Hollow Ring Fuel Injector for a Gas Turbine Engine

Abstract

A fuel injector assembly (112) for a combustor of a gas turbine engine includes an annular body defining a hollow interior space (110), a first and a second opening into the interior space, and a chamber defining a fluid manifold (310). The first and second openings are each proximate to opposing first and second ends of the annular body. The first end is upstream of the second end. The fuel injector assembly includes an annular fuel nozzle (304) positioned within the interior space and spaced from the annular body. The annular fuel nozzle includes a plurality of fuel injection ports (306) configured to inject fuel into the combustor. The fuel injector assembly also includes one or more fuel supply struts (308) coupled to the annular fuel nozzle and the annular body. The fuel supply struts are fluidly coupled and communicate with the fluid manifold and the annular fuel nozzle to deliver fuel therethrough.

Description

Technical Field

[0001] The present invention specifically relates to gas turbine engines and generally to combustion systems, and more particularly to a halo-ring fuel injector for use in a combustion system of a gas turbine engine.

[0002] Combustion of a wide range of fuels, including (but not limited to) blends of hydrogen in conventional combustion systems of gas turbine engines, can cause several technical problems. For example, one technical problem is flashback and flame holding at or near the main fuel injector of the combustion system. Flashback can occur when the fuel is contained in the boundary layer of the combustion air flow. Another technical problem is the formation of nitrogen oxides (NOx) and carbon monoxide (CO). The technical problems are caused, at least in part, by the high flame speed and short ignition delay times due to the use of highly reactive fuel components such as hydrogen in the fuel gas mixture. Low pollutant formation requires an optimal air-fuel mixing profile while preventing excessive thermoacoustics.

Summary of the Invention

[0003] This summary of the invention is provided to introduce a selected simplification of concepts that are further described in the following detailed description. This summary of the invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the present disclosure will become apparent from the following detailed description of the embodiments and the accompanying drawings.

[0004] In one aspect, a fuel injector assembly is provided. The fuel injector assembly includes an annular body defining a hollow interior space, a first and a second opening into the interior space, and a chamber defining a fluid manifold. The first and second openings are each proximate to opposing first and second ends of the annular body. The first end is upstream of the second end. The fuel injector assembly also includes an annular fuel nozzle positioned within the interior space. The annular fuel nozzle is spaced apart from the annular body. The annular fuel nozzle includes a plurality of fuel injection ports. Further, the annular fuel nozzle includes one or more fuel supply struts coupled to the annular fuel nozzle and the annular body. The one or more fuel supply struts are fluidly coupled in communication with the fluid manifold and the annular fuel nozzle.

[0005] In another aspect, a combustor is provided. The combustor includes a cylindrical combustion liner having an inlet end, an outlet end, and a central axis. The combustion liner defines a combustion chamber. The combustor also includes a fuel injector assembly positioned radially outward of the cylindrical combustion liner relative to the central axis. The fuel injector assembly includes an annular body defining a hollow interior space, a first and a second opening into the interior space, and a chamber defining a fluid manifold. The first and second openings are each proximate to opposing first and second ends of the annular body. The first end is upstream of the second end. The fuel injector assembly also includes an annular fuel nozzle positioned within the interior space. The annular fuel nozzle is spaced apart from the annular body. The annular fuel nozzle includes a plurality of fuel injection ports. Further, the annular fuel nozzle includes one or more fuel supply struts coupled to the annular fuel nozzle and the annular body. The one or more fuel supply struts are fluidly coupled in communication with the fluid manifold and the annular fuel nozzle.

[0006] Various additional aspects are described in the following detailed description. These aspects can relate to individual features and combinations of features. The advantages of these and other aspects will become more apparent to those skilled in the art from the following description of the exemplary embodiments illustrated and described by way of example. As will be recognized, the aspects described herein can have other aspects and different aspects, and their details can be modified in various respects. Accordingly, the drawings and description should be regarded as illustrative in nature and not as restrictive.

Brief Description of the Drawings

[0007] The figures described below depict various aspects of the systems and methods disclosed herein. It should be understood that each figure depicts an embodiment of a particular aspect of the disclosed systems and methods, and that each of the figures is intended to be in accordance with its possible embodiments. Further, to the extent possible, the following description refers to the reference numbers included in the following figures, and features depicted in multiple figures are designated with consistent reference numbers.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

[0008] Unless otherwise indicated, the figures provided in this specification are intended to illustrate features of embodiments of the present disclosure. These features are believed to be applicable in a variety of systems including one or more embodiments of the present disclosure. Accordingly, the figures are not meant to include all conventional features known to those skilled in the art that are necessary for the practice of the embodiments disclosed herein.

Best Mode for Carrying Out the Invention

[0009] The following detailed description of embodiments of the disclosure refers to the accompanying drawings. The embodiments are intended to describe aspects of the disclosure in sufficient detail to enable one of ordinary skill in the art to practice the disclosure. The embodiments of the disclosure are illustrated by way of example and not by way of limitation. Other embodiments may be utilized and changes may be made without departing from the scope of the claims. Accordingly, the following description is not limiting. The scope of the disclosure is defined only by the appended claims together with the full scope of equivalents to which such claims are entitled.

[0010] Generally, fuel injectors for gas turbine engine combustors include a halo-ring nozzle that "floats" within the free air flow of an intake channel. The nozzle injects fuel into the center of the air flow, thereby reducing or eliminating fuel within the boundary layer of the air flow. Further, the halo-ring nozzle injects air at an angle with respect to the main direction of the air flow, which facilitates improving the mixing of fuel and air. Complete mixing of air and fuel facilitates reducing NOx and CO emissions of a gas turbine engine. In certain embodiments, the fuel injector further includes support struts configured to cause swirl in at least a portion of the air flow, thereby further promoting mixing of fuel and air.

[0011] Referring now more particularly to the drawings and first to FIG. 1, a combustor intended for use in a gas turbine engine (not shown) is generally designated by the numeral 100. In an exemplary embodiment, the combustor 100 extends longitudinally along a central axis "A". The combustor 100 includes a generally cylindrical flow sleeve 102. The flow sleeve 102 surrounds a generally cylindrical and coaxial combustion liner 104 and defines at least a portion of an axially extending annular passage 110 therebetween. The combustion liner 104 has an inlet end 106 and an outlet end 108 and defines a combustion chamber therebetween. The flow sleeve 102 is configured to direct an air flow of compressed air through the passage 110 along the outer surface of the combustion liner 104.

[0012] The combustor 100 includes a halo-ring fuel injector assembly 112 positioned radially outside the combustion liner 104. The halo-ring fuel injector 112 is located proximate to the downstream end of the flow sleeve 102. As shown in FIG. 2, the halo-ring fuel injector 112 feeds an adjusted amount of fuel 126 into the air stream to provide a fuel-air mixture for the combustor 100. In particular, the halo-ring fuel injector 112 receives compressed air from a compressor of a gas turbine engine (not shown) via a passage 110 from the upstream end 114 to the downstream end 116 of the combustor 100.

[0013] The compressed air passes through a plurality of perforations (not shown) within the flow sleeve 102, enters the passage 110 (i.e., the hollow annular space between the flow sleeve 102 and the combustion liner 104), and flows downstream toward the downstream end 116. As a result, the compressed air operates, in part, to cool the combustor 100 before mixing with the fuel 126 for combustion. The compressed air flows into the halo-ring fuel injector 112 for mixing with the fuel 126. The fuel 126 injected by the halo-ring fuel injector 112 mixes with the compressed air and continues to move in the forward direction toward the downstream end 116, where at the downstream end 116, the fuel / air mixture reverses direction, enters the combustion liner 104, and where combustion of the mixture occurs. The air-fuel mixture burns downstream of the halo-ring fuel injector 112 within the combustor 100. The mixing of the air stream and the fuel stream can depend on the characteristics of each stream such as the heating value, flow rate, and temperature of the fuel. As will be discussed in detail herein, the halo-ring fuel injector 112 includes various features to prevent flashback and / or flameholding at or near the halo-ring fuel injector 112 and to reduce or eliminate the boundary layer of the air stream from containing fuel such as the fuel 126.

[0014] In an exemplary embodiment, the combustor 100 includes a combustor dome assembly 120 that surrounds the inlet end 106 of the combustion liner 104. The combustor dome assembly 120 includes a generally hemispherical wall 122 that extends from near the halo-ring fuel injector 112 to a location a distance within the inlet end 106 of the combustion liner 104. That is, the dome assembly 120 turns direction through the hemispherical wall 122 and extends a distance into the combustion liner 104 through the inner wall 124 of the dome assembly.

[0015] Referring to FIG. 2, the injected fuel 126, which can be a fuel mixture, can be any fuel composition, such as natural gas, hydrogen, syngas (or synthesis gas). In an exemplary embodiment, the fuel 126 is injected into the air stream via one or more halo-ring fuel injectors 112 positioned within the air stream, and each halo-ring fuel injector 112 has a plurality of angled fuel injection ports 306 (shown in FIG. 3) defined within a generally wing-shaped annular fuel nozzle 304. The annular fuel nozzle 304 is supported by a plurality of fuel supply struts 308, each of which is fluidly connected in communication with a chamber that defines a common annular fluid manifold 310.

[0016] Various detailed views of an exemplary hollow-ring fuel injector 112 are shown in FIGS. 3-9. In certain implementations, the hollow-ring fuel injector 112 is a unitary component that can be manufactured using various techniques, including but not limited to additive manufacturing. Additive manufacturing is a technology that enables the “3D printing” of components from a variety of materials, including metals, ceramics, and plastics. In additive manufacturing, parts are built layer by layer, for example, by flattening metal powder and selectively melting or fusing the powder within the layer using a high-power laser or electron beam. After each layer, more powder is added and the laser patterns and simultaneously melts or fuses the next layer to the previous layer to create the complete component. In one embodiment, the hollow-ring fuel injector 112 can be manufactured using a direct metal laser melting (DMLM) process. The geometry of the hollow-ring fuel injector 112 is difficult to form using conventional casting techniques, and thus, the manufacture of the hollow-ring fuel injector 112 using a DMLM process or an electron beam melting process can be advantageous, for example, in the exemplary embodiments. However, it is contemplated that any manufacturing process that enables the hollow-ring fuel injector 112 to be fabricated as described herein can be used. Further, it should be noted that the hollow-ring fuel injector 112 may require post-processing to provide the desired structural properties.

[0017] In this exemplary embodiment, the halo-ring fuel injector 112 is formed substantially symmetrically with respect to the central axis "B". The halo-ring fuel injector 112 includes a generally cylindrical body 302. The body 302 is formed in a generally frustoconical shape and has a hollow internal space 314 defined therein. The upstream flange 312 of the body 302 defines an opening 316 into the internal space 314. The cylindrical downstream wall 318 extends generally axially downstream from the upstream flange 312 towards the downstream rim 320 of the body 302, and the downstream rim 320 defines a second opening into the internal space 314. The tapered wall 322 extends downstream at an inward angle from a portion of the upstream flange 312 to the downstream wall 318 of the body 302. The annular manifold 310 is triangular in cross-section (as depicted in FIGS. 6 and 8) and is generally defined between the upstream flange 312, the downstream wall 318, and the tapered wall 322. Proximate to the downstream rim 320, the body 302 includes a plurality of mounting tabs 324.

[0018] Referring to FIG. 5, the exemplary halo-ring fuel injector 112 includes a plurality of arcuate channels 342a, 342b, and 342c defined within the upstream flange 312 of the body 302. The arcuate channels 342a, 342b, and 342c are substantially concentric with the central axis "B" of the halo-ring fuel injector 112. The arcuate channels 342a, 342b, and 342c are configured to allow air to pass therethrough, for example, to supply an air flow to a pilot fuel nozzle (not shown) of the combustor 100. The arcuate channels 342a, 342b, and 342c extend arcuately at an angle in the range of about 90 degrees (90°) to about 110 degrees (110°).

[0019] As described above, the exemplary halo-ring fuel injector 112 includes an annular fuel nozzle 304. The annular fuel nozzle 304 is spaced a predetermined distance inside the downstream wall 318. As depicted in FIG. 2, the annular fuel nozzle 304 is generally positioned within the air flow so as to be spaced from the combustion liner 104. This facilitates a portion of the air flow to pass above and below the annular fuel nozzle 304 such that fuel 126 is injected into the air flow and the boundary layer of the air flow is reduced or eliminated from containing fuel.

[0020] The annular fuel nozzle 304 is held in place by a plurality of support struts 326 and a plurality of fuel supply struts 308. In an exemplary embodiment, the halo-ring fuel injector 112 includes six of each of the support struts 326 and fuel supply struts 308 equally spaced about a central axis “B”. Further, each support strut 326 is downstream of a respective fuel supply strut 308 and is generally axially aligned with the respective fuel supply strut 308. However, the halo-ring fuel injector 112 may include fewer or more support struts 326 and / or fuel supply struts 308, and the overall alignment of each may be any desired alignment that enables the halo-ring fuel injector 112 to function as described herein.

[0021] In an exemplary embodiment, each of the support strut 326 and the fuel supply strut 308 extends inwardly and downstream from the downstream wall 318 to the annular fuel nozzle 304 at an angle in the range of about 35 degrees (35°) to about 55 degrees (55°) with respect to the central axis "B". More specifically, each of the support strut 326 and the fuel supply strut 308 extends inwardly and downstream at an angle of about 45 degrees (45°). In an exemplary embodiment, each of the support strut 326 and the fuel supply strut 308 is substantially circular in cross-section. However, it is contemplated that the cross-sectional shape of the support strut 326 and the fuel supply strut 308 can be any shape that enables the halo-ring fuel injector 112 to function as described herein. For example, in some embodiments, the support strut 326 and the fuel supply strut 308 can have an airfoil shape, an elliptical shape, etc.

[0022] In an exemplary embodiment, each of the fuel supply struts 308 is substantially hollow. Further, the annular fuel nozzle 304 is substantially hollow. The fuel supply strut 308 is fluidly coupled to the common annular manifold 310 and the annular fuel nozzle 304 to facilitate sending fuel, such as fuel 126 (shown in FIG. 2), therebetween.

[0023] Referring to FIG. 4, the upstream flange 312 of the body 302 includes one or more fuel supply ports 328. Each fuel supply port 328 is configured to be coupled to a fuel supply source of a gas turbine engine to receive fuel, such as fuel 126, therefrom. In an exemplary embodiment, the fuel supply port 328 is positioned on the axial end of the upstream flange 312 to receive fuel axially. In certain embodiments, the fuel supply port 328 can be sized and shaped to receive fuel radially. When fuel enters through the fuel supply port 328, the fuel flows into the annular manifold 310. Fuel, such as fuel 126, flows from the annular manifold 310 into the fuel supply strut 308. The fuel flows from the fuel supply strut 308 into the annular fuel nozzle 304, where it is injected into the air stream through the fuel injection ports 306.

[0024] As depicted in FIG. 7, the annular manifold 310 is divided into two separate sections 330 and 332. The first section 332 extends at an angle α1 of approximately 120 degrees (120°) around the central axis “B” of the halo-ring fuel injector 112. The second section 330 extends to the remaining annular portion or extends at an angle α2 of approximately 240 degrees (240°) around the central axis “B” of the halo-ring fuel injector 112. The first section 332 of the halo-ring fuel injector 112 is used to generate a main 1 flame, and the second section 330 of the halo-ring fuel injector 112 is used to generate a main 2 flame. Each of the first section 330 and the second section 332 includes one of the fuel supply ports 328.

[0025] The annular fuel nozzle 304 is shown in FIG. 8 as being substantially wing-shaped in cross-section, and the wing shape is substantially constant around the annular fuel nozzle 304. In particular, in an exemplary embodiment, the annular fuel nozzle 304 is a symmetric wing. The symmetric wing has substantially identical upper and lower surfaces with respect to the chord line. The leading edge 334 is located upstream, proximate to the upstream flange 312. The trailing edge 336 is located downstream of the leading edge 334, proximate to the downstream rim 320 of the body 302. The annular fuel nozzle 304 is substantially hollow, defining a cavity 340 therein. The trailing edge 336 of the annular fuel nozzle 304 has a channel 338 defined therein. A plurality of fuel injection ports 306 extend from the cavity 340 to the channel 338. The channel is configured to facilitate the mixing of the fuel flowing through the fuel injection ports 306, and a substantially continuous fuel curtain rather than a plurality of individual fuel jets is injected into the air stream.

[0026] Referring to FIG. 9, the plurality of fuel injection ports 306 extend substantially axially along the central axis "B". Further, although it is conceivable that the plurality of fuel injection ports 306 are oriented parallel to the central axis "B", in the illustrated example, the plurality of fuel injection ports 306 are formed at an angle with respect to the central axis "B". This facilitates the mixing of fuel, such as fuel 126, with the air flow by inducing swirl in the injected fuel stream. In an exemplary embodiment, the plurality of fuel injection ports 306 are formed at an angle α3 in the range of about 15 degrees (15°) to about 50 degrees (50°) with respect to the central axis "B". More specifically, in one embodiment, the fuel injection port 306 is formed at an angle of about 40 degrees (40°).

[0027] Referring back to FIG. 2, it should be noted that the cylindrical downstream wall 318 is substantially arcuate between the upstream flange 312 and the downstream rim 320 of the body 302 so as to occupy the volume of the nozzle 304. Positioning the annular fuel nozzle 304 of the halo-ring fuel injector 112 within the air flow flowing into the combustor 100 restricts the air flow. The volume of the annular fuel nozzle 304 reduces the amount of air entering the inlet end 106 of the combustion liner 104 if the downstream wall 318 is not shaped to account for the annular fuel nozzle 304. As a result, the downstream wall 318 is shaped and sized to allow substantially the same amount of air that passes through an injector of a prior art gas turbine engine (not shown) to pass through the halo-ring fuel injector 112. The amount and / or shape of the arc of the downstream wall 318 is determined in part based on the size and shape of the annular fuel nozzle 304 and the air flow requirements of the gas turbine engine.

[0028] Figures 10-14 depict various detailed views of another embodiment of a halo-ring fuel injector assembly 400 that can be used in a gas turbine engine combustor such as combustor 100 (shown in FIG. 1). In some implementations, the halo-ring fuel injector 400 is a monolithic component that can be manufactured using various techniques, including but not limited to additive manufacturing. In one embodiment, the halo-ring fuel injector 400 can be fabricated using a DMLM process. The geometry of the halo-ring fuel injector 400 is difficult to form using conventional casting techniques, and thus, the manufacture of the halo-ring fuel injector 400 using a DMLM process or an electron beam melting process can be advantageous, for example, in exemplary embodiments. However, it is contemplated that any manufacturing process that enables the halo-ring fuel injector 400 to be fabricated as described herein can be used. Further, it should be noted that the halo-ring fuel injector 400 may require post-processing to provide the desired structural properties.

[0029] In an exemplary embodiment, the halo-ring fuel injector 400 is formed substantially symmetrically with respect to a central axis “C”. The halo-ring fuel injector 400 includes a generally cylindrical body 402. The body 402 is formed in a generally frustoconical shape and has a hollow internal space 414 defined therein. The upstream flange 412 of the body 402 is proximate to an upstream opening 416 into the internal space 414. A cylindrical downstream wall 418 extends generally axially downstream from the upstream flange 412 towards a downstream rim 420 of the body 402. The downstream wall 418 generally tapers inwardly at an angle from a portion downstream of the upstream flange 412 to the downstream rim 420 of the body 402. The upstream wall 422 extends upstream from the upstream flange 412 and defines the upstream opening 416. A chamber that defines an annular fluid manifold 410 is generally defined between the upstream flange 412, the downstream wall 418, and the upstream wall 422. Proximate to the downstream rim 420, the body 402 includes a plurality of mounting tabs 424.

[0030] Similar to the halo-ring fuel injector 112 described above, an exemplary halo-ring fuel injector 400 includes an annular fuel nozzle 404. The annular fuel nozzle 404 is spaced a predetermined distance inside the downstream wall 418. As described above, the annular fuel nozzle 404 is substantially similar to the annular fuel nozzle 304 described above. Thus, similar to that depicted in FIG. 2, the annular fuel nozzle 404 is generally positioned within the air flow so as to be spaced from the combustion liner 104. This facilitates a portion of the air flow to pass above and below the annular fuel nozzle 404 so that fuel, such as fuel 126, is injected into the air flow and the boundary layer of the air flow is reduced or eliminated from containing fuel.

[0031] The annular fuel nozzle 404 is held in place by a plurality of fuel supply struts 426. In an exemplary embodiment, the halo-ring fuel injector 400 includes 24 fuel supply struts 426 equally spaced around a central axis "C". Each of the fuel supply struts 426 extends inwardly and downstream from the downstream wall 418 to the annular fuel nozzle 404 at an angle in the range of about 35 degrees (35°) to about 55 degrees (55°) with respect to the central axis "C". More particularly, each of the fuel supply struts 426 extends inwardly and downstream at an angle of about 45 degrees (45°).

[0032] In an exemplary embodiment, each of the fuel supply struts 426 is substantially airfoil-shaped in cross-section (see FIG. 13). However, it is contemplated that the cross-sectional shape of the fuel supply struts 426 can be any shape that enables the halo-ring fuel injector 400 to function as described herein. As depicted in FIG. 12, each of the fuel supply struts 426 is positioned at an angle α4 with respect to the central axis “C”. In particular, the airfoil shape is substantially symmetric, and the chord of the airfoil shape is positioned at the angle α4. The fuel supply struts 426 can be configured at any angle between 0 degrees (0°) and 45 degrees (45°), but in the depicted example, the angle α4 is in the range of about 10 degrees (10°) to about 20 degrees (20°). More particularly, each of the fuel supply struts 426 is positioned at an angle of about 15 degrees (15°). The angle α4 facilitates inducing a swirl in the air flow passing between the annular fuel nozzle 404 and the downstream wall 418. The halo-ring fuel injector 400 can include fewer or more fuel supply struts 426, and the overall alignment of each can be any desired alignment that enables the halo-ring fuel injector 400 to function as described herein.

[0033] In an exemplary embodiment, each of the fuel supply struts 426 is substantially hollow. Further, the annular fuel nozzle 404 is substantially hollow. The fuel supply struts 426 are fluidly coupled to the annular manifold 410 and the annular fuel nozzle 404 to facilitate sending fuel, such as fuel 126 shown in FIG. 2, therebetween.

[0034] Referring to FIG. 12, the upstream flange 412 of the body 402 includes one or more fuel supply ports 428. Each fuel supply port 428 is configured to be coupled to a fuel supply source of a gas turbine engine to receive fuel such as fuel 126 therefrom. In an exemplary embodiment, the fuel supply ports 428 are positioned on the radial surface of the upstream flange 412 to receive fuel radially. When fuel enters through the fuel supply ports 428, the fuel flows into the annular manifold 410. Fuel such as fuel 126 flows from the annular manifold 410 into the fuel supply strut 426. Next, the fuel flows from the fuel supply strut 426 into the annular fuel nozzle 404, where it is injected into the air stream through a plurality of fuel injection ports 406.

[0035] In an exemplary embodiment, the annular manifold 410 is divided into two sections. The first section extends at an angle of approximately 120 degrees (120°) around the central axis "C", and the second section extends at an angle of approximately 240 degrees (240°) around the remaining annular portion or the central axis "C". The first section of the cannular fuel injector 400 is used to generate a main 1 flame, and the second section of the cannular fuel injector 400 is used to generate a main 2 flame.

[0036] As depicted in FIG. 12, the annular fuel nozzle 404 is substantially airfoil-shaped in cross-section. In particular, in an exemplary embodiment, the annular fuel nozzle 404 is a symmetric airfoil. The leading edge 434 is located upstream, proximate to the upstream flange 412. The trailing edge 436 is located downstream of the leading edge 434, proximate to the downstream rim 420 of the body 402. The trailing edge 436 of the annular fuel nozzle 404 has a channel 438 defined therein.

[0037] In an exemplary embodiment, the annular fuel nozzle 404 is substantially hollow and defines a cavity 440 therein. Referring to FIG. 14, the nozzle includes a perforated wall 442 positioned within the cavity 440. The perforated wall 442 divides the cavity into two portions and facilitates the uniform distribution of fuel, such as fuel 126, to the fuel injection ports 406. In particular, the first portion is in direct fluid communication with a plurality of fuel supply struts 426, and the second portion is in direct fluid communication with a plurality of fuel injection ports 406. The first and second portions are in fluid communication with each other via a plurality of perforations defined in the perforated wall 442.

[0038] As depicted in FIG. 13, in this exemplary embodiment, the plurality of fuel injection ports 406 extend from the cavity 440 to the channel 438. The channel is configured to facilitate the mixing of the fuel flowing through the fuel injection ports 406, such that a substantially continuous fuel curtain, rather than a plurality of individual fuel jets, is injected into the air stream. In the depicted example, the plurality of fuel injection ports 406 are considered to be oriented parallel to the central axis "C", although the plurality of fuel injection ports 406 may be angled with respect to the central axis "C". This angle facilitates the mixing of fuel, such as fuel 126, with the air stream by causing a swirl in the injected fuel stream. In an exemplary embodiment, the plurality of fuel injection ports 406 are formed at an angle α5 with respect to the central axis "C" in the range of about 15 degrees (15°) to about 50 degrees (50°). More specifically, in one embodiment, the fuel injection port 406 is formed at an angle of about 40 degrees (40°).

[0039] The cylindrical downstream wall 418 is substantially arcuate between the upstream opening 416 and the downstream rim 420 of the body 402. As described above with respect to the nozzle 304 of the halo-ring fuel injector 112, the annular fuel nozzle 404 of the halo-ring fuel injector 400 is positioned within the air flow flowing into the combustor 100, whereby the air flow is restricted. The volume of the annular fuel nozzle 404 reduces the amount of air entering the inlet end 106 of the combustion liner 104 if the downstream wall 418 is not shaped to account for the annular fuel nozzle 404. As a result, the downstream wall 418 is shaped and sized to allow substantially the same amount of air to pass through the halo-ring fuel injector 400 as passes through the injector of a prior art gas turbine engine (not shown). The amount and / or shape of the arc of the downstream wall 418 is determined based in part on the size and shape of the annular fuel nozzle 404 and the air flow requirements of the gas turbine engine.

[0040] As described above, each of the fuel supply struts 426 is positioned at an angle of approximately 15 degrees (15°), and the fuel injection ports 406 are formed at an angle of approximately 40 degrees (40°). Similar to that shown in FIG. 2, the air passing between the combustion liner 104 and the annular fuel nozzle 404 can pass substantially straight through the halo-ring fuel injector 400. The air passing between the downstream wall 418 and the annular fuel nozzle 404 is deflected at an angle of approximately 15 degrees (15°) by the fuel supply struts 426, thereby causing a swirl in this portion of the air flow. In addition, at the trailing edge 436 of the nozzle, the fuel flow is injected into the air flow at an angle of approximately 40 degrees (40°). This provides additional turbulence and further facilitates complete mixing of the fuel and air, thereby supporting low NOx and low CO emissions when combusting the air / fuel mixture within the combustor.

[0041] The advantages of the fuel injection system described above include reducing or eliminating fuel within the boundary layer of the air flow passing through the combustor. The boundary layer is a low velocity flow region adjacent to geometric features. The disclosed halo-ring fuel injector includes a nozzle that "floats" within the free stream of the premixed fuel channel, ensuring that the boundary layer entering the combustion chamber is fuel-free. Fuel within the boundary layer can cause flashback. Further, the nozzle injects fuel at an angle to the air flow to facilitate good mixing of fuel and air, which is the key to reduced or low NOx and CO emissions.

[0042] Additional Considerations In this description, references to "one embodiment," "an embodiment," or "embodiments" mean that one or more of the features recited are included in at least one embodiment of the technology. Separate references to "one embodiment," "an embodiment," or "embodiments" in this description do not necessarily refer to the same embodiment and are not mutually exclusive unless stated otherwise and / or unless readily apparent to one of ordinary skill in the art from the description. For example, features, structures, acts described in one embodiment may be included in other embodiments but not necessarily included. Thus, the technology can include various combinations and / or integrations of the embodiments described herein.

[0043] This application describes in detail a number of different embodiments, but it should be understood that the legal scope of the description is defined by the words of the claims and equivalent language. The detailed description should be construed as illustrative only and is not intended to describe all possible embodiments, as it is not practical to describe all possible embodiments. Using any of the technology developed after the filing date of this technology or this patent application, a number of alternative embodiments can be implemented and they are still included within the scope of the claims.

[0044] Throughout this specification, multiple examples may implement components, operations, or structures described as a single example. Although individual operations of one or more methods are illustrated and described as separate operations, one or more of the individual operations may be executed simultaneously and need not be executed in the order described or illustrated. Structures and functions presented as separate components in an exemplary configuration may be implemented as a combined structure or component. Similarly, structures and functions presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements fall within the scope of the subject matter of this specification. The foregoing description in this paragraph applies unless otherwise stated in this description and / or is readily apparent to one of ordinary skill in the art from this description.

[0045] The various operations of the exemplary methods described herein may be at least partially executed by one or more processors temporarily configured (e.g., by software) to perform the relevant operations or permanently configured to perform the relevant operations. Whether temporarily or permanently configured, such processors may constitute processor-implemented modules that operate to perform one or more operations or functions. As used herein, a module, in some exemplary embodiments, may comprise a processor-implemented module.

[0046] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," or any other variation thereof are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0047] The present disclosure has been described with reference to embodiments illustrated in the accompanying drawings, but it should be noted that equivalents may be employed and substitutions may be made herein without departing from the scope of the present disclosure as set forth in the claims.

[0048] Although the various embodiments of the present disclosure have been described as such, what is claimed as new and desired to be protected by letters patent includes the following.

Claims

1. A fuel injector assembly comprising: An annular body having: A hollow internal space; and First and second openings into the internal space, the first and second openings being at opposed first and second ends of the annular body, the first end being upstream of the second end, the first and second openings being respectively adjacent to the first and second ends; An annular body defining a chamber that defines a fluid manifold; An annular fuel nozzle positioned within the internal space and spaced from the annular body, the annular fuel nozzle having a plurality of fuel injection ports; One or more fuel supply struts coupled to the annular fuel nozzle and the annular body, The one or more fuel supply struts being fluidly coupled to the fluid manifold and the annular fuel nozzle.

2. The fuel injector assembly of claim 1, wherein the annular fuel nozzle is airfoil-shaped in cross section.

3. The fuel injector assembly of claim 2, wherein the annular fuel nozzle has a leading edge adjacent to the first end of the annular body and a trailing edge adjacent to the second end of the annular body.

4. The annular nozzle defines a cavity therein, The trailing edge has a channel defined therein, The fuel injector assembly of claim 3, wherein the plurality of fuel injection ports extend from the cavity to the channel.

5. The annular body defines a central axis, The fuel injector assembly according to claim 4, wherein each of the plurality of fuel injection ports is formed at an angle in the range of about 15 degrees (15°) to about 50 degrees (50°) with respect to the central axis. **Claim 6** The annular nozzle includes a perforated wall positioned within the cavity, The fuel injector assembly according to claim 4, wherein the perforated wall divides the cavity into a first portion in direct fluid communication with the plurality of fuel supply struts and a second portion in direct fluid communication with the plurality of fuel injection ports. **Claim 7** The annular body defines a central axis, The fuel injector assembly according to claim 1, wherein each of the plurality of fuel injection ports is formed at an angle in the range of about 15 degrees (15°) to about 50 degrees (50°) with respect to the central axis. **Claim 8** The annular body defines a central axis, The fluid manifold is divided into a first section and a separate second section, The first section extends at an angle of about 120 degrees (120°) with respect to the central axis, The fuel injector assembly according to claim 1, wherein the second section extends at an angle of about 240 degrees (240°) with respect to the central axis. **Claim 9** The first section includes a first fuel supply port configured to receive fuel therethrough, The fuel injector assembly according to claim 8, wherein the second section includes a second fuel supply port configured to receive fuel therethrough. **Claim 10** The fuel injector assembly further includes one or more support struts coupled to the annular fuel nozzle and the annular body, Each of the one or more support struts is positioned downstream from a respective one of the one or more fuel supply struts, The fuel injector assembly according to claim 1, wherein each of the one or more support struts is axially aligned with one of the one or more fuel supply struts.

11. The fuel injector assembly according to claim 1, wherein each of the one or more fuel supply struts is airfoil-shaped in cross-section.

12. The annular body defines a central axis, The fuel injector assembly according to claim 11, wherein the chord of each of the one or more fuel supply struts is positioned at an angle in the range of about 10 degrees (10°) to about 20 degrees (20°) with respect to the central axis.

13. The fuel injector assembly according to claim 12, wherein each of the plurality of fuel injection ports is formed at an angle in the range of about 15 degrees (15°) to about 50 degrees (50°) in the same direction as the one or more fuel supply struts with respect to the central axis.

14. A combustor, A cylindrical combustion liner having an inlet end, an outlet end, and a central axis, the combustion liner defining a combustion chamber, and A fuel injector assembly positioned radially outside the cylindrical combustion liner with respect to the central axis, the fuel injector assembly comprising An annular body, A hollow internal space, and First and second openings into the internal space, the first and second openings being opposite first and second ends of the annular body, the first end being upstream of the second end, and the first and second openings being proximate to the first and second ends respectively. An annular body defining a chamber that defines a fluid manifold, and An annular fuel nozzle positioned within the internal space and spaced apart from the annular body and the cylindrical combustion liner, the annular fuel nozzle comprising a plurality of fuel injection ports. One or more fuel supply struts coupled to the annular fuel nozzle and the annular body, One or more fuel supply struts, wherein the one or more fuel supply struts are fluidly coupled to the fluid manifold and the annular fuel nozzle, and a fuel injector assembly comprising the same, a combustor. **Claim 15** The annular body of the fuel injector assembly, An upstream flange defining the first opening, A cylindrical downstream wall extending substantially axially downstream from the upstream flange and being a downstream rim of the annular body, the downstream rim defining the second opening, the combustor according to claim 14. **Claim 16** The cylindrical downstream wall is arcuate between the upstream flange and the downstream rim so as to occupy the volume of the annular fuel nozzle, the combustor according to claim 15. **Claim 17** The annular fuel nozzle is airfoil-shaped in cross-section, the combustor according to claim 14. **Claim 18** The annular fuel nozzle includes a leading edge proximate to the first end of the annular body and a trailing edge proximate to the second end of the annular body, the combustor according to claim 17. **Claim 19** The annular nozzle defines a cavity therein, The trailing edge includes a channel defined therein, The plurality of fuel injection ports extend from the cavity to the channel, the combustor according to claim 18. **Claim 20** The annular body defines a central axis, Each of the plurality of fuel injection ports is formed at an angle in the range of about 15 degrees (15°) to about 50 degrees (50°) with respect to the central axis, the combustor according to claim 19.

Images