to the axial centerline of a particular component, the term "axial" refers to relative directions that are substantially parallel and / or coaxially aligned with the axial centerline of a particular component, and the term "circumferential" refers to relative directions that extend around the axial centerline of a particular component.

[0015] Approximate terms such as "generally" or "about" include values ​​within plus or minus 10 percent of the stated value. When used in the context of angles or directions, such terms include a range of plus or minus 10 degrees of the stated angle or direction. For example, "generally perpendicular" includes directions within 10 degrees of perpendicular in any direction, e.g., clockwise or counterclockwise.

[0016] 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 industrial or land-based gas turbines unless otherwise expressly 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.

[0017] As shown, the gas turbine 10 generally includes an inlet section 12, a compressor section 14 disposed downstream from the inlet section 12, a plurality of combustors 17 ( FIG. 2 ) in a combustor section 16 disposed downstream from the compressor section 14, a turbine section 18 disposed downstream from the combustor section 16, and an exhaust section 20 disposed downstream from the turbine section 18. Additionally, the gas turbine 10 may include one or more shafts 22 connected between the compressor section 14 and the turbine section 18.

[0018] Compressor section 14 may generally include a plurality of rotor disks 24 (one of which is shown) and a plurality of rotor blades 26 extending radially outward from and connected to each rotor disk 24. Each rotor disk 24 may in turn be connected to or form a portion of a shaft 22 that extends through compressor section 14.

[0019] Turbine section 18 may generally include a plurality of rotor disks 28 (one of which is shown) and a plurality of rotor blades 30 extending radially outward from and connected to each rotor disk 28. Each rotor disk 28 may in turn be connected to or form a portion of a shaft 22 that extends through turbine section 18. Turbine section 18 further includes an outer casing 31 that circumferentially surrounds the portion of shaft 22 and rotor blades 30, thereby at least partially defining a hot gas path 32 through turbine section 18.

[0020] During operation, a working fluid, such as air 15, enters the compressor section 14 through the inlet section 12, where it is gradually compressed, thus providing pressurized or compressed air 19 to the combustors in the combustor section 16. The compressed air is mixed with fuel and burned in each combustor to generate combustion gases 34. The combustion gases 34 enter the turbine section 18 from the combustor section 16 through the hot gas path 32, where energy (kinetic and / or thermal energy) is transferred from the combustion gases 34 to the rotor blades 30, causing rotation of the shaft 22. This mechanical rotational energy can then be used to operate the compressor section 14 and / or generate electricity. The combustion gases 34 exiting the turbine section 18 may then be exhausted from the gas turbine 10 through the exhaust section 20.

[0021] 2 is a schematic diagram of a combustor 17 that may be included in a cannular combustion system for a large gas turbine. In a cannular combustion system, multiple (e.g., 8, 10, 12, 14, 16, or more) combustors 17 are arranged in an annular array about a shaft 22 that connects the compressor section 14 to a turbine section 18. The turbine section 18 may be operably connected (e.g., by shaft 22) to a generator (not shown) to generate electrical power.

[0022] 2, combustor 17 may define an axial direction A and a circumferential direction C extending about axial direction A. Additionally, combustor 17 may define a radial direction R perpendicular to axial direction A.

[0023] In FIG. 2 , the combustor 17 includes a combustion liner 42 that contains and channels the combustion gases 34 to the turbine. The combustion liner 42 can have a cylindrical liner portion and a tapered transition portion separate from the cylindrical liner portion, as in many conventional combustion systems. Alternatively, the combustion liner 42 can have a one-piece body (or “unibody”) configuration in which the cylindrical portion and the tapered portion are integrated with one another. Thus, the description of the combustion liner 42 herein is intended to encompass both conventional combustion systems having separate liners and transition pieces, as well as combustion systems having unibody liners. Furthermore, the present disclosure is equally applicable to combustion systems in which the transition piece and the turbine first-stage nozzle are integrated into a single unit, sometimes referred to as a “transition nozzle” or “integrated outlet piece.”

[0024] The combustion liner 42 is surrounded by an outer sleeve 44, which is spaced radially outward from the combustion liner 42 to define a cooling flow annulus 132 between the combustion liner 42 and the outer sleeve 44. The outer sleeve 44 may include a flow sleeve portion located at a forward end and an impingement sleeve portion located at an aft end, similar to many conventional combustion systems. Alternatively, the outer sleeve 44 may have a one-piece body (or "unisleeve") configuration in which the flow sleeve portion and the impingement sleeve portion are integral with one another in the axial direction A. As previously mentioned, the description of the outer sleeve 44 herein is intended to encompass both conventional combustion systems having separate flow sleeves and impingement sleeves, as well as combustion systems having a unisleeve outer sleeve.

[0025] A head end portion 120 of the combustor 17 includes one or more fuel nozzles 122 extending from an end cover 126 at the forward end of the combustor 17. The fuel nozzles 122 have fuel inlets 124 at their upstream ends (or inlet ends). The fuel inlets 124 may be formed through the end cover 126. The downstream ends (or outlet ends) of the fuel nozzles 122 extend through a combustor cap 128.

[0026] The head-end section 120 of the combustor 17 is at least partially surrounded by a forward casing 130, which is physically coupled and fluidly connected to a compressor discharge case 140. The compressor discharge case 140 is fluidly connected to an outlet of the compressor section 14 (shown in FIG. 1 ) and defines a compressed air plenum 142 that surrounds at least a portion of the combustor 17. Compressed air 19 flows from the compressor discharge case 140 through holes in the outer sleeve 44 near the aft end 118 of the combustor 17 and into the cooling flow annulus 132. Because the cooling flow annulus 132 is fluidly coupled to the forward end section 120, the compressed air 19 travels upstream from near the aft end 118 of the combustor 17 to the head-end section 120, where it reverses direction and enters the fuel nozzles 122.

[0027] The fuel nozzles 122 introduce fuel and air as the primary fuel / air mixture 46 into a primary combustion zone 50 at the forward end of the combustion liner 42 where the fuel and air are combusted. In one embodiment, the fuel and air are mixed within the fuel nozzles 122 (e.g., in a premix fuel nozzle). In other embodiments, the fuel and air may be introduced separately into the primary combustion zone 50 and mixed therein (e.g., as may occur in a diffusion nozzle). References herein to a “first fuel / air mixture” should be interpreted as describing both premixed and diffusion fuel / air mixtures, either of which may be produced by the fuel nozzles 122.

[0028] Combustion gases from the primary combustion zone 50 travel downstream toward the aft end 118 of the combustor 17. One or more fuel injectors 100 introduce fuel and air as a secondary fuel / air mixture 56 into the secondary combustion zone 60 where they are ignited by the combustion gases from the primary zone to form a combined combustion gas product stream 34. Such combustion systems having axially separated combustion zones within a single combustor 17 are referred to as "axially fuel-staging" (AFS) systems, and the injector assembly 100 may be referred to herein as an "AFS injector."

[0029] In the illustrated embodiment, fuel for each injector assembly 100 is supplied from the front end of the combustor 17 via a fuel inlet 154. Each fuel inlet 154 is coupled to a fuel supply line 104 that is coupled to a respective injector assembly 100. It should be understood that other methods of providing fuel to the injector assemblies 100 may be used, such as supplying fuel from a ring manifold or from radially directed fuel supply lines that extend through the compressor discharge case 140.

[0030] 2 further illustrates that the injector assembly 100 may be oriented at an angle θ (theta) relative to the centerline 70 of the combustor 17. In the illustrated embodiment, a leading edge portion of the injector 100 (i.e., the portion of the injector 100 closest to the head end) is oriented away from the centerline 70 of the combustor 17, while a trailing edge portion of the injector 100 is oriented toward the centerline 70 of the combustor 17. The angle θ subtended between the longitudinal axis 75 of the injector 100 and the centerline 70 may be between 0 degrees and ±90 degrees, between 0 degrees and ±80 degrees, between 0 degrees and ±70 degrees, between 0 degrees and ±60 degrees, between 0 degrees and ±50 degrees, between 0 degrees and ±40 degrees, between 0 degrees and ±30 degrees, between 0 degrees and ±20 degrees, or between 0 degrees and ±10 degrees, or any intermediate value therebetween.

[0031] 2 shows the orientation of the injector assembly 100 at a positive angle relative to the combustor centerline 70. In other embodiments (not separately shown), it may be desirable to orient the injector 100 at a negative angle relative to the centerline 70, with the leading edge portion closest to the centerline 70 and the trailing edge portion farther from the centerline 70. In one embodiment, all of the injector assemblies 100 of the combustor 17, when positioned at a non-zero angle, are oriented at the same angle (i.e., all oriented at the same positive angle or all oriented at the same negative angle).

[0032] The injector assembly 100 injects the second fuel / air mixture 56 into the combustion liner 42 transverse to the centerline 70 and / or the flow of combustion products from the primary combustion zone, thereby forming the secondary combustion zone 60. The combined combustion gases 34 from the primary and secondary combustion zones travel downstream through the aft end 118 of the combustor 17 to the turbine section 18 ( FIG. 1 ), where the combustion gases 34 expand and drive the turbine section 18.

[0033] Among other things, to increase the operating efficiency and reduce emissions of the gas turbine 10, it is desirable for the injector 100 to thoroughly mix the fuel and compressed gas to form the second fuel / air mixture 56. Accordingly, the injector embodiments described below facilitate improved mixing. Additionally, because the fuel injector 100 includes multiple fuel injection ports, as described further below, it has an enhanced ability to introduce fuels having a wide range of heat release values, providing greater fuel flexibility for gas turbine operators.

[0034] Figure 3 illustrates an exemplary fuel injector assembly 100 according to an embodiment of the present disclosure. As shown, the injector assembly 100 may include a fuel injector 200 and a boss 300. Although the fuel injector 200 and the boss 300 are shown in Figure 3 as being two separate components coupled together, in many embodiments, the fuel injector 200 and the boss 300 may be a single, integrally formed component.

[0035] As shown, fuel injector 200 includes spaced-apart end walls 202 and side walls 204 extending between end walls 202. In numerous embodiments, when incorporated into combustor 17, side walls 204 of fuel injector 200 may extend parallel to axial direction A ( FIG. 5 ). End walls 202 of fuel injector 200 include a leading end wall 206 and a trailing end wall 208 disposed opposite each other. Side walls 204 may be spaced apart and may extend between leading end wall 206 and a trailing end wall 208.

[0036] In numerous embodiments, both the front end wall 206 and the aft end wall 208 can have an arcuate, generally rounded cross-sectional shape, and the side walls can extend generally straight between the end walls 202, such that the end walls 202 and the side walls 204 cooperatively define a first opening 210 having a cross-section shaped as a geometric stadium. In various embodiments, the side walls 204 can be longer than the end walls 202, such that the opening 210 is longest in the axial direction A when installed in the combustor 17. In some embodiments, as shown, the end walls 202 and the side walls 204 can cooperatively define a geometric stadium-shaped area, i.e., a rectangle with rounded ends, that outlines and defines the perimeter of the first opening 210. In other embodiments (as shown in FIGS. 9 and 10 ), the end walls 202 can be straight, such that the end walls 202 and the side walls 204 cooperatively define a rectangular area.

[0037] In various embodiments, the first opening 210 may function to provide a path through which the compressed air 19 from the compressed air plenum 142 passes to be mixed with fuel before reaching the secondary combustion zone 60. As shown in FIG. 3 , the fuel injector 200 may further include at least one fuel injection member 212 disposed within the first opening 210 and may extend between the end walls 202. In exemplary embodiments, the fuel injection member 212 may extend axially between the end walls 202. The fuel injection member 212 may be a substantially hollow body that functions to supply fuel to the first opening 210 via a plurality of fuel ports 214 defined therethrough. Each fuel injection member 212 may extend from a first end located at the forward end wall 206 to a second end located at the aft end wall 208. In many embodiments, the fuel injection member 212 may extend in an axial direction A in a straight line from the front end wall 206 to the rear end wall 208, i.e., without any abrupt changes in direction.

[0038] 3, the fuel injector is shown as having two fuel injection members 212 spaced apart from one another within the opening 210. However, the fuel injector 200 may have any number (e.g., one, three, four, five, six, or more) of fuel injection members 212 disposed within the first opening 210, and the present disclosure is not limited to any particular number of fuel injection members 212 unless specifically recited in the claims.

[0039] 3, fuel injector 200 further includes a conduit fitting 220 integrally formed with front end wall 206. Conduit fitting 220 may be fluidly coupled to fuel supply line 104 such that conduit fitting 220 operates to receive a flow of fuel from fuel supply line 104. Conduit fitting 220 may then distribute the fuel to fuel injection member 212 and / or each of sidewall fuel injection members 222, 224 (FIG. 4) for injection into first opening 210 and mixing with compressed air 19. Conduit fitting 220 may have any suitable size and shape and may be integrally formed with or coupled to any suitable portion of fuel injector 200 that enables conduit fitting 220 to function as described herein.

[0040] In numerous embodiments, the entire fuel injector 200 may be integrally formed as a single component. That is, each of the subcomponents of the fuel injector 200, such as the end wall 202, the side wall 204, the fuel injection member 212, and any other subcomponents, may be manufactured together as a single unit. In exemplary embodiments, this unitary structure of the fuel injector 200 may be manufactured using additive manufacturing methods, such as 3D printing. In this regard, additive manufacturing methods may be used to form the fuel injector 200 as a single, continuous piece of metal, thereby reducing the number of subcomponents and / or joints involved compared to previous designs. The integral formation of the fuel injector 200 through additive manufacturing may advantageously improve the overall assembly process. For example, integral formation may reduce the number of separate parts that must be assembled, thereby reducing the associated time and overall assembly costs. Furthermore, existing issues, such as leakage, joint quality between separate parts, and overall performance, may be advantageously mitigated. In other embodiments, manufacturing techniques such as casting or other suitable techniques may be used.

[0041] As shown in FIG. 3 , the fuel injector assembly 100 may further include a boss 300. As shown in FIGS. 4 and 5 , the boss 300 may be fixedly coupled to the combustion liner 42 at a first end 302 and may extend radially through the cooling flow annulus 132 to a flange portion 306 disposed at a second end 304. The flange portion 306 may be substantially flat and planar to provide a smooth surface for leak-tight coupling of the fuel injector 200 that minimizes the possibility of fuel / air leakage during operation of the gas turbine 10. In numerous embodiments, the boss 300 may include a jacket portion 308 extending between the first end 302 and the flange portion 306.

[0042] The boss 300 may define a second opening 310 that aligns with the first opening 210 and forms a pathway for introducing fuel and air into the secondary combustion zone 60 ( FIG. 4 ). For example, in some embodiments, the second opening 310 and the first opening 210 may share a common central axis ( FIGS. 4 and 5 ). In this configuration, the boss 300 provides fluid communication between the fuel injector 200 and the secondary combustion zone 60. More specifically, the second opening 310 may be defined by a flange portion 306 and a jacket portion 308 of the boss 300 and may be shaped as a geometric stadium, i.e., a rectangle with semicircular ends.

[0043] In numerous embodiments, the size of the second openings 310 may vary between the fuel injector assemblies 100 on the combustor 17. For example, because the second openings 310 function, at least in part, to meter the flow of air and fuel introduced into the secondary combustion zone 60, it may be advantageous in some embodiments to introduce more or less air and fuel through one or more of the fuel injector assemblies 100 on the combustor 17 than others. This differential metering may be achieved by varying the size of the second openings 310 of at least one fuel injector assembly 100 compared to at least one other fuel injector assembly 100 depending on the desired amount of air and fuel to be introduced into the secondary combustion zone 60 at a given circumferential location.

[0044] FIG. 4 illustrates a cross-sectional view of the fuel injection assembly 100 coupled to the combustor 17. As shown in FIG. 4, the jacket portion 308 extends from the flange 306 through the cooling flow annulus 132 to the combustion liner 42. In many embodiments, the jacket portion 308 creates an obstruction to the flow of compressed air 19 through the cooling flow annulus 132 ( FIG. 4 ). However, as shown in FIG. 3, the jacket portion 308 is shaped as a geometric stadium with a major axis parallel or substantially parallel to the direction of flow of the compressed air 19. This advantageously reduces the obstruction to the compressed air 19 in the cooling flow annulus 132 compared to, for example, a jacket portion having a circular shape, while still providing an adequate area for fuel and air to be introduced through the second opening 310 and entrained in the secondary combustion zone 60.

[0045] In numerous embodiments, as shown, the sidewall 204 may include a first fuel injection member 222 and a second fuel injection member 224. For example, the first and second fuel injection members 222, 224 may be integrally formed within the sidewall 204 to both serve to partially define the first opening 210 and to inject fuel through the plurality of fuel ports 214 for mixing within the fuel injector 200. In various embodiments, as shown, the fuel injection member 212 may include a third fuel injection member 226 and a fourth fuel injection member 228 disposed between the first and second fuel injection members 222, 224 defined within the sidewall 204.

[0046] In embodiments having four fuel injection members, there may be six injection surfaces within the fuel injector 200. For example, a single row of fuel ports 214 may be defined in each of the sidewall fuel injection members 222, 224, providing two of the fuel injection surfaces. Four additional fuel injection surfaces may be located on the centrally located fuel injection members 226, 228. For example, each of the fuel injection members 226, 228 may have a single row of fuel ports 214 located on either side of the fuel injection members 226, 228, thereby providing four fuel injection surfaces. In some embodiments, the first and second fuel injection members 222, 224 may converge toward each other as they extend radially inward. In this manner, the overall geometric stadium area defined by the end wall 202 and side wall 204 gradually decreases from the radially outer surface to the radially inner surface of the fuel injector 200.

[0047] As shown in FIG. 4 , each of the fuel injection members 226, 228 may have an outer cross-sectional shape 240 that defines a teardrop shape. As shown, the teardrop shape is characterized by a leading edge 234, a trailing edge 236 opposite the leading edge 234, and a wall 238. The wall 238 may extend between the leading edge 234 and the trailing edge 236. In numerous embodiments, the wall 238 of each fuel injection member 226, 228 defines a plurality of fuel injection ports 214. In at least one embodiment, the fuel injection ports 214 may be arranged in a row ( FIG. 6 ). While the fuel injection members 226, 228 are shown in FIG. 4 as having an outer cross-sectional shape 240 that defines a teardrop shape, each of the fuel injection members 226, 228 may have an outer cross-sectional shape that defines a circle, a triangle, a diamond, a rectangle, or any other suitable cross-sectional shape.

[0048] 3-5 collectively, the outer cross-sectional shape 240 of the fuel injection members 226, 228 may be uniform in the axial direction A such that there are no abrupt changes in shape or orientation in the axial direction A extension from the leading end wall 206 to the trailing end wall 208. In this manner, the outer cross-sectional shape 240 may be uniform in the axial direction A, although the internal shape may vary along the axial direction A, as shown in FIGS.

[0049] FIG. 5 illustrates a partial cross-sectional plan view of the fuel injection assembly 100. As shown, the fuel injector 200 may further include a fuel circuit 250 defined therein. As shown, the fuel circuit 250 may be fluidly coupled to the fuel supply line 104 via a conduit fitting 220. In various embodiments, the fuel circuit 250 includes an inlet plenum 252 defined within the front end wall 206 of the fuel injector 200. The inlet plenum 252 may receive fuel from the fuel supply line 104 and distribute it to one or more fuel passages 254 defined within the sidewall fuel injection members 222, 224 and / or the fuel injection members 226, 228. In some embodiments, as shown in FIG. 5 , each of the fuel passages 254 may extend directly from the inlet fuel plenum 252 to the aft end wall 208 along the axial direction A. In various embodiments, each of the fuel passages 254 may be parallel to one another.

[0050] 5 , a plurality of fuel ports 214 may be defined in the sidewall fuel injection members 222, 224 and / or the fuel injection members 226, 228 and may be in fluid communication with a respective fuel passage 254 for supplying fuel to the first opening 210 to be mixed with the compressed air 19 before entering the secondary combustion zone 60. For example, in various embodiments, each fuel port 214 of the plurality of fuel ports 214 may extend between a respective fuel passage 254 and the opening 210.

[0051] 6-8 illustrate cross-sectional side views of fuel injector 200 illustrating a fuel injection member 260 according to an embodiment of the present disclosure. Fuel injection member 260 shown in FIGS. 6-8 may be representative of either or both of sidewall fuel injection members 222, 224 and / or fuel injection members 226, 228 described herein. As shown, injection member 260 is disposed within first opening 210 and extends axially between end walls 202.

[0052] As described herein, the fuel injector 200 may further define a fuel circuit 250 having an inlet plenum 252 and a fuel passage 254. In various embodiments, the inlet plenum 252 may be defined within the front end wall 206 of the fuel injector 200. The fuel passage 254 may extend directly from the inlet plenum 252 within the fuel injection member 260 and terminate near the rear end wall 208. In various embodiments, fuel from the inlet fuel plenum 252 may enter the fuel passage 254 for injection into the opening 210 via a plurality of fuel ports 214 disposed along the fuel injection member 260. In some embodiments, the fuel passage 254 may terminate within the rear end wall 208. In other embodiments, the fuel passage 254 may terminate forward of the rear end wall 208.

[0053] In many embodiments, the fuel passage 254 may have a cross-sectional area that varies along the axial length 256 of the fuel injection member 260. Specifically, as shown, the radial height 258, i.e., the width of the fuel passage 254 measured in the radial direction, may vary as the passage extends along its length in the axial direction A, thereby reducing the overall cross-sectional area of ​​the fuel passage 254. In some embodiments, the fuel passage 260 may include a radially inner edge 262 and a radially outer edge 264 that define radially inner and outer flow boundaries of the fuel passage 254, respectively.

[0054] 6 , the radially outer edge 264 may be a straight line that is generally parallel to the leading edge 234 of the fuel injection member 260 along the axial direction A. The radially inner edge 262 of the flow passage 254 may gradually taper toward the radially outer edge 264 as the passage extends in the axial direction A. In other words, the radially inner edge 262 may be a straight edge (no curve) that slopes toward the radially outer edge 264 such that the radially inner edge 262 gradually and continuously converges toward the radially outer edge 264 as it extends in the axial direction A. In this configuration, the radial height 258 may decrease at a constant rate as the flow passage 254 extends in the axial direction A from the front end wall 206 to the aft end wall 208.

[0055] 6, the radially inner edge 262 is shown as including a taper, and the radially outer edge 264 is shown as being parallel to the leading edge 234. In other embodiments (not shown), the radially outer edge 264 may include a taper, and the radially inner edge 262 may be parallel to the leading edge 234.

[0056] As shown in FIG. 7 , the fuel passage 254 may include a straight portion 265, a first converging portion 266 along the radial direction R, a diverging portion 268, and a second converging portion 270. The straight portion 265 of the fuel passage 254 may extend from the inlet plenum 252 to the first converging portion 266, and the diverging portion 268 may extend from the first converging portion 266 to the second converging portion 270. As shown in FIG. 7 , the straight portion may be a portion of the fuel passage 254 that has a uniform, i.e., constant or unchanging, cross-sectional area as the fuel passage 254 extends in the radial direction A. The converging portions 266, 270 of the fuel passage 254 may be portions of the fuel passage 254 that decrease in cross-sectional area as the fuel passage 254 extends along the axial direction A. Conversely, the diverging portion 268 may be a portion of the fuel passage where the cross-sectional area of ​​the passage increases as the fuel passage 254 extends along the axial direction A.

[0057] 7 , the radially outer edge 264 may be a straight line that is generally parallel to the leading edge 234 of the fuel injection member 260 throughout the axial length 256 of the fuel injection member 260. As shown, in the straight portion 265, the radially outer edge 264 and the radially inner edge 262 may be parallel to one another such that the radial height 258 is constant throughout the straight portion 265. In the converging portions 266, 270 of the fuel passage 254, the radially inner edge 262 may be arcuate and converge toward the radially outer edge 264 as the fuel passage extends in the axial direction A, thereby decreasing the radial height 258 and total cross-sectional area of ​​the fuel passage 254 along the axial direction A. Conversely, in the diverging portion 268 of the fuel passage 254, the radially inner edge 262 may be arcuate and diverge away from the radially outer edge 264, thereby increasing the radial height 258 and total cross-sectional area of ​​the fuel passage 254 along the axial direction A.

[0058] 8 , the radially outer edge 264 may include a curved portion 272. As shown, the curved portion 272 of the radially outer edge 264 may be arcuate, converging toward the radially inner edge 262 and then diverging away from the radially inner edge 262 as the fuel passage 254 extends in the axial direction A, thereby varying the radial height 258 and total cross-sectional area of ​​the fuel passage 254 along the axial direction A. In numerous embodiments, as shown, the curved portion 272 may have a generally parabolic or “U” shape. The curved portion may function to advantageously reduce flow separation, recirculation, and flow vortices that may occur if the fuel passage 254 were completely straight.

[0059] 6-8, the radially inner edge 262 is shown as tapered and / or curved along the axial direction A, while the radially outer edge is generally straight or mostly straight. However, in other embodiments (not shown), the edge geometries can be reversed such that the radially inner edge 262 is straight or mostly straight, while the radially outer edge 264 is curved along the axial direction A.

[0060] 6-8 and described herein, the fuel passages 254 may be defined within the fuel injection member 260 and may have a cross-section that varies in the axial direction A. However, the outer cross-sectional shape 240, which in some embodiments may be shaped as a teardrop, may be constant, uniform, and / or unchanging as the fuel injector 260 extends axially. Advances in manufacturing methods, such as the additive manufacturing methods described herein, allow for complex and varying fuel passages 254 within the fuel injection member 260 while maintaining a constant outer cross-sectional shape 240, which is important for uniform airflow across the fuel injection member 260.

[0061] 9-12 illustrate plan views of a fuel injector 200 according to an embodiment of the present disclosure, taken along a radial direction R, from a radially outward direction of the fuel injector 200. As shown, the fuel injector 200 includes only a single fuel injection member 260. It will be appreciated that the features of the fuel injection member 260 illustrated in FIGS. 9-12 may be incorporated into any of the fuel injection members described herein, such as the sidewall fuel injection members 222, 224 and / or the fuel injection members 226, 228. As shown in FIGS. 9-12, the fuel injector 200 may include a transverse direction T that is tangential to the circumferential direction C of the combustor and perpendicular to both the radial direction R and the axial direction A.

[0062] 9 , the fuel passage 254 may further include a converging portion 274 and a diverging portion 276 along the transverse direction T. As shown, the opposing walls 238 of the fuel injection member 260 may include oppositely positioned inner surfaces 278, 280 that form flow boundaries in the transverse direction T for fuel traveling through the fuel passage 254. In the converging portion 274 of the fuel passage 254, the inner surfaces 278, 280 may be arcuate and converge toward each other as the fuel passage 254 extends in the axial direction A, thereby reducing the transverse length 282 and total cross-sectional area of ​​the fuel passage 254 along the axial direction A.

[0063] Conversely, in the diverging portion 276, the inner surfaces 278, 280 may be arcuate and may diverge away from each other as the fuel passage 254 extends in the axial direction A, thereby increasing the lateral length 282 and total cross-sectional area of ​​the fuel passage 254 along the axial direction A. Varying the lateral length 282 within the fuel passage 254 may advantageously reduce fuel flow separation, recirculation, and flow vortices in the fuel passage.

[0064] 11 and 12, the first and second inner surfaces 278, 280 may be straight such that the lateral length 282 is axially uniform. Thus, in certain embodiments, the fuel passages 254 may vary in radial length only, lateral length only, or both radial and lateral lengths.

[0065] In the embodiment shown in FIG. 10 , the fuel passage 254 may converge or taper as it extends axially from the inlet plenum 252 such that its transverse length 282 decreases at a constant rate in the axial direction. As shown, the opposing walls 238 of the fuel injection member 260 may include oppositely positioned inner surfaces 278, 280 that form flow boundaries in the transverse direction T for fuel traveling through the fuel passage 254. In the embodiment shown in FIG. 10 , the inner surfaces 278, 280 may taper toward each other at a constant rate, thereby reducing the transverse length 282 and total cross-sectional area of ​​the fuel passage 254 along the axial direction A. The gradual decrease in the transverse length 282 within the fuel passage 254 may advantageously reduce fuel flow separation, recirculation, and flow vortices in the fuel passage.

[0066] 9 and 10 , each of the plurality of fuel ports 214 may be defined in the wall 238 of the fuel injection member 260. More specifically, each of the plurality of fuel ports 214 may extend between a respective inner surface 278, 280 of the wall 238 and a respective outer surface 288, 290 of the wall 238.

[0067] As shown in FIG. 11 , each of the plurality of fuel ports 214 may include a chamfered inlet 286. The chamfered inlet 286 may be conical such that the fuel port 214 gradually tapers from a first diameter 292 at the inlet to a second diameter 294 at a transition point 296 disposed between the inlet and outlet of the fuel port 214. As shown in FIG. 11 , the first diameter 292 may be larger than the second diameter 294. At the transition point 296, each of the fuel ports 214 may transition from a conical shape to a cylindrical shape such that the second diameter is constant from the transition point 296 to the outlet of the fuel port 214. Utilizing fuel ports 214 with chamfered inlets 286 may advantageously provide a more uniform fuel distribution within the first opening 210, allowing for more uniform mixing of the fuel and air entering the secondary combustion chamber 60. As described herein, a homogeneously mixed fuel / air mixture may enhance the overall performance of the gas turbine 10 .

[0068] As shown in FIG. 12 , each of the plurality of fuel ports 214 can include a rounded inlet 287. For example, the rounded inlet 287 of each fuel port 214 can be generally convex or otherwise rounded such that the fuel port 214 gradually tapers from a first diameter 293 at the inlet to a second diameter 295 at a transition point 297 disposed between the inlet and outlet of the fuel port 214. As shown in FIG. 12 , the first diameter 293 can be larger than the second diameter 295. At the transition point 297, each of the fuel ports 214 can transition from a rounded shape to a cylindrical shape such that the second diameter 295 is constant from the transition point 297 to the outlet of the fuel port 214. Utilizing fuel ports 214 having rounded inlets 287 may advantageously provide a more uniform distribution of fuel within first opening 210 and may allow for more uniform mixing of the fuel and air entering secondary combustion chamber 60. As described herein, a uniformly mixed fuel / air mixture may enhance the overall performance of gas turbine 10.

[0069] As disclosed herein, varying the cross-sectional area of ​​the fuel passages 254 along the length of the fuel injection member 260, rather than, for example, having fuel passages with a uniform cross-sectional area, advantageously minimizes fuel recirculation, flow separation, and flow vortices moving through the fuel passages 254. This variation in cross-section results in even fuel distribution through the fuel ports 214. Even fuel distribution improves fuel and air mixing within the fuel injector 200, thus improving the overall operating efficiency of the gas turbine 10. Furthermore, reducing the cross-sectional area of ​​the fuel passages 254 in certain portions allows the fuel to have a much more uniform pressure along the entire length of the fuel injection member 260. For example, although there is a loss of pressure at each of the fuel ports 214, the reduction in the cross-sectional area of ​​the fuel passages 254 increases the fuel pressure, compensating for the drop caused by the fuel ports 214.

[0070] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any related 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 encompassed within the scope of the claims if they contain structural elements that do not deviate from the literal language of the claims, or if they contain equivalent structural elements that do not deviate substantially from the literal language of the claims. [Explanation of symbols]

[0071] 10. Gas turbine 12 Entrance Section 14 Compressor Section 15. Air 16 Combustor Section 17 Combustor 18 Turbine Section 19 Pressurized Air 20 Exhaust Section 22 shaft 24 rotor disc 26 rotor blades 28 rotor disc 30 rotor blades 31 outer casing 32 Hot gas path 34 Combustion Gas 42 Combustion Liner 44 Outer sleeve 46 Primary Fuel / Air Mixture 50 Primary Combustion Zone 56 Second fuel / air mixture, secondary fuel / air mixture 60 Secondary combustion zone, secondary combustion chamber 70 center line 75 Longitudinal axis 100 Fuel injector assembly, fuel injection assembly 104 Fuel supply line 118 Rear end 120 Head end part 122 fuel nozzle 124 Fuel inlet 126 End Cover 128 Combustor Cap 130 Front casing 132 Cooling flow annulus 140 Compressor discharge case 142 Pressurized Air Plenum 154 Fuel inlet 200 fuel injector 202 End Wall 204 Side wall 206 Front end wall 208 Back end wall 210 Opening 212 Fuel injection member 214 Fuel injection port 220 Pipe fittings 222 first sidewall fuel injection member 224 second sidewall fuel injection member 226 Third fuel injection member 228 Fourth fuel injection member 234 leading edge 236 Trailing edge 238 Wall 240 External cross-sectional shape 250 Fuel circuit 252 Inlet fuel plenum 254 Fuel passages, flow paths 256 axial length 258 Radial Height 260 Fuel injection member, fuel injector 262 radial inner edge 264 Radial Outer Edge 265 Straight section 266 First Convergence Section 268 Divergent Part 270 Second Convergence 272 curved part 274 Convergence 276 Divergent Part 278 Inner 280 Interior 282 Horizontal length 286 Chamfered Entrance 287 Rounded Entrance 288 Exterior 290 Exterior 292 First Diameter 293 First Diameter 294 Second Diameter 295 Second Diameter 296 Transition Point 297 Transition Point 300 Boss 302 first end 304 Second End 306 flange part 308 Jacket part 310 Second Opening

Claims

1. A fuel injector (200), comprising: a front end wall (206) and a rear end wall (208) disposed opposite the front end wall (206); a side wall (204) extending between the front end wall (206) and the rear end wall (208), the side wall (204) cooperating with the front end wall (206) and the rear end wall (208) defining an opening (210) for the passage of air; at least one fuel injection member (212) disposed within the opening (210) and extending between the front end wall (206) and the rear end wall (208); a fuel circuit (250) defined within the fuel injector (200); The fuel circuit (250) comprises: an inlet plenum (252) defined in the front end wall (206) of the fuel injector (200); a fuel passage (254) extending from and in fluid communication with the inlet plenum (252); wherein the fuel passage (254) is defined in the at least one fuel injection member (212), the fuel passage (254) has a cross-sectional area that varies along a length of the fuel injection member (212), and the fuel passage (254) includes a first converging portion (266), a diverging portion (268), and a second converging portion (270).

2. The fuel injector (200) of claim 1, wherein the fuel injection member (212) includes a uniform outer cross-sectional shape along the entire length of the fuel injection member (212).

3. A fuel injector (200) as described in claim 1, further comprising a plurality of fuel ports (214) defined on the fuel injection member (212), the plurality of fuel ports (214) providing fluid communication between the fuel passage (254) and the opening (210).

4. The fuel injector (200) of claim 3, wherein each of the plurality of fuel ports (214) includes one of a chamfered inlet (286) or a rounded inlet (287).

5. 2. The fuel injector of claim 1, wherein the at least one fuel injection member comprises a pair of fuel injection members disposed between the sidewalls, the fuel passage being defined in a first fuel injection member of the pair of fuel injection members, and the second fuel passage being defined in a second fuel injection member of the pair of fuel injection members.

6. 6. The fuel injector of claim 5, wherein the first fuel passage and the second fuel passage each have a respective cross-sectional area that varies from the inlet plenum to the aft end wall.

7. 6. The fuel injector of claim 5, wherein the sidewall includes a first sidewall fuel injection member and a second sidewall fuel injection member, a first sidewall fuel passage defined in the first sidewall fuel injection member and a second sidewall fuel passage defined in the second sidewall fuel injection member, the first sidewall fuel passage and the second sidewall fuel passage extending from and in fluid communication with the inlet plenum.

8. 6. The fuel injector of claim 5, wherein the first sidewall fuel passage and the second sidewall fuel passage each have a respective cross-sectional area that varies from the inlet plenum to the aft end wall.

9. A combustor (17), comprising: an end cover (126); at least one fuel nozzle extending between the end cover and a combustion liner, the combustion liner extending between the at least one fuel nozzle and an aft frame and defining a combustion chamber; A fuel injector (200) according to any one of claims 1 to 8, disposed downstream of the at least one fuel nozzle (122) and in fluid communication with the combustion chamber; A combustor (17) comprising:

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