Fuel mixer

Abstract

A fuel mixer is configured to provide a fuel-air mixture to a burner of an engine. The fuel mixer may include a mixer body having a mixer outer wall, a center body, an annular passage defined between the mixer outer wall and the center body, and a fuel pipe assembly placed circumferentially around the mixer body. The fuel pipe assembly may include at least one fuel channel for injecting a fuel flow into the annular passage. The fuel pipe assembly may be configured to cool a boundary layer flow present in the annular passage. The fuel pipe assembly may be configured to cool the mixer outer wall, the center body, or both the mixer outer wall and the center body. Heat from the mixer outer wall, the center body, or both the mixer outer wall and the center body may be transferred to the fuel flow in the fuel pipe assembly.

Description

Technical Field

[0001] The present disclosure relates to a fuel mixer. More particularly, the present disclosure relates to a mixer including a fuel line assembly. Background Art

[0002] Current mixers for natural gas powered turbine engines mix fuel with air to create a fuel-air mixture to provide the fuel-air mixture to the engine's burner. Conventional mixers mix inlet air and inlet fuel to create a fuel-air mixture. Inlet air can be directed to the burner without creating a swirl. Current mixers may include a fuel inlet and an air inlet that mix in an annular passage in the mixer. Summary of the invention

[0003] According to an embodiment, a fuel mixer configured to provide a fuel-air mixture to a burner of an engine may include a mixer body having a mixer outer wall; a center body; an annular passage defined between the mixer outer wall and the center body; and a fuel pipe assembly placed circumferentially around the mixer body, the fuel pipe assembly including at least one fuel channel for injecting a fuel flow into the annular passage. The fuel pipe assembly may be configured to cool a boundary layer flow present in the annular passage. The fuel pipe assembly may be configured to cool the mixer outer wall, the center body, or both the mixer outer wall and the center body. Heat from the mixer outer wall, the center body, or both the mixer outer wall and the center body may be transferred to the fuel flow in the fuel pipe assembly.

[0004] According to an embodiment, a method of cooling a fuel mixer in a combustor may include: injecting an air flow into an annular passage of the fuel mixer; injecting a fuel flow into the annular passage downstream of the air flow; mixing the fuel flow and the air flow in the annular passage to provide a fuel-air flow; cooling the fuel-air flow with the fuel flow; cooling an outer mixer wall of the fuel mixer with the fuel flow; and cooling a center body of the fuel mixer with the fuel flow. The fuel flow may be provided within the outer mixer wall.

[0005] Additional features, advantages and embodiments of the present disclosure are set forth or apparent by consideration of the following detailed description, drawings and claims. In addition, it should be understood that the foregoing overview and the following detailed description of the present disclosure are exemplary and are intended to provide further explanation without limiting the scope of the present disclosure as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The foregoing and other features and advantages will become apparent from the following more particular description of various exemplary embodiments as illustrated in the accompanying drawings, in which like reference numerals generally indicate identical, functionally similar, and / or structurally similar elements.

[0007] Figure 1 A schematic perspective view of a mixer array with a combustion liner according to an embodiment of the present disclosure is shown.

[0008] Figure 2 A schematic partial cross-sectional view of a mixer taken through the centerline of the mixer is shown according to an embodiment of the present disclosure.

[0009] Figure 3 A schematic partial perspective view of a mixer according to an embodiment of the present disclosure is shown.

[0010] Figure 4 A cross-sectional view taken through the centerline of a mixer according to an embodiment of the present disclosure is shown. Figure 3 Schematic partial cross-sectional view of a mixer.

[0011] Figure 5 A cross-sectional view taken through the centerline of a mixer according to an embodiment of the present disclosure is shown. Figure 3 Schematic partial cross-sectional view of a mixer.

[0012] Figure 6 The embodiment according to the present disclosure is shown Figure 3 Schematic diagram of a mixer.

[0013] Figure 7 The embodiment according to the present disclosure is shown Figure 4 Schematic cross-sectional view taken along section line 7-7 in FIG.

[0014] Figure 8 The embodiment according to the present disclosure is shown Figure 3 A schematic perspective view of a fuel pipe assembly of a mixer.

[0015] Fig. 9 A schematic perspective view of a fuel line assembly according to an embodiment of the present disclosure is shown.

[0016] Fig.10 The embodiment according to the present disclosure is shown Fig. 9 A schematic plan view of a fuel pipe assembly.

[0017] Fig.11 The embodiment according to the present disclosure includes Fig. 9 Schematic diagram of the fuel line assembly with a mixer.

[0018] Fig.12 A schematic cross-sectional view of a mixer taken through the centerline of the mixer is shown according to an embodiment of the present disclosure.

[0019] Fig.13 A schematic cross-sectional view of a mixer taken through the centerline of the mixer is shown according to an embodiment of the present disclosure.

[0020] Fig.14 The embodiment according to the present disclosure is shown Fig.13 A schematic plan view of a mixer fuel pipe assembly.

[0021] Fig.15 A schematic cross-sectional view of a mixer taken through the centerline of the mixer is shown according to an embodiment of the present disclosure.

[0022] Fig.16 The embodiment according to the present disclosure is shown Fig.15 A schematic plan view of a mixer fuel pipe assembly. DETAILED DESCRIPTION

[0023] Various embodiments are discussed in detail below. Although specific embodiments are discussed, this is for illustrative purposes only. Those skilled in the relevant art will recognize that other components and configurations may be used without departing from the spirit and scope of the present disclosure.

[0024] The fuel pipe assembly of the present invention can be arranged in the mixer of the burner of the engine (such as gas turbine engine). The fuel pipe assembly of the present invention can help reduce the flashback / flame holding risk when burning hydrogen or hydrogen mixed fuel at nominal flow rate in traditional mixing tube. Due to the high combustion speed of hydrogen fuel, the flame may propagate into the mixing tube through the boundary layer and stabilize, thereby causing damage to the premixer hardware. The fuel pipe assembly of the present invention provides cooling channels, which can prevent or reduce the flame holding in the mixing tube by cooling the boundary layer (before the fuel is injected) with fuel. The temperature of the fuel may be lower than the compressor exhaust temperature (for example, the temperature of the air entering the mixer). Before the fuel is injected into the air flow through the fuel outlet orifice, the boundary layer cooling can be realized by the (built-in) fuel channel additionally made in a serpentine or spiral manner. The positioning of the fuel orifice relative to the mixing tube outlet is optimized for the flame pre-mixing of fuel and air and the sufficient cooling of the boundary layer to prevent the risk of flame holding. The fuel pipe assembly of the present invention can allow the combustion of hydrogen fuel.

[0025] The present disclosure describes a mixer having a fuel line assembly disposed around the body of the mixer. The fuel line assembly may include one or more curved or serpentine channels. The fuel line assembly may provide fuel to the mixer and may also operate to cool the outer mixer wall before the fuel is injected into the mixer passage. The fuel line assembly may extend longitudinally and circumferentially around the mixer body. In some embodiments, the fuel line assembly may be placed spirally around the mixer. In some embodiments, the fuel line assembly may include one or more fuel line subassemblies. In some embodiments, the fuel line assembly may be placed around a bluff body within the mixer.

[0026] refer to Figure 1, shows a schematic perspective view of a mixer array 100. The mixer array 100 may include one or more mixers 102. The mixer array 100 may be divided into one or more zones. Figure 2 In the embodiment of the present invention, the mixer array 100 can be divided into a plurality of zones: zone A, zone B, zone C, etc. The one or more mixers 102 disposed in zones A, B, and C can all be of the same structure, or can all be of different structures, or can include some mixers of the same structure and some mixers of different structures. The mixer array 100, and therefore one or more mixers 102, can be located on a support 104 coupled to a combustion liner 106.

[0027] refer to Figure 2 , shows a cross-sectional view of the mixer 200. The mixer 200 may be arranged at Figure 1 In the mixer array 100 (for example, the mixer 200 may replace Figure 1 One or more mixers 102 in the mixer array 100 of the mixer 200). The mixer 200 may be included in an engine, for example, in a DLE engine. The mixer 200 may include an annular mixer channel 202, one or more openings 208, and a central channel 210. Fuel may be injected from one or more openings 204 on the truncated cone 206. The mixer 200 may also include a bluff body 207, also referred to herein as a central body. As shown, the bluff body 207 may form an annular mixing channel 202. The air flowing out of the bluff body 207 may be an axial flow fed through the central channel 210. The fuel may be injected at the front side of the mixer 200. The mixer 200 may allow hydrogen fuel (H 2 A fuel mixture with a lower mixing percentage of fuel).

[0028] exist Figure 3 and 4 In the exemplary mixer 300, a fuel pipe assembly 308 may be provided. The mixer 300 may be provided at Figure 1 In the mixer array 100 (for example, the mixer 300 may replace Figure 1 1 and 2. The mixer 300 may be one or more mixers 102 in the mixer array 100 of the embodiment of the present invention. The mixer 300 may be the mixer 200 or may be any known mixer with the addition of a fuel tube assembly (e.g., fuel tube assembly 308). The mixer 300 may include a central passage 310, a first plurality of openings 306, and a second plurality of openings 304. The mixer 300 may include an annular passage 301, a mixer body 302, and a center body or bluff body 317.

[0029] The air flow may be introduced through the first plurality of openings 306 and the second plurality of openings 304 to mix with the fuel flow A ( Figure 4 ) mixture. The fuel stream can be hydrogen (H 2) fuel flow. The fuel flow can be introduced through the fuel pipe assembly 308. Figure 6 As shown, the fuel tube assembly 308 may include one or more fuel tube subassemblies, such as fuel tube subassembly 308a, fuel tube subassembly 308b, and fuel tube subassembly 308c. Figure 3 The fuel tube subassembly may be placed circumferentially around the mixer body 302 of the mixer 300 and longitudinally along the mixer body 302, such as Figure 3 and Figure 6 The arrangement of the subassemblies may define a fuel tube assembly 308. The fuel tube assembly 308 may include subassemblies that are evenly spaced, randomly spaced, or spaced in a predetermined pattern around the circumference of the mixer body 302. Figures 3 to 8 As shown, the fuel pipe subassembly can be a fuel pipe extending axially along the wall of the mixer 300. The fuel pipe can provide H to the mixer. 2 fuel.

[0030] Figures 4 to 8 The mixer 300 is shown with a fuel pipe assembly 308. As described above, the fuel pipe assembly 308 may include one or more fuel pipe subassemblies, such as fuel pipe subassembly 308a, fuel pipe subassembly 308b, and fuel pipe subassembly 308c. Each fuel pipe subassembly of the fuel pipe assembly 308 may define a flow channel therein. For example, Figure 8 As shown, the fuel tube subassembly may include a fuel inlet 318 and a fuel outlet 314. A passage or fuel channel 315 may extend between the fuel inlet 318 and the fuel outlet 314. The fuel channel 315 may be a serpentine passage. The fuel channel 315 may be defined by a vertical portion 320, one or more longitudinally extending portions 312, and one or more curved portions 316. In this manner, as shown in FIG. Figure 8 As shown in the exemplary fuel tube assembly 308 of FIG. 1 , the fuel passage or fuel channel 315 of the fuel tube subassembly can extend from the fuel inlet 318 along the vertical portion 320 downward to the longitudinal extension portion 312. The longitudinal extension portion 312 can be bent or bent at the bend portion 316 to the second longitudinal extension portion 312. The bend portion 316 can be substantially semicircular in plan view. There can be any number of bends or bends and longitudinal extensions between the fuel inlet 318 and the fuel outlet 314 of the subassembly. The number of channels that make up the fuel channel 315 (also called a serpentine passage) can be determined based on the desired fuel flow, the desired engine operation, the desired cooling of the annular passage 301, or any combination thereof.

[0031] refer to Figure 4 and Figure 5Each fuel outlet 314 of the subassembly of the fuel tube assembly 308 can exit into the annular passage 301 for mixing with the air flow provided through the second plurality of openings 304 and the first plurality of openings 306. The annular passage 301 can be formed around the bluff body 317. The fuel flow A can be from each fuel inlet 318 ( Figure 8 ) travels through the fuel channel 315 of the corresponding subassembly and exits each fuel outlet 314 into the annular passage 301.

[0032] As mentioned and referenced Figure 6 , the subassemblies of the fuel tube assembly 308 can be placed circumferentially around the mixer body 302 of the mixer 300. The fuel tube assembly 308 can further extend a longitudinal distance (e.g., along the length of the mixer body 302). The longitudinal distance can be defined by the longitudinal distance between the opposite ends of the serpentine channel. For example, the longitudinal distance can be defined by the opposite bends 316. Although in Figure 8 Six subassemblies (e.g., fuel tube subassemblies 308a, 308b, 308c, 308d, 308e, and 308f) are shown, but more or fewer subassemblies may be provided. The number of subassemblies, the length along the mixer body 302, the number of twists of the serpentine channel, or any combination thereof may be selected or optimized. For example, Figure 8 As shown, a fuel tube subassembly (e.g., 308a) may include four torsions. In another example, as Fig. 9 As shown, a fuel tube subassembly (e.g., 408a) may include nine twists. Although shown as extending completely around the mixer body 302 (e.g., Figure 8 ), but the fuel tube assembly 308 may only partially extend around the mixer body 302. In an embodiment, a portion of the fuel tube subassembly may partially extend around the mixer body 302 so that the fuel outlet 314 may be located at a different axial position on the outer wall of the mixer relative to other fuel outlets 314 of other fuel tube subassemblies. This may result in a change in the fuel distribution at the mixer outlet, resulting in a change in the heat release area, which may help reduce dynamics.

[0033] The fuel tube subassemblies can be considered to be serpentine channels. These serpentine channels can operate as a heat exchanger with the outer wall of the mixer. That is, as relatively cool fuel (e.g., cool relative to the mixer body and the flow within the annular channel) flows through the serpentine channels from the fuel inlet 318 to the fuel outlet 314, the fuel can absorb heat from the mixer body and the flow therein. This can reduce the temperature of the mixer body material. Therefore, as the fuel flows within the serpentine channels, the fuel can continue to absorb heat. Figures 9 to 16A similar effect occurs with the fuel line assemblies of the mixer, which can similarly be thought of as serpentine channels operating as heat exchangers with the outer wall of the mixer.

[0034] Return to reference Figure 4 , fuel (e.g. H 2 The fuel) can be injected radially inward from the outer wall of the mixer 300. 2 The fuel may be provided by a fuel manifold 311 defined by a flange 313 of the mixer 300. Figure 7 As shown, fuel inlet 318 is connected to fuel manifold 311 .

[0035] Figures 9 to 11 An exemplary fuel line assembly 408 for the mixer 400 is shown. The mixer 400 may be located at Figure 1 406 and 408a. The mixer 400 may include a mixer body 402 and openings 404 and 406 to provide an air flow to the mixer 400. The fuel pipe assembly 408 may be provided with any mixer described herein or a mixer known in the art. The fuel pipe assembly 408 may include a plurality of fuel pipe subassemblies, such as fuel pipe subassemblies 408a, 408b, and 408c. Each subassembly may define a channel 415. The channel 415 may include a fuel inlet 418, a vertically extending portion 420, and a fuel outlet 414. Between the fuel inlet 418 and the fuel outlet 414, a serpentine channel defined by a circumferentially extending portion 412 and a curved portion 416 may be provided. The serpentine channel may be similar to Figure 8 The serpentine channel of the fuel pipe assembly 308. However, in Figure 8 In the embodiment, the portion 312 can extend longitudinally along the length of the mixer body 302, so that the portion 312 forms a longitudinally extending portion 312, while in Fig. 9 In the embodiment, the portion 412 may extend along the circumference of the mixer body 302 such that the portion forms a circumferentially extending portion 412 .

[0036] like Fig.10 As shown, adjacent subassemblies (e.g., fuel tube subassemblies 408a, 408b, and 408c) may be circumferentially aligned such that curved portions 416 of adjacent subassemblies are aligned. For example, curved portion 416a of fuel tube subassembly 408a may have a central axis A that is aligned with curved portion 416b of fuel tube subassembly 408b and aligned with curved portion 416c of fuel tube subassembly 408c. In another embodiment, the curved portions may not be aligned such that curved portions 416a, 416b, and 416c have an axis that is offset from at least one other curved portion of an adjacent subassembly.

[0037] Figures 9 to 11 The fuel pipe can provide for fuel (such as hydrogen (H 2) fuel flow path. Before the fuel is injected into the mixer channel (not visible), H 2 The fuel may cool the outer wall of the mixer 400. The tubes may be positioned circumferentially within the section of the mixer body. The outlet of the mixer 400 sees the lowest temperature because H 2 The fuel may absorb heat from the metal toward the front side of the tube (eg, near the fuel inlet 418). This may occur when the fuel is injected at the fuel inlet 418 in an upstream position compared to the fuel outlet 414.

[0038] refer to Fig.12 , a schematic diagram of a mixer 500 is shown with a fuel tube assembly 508. The fuel tube assembly 508 may have one or more fuel passages 508a, 508b, 508c, 508d, 508e, and 508f that exit into the annular passage 501 of the mixer 500. Fig.12 As shown, the fuel outlets may be axially and / or circumferentially offset from each other. For example, fuel passages 508a, 508b, and 508c may exit axially after fuel passages 508d, 508e, and 508f. Thus, the fuel outlets may be located at different axial and circumferential positions to achieve desired cooling and fuel-air mixing within the mixer 500.

[0039] refer to Fig.13 and 14 , a schematic diagram of a mixer 600 is shown with a fuel tube assembly 608. The fuel tube assembly 608 may be formed of one or more subassemblies spirally formed around the outer surface of the mixer body. Fig.13 and 14 In the embodiment of the present invention, a plurality of fuel tube assembly coils may be placed around the outer wall of the mixer to cool the outer wall.

[0040] refer to Fig.15 and 16 , shows a schematic diagram of a mixer 700 having a fuel line assembly 708 and a fuel line assembly 728. The fuel line assembly 708 can be a fuel line assembly that extends around the mixer body 702. The fuel line assembly 708 can be any of the fuel line assemblies described above. The fuel line assembly 728 can be a fuel line assembly that extends around the center body or bluff body 717 of the mixer 700. The fuel line assembly 708, the fuel line assembly 728, or both can be fuel line assemblies that extend helically around the mixer 700. For example, the fuel line assembly 708 can include a first helically extending channel, and the fuel line assembly 728 can include a second helically extending channel. Thus, there can be H on both the outer mixer wall and along the center body wall (e.g., bluff body). 2The fuel flow can flow in the same direction (e.g., clockwise or counterclockwise) in fuel tube assemblies 708 and 728. Alternatively, the fuel flows can be opposite to each other (e.g., one flow is clockwise and the other flow is counterclockwise). In some embodiments, H can be injected from the outer wall as well as the inner wall. 2 The split of the fuel flow (e.g., how much fuel is injected into fuel tube assembly 728 and fuel tube assembly 708) can vary. Depending on the power conditions or application, the split of the fuel flow can vary from 0% to 100%. For example, inner fuel tube assembly 728 can have 100% H 2 fuel, and the outer fuel tube assembly 708 may have H 2 and natural gas mixture.

[0041] Figures 12 to 15 The fuel tube assembly of the H may provide a plurality of fuel coils around the outer wall of the mixer to cool the wall to prevent autoignition on the mixer wall and / or to prevent or limit flashback. The coils of these tubes may be on the center body as well as on the center body surface. Each H 2 The fuel outlets may be located at different axial and circumferential locations to produce variations in circumferential fuel concentration at the mixer outlet and, therefore, heat release rates that may improve dynamics in a positive manner. The fuel tube assembly may provide any shape of cooling flow path cross section, and the shape and / or size may vary along the coil of tubes. For example, the tubes in the rear end of the mixer may be larger than those in the front end of the mixer. 2 The fuel flow can be from the front side to the rear side, or from the rear side to the front side. In some examples, the fuel pipe assembly can flow to the rear side and some flow to the front side. The fuel flow direction of the mixer outer wall can be in the same direction as the center body, or they can be in opposite directions (e.g., from front to rear direction and angular timing direction, such as clockwise / counterclockwise).

[0042] The fuel line assembly of the present disclosure may allow for the transfer of fuels such as hydrogen (H 2 ) fuel) is injected into the mixer body. The fuel pipe assembly of the present disclosure may allow the use of hydrogen fuel while reducing concerns about flame holding. The fuel pipe assembly may accommodate fuel mixtures ranging from 0% to 100% hydrogen and any value or range therein. In some examples, the fuel pipe assembly may accommodate a fuel mixture with 100% hydrogen content. The fuel pipe assembly of the present disclosure may allow the fuel to cool the outer wall of the mixer wall before the fuel is injected into the annular channel in the mixer. The fuel pipe assembly of the present disclosure may include a fuel pipe extending axially along the mixer wall.

[0043] The fuel line assembly of the present disclosure may include a plurality of fuel serpentines along the mixer wall, wherein H 2The fuel is connected from the fuel manifold. The tube can be operated to cool the wall. This can avoid autoignition and / or flashback in the annular mixer channel. 2 After the fuel is used to cool the mixer walls, the fuel is discharged radially or at an angle from the outer wall of the mixer into the annular mixer channel. 2 Fuels are described, but other fuels may be provided.

[0044] The fuel pipe assembly of the present disclosure may include a fuel pipe subassembly having a separate fuel outlet (e.g., a fuel injector). Each fuel injector may have a separate cooling path to cool the walls in a specific sector of the mixer. Although shown in a circular cross-section, the cooling flow channel (e.g., a fuel pipe) may have any cross-sectional shape. Although shown as extending longitudinally (e.g., in the mainstream direction through the annular mixer passage) or circumferentially (e.g., 90 degrees to the mainstream direction through the annular mixer passage), the fuel pipe may be placed at an angle relative to the mainstream direction.

[0045] The fuel pipe assembly of the present disclosure may include a manifold connected to the serpentine fuel channel. The manifold may be placed at the front side or the rear side of the mixer.

[0046] The fuel line assembly of the present disclosure may include multiple cooling channels, as described herein, with each injector and cooling circuit connected to a manifold. In some examples, the fuel line assembly of the present disclosure may include a set of cooling tubes that can provide fuel flow to multiple injectors. In some examples, the fuel line assembly of the present disclosure may include only one cooling tube of varying diameter that cools the entire mixer and is connected to all fuel orifices. For example, the fuel line assembly may have a larger diameter at the inlet (e.g., at the manifold) and a cross-section that becomes smaller (i.e., decreases) as the fuel line assembly reaches the injector location (e.g., fuel outlet).

[0047] The fuel tube assembly of the present disclosure may include a plurality of serpentine cooling tubes on a center body (eg, bluff body) or on both the outer wall of the mixer and the center body.

[0048] The fuel tube assembly of the present disclosure may include an inner mixing tube surface on the outer wall of the mixer and an outer surface of the center body near the outlet, which may be coated with a passivating agent, such as SiO 2 Or other coating agents. The coating agent can prevent the catalytic reaction of hydrogen fuel. The boundary layer thickness near the outlet of the mixing tube can be reduced by converging the flow path and accelerating the flow. The pressure drop near the outlet can be optimized by the mixing tube air inlet pressure drop.

[0049] The fuel tube assembly of the present disclosure may include serpentine channels that may be additionally fabricated and optimized for boundary layer cooling performance and manufacturability. Optimization of fuel pressure drop through the channels and temperature drop in the boundary layer may be achieved for a range of engine operating conditions. The fuel tube assembly of the present disclosure may eliminate flashback and flame holding risks without increasing burner pressure drop that degrades engine performance. During low power operation, flame holding risk may increase with higher flame temperatures, but the cooling channels provided by the fuel tube assembly of the present disclosure may effectively cool the walls and may therefore be more effective at higher fuel flow conditions to reduce flame holding risk.

[0050] The fuel pipe assembly of the present disclosure can provide internal, built-in pipe cooling channels to provide a means for safe operation of a hydrogen combustion burner, which can ensure the durability of the premixer. The fuel pipe assembly of the present disclosure can directly address the flashback / flame holding risk of burning hydrogen fuel by actively cooling the boundary layer to quench the flame when the flame propagates into the mixing tube, can produce a compact flame array that is stabilized by the back of the premixer, and can produce active boundary layer cooling. This can provide the advantages of a high-performance premixer / burner designed for emissions without compromising the design that addresses the flashback / flame holding risk.

[0051] Further aspects of the disclosure are provided by the subject matter of the following clauses.

[0052] 1. A fuel mixer, the fuel mixer being configured to provide a fuel-air mixture to a combustor of an engine, the fuel mixer comprising: a mixer body having a mixer outer wall; a center body; an annular passage defined between the mixer outer wall and the center body; and a fuel pipe assembly, the fuel pipe assembly being circumferentially disposed around the mixer body, the fuel pipe assembly comprising at least one fuel channel for injecting a fuel flow into the annular passage, wherein the fuel pipe assembly is configured to cool a boundary layer flow present in the annular passage, wherein the fuel pipe assembly is configured to cool the mixer outer wall, the center body, or both the mixer outer wall and the center body, and wherein heat from the mixer outer wall, the center body, or both the mixer outer wall and the center body is transferred to the fuel flow in the fuel pipe assembly.

[0053] 2. A fuel mixer according to any one of the preceding clauses, wherein the boundary layer flow exists near the mixer outer wall, near the center body, or near both the mixer outer wall and the center body.

[0054] 3. A fuel mixer according to any one of the preceding clauses, wherein the fuel pipe assembly comprises a plurality of fuel pipe sub-assemblies, each fuel pipe sub-assembly having a fuel inlet and a fuel outlet.

[0055] 4. A fuel mixer according to any preceding clause, wherein the fuel inlet is downstream of the fuel outlet.

[0056] 5. A fuel mixer according to any one of the preceding clauses, wherein the fuel outlets are axially offset, circumferentially offset, or both axially and circumferentially offset from each other.

[0057] 6. The fuel mixer according to any of the preceding clauses, further comprising a fuel manifold coupled to the fuel line assembly to supply fuel to the fuel line assembly.

[0058] 7. A fuel mixer according to any one of the preceding clauses, wherein the fuel tube assembly is arranged helically around the mixer body.

[0059] 8. A fuel mixer according to any one of the preceding clauses, further comprising an additional fuel tube assembly, the additional fuel tube assembly being arranged helically around the center body to cool the boundary layer flow on the center body.

[0060] 9. A fuel mixer according to any of the preceding clauses, wherein the flow through the fuel tube assembly is a counter-flow to the flow through the additional fuel tube assembly, and wherein the counter-flow is an axial counter-flow or a radial counter-flow.

[0061] 10. A fuel mixer according to any one of the preceding clauses, wherein the mixer outer wall, the centre body, or both the mixer outer wall and the centre body are coated with a passivating agent.

[0062] 11. A fuel mixer according to any one of the preceding clauses, wherein the fuel pipe assembly includes: a fuel inlet; a fuel outlet; and a serpentine channel, wherein the serpentine channel is defined between the fuel inlet and the fuel outlet, wherein the fuel flow flows from the fuel inlet to the fuel outlet through the serpentine channel, and wherein, when the fuel flow flows through the serpentine channel, the fuel flow is received from the outer wall of the mixer, thereby cooling the outer wall of the mixer.

[0063] 12. A fuel mixer according to any preceding clause, wherein the serpentine channel comprises a longitudinally extending channel extending along the length of the mixer body in the direction of flow.

[0064] 13. A fuel mixer according to any preceding clause, wherein the serpentine channel comprises a circumferentially extending channel extending along the circumference of the mixer body.

[0065] 14. A fuel mixer according to any preceding clause, wherein the serpentine channel is angled relative to a main flow through the mixer body.

[0066] 15. A mixer array comprising one or more fuel mixers according to any one of the preceding clauses.

[0067] 16. A method for cooling a fuel mixer in a combustor, the method comprising: injecting an air flow into an annular passage of the fuel mixer; injecting a fuel flow into the annular passage downstream of the air flow; mixing the fuel flow and the air flow in the annular passage to provide a fuel-air flow; cooling the fuel-air flow with the fuel flow; cooling an outer mixer wall of the fuel mixer with the fuel flow; and cooling a center body of the fuel mixer with the fuel flow, wherein the fuel flow is provided within the outer mixer wall.

[0068] 17. The method according to any of the preceding clauses, further comprising providing a serpentine channel in the outer mixer wall, wherein the fuel flow is provided in the serpentine channel, and wherein the fuel flow flows through the serpentine channel before being injected into the annular passage.

[0069] 18. A method according to any of the preceding clauses, wherein the fuel flow at the inlet of the serpentine channel is hotter than the fuel flow at the outlet of the serpentine channel due to the fuel flow obtaining heat from the fuel mixer during cooling.

[0070] 19. A method according to any of the preceding clauses, wherein cooling the fuel-air flow with the fuel flow includes: providing a fuel pipe assembly around the fuel mixer, the fuel pipe assembly being located downstream of the fuel mixer; and injecting the fuel flow through the fuel pipe assembly before injecting the fuel flow into the annular passage, wherein the fuel flow in the fuel pipe assembly cools the fuel-air flow before the fuel flow leaves the fuel pipe assembly and enters the annular passage.

[0071] 20. A method according to any of the preceding clauses, wherein the fuel pipe assembly includes a first spirally extending channel surrounding the fuel mixer and a second spirally extending channel surrounding a center body of the fuel mixer, and the method further includes causing fuel to flow in the first spirally extending channel and the second spirally extending channel.

[0072] Although the foregoing description is directed to a preferred embodiment, it should be noted that other variations and modifications will be apparent to those skilled in the art and may be made without departing from the spirit or scope of the present disclosure. In addition, features described in conjunction with one embodiment may be used in conjunction with other embodiments, even if not explicitly stated above.

Claims

1. A fuel mixer, characterized in that: The fuel mixer is configured to provide a fuel-air mixture to a combustor of an engine, the fuel mixer comprising: a mixer body, the mixer body having a mixer outer wall; centrosome; an annular passage defined between the mixer outer wall and the center body; a first plurality of openings extending through the mixer outer wall for introducing air into the annular passage; a second plurality of openings extending through the mixer outer wall and axially spaced apart from the first plurality of openings, the second plurality of openings directing air into the annular passage; and a plurality of fuel tube assemblies disposed circumferentially about the mixer body, each of the plurality of fuel tube assemblies including at least one fuel channel for injecting a flow of fuel into the annular passage, the at least one fuel channel extending from a fuel inlet to a fuel outlet extending through an outer wall of the mixer, the fuel inlet downstream of the fuel outlet; wherein the plurality of fuel tube assemblies are configured to cool the boundary layer flow present in the annular passage and cool the mixer outer wall, the center body, or both the mixer outer wall and the center body, and Wherein heat from the mixer outer wall, the center body, or both the mixer outer wall and the center body is transferred to the fuel flow in the plurality of fuel tube assemblies.

2. The fuel mixer according to claim 1, characterized in that in, The boundary layer flow exists near the mixer outer wall, near the center body, or near both the mixer outer wall and the center body.

3. The fuel mixer according to claim 1, characterized in that in, The plurality of fuel tube assemblies includes a plurality of fuel tube subassemblies, each fuel tube subassembly having a fuel inlet and a fuel outlet.

4. The fuel mixer according to claim 3, characterized in that: Further included is a plurality of fuel outlets, wherein the fuel outlets are axially offset, circumferentially offset, or both axially offset and circumferentially offset from each other.

5. The fuel mixer according to claim 1, characterized in that Further included is a fuel manifold coupled to the plurality of fuel tube assemblies to supply fuel to the plurality of fuel tube assemblies.

6. The fuel mixer according to claim 1, characterized in that in, The plurality of fuel tube assemblies are spirally arranged around the mixer body.

7. The fuel mixer according to claim 6, characterized in that Further included is an additional fuel tube assembly spirally arranged around the center body to cool the boundary layer flow on the center body.

8. The fuel mixer according to claim 7, characterized in that in, The flow through the plurality of fuel tube assemblies is a counterflow to the flow through the additional fuel tube assemblies, and wherein the counterflow is an axial counterflow or a radial counterflow.

9. The fuel mixer according to claim 1, characterized in that in, The mixer outer wall, the center body, or both the mixer outer wall and the center body are coated with a passivating agent.

10. A mixer array, characterized in that: The mixer array comprises one or more fuel mixers according to claim 1.

11. A method for cooling a fuel mixer in a burner, characterized in that: The method comprises: injecting a first air stream into an annular passage of the fuel mixer; injecting a second air flow into the annular passage downstream of the first air flow; injecting a fuel flow into the annular passage downstream of the second air flow; mixing the fuel flow, the first air flow, and the second air flow in the annular passage to provide a fuel-air flow; cooling the fuel-air stream with the fuel stream; cooling a mixer outer wall of the fuel mixer with the fuel flow; and cooling a center body of the fuel mixer with the fuel flow, wherein the fuel flow is provided within the outer wall of the mixer; and Wherein the fuel flow in the mixer outer wall provides cooling of the fuel-air flow.

12. The method according to claim 11, characterized in that Further comprising providing a serpentine channel in the mixer outer wall, wherein the fuel flow is provided in the serpentine channel, and wherein the fuel flow flows through the serpentine channel before being injected into the annular passage.

13. The method according to claim 12, characterized in that in, Since the fuel flow receives heat from the fuel mixer during cooling, the fuel flow at the inlet of the serpentine channel is hotter than the fuel flow at the outlet of the serpentine channel.

14. The method according to claim 11, characterized in that in, Cooling the fuel-air stream with the fuel stream comprises: providing a fuel line assembly about the fuel mixer, the fuel line assembly being located at a downstream end of the fuel mixer; and injecting the fuel flow through the fuel pipe assembly before injecting the fuel flow into the annular passage, Wherein the fuel flow in the fuel tube assembly cools the fuel-air flow before the fuel flow exits the fuel tube assembly and enters the annular passage.

15. The method according to claim 14, characterized in that in, The fuel tube assembly includes a first helically extending channel surrounding the fuel mixer and a second helically extending channel surrounding the center body of the fuel mixer, the method further including flowing fuel in the first helically extending channel and the second helically extending channel.

Images