Post-flame stage combustor and gas turbine

Abstract

The application discloses a rear flame stage combustor and a gas turbine, the rear flame stage combustor comprises a flame tube and a rear flame stage nozzle, the rear end of the flame tube forms a transition section, the pipe wall of the transition section is provided with a mounting hole, the rear flame stage nozzle comprises an outer pipe and a swirl passage, the outer pipe is arranged on the pipe wall of the transition section, the outer pipe defines the swirl passage which is communicated with the inner cavity of the transition section, one end of the pipe wall of the outer pipe which is away from the inner cavity of the transition section is provided with a fuel inlet which is communicated with the swirl passage, and a swirl device is arranged at one end of the swirl passage which is adjacent to the inner cavity of the transition section. The rear flame stage combustor provided by the application reduces the risk of backfire under high-temperature conditions, reduces thermal stress and the risk of thermal-acoustic oscillation caused by backfire, widens the working range of the combustion chamber, and enhances the service life and effectiveness of the structure of the combustion chamber.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, and more specifically to a post-flame stage burner and a gas turbine. Background Technology

[0002] Axial staged combustion technology for gas turbines is one of the important research directions in the field of combustion. This technology, based on conventional lean premixed combustion technology, performs axial staged combustion of the fuel, aiming to resolve the contradiction between the gas turbine combustor outlet temperature and nitrogen oxide emissions, and improve the cycle efficiency of the gas turbine. The afterburner nozzle is located at the rear end of the gas turbine combustor, that is, in the transition section at the rear end of the flame tube. This area is in the high-temperature zone after the first-stage combustion zone, and is prone to boundary layer backfire and central zone backfire. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] To this end, embodiments of the present invention propose a post-flame stage burner that reduces the risk of backfire under high-temperature conditions, reduces thermal stress and the risk of thermoacoustic oscillations caused by backfire, broadens the working range of the combustion chamber, and enhances the lifespan and effectiveness of the combustion chamber structure.

[0005] Embodiments of the present invention also propose a gas turbine.

[0006] The rear flame stage burner of this invention includes a flame tube and a rear flame stage nozzle. The rear end of the flame tube forms a transition section, and the tube wall of the transition section is provided with an installation hole. The rear flame stage nozzle includes an outer tube and a swirl channel. The outer tube is disposed on the tube wall of the transition section and defines a swirl channel communicating with the inner cavity of the transition section. One end of the outer tube wall away from the inner cavity of the transition section is provided with a fuel inlet communicating with the swirl channel. The swirl device is disposed at one end of the swirl channel adjacent to the inner cavity of the transition section.

[0007] The afterflame burner of this invention, by setting a swirling device at one end of the inner cavity of the adjacent transition section of the swirling channel, allows the airflow and fuel to move circumferentially under the guidance of the swirling device when entering the swirling channel and passing through the swirling device. When entering the inner cavity of the transition section, the fuel expands outward 360°, which effectively eliminates the flow separation generated on the outer wall of the outer tube, reduces the risk of backfire under high temperature conditions, reduces thermal stress and the risk of thermoacoustic oscillation caused by backfire, widens the working range of the combustion chamber, and enhances the life and effectiveness of the combustion chamber structure.

[0008] In some embodiments, the post-flame stage nozzles are multiple and arranged at circumferential intervals along the transition section.

[0009] In some embodiments, the post-flame stage nozzle further includes a central tube disposed within the swirling channel, and the swirling device is disposed at one end of the central tube adjacent to the inner cavity of the transition section.

[0010] In some embodiments, the rear flame stage nozzle further includes a first fuel conduit, which is disposed in the swirl channel and communicates with the fuel inlet. The extension direction of the first fuel conduit is orthogonal to the axial direction of the outer tube, and a first fuel injection hole is provided on the wall of the first fuel conduit.

[0011] In some embodiments, the first fuel conduit is connected to the central pipe, and the central pipe has a second fuel injection hole on its wall.

[0012] In some embodiments, the diameter of the first fuel injection orifice is d1, and the diameter of the second fuel injection orifice is d2, wherein d1 > d2, and 0.8 mm ≤ d1 ≤ 2 mm.

[0013] In some embodiments, the rear flame stage nozzle further includes a second fuel conduit disposed in the swirl channel, the extension direction of the second fuel conduit being orthogonal to the axial direction of the outer tube, the second fuel conduit connecting the fuel inlet and the central tube, and the central tube having a third fuel injection hole on its wall.

[0014] In some embodiments, the cross-sectional area of ​​the end of the swirling channel away from the inner cavity of the transition section gradually decreases toward the inner cavity of the transition section;

[0015] And / or, the rear flame stage nozzle further includes a shroud connected to one end of the outer tube opposite to the inner cavity of the transition section.

[0016] In some embodiments, the afterburner further includes a flow guide bushing disposed on the outer periphery of the transition section, defining an annular cooling air passage between the flow guide bushing and the transition section, the flow guide bushing having cooling holes corresponding to the annular cooling air passage, and at least a portion of the outer tube passing through the flow guide bushing and located outside the flow guide bushing.

[0017] The gas turbine of this invention includes a post-flame stage burner as described in any of the above embodiments.

[0018] The technical advantages of the gas turbine in this embodiment are the same as those of the afterflame stage burner in the above embodiments, and will not be repeated here. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of the afterflame stage burner according to an embodiment of the present invention.

[0020] Figure 2 yes Figure 1 Enlarged view of the nozzle at the mid-to-rear flame stage.

[0021] Figure 3 yes Figure 2 A magnified view of a portion of the image.

[0022] Figure label: 1. Transition section; 2. Rear flame stage nozzle; 21. Outer pipe; 211. Swirl channel; 22. Swirl device; 23. Central pipe; 24. First fuel pipeline; 241. First fuel nozzle; 3. Guide bushing; 31. Annular cooling air channel. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] The following is combined Figures 1-3 A post-flame stage burner according to an embodiment of the present invention is described.

[0025] The rear flame stage burner of this invention includes a flame tube and a rear flame stage nozzle 2. The rear end of the flame tube forms a transition section 1, and the tube wall of the transition section 1 is provided with mounting holes. The rear flame stage nozzle 2 includes an outer tube 21 and a swirl channel 211. The outer tube 21 is disposed on the tube wall of the transition section 1 and defines a swirl channel 211 that communicates with the inner cavity of the transition section 1. A fuel inlet communicating with the swirl channel 211 is provided at one end of the tube wall of the outer tube 21 away from the inner cavity of the transition section 1. A swirl device 22 is disposed at one end of the swirl channel 211 adjacent to the inner cavity of the transition section 1.

[0026] The afterflame burner of this invention, by setting a swirl device 22 at one end of the cavity of the adjacent transition section 1 of the swirl channel 211, allows the airflow and fuel to move circumferentially under the guidance of the swirl device 22 when entering the swirl channel 211 and passing through the swirl device 22. When entering the cavity of the transition section 1, the fuel expands outward 360° to effectively eliminate the flow separation generated on the outer wall of the outer tube 21, reduce the risk of backfire under high temperature conditions, reduce thermal stress and the risk of thermoacoustic oscillation caused by backfire, broaden the working range of the combustion chamber, and enhance the life and effectiveness of the combustion chamber structure.

[0027] It should be noted that the first end face of the outer tube 21 is roughly flush with the inner wall of the transition section 1, and the second end opening of the outer tube 21 is the airflow inlet. The airflow entering the swirl channel 211 from the second end opening of the outer tube 21 and the fuel entering the swirl channel 211 from the fuel inlet are fully mixed under the swirling action of the swirling device 22.

[0028] In some embodiments, the rear flame stage nozzles 2 are multiple and arranged at circumferential intervals along the transition section 1.

[0029] This allows the mixed airflow entering the transition section 1 from the rear flame stage nozzle 2 to be uniformly mixed with the high-temperature gas in the transition section 1, effectively suppressing the generation of local high-temperature zones and further enhancing the lifespan and effectiveness of the combustion chamber structure.

[0030] For example, the rear flame stage nozzle 2 can be four and arranged at equal intervals along the circumference of the transition section 1, or the rear flame stage nozzle 2 can be five, six, seven, eight or more.

[0031] In some embodiments, the rear flame stage nozzle 2 further includes a central tube 23 disposed within the swirling channel 211, and a swirling device 22 disposed at one end of the central tube 23 adjacent to the inner cavity of the transition section 1.

[0032] By connecting the swirl device 22 to the central tube 23 and installing the central tube 23 inside the swirl channel 211, the installation of the swirl device 22 within the swirl channel 211 is achieved, making the assembly and disassembly of the central tube 23 and the swirl channel 211 convenient. Furthermore, a jet can be provided through the central tube 23, effectively eliminating the central backflow zone caused by the swirl.

[0033] For example, the outer contour of the cross-section of the swirl channel 211 is circular, and the central axis of the central tube 23 largely coincides with the central axis of the swirl channel 211.

[0034] In some embodiments, such as Figure 2 and Figure 3 As shown, the rear flame stage nozzle 2 also includes a first fuel pipe 24, which is located in the swirl channel 211 and connected to the fuel inlet. The extension direction of the first fuel pipe 24 is orthogonal to the axial direction of the outer pipe 21, and a first fuel injection hole 241 is provided on the pipe wall of the first fuel pipe 24.

[0035] Thus, after the fuel enters the first fuel pipe 24, it is ejected from the first fuel nozzle 241 into the swirling channel 211, where it can be more evenly mixed with the swirling air under the swirling action of the swirling device 22.

[0036] For example, the first fuel injection hole 241 faces the transition section 1, and there are at least two first fuel injection holes 241 arranged at axial intervals along the first fuel conduit 24.

[0037] In some embodiments, the first fuel conduit 24 is connected to the central pipe 23, and the wall of the central pipe 23 is provided with a second fuel injection hole.

[0038] Therefore, the fuel entering the first fuel pipe 24 can also enter the central pipe 23 and enter the swirl channel 211 through the second fuel nozzle, further improving the uniformity of fuel mixing with swirling air.

[0039] For example, the second fuel injection hole may be provided at one end of the inner cavity of the transition section 1 adjacent to the pipe wall of the central tube 23. The second fuel injection hole may be at least two and arranged at intervals along the axial direction of the central tube 23, or at least two second fuel injection holes may be arranged at intervals along the circumferential direction of the central tube 23.

[0040] In some embodiments, the diameter of the first fuel injection orifice 241 is d1, and the diameter of the second fuel injection orifice is d2, wherein d1 > d2, and 0.8 mm ≤ d1 ≤ 2 mm.

[0041] That is, the small diameter of the second fuel injection hole results in a small fuel quantity and a low equivalence ratio, which better prevents backfire of the boundary layer on the wall of the central tube 23, and further improves the life and effectiveness of the combustion chamber structure.

[0042] For example, the diameter d1 of the first fuel injection hole 241 can be 0.8 mm, 1.4 mm, and 2 mm.

[0043] In some embodiments, the rear flame stage nozzle 2 further includes a second fuel conduit, which is disposed in the swirl channel 211. The extension direction of the second fuel conduit is orthogonal to the axial direction of the outer tube 21. The second fuel conduit connects the fuel inlet and the central tube 23. The central tube 23 has a third fuel injection hole on its wall.

[0044] That is, the fuel entering the second fuel pipe will only enter the central pipe 23 and enter the swirl channel 211 through the third fuel nozzle, ensuring the amount of fuel at the third fuel nozzle while further reducing the risk of backfire in the central recirculation zone.

[0045] For example, the third fuel injection hole may be provided at one end of the inner cavity of the adjacent transition section 1 of the pipe wall of the central tube 23. The third fuel injection hole may be at least two and arranged at intervals along the axial direction of the central tube 23, or at least two third fuel injection holes may be arranged at intervals along the circumferential direction of the central tube 23.

[0046] In some embodiments, the cross-sectional area of ​​the end of the swirl channel 211 away from the inner cavity of the transition section 1 gradually decreases towards the inner cavity of the transition section 1. That is, the airflow inlet of the outer tube 21 is in the shape of a trumpet, which provides a guiding function for the airflow to optimize the flow state of the airflow before reaching the swirl device 22, and ensure the injection performance and reliability of the rear flame stage nozzle 2.

[0047] And / or, the rear flame stage nozzle 2 also includes a shroud, which is connected to one end of the outer tube 21 away from the inner cavity of the transition section 1. The shroud can pre-rectify the airflow entering the swirl channel 211, optimizing the flow state of the airflow before reaching the swirl device 22.

[0048] In some embodiments, such as Figure 1 As shown, the afterburner also includes a flow guide bushing 3, which is located on the outer periphery of the transition section 1. An annular cooling air passage 31 is defined between the flow guide bushing 3 and the transition section 1. The flow guide bushing 3 is provided with cooling holes that correspond to the annular cooling air passage 31. At least a portion of the outer tube 21 passes through the flow guide bushing 3 and is located outside the flow guide bushing 3.

[0049] A portion of the high-pressure air delivered from the compressor enters the annular cooling air passage 31 through the cooling holes to achieve film cooling of the wall of the transition section 1, while also preventing the heat from the outer wall of the transition section 1 from being transferred to the outer shell of the combustion chamber, effectively reducing the operating temperature of the outer shell.

[0050] The gas turbine of this invention includes a post-flame stage burner as described in any of the above embodiments.

[0051] The technical advantages of the gas turbine in this embodiment are the same as those of the afterflame stage burner in the above embodiments, and will not be repeated here.

[0052] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0056] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A post-flame stage burner, characterized in that, include: A flame tube, wherein a transition section (1) is formed at the rear end of the flame tube, and the tube wall of the transition section (1) is provided with mounting holes; The rear flame stage nozzle (2) includes an outer tube (21) and a swirling device (22). The outer tube (21) is disposed on the wall of the transition section (1). The outer tube (21) defines a swirling channel (211) that communicates with the inner cavity of the transition section (1). A fuel inlet communicating with the swirling channel (211) is provided at one end of the outer tube (21) away from the inner cavity of the transition section (1). The swirling device (22) is disposed at one end of the swirling channel (211) adjacent to the inner cavity of the transition section (1).

2. The afterflame stage burner according to claim 1, characterized in that, The rear flame stage nozzles (2) are multiple and arranged circumferentially at intervals along the transition section (1).

3. The afterflame stage burner according to claim 1, characterized in that, The rear flame stage nozzle (2) also includes a central tube (23), which is located in the swirling channel (211), and the swirling device (22) is located at one end of the central tube (23) adjacent to the inner cavity of the transition section (1).

4. The afterflame stage burner according to claim 3, characterized in that, The rear flame stage nozzle (2) also includes a first fuel conduit (24), which is located in the swirl channel (211) and communicates with the fuel inlet. The extension direction of the first fuel conduit (24) is orthogonal to the axial direction of the outer tube (21), and a first fuel injection hole (241) is provided on the wall of the first fuel conduit (24).

5. The afterflame stage burner according to claim 4, characterized in that, The first fuel pipe (24) is connected to the central pipe (23), and the wall of the central pipe (23) is provided with a second fuel injection hole.

6. The afterflame stage burner according to claim 5, characterized in that, The diameter of the first fuel injection hole (241) is d1, and the diameter of the second fuel injection hole is d2, wherein d1>d2, 0.8mm≤d1≤2mm.

7. The afterflame stage burner according to claim 3 or 4, characterized in that, The rear flame stage nozzle (2) also includes a second fuel conduit, which is located in the swirl channel (211). The extension direction of the second fuel conduit is orthogonal to the axial direction of the outer tube (21). The second fuel conduit connects the fuel inlet and the central tube (23). The central tube (23) has a third fuel injection hole on its wall.

8. The afterflame stage burner according to claim 1, characterized in that, The cross-sectional area of ​​the end of the swirling channel (211) away from the inner cavity of the transition section (1) gradually decreases toward the inner cavity of the transition section (1); And / or, the rear flame stage nozzle (2) further includes a shroud connected to one end of the outer tube (21) away from the inner cavity of the transition section (1).

9. The afterflame stage burner according to claim 1, characterized in that, The afterburner also includes a flow guide bushing (3), which is located on the outer periphery of the transition section (1). An annular cooling air passage (31) is defined between the flow guide bushing (3) and the transition section (1). The flow guide bushing (3) is provided with cooling holes connected to the annular cooling air passage (31). At least a portion of the outer tube (21) passes through the flow guide bushing (3) and is located outside the flow guide bushing (3).

10. A gas turbine, characterized in that, Includes the afterflame stage burner according to any one of claims 1-9.

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