Hydrogen-compatible fuel injector

Abstract

We provide hydrogen-compatible fuel injectors. [Solution] A fuel injector (200) for a gas turbine combustor (17) is provided. The fuel injector (200) includes an annular main body (300) extending from a first end (301) to a second end (302). The annular main body (300) defines a central axis (303) extending from the first end (301) to the second end (302), and at least a portion of a fuel circuit (320) extends along the central axis (303). A first plurality of fluid inlets (345) are arranged around the fuel circuit (320), and a second plurality of fluid inlets (350) are arranged around the first plurality of fluid inlets (345). The fuel circuit (320) includes a fuel inlet (324) and a fuel outlet (330) that is in fluid communication with the fuel inlet (324). The outer surface of the fuel outlet (330) forms a fuel outlet angle (500) with respect to the center axis (303).

Description

Technical Field

[0001] The present disclosure generally relates to fuel injectors for gas turbine combustors.

Background Art

[0002] Turbo machines are used in various industries and applications for energy transfer purposes. For example, a gas turbine engine generally includes a compressor section, a combustion section, a turbine section, and an exhaust section. The compressor section gradually increases the pressure of the 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 within the combustion section and burned within the combustion chamber to generate high-pressure and high-temperature combustion gases. The combustion gases flow from the combustion section into the turbine section, where they expand to generate work. For example, the expansion of the combustion gases in the turbine section can rotate a rotor shaft connected to a generator to generate electricity. Then, the combustion gases exit the gas turbine engine through the exhaust section.

[0003] In some combustors, the generation of combustion gases occurs in two or more axially spaced-apart stages. Such combustors are herein referred to as including an "axial fuel staging" (AFS) system, which delivers fuel and oxidant to one or more fuel injectors downstream of the head end of the combustor. In a combustor having an AFS system, a primary fuel nozzle at the upstream end of the combustor injects fuel and air (or a fuel / air mixture) axially into a primary combustion zone, and an AFS fuel injector located at a location downstream of the primary fuel nozzle injects fuel and air (or a second fuel / air mixture) as a crossflow into a secondary combustion zone downstream of the primary combustion zone. The crossflow generally crosses the flow of combustion products from the primary combustion zone.

[0004] Conventional gas turbine engines include one or more combustors that burn a mixture of natural gas and air in a combustion chamber to produce high-pressure, high-temperature combustion gases. By-products include nitrogen oxides (NOx), carbon dioxide (CO2), and other pollutants, which are generated and emitted through the exhaust section. Regulatory requirements for low emissions from gas turbines are becoming increasingly stringent, and environmental agencies worldwide are now demanding even lower emissions of NOx and other pollutants from both new and existing gas turbines.

[0005] Burning a mixture of natural gas and a large amount of hydrogen in a combustor, and / or burning pure hydrogen instead of natural gas, significantly reduces or eliminates CO2 emissions. However, because the combustion characteristics of hydrogen differ from those of natural gas, conventional combustion systems, including conventional AFS fuel injectors, cannot burn high levels of hydrogen and / or pure hydrogen without problems. For example, burning high levels of hydrogen and / or pure hydrogen in a conventional combustion system can promote flashback or flame-holding conditions, where the combustion flame moves towards the fuel supplied by the injector, potentially causing serious damage to the injector in a relatively short time.

[0006] Therefore, there is a need in the art for a fuel injector that can deliver alternative fuels (such as hydrogen) and air to the secondary combustion zone without causing flame-holding or flashback problems. [Overview of the Initiative]

[0007] The embodiments and advantages of the fuel injectors and combustors described herein are partially described in the following description, or become apparent from the description, or can be learned through the practice of the present technology.

[0008] According to one embodiment, a fuel injector for a gas turbine combustor is provided. The fuel injector includes an annular main body extending from a first end to a second end. The annular main body defines a central axis extending from the first end to the second end, and at least a portion of the fuel circuit extends along the central axis. A first plurality of fluid inlets are arranged around the fuel circuit, and a second plurality of fluid inlets are arranged around the first plurality of fluid inlets. The fuel circuit includes a fuel inlet and a fuel outlet that is in fluid communication with the fuel inlet. The outer surface of the fuel outlet forms a fuel outlet angle with respect to the central axis.

[0009] According to another embodiment, a combustor is provided. The combustor includes at least one fuel nozzle, a combustion liner extending downstream of at least one fuel nozzle and defining a combustion chamber, an outer sleeve disposed apart from the combustion liner and surrounding the combustion liner such that an annular portion is defined between the outer sleeve and the combustion liner, and a fuel injector disposed downstream of at least one fuel nozzle and in fluid communication with the combustion chamber. The fuel injector includes an annular main body extending from a first end to a second end. The annular main body defines a central axis extending from the first end to the second end, and a fuel circuit extends along the central axis. A first plurality of fluid inlets are arranged around the fuel circuit, and a second plurality of fluid inlets are arranged around the first plurality of fluid inlets. The fuel circuit includes a fuel inlet and a fuel outlet in fluid communication with the fuel inlet. The outer surface of the fuel outlet forms a fuel outlet angle with respect to the central axis.

[0010] The features, aspects, and advantages of this fuel injector and combustor will be better understood by referring to the following description and the appended claims. The appended drawings, which are incorporated herein and constitute part of this specification, illustrate embodiments of the art and, together with the description in the specification, are useful in explaining the principles of the art.

[0011] A complete and implementable disclosure of the fuel injector and combustor, including the best modes of manufacture and use of the system and method, intended for those skilled in the art, is described herein with reference to the accompanying drawings. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of a turbomachinery according to an embodiment of the present disclosure. [Figure 2] This is a schematic diagram of a combustor that may be used in the turbomachinery shown in Figure 1, according to an embodiment of the present disclosure. [Figure 3] This is a see-through perspective view of a fuel injector that may be used in the combustor shown in Figure 2, according to an embodiment of the present disclosure. [Figure 4] This is a detailed bottom view of the main body of the fuel injector shown in Figure 3, according to an embodiment of the present disclosure. [Figure 5] This is a detailed cross-sectional view of the central portion of the fuel injector shown in Figure 3, according to an embodiment of the present disclosure. [Figure 6] This is a schematic cross-sectional view of the fuel injector shown in Figure 3, according to an embodiment of the present disclosure. [Figure 7] This is a schematic diagram of a fuel-air mixture that can be produced by the fuel injector shown in Figure 3, according to embodiments of the present disclosure. [Figure 8A] This is a schematic diagram of the first stage of the fuel-air mixture shown in Figure 7, according to an embodiment of the present disclosure. [Figure 8B] This is a schematic diagram of the second stage of the fuel-air mixture shown in Figure 7, according to an embodiment of the present disclosure. [Figure 8C] This is a schematic diagram of the third stage of the fuel-air mixture shown in Figure 7, according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0013] Hereinafter, embodiments of the fuel injector and combustor are given in detail, one or more of which are shown in the drawings. Each example is provided for illustrative purposes of the Art and is not intended to limit the Art. In fact, it will be apparent to those skilled in the art that modifications and changes can be made in the Art without departing from the scope or spirit of the claimed Art. For example, features illustrated or described as part of one embodiment can also be used in conjunction with another embodiment to bring about further embodiments. Accordingly, this disclosure is intended to encompass such modifications and changes within the scope of the appended claims and their equivalents.

[0014] The term “exemplary” is used herein to mean “serving as an example, case, or illustration.” Any implementation described herein as “exemplary” should not necessarily be construed as being preferable or advantageous to other implementations. In addition, unless otherwise specified, all embodiments described herein should be considered exemplary.

[0015] Modes for carrying out the invention use numerals and letters to refer to features in the drawings. Similar or identical reference numerals in the drawings and description are used to refer to similar or identical parts of the subject art. As used herein, the terms “first,” “second,” and “third” can be used interchangeably to distinguish one component from another and are not intended to imply the position or importance of any individual component.

[0016] The term "fluid" can refer to a gas or a liquid. The term "fluid communication" means that a fluid can flow or be transported between designated areas.

[0017] As used herein, the terms “upstream” (or “forward”) and “downstream” (or “backward”) refer to relative directions of fluid flow in a fluid path. For example, “upstream” refers to the direction in which the fluid is flowing, and “downstream” refers to the direction in which the fluid is flowing. 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 coaxial 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.

[0018] Approximate terms such as “approximately,” “about,” “generally,” and “substantially” are not limited to specified exact values. In at least some cases, approximation may correspond to the precision of an instrument used to measure a value, or to the precision of a method or machine used to construct or manufacture a component and / or system. For example, approximation may refer to being within a margin of 1, 2, 4, 5, 10, 15, or 20% at any of the endpoints defining an individual value, a range of values, and / or a range of values. When used in the context of angles or directions, such terms include a range of plus or minus 5 degrees from the stated angle or direction. For example, “nearly perpendicular” includes any direction from perpendicular, e.g., within a range of 10 degrees clockwise or counterclockwise.

[0019] Terms such as "coupled", "fixed", "attached", etc., unless otherwise specified herein, refer to both direct coupling, fixing or attachment and indirect coupling, fixing or attachment through one or more intermediate components or features. Terms such as "directly coupled", "directly fixed", "directly attached", etc., indicate that the first component is joined to the second component without an intervening structure. As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", or any other variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, article, or apparatus that includes a list of features is not necessarily limited to only those features, and may include other features not explicitly listed, or other features inherent to such a process, method, article, or apparatus.

[0020] Here, throughout the specification and claims, a range limitation includes all sub-ranges contained therein unless the context or language specifically indicates otherwise. For example, all ranges disclosed herein include their endpoints, and the endpoints are combinable independently of each other.

[0021] As used herein, the term "premix" can be used to describe a component, passage, or cavity upstream of each combustion zone where mixing of two (or more) fluids occurs. For example, "premix" may be used to describe a component, passage, or cavity where two fluids (such as fuel and air) are mixed together before being discharged from such a component, passage, or cavity (e.g., into a combustion zone).

[0022] Referring now to the drawings, FIG. 1 shows a schematic view of an exemplary embodiment of a turbomachine, which in the illustrated embodiment is a gas turbine engine 10. Although industrial or land-based gas turbines are shown and described herein, the present disclosure is not limited to industrial or land-based gas turbine engines unless specifically recited in the claims. For example, the technology described herein can be used in any type of turbomachine including, but not limited to, steam turbines, aircraft gas turbines, or marine gas turbines.

[0023] As shown, gas turbine engine 10 generally includes an inlet section 12, a compressor section 14 disposed downstream of inlet section 12, a plurality of combustors 17 (shown in FIG. 2) within a combustion section 16 disposed downstream of compressor section 14, a turbine section 18 disposed downstream of combustion section 16, and an exhaust section 20 disposed downstream of turbine section 18. Additionally, gas turbine engine 10 may include one or more shafts 22 coupled between compressor section 14 and turbine section 18. Shaft 22 may be coupled to a generator (not shown) for generating electricity.

[0024] 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 each rotor disk 24 and connected to each rotor disk 24. Each rotor disk 24 may then be coupled to an upstream portion of shaft 22 extending through compressor section 14 or may form a part thereof. Compressor section 14 further includes a plurality of stationary vanes (not shown) arranged in stages and guiding the flow with respect to rotor blades 26.

[0025] The turbine section 18 may generally include a plurality of rotor disks 28 (one of which is illustrated) and a plurality of rotor blades 30 extending radially outward from each rotor disk 28 and interconnected with each rotor disk 28. Each rotor disk 28 may then be coupled to or form part of the downstream portion of a shaft 22 extending through the turbine section 18. The turbine section 18 further includes an outer casing 31 circumferentially surrounding the downstream portion of the shaft 22 and the rotor blades 30, thereby at least partially defining a hot gas path 32 through the turbine section 18. The turbine section 18 further includes a plurality of fixed vanes (not shown) arranged in stages with the rotor blades 30 and directing flow toward the rotor blades 30.

[0026] During operation, a working fluid such as air flows through the inlet section 12 into the compressor section 14, where it is gradually compressed by multiple compressor stages of rotor blades 26 and fixed vanes, thus supplying compressed air 15 to the combustors 17 of the combustion section 16. The compressed air 15 is mixed with fuel and burned in each combustor 17 to produce combustion gases 34. The combustion gases 34 flow from the combustion section 16 through the hot gas path 32 into the turbine section 18, where energy (kinetic energy and / or thermal energy) is transferred from the combustion gases 34 to the rotor blades 30, causing the shaft 22 to rotate. This mechanical rotational energy can then be used to power the compressor section 14 and / or generate electricity. The combustion gases 34 exiting the turbine section 18 are then exhausted from the gas turbine engine 10 through the exhaust section 20.

[0027] Figure 2 is a schematic diagram of a combustor 17 that may be included in the combustion section 16 of a gas turbine engine 10. The combustion section 16 may be a cannular combustion system. In a cannular combustion system, multiple combustors 17 (e.g., 8, 10, 12, 14, 16, or more) are arranged in an annular array around the shaft 22.

[0028] As shown in Figure 2, the combustor 17 may define a cylindrical coordinate system. The cylindrical coordinate system may define an axial direction A (e.g., downstream direction) substantially parallel to and / or along the axial centerline 170 of the combustor 17, a radial direction R perpendicular to the axial centerline 170, and a circumferential direction C extending around the axial centerline 170.

[0029] The combustor 17 includes a combustion liner 46 that defines a combustion chamber 70 in which combustion occurs. The combustion liner 46 may be positioned within an outer sleeve 48 such that an annular portion 47 is formed between the combustion liner 46 and the outer sleeve 48 (i.e., it may be circumferentially enclosed by the outer sleeve 48). The combustion liner 46 can contain combustion gases and transport them to the turbine section 18. As shown in Figure 2, the combustion liner 46 may extend between the fuel nozzle 40 and the rear frame 118. The combustion liner 46 may have a substantially cylindrical liner portion and a tapered transition portion separate from the substantially cylindrical liner portion, as in many conventional combustion systems. Alternatively, the combustion liner 46 may have a unibody configuration in which the substantially cylindrical portion and the tapered portion are integrated with each other. Thus, the description of the combustion liner 46 herein is intended to encompass both conventional combustion systems having separate liners and transition pieces and combustion systems having a unibody liner. Furthermore, the present disclosure is also applicable to combustion systems in which the transition piece and the first-stage nozzle of the turbine section 18 are integrated into a single unit (without the rear frame 118), which may be called a “transition nozzle” or “integrated outlet piece.”

[0030] Figure 2 shows a combustor 17 having both a fuel nozzle 40 and a fuel injection assembly 80 (also called an axial fuel staging ("AFS") system), as will be further described herein. At least one fuel nozzle 40 may be located at the front end of the combustor 17. Fuel may be introduced into the fuel nozzle 40 through a fuel supply conduit 38 extending through an end cover 42. The fuel nozzle 40 delivers the fuel and compressed air 15 into a primary combustion zone 72 where combustion occurs. In some embodiments, the fuel and compressed air 15 are combined as a mixture (i.e., "premixed") before reaching the primary combustion zone 72.

[0031] To define an annular section 47 through which compressed air 15 flows to the head end of the combustor 17, the combustion liner 46 may be surrounded by an outer sleeve 48 positioned radially outward from the combustion liner 46. For example, the compressed air 15 may enter the annular section 47 through the outer sleeve 48 (e.g., through an impingement hole adjacent to the rear frame 118) and move toward the end cover 42, so that the compressed air 15 in the annular section 47 flows in the opposite direction to the combustion gas 172 in the combustion liner 46 (34 in Figure 1). Heat is convectivally transferred from the combustion liner 46 to the compressed air 15, thus cooling the combustion liner 46 and warming the compressed air 15.

[0032] In some exemplary embodiments, the outer sleeve 48 may include a flow sleeve and an impingement sleeve coupled together. The flow sleeve may be located at the front end, and the impingement sleeve may be located at the rear end. Alternatively, the outer sleeve 48 may have a configuration of a single body (or "uni-sleeve") in which the flow sleeve and the impingement sleeve are integrated with each other in the axial direction. As stated above, the description of the outer sleeve 48 herein is intended to encompass both conventional combustion systems having separate flow sleeves and impingement sleeves and combustion systems having a uni-sleeve outer sleeve.

[0033] The forward casing 50 and the end cover 42 of the combustor 17 define a head end air plenum 122 containing one or more fuel nozzles 40. The fuel nozzles 40 may be any type of fuel nozzle, such as bundle fuel nozzles or swirl nozzles (often called “swozles”). The fuel nozzles 40 may be located within the head end air plenum 122, which is at least partially defined by the forward casing 50. In many embodiments, the fuel nozzles 40 may extend from the end cover 42. For example, each fuel nozzle 40 may be coupled to the rear surface of the end cover 42 via a flange (not shown). As shown in Figure 2, at least one fuel nozzle 40 may be partially enclosed by a combustion liner 46. The rear or downstream ends of the fuel nozzles 40 extend through or collectively define a cap plate 44 that defines the upstream end of the combustion chamber 70.

[0034] The fuel nozzle 40 may be in fluid communication with a first fuel source 150 configured to supply the first fuel 158 to the fuel nozzle 40. In many embodiments, the first fuel 158 may be a fuel mixture containing natural gas (e.g., one or more of methane, ethane, propane, or other suitable natural gases) and hydrogen. In some embodiments, hydrogen may constitute the majority of the fuel mixture (e.g., more than 50%). In other embodiments, the first fuel 158 may be pure natural gas or pure hydrogen (e.g., 100% hydrogen, which may or may not contain any trace amounts of contaminants), so that the first fuel is not a mixture of multiple fuels. In exemplary embodiments, the first fuel 158 and compressed air 15 may be mixed together within the fuel nozzle 40 before being discharged (or injected) into the primary combustion zone 72 by the fuel nozzle 40 to form a first mixture of compressed air 15 and the first fuel 158.

[0035] The forward casing 50 can be fluidly and mechanically connected to a compressor discharge casing 60 that defines a high-pressure plenum 66 around the combustion liner 46 and outer sleeve 48. Compressed air 15 from the compressor section 14 travels through the high-pressure plenum 66 and enters the combustor 17 through an opening (not shown) at the downstream end of the outer sleeve 48 (indicated by an arrow near the rear frame 118). The compressed air moves upstream through the annular section 47, is rotated by the end cover 42, and enters the fuel nozzle 40 to cool the head end. In particular, the compressed air 15 flows from the high-pressure plenum 66 into the annular section 47 at the rear end of the combustor 17 through an opening defined in the outer sleeve 48. The compressed air 15 moves upstream from the rear end of the combustor 17 to the head end air plenum 122, where it reverses direction and enters the fuel nozzle 40.

[0036] In the exemplary embodiment shown in Figure 2, the fuel injection assembly 80 is provided to deliver a second fuel / air mixture to a secondary combustion zone 74 downstream of the primary combustion zone 72. For example, the second flow of fuel and air may be introduced into the secondary combustion zone 74 by one or more fuel injectors 200.

[0037] The primary combustion zone 72 and the secondary combustion zone 74 may each be a part of the combustion chamber 70 and therefore may be defined by the combustion liner 46. For example, the primary combustion zone 72 may be defined from the outlet of the fuel nozzle 40 to the fuel injector 200, and the secondary combustion zone 74 may be defined from the fuel injector 200 to the rear frame 118. In this configuration, the foremost boundary of the fuel injector 200 may define the end of the primary combustion zone 72 and the beginning of the secondary combustion zone 74 (for example, at the axial position where the second flow of fuel and air is introduced).

[0038] Such a combustion system having axially separated combustion zones is described as an "axial fuel staging" (AFS) system. The fuel injection assemblies 80 may be arranged circumferentially apart from one another on the outer sleeve 48 (for example, equally spaced in some embodiments). In some exemplary embodiments, the combustor 17 may include four fuel injection assemblies 80 arranged circumferentially apart from one another and configured to inject a second mixture of fuel and air into the secondary combustion zone 74 via fuel injectors 200. In other exemplary embodiments, the combustor 17 may include any number of fuel injection assemblies 80 (e.g., 1, 2, 3, or up to 10).

[0039] As shown in Figure 2, each fuel injection assembly 80 may include a fuel injector 200. The fuel injector 200 may be coupled to the outer sleeve 48. For example, the fuel injector 200 may be coupled to the radially outer surface of the outer sleeve 48 and extend radially through an annular portion 47 between the outer sleeve 48 and the combustion liner 46.

[0040] A fuel supply conduit 102 may be fluidically coupled to each fuel injector 200. The fuel injectors 200 may be in fluid communication with a second fuel source 152 configured to supply a second fuel 160 to the fuel injectors 200 via the fuel supply conduit 102. The second fuel source 152 may be the same as or different from the first fuel source 150 so that the fuel injectors 200 may be supplied with the same or different fuel as the fuel nozzles 40. In many embodiments, the second fuel 160 may be a fuel mixture containing natural gas (e.g., one or more of methane, ethane, propane, or other suitable natural gases) and hydrogen. In some embodiments, hydrogen may constitute the majority of the fuel mixture (e.g., more than 50%). In other embodiments, the second fuel 160 may be pure natural gas or pure hydrogen (e.g., 100% hydrogen, which may or may not contain any trace amounts of contaminants) so that the second fuel is not a mixture of multiple fuels. In exemplary embodiments, the second fuel 160 and compressed air 15 may be mixed together in the fuel injector 200 before being injected into the secondary combustion zone 74 to form a mixture of compressed air 15 and the second fuel 160.

[0041] Figure 3 is a see-through perspective view of a fuel injector 200 that may be used in the combustor 17 of Figure 2 according to an embodiment of the present disclosure.

[0042] In at least one exemplary embodiment, the fuel injector 200 includes an annular main body 300 extending along a central axis 303 between a first end 301 and a second end 302. The annular main body 300 may include a first end wall 305 adjacent to the first end 301, a second end wall 310 adjacent to the second end 302, and an annular side wall 315 between the first end wall 305 and the second end wall 310. The annular side wall 315 may extend around the first end wall 305 and the second end wall 310.

[0043] At least a portion of the fuel circuit 320 extends along the center axis 303. For example, the first end wall 305 of the annular main body 300 may define an opening 325 for receiving at least a portion of the fuel circuit 320. The fuel circuit 320 may include a fuel inlet nozzle 322, a fuel inlet 324, and a fuel outlet 330. The fuel inlet nozzle 322 may be in fluid communication with a fuel supply conduit 102 and configured to receive fuel, such as a second fuel 160, from a second fuel supply source 152. The fuel inlet 324 is in fluid communication with the fuel inlet nozzle 322 and the fuel outlet 330. Thus, the fuel inlet 324 is configured to deliver fuel from the fuel inlet nozzle 322 to the fuel outlet 330. The fuel outlet 330 may be located in the second end wall 310 of the annular main body 300 and extend along the center axis 303. The fuel outlet 330 may be configured to receive fuel from the fuel inlet 324 and deliver the fuel to the mixing chamber 335 downstream of the fuel outlet 330, as will be described in detail below.

[0044] In at least one exemplary embodiment, the fuel injector 200 defines a first plurality of fluid inlets 345 and a second plurality of fluid inlets 350 located on at least a portion of the second end wall 310. The first plurality of fluid inlets 345 and the second plurality of fluid inlets 350 may be in fluid communication with one or both of the high-pressure plenum 66 and the annular portion 47. For example, the first plurality of fluid inlets 345 and the second plurality of fluid inlets 350 may be configured to receive air, such as compressed air 15 (Figure 2), from the high-pressure plenum 66 and / or the annular portion 47. The first plurality of fluid inlets 345 and the second plurality of fluid inlets 350 may deliver the compressed air 15 to a mixing chamber 335 for mixing with the fuel 160 so that a fuel-air mixture is formed. In such an exemplary embodiment, the fuel-air mixture may be delivered from the mixing chamber 335 to a secondary combustion zone 74 (shown in Figure 2).

[0045] Referring to Figure 3, the second end wall 310 of the annular main body 300 may include an internal wall portion 355 adjacent to the center axis 303 and an external wall portion 360 extending radially from the internal wall portion 355. For example, the external wall portion 360 may be located between the internal wall portion 355 and the annular side wall 315, such that the annular side wall 315 extends around the external wall portion 360. In at least one exemplary embodiment, the internal wall portion 355 extends at an arbitrary angle relative to the external wall portion 360, as shown in Figure 3 (Figure 5 also shows the angle of the internal wall portion 355 with the external wall portion 360 omitted). In other exemplary embodiments, the internal wall portion 355 and the external wall portion 360 are parallel or continuous. Furthermore, the internal wall portion 355 of the second end wall 310 may define a fuel outlet 330, a first plurality of fluid inlets 345, and a second plurality of fluid inlets 350, as shown in Figure 3.

[0046] In at least one exemplary embodiment, the components of the fuel injector 200 described herein may be formed integrally as a single component. That is, each of the dependent components, such as the annular main body 300, the fuel inlet nozzle 322, the fuel inlet 324, the fuel outlet 330, the mixing chamber 335, the first plurality of fluid inlets 345, and the second plurality of fluid inlets 350, may be manufactured together as a single body (e.g., by additive manufacturing). In other exemplary embodiments, one or more of the annular main body 300, the fuel inlet nozzle 322, the fuel inlet 324, the fuel outlet 330, the mixing chamber 335, the first plurality of fluid inlets 345, and the second plurality of fluid inlets 350 may be separate components.

[0047] Figure 4 is a detailed bottom view of the main body 300 of the fuel injector 200 shown in Figure 3, according to an embodiment of the present disclosure.

[0048] In at least one exemplary embodiment, the first plurality of fluid inlets 345 are arranged around the fuel circuit 320. More specifically, the first plurality of fluid inlets 345 are arranged around the fuel outlet 330. The second plurality of fluid inlets 350 are arranged around the first plurality of fluid inlets 345, and radially outward from there. For example, as shown in Figure 4, the first plurality of fluid inlets 345 define a first ring 400 surrounding the fuel outlet 330, and the second plurality of fluid inlets 350 define a second ring 405 surrounding the first ring 400 of the first plurality of fluid inlets 345. Thus, the first ring 400 of the first plurality of fluid inlets 345 is between the fuel outlet 330 and the second ring 405 of the second plurality of fluid inlets 350.

[0049] In at least one exemplary embodiment, the first ring 400 of the first plurality of fluid inlets 345 and the second ring 405 of the second plurality of fluid inlets 350 are coaxial with the central axis 303 (i.e., the central axis 303 defines the centers of a first virtual circle extending through the first ring 400 and a second virtual circle extending through the second ring 405). The first plurality of fluid inlets 345 may be arranged equally spaced around the central axis 303, and the second plurality of fluid inlets 350 may be arranged equally spaced around the central axis 303. Furthermore, the second plurality of fluid inlets 350 may be circumferentially offset from the first plurality of fluid inlets 345. For example, each of the second plurality of fluid inlets 350 may be arranged between adjacent ones of the first plurality of fluid inlets 345, as shown in Figure 4. In other exemplary embodiments, the first plurality of fluid inlets 345 and / or the second plurality of fluid inlets 350 may be arranged at uneven spacing around the central axis 303.

[0050] In at least one exemplary embodiment, the number of first multiple fluid inlets 345 may be the same as the number of second multiple fluid inlets 350. For example, as shown in Figure 4, there may be four of the first multiple fluid inlets 345 and four of the second multiple fluid inlets 350. However, it should be understood that there may be any number of first multiple fluid inlets 345 and second multiple fluid inlets 350. For example, there may be two or more of the first multiple fluid inlets 345 and two or more of the second multiple fluid inlets 350. Furthermore, in other exemplary embodiments, the number of first multiple fluid inlets 345 may be different from the number of second multiple fluid inlets 350.

[0051] Figure 5 is a detailed cross-sectional view of the central portion of the fuel injector 200 of Figure 3 according to an embodiment of the present disclosure. More specifically, Figure 5 shows a cross-sectional view of the fuel outlet 330.

[0052] In at least one exemplary embodiment, the fuel outlet 330 extends along the center axis 303 from the fuel inlet 324 toward the second end 302 of the fuel injector 200. Furthermore, the fuel outlet 330 extends from the second end wall 310 toward the mixing chamber 335. In some exemplary embodiments, the fuel outlet 330 may have a conical shape. For example, as shown in Figure 5, the outer surface of the fuel outlet 330 tapers from the first end 301 toward the second end 302. Furthermore, the outer surface of the fuel outlet 330 may define a fuel outlet angle 500 with respect to the center axis 303. In at least one exemplary embodiment, the fuel outlet angle 500 may be between 5° and 30°. For example, the fuel outlet angle 500 may be about 10°.

[0053] In other exemplary embodiments, the fuel outlet 330 may have a cylindrical shape.

[0054] In at least one exemplary embodiment, a mixing structure such as a delta wing 505 may be located in one or more of the first plurality of fluid inlets 345. The delta wing 505 can accelerate the mixing of fuel and air in the mixing chamber 335.

[0055] Figure 6 is a schematic cross-sectional view of the fuel injector 200 of Figure 3 according to an embodiment of the present disclosure.

[0056] Referring to Figure 6, each of the first plurality of fluid inlets 345 and the second plurality of fluid inlets 350 may have a cylindrical shape (as also shown in Figures 3 and 4). For example, the first plurality of fluid inlets 345 and the second plurality of fluid inlets 350 may be defined by a plurality of pipes and / or conduits. In at least one exemplary embodiment, the first plurality of fluid inlets 345 and the second plurality of fluid inlets may have a diameter of 0.05 inches or more and 0.50 inches or less. In other exemplary embodiments, each of the first plurality of fluid inlets 345 and the second plurality of fluid inlets 350 includes a conical shape.

[0057] Each of the first plurality of fluid inlets 345 extends along an axis indicated by a first inlet arrow 600. Each of the first plurality of fluid inlets 345 defines a first fluid inlet angle 610 with respect to the centerline axis 303 and the first inlet arrow 600. The first fluid inlet angle 610 may be the same as the fuel outlet angle 500. For example, the first plurality of fluid inlets 345 may extend parallel to the outer surface of the fuel outlet 330. In at least one exemplary embodiment, the first fluid inlet angle 610 may be between 5° and 30°. For example, the first fluid inlet angle 610 may be about 10°.

[0058] Each of the second plurality of fluid inlets 350 also extends along the axis indicated by the second inlet arrow 605. Each of the second plurality of fluid inlets 350 defines a second fluid inlet angle 615 with respect to the centerline axis 303 and the second inlet arrow 605. The second fluid inlet angle 615 may be greater than or equal to one or both of the first fluid inlet angle 610 and the fuel outlet angle 500. In at least one exemplary embodiment, the second fluid inlet angle 615 may be between 10° and 60°. For example, the second fluid inlet angle 615 may be about 20°.

[0059] In at least one exemplary embodiment, a vortex structure is generated that promotes the mixing of fuel and air by introducing air, such as compressed air 15, into the mixing chamber 335 through a first plurality of fluid inlets 345 at a first fluid inlet angle 610 and a second plurality of fluid inlets 350 at a second fluid inlet angle 615. For example, fuel flows into the mixing chamber 335 along a fuel streamline 620, from the fuel inlet 324 through the fuel outlet 330. As shown in Figure 6, the fuel streamline 620 extends along the central axis 303. A first portion of air, such as a first portion of compressed air 15, flows through the first plurality of fluid inlets 345 at a first fluid inlet angle 610, as indicated by the first inlet arrow 600, and is discharged into the mixing chamber 335. The second portion of air, such as the second portion of compressed air 15, flows through the second fluid inlets 350 at a second fluid inlet angle 615, as indicated by the second inlet arrow 605, and is also discharged into the mixing chamber 335. Since the second fluid inlet angle 615 is greater than the first fluid inlet angle 610, the second portion of air (indicated by the second inlet arrow 605) intersects with the first portion of air and fuel (indicated by the first inlet arrow 600 and fuel streamline 620, respectively). The second portion of air moves inward toward the center axis 303, as indicated by the arrow 625, and the first portion of air and fuel is pushed outward from the center axis 303, as indicated by the arrow 630. Thus, a double vortex is formed (shown in Figures 8B to 8C), promoting the mixing of air and fuel to form an air-fuel mixture in the mixing chamber 335.

[0060] In at least one exemplary embodiment, one or more mixing structures may be positioned in the first plurality of fluid inlets 345 to facilitate the mixing of air and fuel. For example, one or more mixing structures may be coupled to the inner surface of the first plurality of fluid inlets 345 and extend from there. One or more mixing structures can introduce turbulence into the air flowing through the first plurality of fluid inlets 345 to facilitate mixing before introducing the fuel into the air, thereby preventing flame-holding conditions. In at least one exemplary embodiment, one or more mixing structures may include a delta wing (e.g., the delta wing 505 shown in Figure 5) or a chevron.

[0061] Figure 7 is a schematic diagram of a fuel-air mixture that can be produced by the fuel injector 200 of Figure 3 according to an embodiment of the present disclosure. Figure 8A is a schematic diagram of the first stage 710 of the fuel-air mixture of Figure 7 according to an embodiment of the present disclosure. Figure 8B is a schematic diagram of the second stage 715 of the fuel-air mixture of Figure 7 according to an embodiment of the present disclosure. Figure 8C is a schematic diagram of the third stage 720 of the fuel-air mixture of Figure 7 according to an embodiment of the present disclosure.

[0062] As described above with respect to Figure 6, the fuel injector 200 facilitates the mixing of air and fuel before injecting the fuel-air mixture into the secondary combustion zone 74 of the combustor 17 (Figure 2). The fuel enters the mixing chamber 335 via the fuel outlet 330, and the air enters the mixing chamber 335 via the first multiple fluid inlets 345 and the second multiple fluid inlets 350. For example, the fuel and air enter the mixing chamber 335 in the first stage 710. Referring to Figure 8A, the fuel flows along the fuel streamline 620 (shown in Figure 6), enters the mixing chamber 335, and defines a fuel zone 700 coaxial with the centerline axis 303. Furthermore, a first portion of the air enters the mixing chamber 335 from the first multiple fluid inlets 345, indicated by the first inlet arrow 600 in Figure 6, and defines a plurality of first fluid inlet zones 800. The number of first fluid inlet zones 800 may correspond to the number of first multiple fluid inlets 345. For example, there may be four of the multiple first fluid inlet zones 800 and four of the multiple first fluid inlets 345. Furthermore, the second portion of air enters the mixing chamber 335 through the second multiple fluid inlets 350, indicated by the second inlet arrow 605 in Figure 6, defining multiple second fluid inlet zones 805 in the first stage 710. The number of second fluid inlet zones 805 may also correspond to the number of second multiple fluid inlets 350. For example, there may be four of the multiple second fluid inlet zones 805 and four of the multiple second fluid inlets 350.

[0063] Referring here to Figures 7 and 8B, the mixing chamber 335 defines a second stage 715 downstream of the first stage 710. For example, the vortex structure described above is shown with respect to Figure 6. More specifically, it shows a plurality of double vortices 810. A plurality of double vortices 810 can be formed when a second portion of air moves inward toward the central axis 303, as indicated by arrow 625 in Figure 6, and a first portion of air and fuel is pushed outward from the central axis 303, as indicated by arrow 630 in Figure 6. The number of plurality of double vortices 810 may correspond to the number of first plurality of fluid inlets 345 and the number of second plurality of fluid inlets 350. For example, each of the plurality of double vortices 810 may be formed by a pair of one of the first plurality of fluid inlets 345 and one of the second plurality of fluid inlets 350. In at least one exemplary embodiment, the fuel injector 200 includes four of a first plurality of fluid inlets 345 and four of a second plurality of fluid inlets 350, as shown in Figure 8B, thereby forming four of a plurality of double vortices 810.

[0064] Multiple double vortices 810 generate a flow that facilitates the mixing of air and fuel within the mixing chamber 335. Referring to Figures 7 and 8C, the third stage 720 downstream of the second stage 715 includes multiple double vortices 810. As the fuel and air move from the first end 301 to the second end 302, the fuel in the fuel zone 700 is further mixed with the air in the surrounding area 705 of the mixing chamber 335. Thus, the fuel injector 200 can produce a homogeneous mixture of air and fuel before injecting the fuel-air mixture into the secondary combustion zone 74, while also preventing flame retention within the fuel injector 200. When operating with fuels including natural gas, such mixing in the mixing chamber 335 promotes complete combustion and reduces the formation of emissions in the secondary combustion zone 74.

[0065] This specification discloses the present invention, including its best mode, using examples, and enables any person skilled in the art to practice the invention, including the fabrication and use of any device or system, and the execution of any incorporated method. The patentable scope of the present invention is defined by the claims and may include other examples that a person skilled in the art may conceive. Such other embodiments are intended to be within the scope of the claims if they include structural elements that are not different from the language of the claims, or equivalent structural elements that do not substantially differ from the language of the claims.

[0066] Further aspects of the present invention are provided by the subject matter of the following clauses.

[0067] A fuel injector for a gas turbine combustor, comprising: an annular main body extending from a first end to a second end, the annular main body defining a central axis extending from the first end to the second end, at least a portion of a fuel circuit extending along the central axis, a first plurality of fluid inlets arranged around the fuel circuit, and a second plurality of fluid inlets arranged around the first plurality of fluid inlets, wherein the fuel circuit comprises a fuel inlet and a fuel outlet in fluid communication with the fuel inlet, and the outer surface of the fuel outlet forms a fuel outlet angle with respect to the central axis.

[0068] One or more fuel injectors from these provisions, with a fuel outlet angle of approximately 10°.

[0069] A fuel injector having one or more of these features, wherein a second plurality of fluid inlets are arranged radially away from a first plurality of fluid inlets with respect to the central axis, and the first plurality of fluid inlets are arranged between the fuel outlet and the plurality of second fluid inlets.

[0070] A fuel injector having one or more of the following features: a first set of fluid inlets arranged at equal intervals around a central axis, and a second set of fluid inlets arranged at equal intervals around a central axis.

[0071] One or more fuel injectors of these provisions, wherein a second plurality of fluid inlets are circumferentially offset from the first plurality of fluid inlets.

[0072] A fuel injector having one or more of the following conditions: each of the first plurality of fluid inlets forms a first fluid inlet angle with respect to the center axis, the first fluid inlet angle is equal to the fuel outlet angle, and each of the second plurality of fluid inlets forms a second fluid inlet angle with respect to the center axis, the second fluid inlet angle is greater than the first fluid inlet angle.

[0073] One or more fuel injectors having a first fluid inlet angle of approximately 10° and a second fluid inlet angle of approximately 20°.

[0074] One or more fuel injectors, wherein the first plurality of fluid inlets comprises four fluid inlets, and the second plurality of fluid inlets comprises four fluid inlets.

[0075] One or more fuel injectors from these clauses, further comprising a mixing chamber located downstream of the fuel outlet, the first plurality of fluid inlets, and the second plurality of fluid inlets, and in fluid communication with the fuel outlet, the first plurality of fluid inlets, and the second plurality of fluid inlets.

[0076] One or more fuel injectors of these types, wherein the outer surface of the fuel outlet is tapered from a first end to a second end.

[0077] One or more fuel injectors among these provisions, wherein the first and second plurality of fluid inlets are cylindrical.

[0078] A fuel injector comprising one or more mixing structures positioned at a first plurality of fluid inlets, wherein one or more mixing structures include delta wings.

[0079] A combustor comprising: at least one fuel nozzle; a combustion liner extending downstream of at least one fuel nozzle and defining a combustion chamber; an outer sleeve disposed apart from the combustion liner, surrounding the combustion liner such that an annular portion is defined between the outer sleeve and the combustion liner; and a fuel injector disposed downstream of at least one fuel nozzle and in fluid communication with the combustion chamber, wherein the fuel injector comprises an annular main body extending from a first end to a second end, the annular main body defining a central axis extending from the first end to the second end; a fuel circuit extending along the central axis; a first plurality of fluid inlets arranged around the fuel circuit; and a second plurality of fluid inlets arranged around the first plurality of fluid inlets, wherein the fuel circuit comprises a fuel inlet and a fuel outlet in fluid communication with the fuel inlet, and the outer surface of the fuel outlet forms a fuel outlet angle with respect to the central axis.

[0080] One or more of these combustors, wherein the fuel inlet of the fuel circuit is configured to be in fluid communication with a fuel supply conduit and to receive fuel from a fuel supply source.

[0081] One or more of these combustors whose fuel source supplies fuel containing pure hydrogen or a fuel mixture of hydrogen and natural gas, and in which hydrogen is the majority component of the fuel mixture.

[0082] One or more of these combustors, wherein a first plurality of fluid inlets and a second plurality of fluid inlets are in fluid communication with an annular portion.

[0083] A combustor having one or more of the following features: each of the first plurality of fluid inlets forms a first fluid inlet angle with respect to the center axis, the first fluid inlet angle is equal to the fuel outlet angle, and each of the second plurality of fluid inlets forms a second fluid inlet angle with respect to the center axis, the second fluid inlet angle is greater than the first fluid inlet angle.

[0084] A combustor having one or more of the following characteristics: a fuel outlet angle of approximately 10°, a first fluid inlet angle of approximately 10°, and a second fluid inlet angle of approximately 20°.

[0085] One or more combustors of these types, wherein a second plurality of fluid inlets are arranged radially away from a first plurality of fluid inlets with respect to the central axis, and the first plurality of fluid inlets are arranged between a fuel outlet and a plurality of second fluid inlets.

[0086] A combustor having one or more of the following features: a first set of fluid inlets arranged equally spaced around a central axis; a second set of fluid inlets arranged equally spaced around a central axis; and the second set of fluid inlets offset circumferentially from the first set of fluid inlets. [Explanation of symbols]

[0087] 10 Gas turbine engines 12 Entrance Section 14 Compressor Section 15 Compressed air 16 Combustion Section 17 Combustor 18 Turbine Section 20 Exhaust Section 22 shafts 24 Rotor Discs 26 rotor blades 28 Rotor Discs 30 rotor blades 31 Outer casing 32 High-temperature gas pathway 34 Combustion gases 38 Fuel supply conduit 40 Fuel Nozzles 42 End cover 44 Cap Plates 46 Combustion Liner 47 Ring section 48 Outer sleeve 50 Front casing 60 Compressor discharge casing 66 High-pressure plenum 70 Combustion Chamber 72 Primary Combustion Zone 74 Secondary combustion zone 80 Fuel injection assembly 102 Fuel supply conduit 118 Rear frame 122 Head end air plenum 150 First fuel source 152 Second fuel source 158 First fuel 160 Second fuel 170 Axial centerline 172 Combustion gases 200 fuel injector 300 Ring-shaped main body 301 First end 302 Second end 303 Centerline axis 305 First end wall 310 Second end wall 315 Annular side wall 320 fuel circuit 322 Fuel Inlet Nozzle 324 Fuel inlet 325 Opening 330 fuel outlet 335 Mixing Chamber 345 First Multiple Fluid Inlets 350 Second Multiple Fluid Inlets 355 Internal wall section 360 External wall section 400 The First Ring 405 The Second Ring 500 Fuel outlet angle 505 DeltaWing 600 First entrance arrow 605 Second entrance arrow 610 First fluid inlet angle 615 Second fluid inlet angle 620 Fuel Streamline 625 Arrow 630 Arrow 700 Fuel Zone 705 Surrounding area 710 Section 1 715 Section 2 720 Third paragraph 800 First fluid inlet zone 805 Second fluid inlet zone 810 Double Vortex A-axis R radial direction C circumferential direction

Claims

1. A fuel injector (200) for a combustor (17) of a gas turbine engine (10), wherein the fuel injector (200) is An annular main body (300) extending from a first end (301) to a second end (302), the annular main body (300) defines a central axis (303) extending from the first end (301) to the second end (302), at least a portion of a fuel circuit (320) extending along the central axis (303), a first plurality of fluid inlets (345) arranged around the fuel circuit (320), and a second plurality of fluid inlets (350) arranged around the first plurality of fluid inlets (345), the annular main body (300) comprises The fuel injector (200) comprises a fuel inlet (324) and a fuel outlet (330) that is in fluid communication with the fuel inlet (324), wherein the outer surface of the fuel outlet (330) forms a fuel outlet angle (500) with respect to the central axis (303).

2. The fuel injector (200) according to claim 1, wherein the fuel outlet angle (500) is approximately 10°.

3. The second plurality of fluid inlets (350) are arranged radially apart from the first plurality of fluid inlets (345) with respect to the central axis (303), The first plurality of fluid inlets (345) are arranged between the fuel outlet (330) and the second plurality of fluid inlets (350). A fuel injector (200) according to claim 1.

4. The first plurality of fluid inlets (345) are arranged equally spaced apart around the central axis (303), The second plurality of fluid inlets (350) are arranged to be equally spaced apart around the central axis (303), A fuel injector (200) according to claim 1.

5. The fuel injector (200) according to claim 1, wherein the second plurality of fluid inlets (350) are offset circumferentially from the first plurality of fluid inlets (345).

6. Each of the first plurality of fluid inlets (345) forms a first fluid inlet angle with respect to the central axis (303), and the first fluid inlet angle (610) is equal to the fuel outlet angle (500). Each of the second plurality of fluid inlets (350) forms a second fluid inlet angle with respect to the central axis (303), and the second fluid inlet angle (615) is greater than the first fluid inlet angle (610). A fuel injector (200) according to claim 1.

7. The first fluid inlet angle (610) is approximately 10°, The second fluid inlet angle (615) is approximately 20°. The fuel injector (200) according to claim 6.

8. The first plurality of fluid inlets (345) comprises four fluid inlets, The second plurality of fluid inlets (350) comprises four fluid inlets. A fuel injector (200) according to claim 1.

9. The fuel injector (200) according to claim 1, further comprising a mixing chamber (335) located downstream of the fuel outlet (330), the first plurality of fluid inlets (345), and the second plurality of fluid inlets (350), and in fluid communication with the fuel outlet (330), the first plurality of fluid inlets (345), and the second plurality of fluid inlets (350).

10. The fuel injector (200) according to claim 1, wherein the outer surface of the fuel outlet (330) is tapered from the first end (301) to the second end (302).

11. The fuel injector (200) according to claim 1, wherein the first plurality of fluid inlets (345) and the second plurality of fluid inlets (350) are cylindrical.

12. The fuel injector (200) according to claim 1, further comprising one or more mixing structures disposed at the first plurality of fluid inlets (345), wherein the one or more mixing structures include delta wings (505).

13. Combustor (17), At least one fuel nozzle (40) and A combustion liner (46) extends downstream of at least one fuel nozzle (40) and defines a combustion chamber (70), An outer sleeve (48) is disposed at a distance from the combustion liner (46), and the annular portion (47) surrounds the combustion liner (46) such that it is defined between the combustion liner (46) and the outer sleeve (48). A fuel injector (200) positioned downstream of at least one fuel nozzle (40) and in fluid communication with the combustion chamber (70), wherein the fuel injector (200) is defined according to any one of claims 1 to 12 and A combustion device (17) equipped with this.

14. The combustor (17) according to claim 13, wherein the fuel inlet (324) of the fuel circuit (320) is configured to fluidly communicate with a fuel supply conduit (102) and receive fuel from a fuel supply source (152), the fuel supply source (152) supplies fuel including pure hydrogen or a fuel mixture of hydrogen and natural gas, and hydrogen is the majority component of the fuel mixture.

15. The combustor (17) according to claim 13, wherein the first plurality of fluid inlets (345) and the second plurality of fluid inlets (350) are in fluid communication with the annular portion (47).

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