Gas turbine combustor, gas turbine, and main nozzle tube for gas turbine combustor

Abstract

To reduce flashback in a gas turbine combustor.SOLUTION: A gas turbine combustor according to at least one embodiment of the present disclosure comprises a pilot burner having a pilot nozzle extending along a first central axis of the combustor, and a main burner having a main nozzle arranged radially outward from the pilot burner about the first central axis and extending along a second central axis that is parallel to the first central axis. A main nozzle tube of the main burner includes a first tube, a second tube having a second inner peripheral surface spaced apart from the first outer peripheral surface in a downstream region of the first tube, and an air flow path defined by the first outer peripheral surface and the second inner peripheral surface and provided around the entire circumference centered on a second central axis so that air can flow toward the downstream side. The first outer peripheral surface is eccentric with respect to the second inner peripheral surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a gas turbine combustor, a gas turbine, and a main nozzle can of a gas turbine combustor. [Background technology]

[0002] A gas turbine combustor equipped with a premixing main burner is known. In such a gas turbine combustor, the main burner is configured to mix fuel and air therein to generate a premixed gas and then eject the generated premixed gas.

[0003] However, near the outlet of the main burner, the premixed gas flows along the inner peripheral surface, which causes a region where the flow velocity is reduced due to the development of a boundary layer, and this region where the flow velocity is reduced may generate a region of high fuel concentration due to the premixed gas.When a low-velocity, high-fuel concentration region is generated near the outlet of the main burner, there is a risk that a flame generated downstream of this region will spread to this region, causing a so-called flashback.

[0004] Therefore, in order to prevent this flashback in conventional gas turbine combustors, a film ring is provided at the downstream end of a swirler tube into which a premixing nozzle is inserted, and the downstream end is fitted into the upstream end. Air taken in from the outside is injected in the form of a film toward the downstream side of the film ring so that the film runs along the inner peripheral surface of the film ring (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-68348 Summary of the Invention [Problem to be solved by the invention]

[0006] When viewed from the downstream side of the outlet of the main burner, the likelihood of flashback occurring varies depending on the position on the inner circumferential surface of the outlet. Therefore, it is desirable to preferentially direct air to areas where flashback is likely to occur. However, the gas turbine combustors described in the above-mentioned patent documents do not preferentially flow air into regions where flashback is likely to occur.

[0007] In view of the above, at least one embodiment of the present disclosure aims to reduce flashback in a gas turbine combustor. [Means for solving the problem]

[0008] (1) A gas turbine combustor according to at least one embodiment of the present disclosure includes: a pilot burner having a pilot nozzle extending along a first central axis of the combustor; a main burner disposed radially outward of the pilot burner about the first central axis and having a main nozzle extending along a second central axis parallel to the first central axis; Equipped with The main burner has a main nozzle cylinder surrounding the main nozzle, The main nozzle cylinder is The first cylinder and a second cylinder having a first outer peripheral surface in a downstream region of the first cylinder and a second inner peripheral surface disposed at a distance from the first outer peripheral surface; an air flow path defined by the first outer peripheral surface and the second inner peripheral surface, the air flow path being provided around the entire circumference of the second central axis so that air flows toward the downstream side; Including, The first outer peripheral surface is eccentric with respect to the second inner peripheral surface.

[0009] (2) A gas turbine according to at least one embodiment of the present disclosure includes: A compressor; a gas turbine combustor having the configuration of (1) above; a turbine driven by combustion gas generated in the gas turbine combustor; Equipped with.

[0010] (3) A main nozzle case of a gas turbine combustor according to at least one embodiment of the present disclosure includes: A main nozzle cylinder of a gas turbine combustor, The first cylinder and a second cylinder having a first outer peripheral surface and a second inner peripheral surface disposed at a distance from the first outer peripheral surface in an area on one side in the axial direction of the first cylinder; an air flow path defined by the first outer peripheral surface and the second inner peripheral surface, the air flow path being continuously provided around the entire circumference of the second cylinder centered on the central axis thereof so that air flows toward the one side; Equipped with The first outer peripheral surface is eccentric with respect to the second inner peripheral surface. [Effects of the Invention]

[0011] At least one embodiment of the present disclosure provides for reduced flashback in a gas turbine combustor. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram illustrating a gas turbine according to some embodiments. [Figure 2] 1 is a cross-sectional view of a combustor according to some embodiments. [Figure 3] FIG. 1 is a cross-sectional view illustrating a main portion of a combustor according to some embodiments. [Figure 4] FIG. 2 is a diagram schematically illustrating a cross section from a burner case to an extension tube in a combustor according to some embodiments. [Figure 5] FIG. 5 is a cross-sectional view taken along the arrows VV in FIG. 4. [Figure 6] 10A and 10B are diagrams for explaining the processing of the inner circumferential surface from the concentric region to the transition region. [Figure 7] 10A and 10B are diagrams for explaining machining of the inner circumferential surface from the eccentric region to the transition region. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions that exclude the presence of other elements.

[0014] (Regarding Gas Turbine 1) FIG. 1 is a schematic configuration diagram illustrating a gas turbine according to some embodiments. A gas turbine, which is an example of an application of a gas turbine combustor and a perforated plate of the gas turbine combustor according to some embodiments, will be described with reference to FIG.

[0015] As shown in Fig. 1, a gas turbine 1 according to some embodiments includes a compressor 2 for generating compressed air as an oxidant, a gas turbine combustor 4 for generating combustion gas FG (see Fig. 3, which will be described later) using the compressed air and fuel, and a turbine 6 configured to be rotationally driven by the combustion gas. In the case of a gas turbine 1 for power generation, a generator (not shown) is connected to the turbine 6, and power is generated by the rotational energy of the turbine 6. In the following description, the gas turbine combustor 4 will also be simply referred to as the combustor 4.

[0016] Specific configuration examples of each part of the gas turbine 1 according to some embodiments will be described. A compressor 2 according to some embodiments includes a compressor casing 10, an air intake 12 provided on the inlet side of the compressor casing 10 for taking in air, a rotor 8 provided to penetrate both the compressor casing 10 and a turbine casing 22 (described later), and various blades arranged within the compressor casing 10. The various blades include an inlet guide vane 14 provided on the air intake 12 side, a plurality of stator vanes 16 fixed to the compressor casing 10 side, and a plurality of rotor blades 18 implanted on the rotor 8 so as to be arranged alternately with respect to the stator vanes 16. The compressor 2 may also include other components such as an unillustrated bleed chamber. In this compressor 2, air taken in through the air intake 12 is compressed as it passes through the plurality of stator vanes 16 and the plurality of rotor blades 18, thereby becoming high-temperature, high-pressure compressed air. The high-temperature, high-pressure compressed air is then sent from the compressor 2 to a downstream combustor 4.

[0017] A combustor 4 according to some embodiments is disposed within a casing 20. As shown in FIG. 1 , a plurality of combustors 4 may be disposed annularly within the casing 20 around a rotor 8. Fuel and compressed air generated by a compressor 2 are supplied to the combustor 4, and the combustor 4 burns the fuel to generate combustion gas FG, which is a working fluid for a turbine 6. The combustion gas FG is then sent from the combustor 4 to the downstream turbine 6. Note that detailed configuration examples of the combustor 4 according to some embodiments will be described later.

[0018] A turbine 6 according to some embodiments includes a turbine casing 22 and various blades arranged in the turbine casing 22. The various blades include a plurality of stator vanes 24 fixed to the turbine casing 22 side and a plurality of moving blades 26 implanted in the rotor 8 so as to be arranged alternately with respect to the stator vanes 24. Note that the turbine 6 may also include other components such as outlet guide vanes. In the turbine 6, the rotor 8 is driven to rotate as combustion gas FG passes through the plurality of stator vanes 24 and the plurality of moving blades 26. This drives a generator connected to the rotor 8. An exhaust chamber 30 is connected to the downstream side of the turbine casing 22 via an exhaust casing 28. The combustion gas FG after driving the turbine 6 is discharged to the outside via the exhaust casing 28 and the exhaust chamber 30.

[0019] (About Combustor 4) Fig. 2 is a cross-sectional view showing a combustor according to some embodiments, and Fig. 3 is a cross-sectional view showing a main part of a combustor according to some embodiments. A detailed configuration of the combustor 4 according to some embodiments will be described with reference to FIGS. 2 and 3. FIG.

[0020] 2 and 3, a plurality of combustors 4 according to some embodiments are arranged annularly around a rotor 8 (see FIG. 1). Each combustor 4 includes a combustor liner 46 provided in a combustor casing 40 defined by a casing 20, and a pilot burner 50 and a plurality of premixing burners (main burners) 60 each arranged within the combustor liner 46. The combustor 4 further includes an outer casing 45 provided inside the casing 20 on the outer circumferential side of an inner casing (swirler support casing) 47 of the combustor liner 46. An air passage 43 through which compressed air flows is formed on the outer circumferential side of the inner casing 47 and on the inner circumferential side of the outer casing 45. The combustor 4 may include other components such as a bypass pipe (not shown) for bypassing the combustion gas FG.

[0021] For example, the combustor liner 46 has an inner cylinder 47 arranged around a pilot burner 50 and a plurality of premix burners 60 , and a transition piece 48 connected to the tip of the inner cylinder 47 . The pilot burner 50 is disposed along the central axis (first central axis AX1) of the combustor liner 46. A plurality of premix burners 60 are arranged spaced apart from one another to surround the pilot burner 50. The pilot burner 50 has a pilot nozzle 54 connected to the fuel port 52, a pilot cone 56 arranged to surround the pilot nozzle 54, and a swirler 58 provided on the outer periphery of the pilot nozzle 54. The pilot nozzle 54 extends along a first central axis AX1.

[0022] The premix burner 60 has a main nozzle 64 connected to the fuel port 62, a burner tube 66 arranged to surround the main nozzle 64, an extension tube 69 connecting the burner tube 66 to the combustor liner 46 (e.g., the inner tube 47), and a swirler 70 provided on the outer periphery of the main nozzle 64. The main nozzle 64 extends along a second central axis AX2 that is parallel to the first central axis AX1.

[0023] In the combustor 4 having the above configuration, high-temperature, high-pressure compressed air generated by the compressor 2 is supplied into the combustor casing 40 through the casing inlet 42 and then flows from the combustor casing 40 into the burner case 66 via the air passage 43. This compressed air is premixed with fuel supplied from the fuel port 62 in the burner case 66. At this time, the premixed air forms a mainly swirling flow by the swirler 70 and flows into the combustor liner 46. Furthermore, the compressed air and fuel injected from the pilot burner 50 through the fuel port 52 are mixed in the combustor liner 46 and are ignited and burned by a pilot light (not shown), generating combustion gas FG. At this time, a portion of the combustion gas FG diffuses to the surroundings accompanied by a flame, and the premixed air flowing into the combustor liner 46 from each premix burner 60 is ignited and burned. That is, the pilot flame generated by the pilot fuel injected from the pilot burner 50 can provide flame stabilization for stable combustion of the premixed gas (premixed fuel) from the premix burner 60.

[0024] For convenience of explanation, the radial direction centered on the first central axis AX1, which is the central axis of the combustor liner 46, will also be referred to as the radial direction of the combustor 4. In addition, within the axial direction of the first central axis AX1, the downstream side (the lower right side in FIGS. 2 and 3 ) of the flow direction of the combustion gas FG flowing through the combustor 4 along the axial direction will also be simply referred to as the downstream side, and the upstream side (the upper left side in FIGS. 2 and 3 ) of the flow direction of the combustion gas FG flowing through the combustor 4 will also be simply referred to as the upstream side.

[0025] (About burner tube 66) FIG. 4 is a diagram schematically illustrating a cross section from a burner case 66 to an extension pipe 69 in a combustor 4 according to some embodiments. FIG. 5 is a cross-sectional view taken along the arrows VV in FIG. 4 and 5, the dimensions in the radial direction about the second center axis AX2 (the radial direction about the first center axis AX1) are exaggerated.

[0026] Near the outlet of the premix burner 60, the premixed gas flows along the inner peripheral surface, and therefore, for example, near the inner wall surface of the extension tube 69, a portion where the flow velocity is reduced due to the development of a boundary layer may occur, and a fuel-rich region due to the premixed gas may occur in this portion where the flow velocity is reduced. If a low-velocity, fuel-rich region occurs near the inner wall surface of the extension tube 69 in this way, there is a risk that a flame generated downstream of this region will spread to such a region, causing a so-called flashback.

[0027] Therefore, in the combustor 4 according to some embodiments, air taken in from the outside of the combustor 4 near the inner wall surface 69i of the extension pipe 69 is injected in the form of a film toward the downstream side of the extension pipe 69 as follows.

[0028] In some embodiments of the combustor 4, the burner tube 66 has a main swirler tube 66A and an outer shell 66B arranged radially outward from the main swirler tube 66A in a downstream region about the second central axis AX2. The main swirler tube 66A has an upstream concentric region 161 that covers the outer periphery of the main nozzle 64, an eccentric region 163 that has smaller inner and outer diameters than the concentric region 161 and is located downstream of the concentric region 161, and a transition region 162 that connects the concentric region 161 and the eccentric region 163. An extension pipe 69 is connected to the downstream end of the outer body 66B. An inner wall surface 69i of the extension pipe 69 is eccentric toward the outside in the radial direction of the combustor 4 as it moves from the upstream side to the downstream side.

[0029] 4 and 6 and 7 described later, the shape of the main swirler tube 66A is depicted simply, so the inner circumferential surface of the main swirler tube 66A is shown as not smoothly connected at the connecting position between the concentric region 161 and the transition region 162, but it is assumed that they are connected smoothly. Similarly, it is assumed that the inner circumferential surface of the main swirler tube 66A is smoothly connected at the connecting position between the transition region 162 and the eccentric region 163.

[0030] The outer body 66B has a cylindrical portion 165 positioned so as to overlap with the eccentric region 163 in the axial direction of the second center axis AX2. An inner circumferential surface 165i of the cylindrical portion 165 is continuously spaced apart from an outer circumferential surface 163o of the eccentric region 163 in the radial direction around the second center axis AX2 over the entire circumferential direction around the second center axis AX2. In the combustor 4 according to some embodiments, an air flow path 167 is formed, which is defined by the outer circumferential surface 163o of the eccentric region 163 and the inner circumferential surface 165i of the cylindrical portion 165. In the combustor 4 according to some embodiments, the air flow path 167 is formed continuously over the entire circumferential circumference around the second central axis AX2, i.e., without interruption in the circumferential direction. A plurality of through holes 166 are provided on the upstream side of the cylindrical portion 165, penetrating the cylindrical portion 165 from its outer peripheral surface 165o to its inner peripheral surface 165i, at intervals in the circumferential direction of the cylindrical portion 165. That is, the outer body 66B has a plurality of through holes 166 that penetrate in the radial direction of the outer body 66B (radial direction about the second center axis AX2) and are arranged at intervals in the circumferential direction of the outer body 66B (circumferential direction centered on the second center axis AX). In the combustor 4 according to some embodiments, the compressed air flowing through the space between the inner peripheral surface of the inner cylinder 47 and the outer peripheral surface 165o of the cylindrical portion 165 flows into the air flow passage 167 via the multiple through holes 166, flows downstream, and then flows in a film-like manner downstream along the inner wall surface 69i of the extension pipe 69.

[0031] In the combustor 4 according to some embodiments, the central axes of the concentric region 161 of the main swirler tube 66A and the outer shell 66B coincide with the second central axis AX2. In the following description, the central axis of the concentric region 161 of the main swirler tube 66A will also be referred to as the upstream-side second central axis AX2U. In the combustor 4 according to some embodiments, the central axis of the eccentric region 163 of the main swirler can 66A is parallel to but deviated from the second central axis AX2. Specifically, the central axis of the eccentric region 163 of the main swirler can 66A is deviated inward from the second central axis AX2 in a radial direction (the radial direction of the combustor 4) centered on a first central axis AX1, which is the central axis of the combustor liner 46. That is, the eccentric region 163 is eccentric to the concentric region 161 inward in the radial direction centered on the first central axis AX1. In the following description, the central axis of the eccentric region 163 of the main swirler can 66A will also be referred to as a downstream second central axis AX2D. The term "eccentricity" refers to the fact that, when the cylinder is viewed in a cross section, the center positions of the outer and inner peripheral surfaces annularly provided on the cylinder are different (displaced) from each other.

[0032] The likelihood of flashback occurring varies depending on the position of the inner wall surface 69i of the extension pipe 69 when viewed from the downstream side (the circumferential position of the extension pipe 69). Therefore, it is desirable to preferentially flow air into areas where flashback is likely to occur. In the combustor 4 according to some embodiments, with respect to the position of the inner wall surface 69i of the extension pipe 69, flashback is more likely to occur in an outer region in the radial direction about the first central axis AX1 than in an inner region in the radial direction.

[0033] In the combustor 4 according to some embodiments, as described above, the eccentric region 163 is eccentric to the inner side in the radial direction (the radial direction of the combustor 4) centered about the first central axis AX1 with respect to the concentric region 161. Therefore, the outer peripheral surface 163o of the eccentric region 163 is eccentric to the inner side in the radial direction centered about the first central axis AX1 with respect to the inner peripheral surface 165i of the tubular portion 165 of the outer body 66B. That is, in the combustor 4 according to some embodiments, as shown in FIG. 5 , when viewed from the downstream side of the outer body 66B, the outer peripheral surface 163o of the eccentric region 163 is eccentric with respect to the inner peripheral surface 165i of the tubular portion 165 of the outer body 66B at least at the position of the downstream end of the main swirler cylinder 66A in the axial direction of the second central axis AX2. As a result, the flow path cross-sectional area of ​​the air flow path 167 is larger in the radially outer region centered on the first center axis AX1 than in the radially inner region centered on the first center axis AX1, at least at the downstream end position of the main swirler tube 66A in the axial direction of the second center axis AX2. At least the downstream end of the main swirler cylinder 66A in the axial direction of the second center axis AX2 is the outlet position of the air flow path 167.

[0034] Therefore, more air flows from the air flow path 167 in a region on the radially outer side centered on the first central axis AX1 at the outlet of the extension pipe 69 than in a region on the radially inner side. This makes it possible to effectively reduce flashback in cases where flashback is more likely to occur in a region on the radially outer side centered on the first central axis AX1 at the outlet of the extension pipe 69 than in a region on the radially inner side.

[0035] In addition, if the total amount of air from the air flow path 167 is increased to reduce flashback, the amount of air in the central region of the extension pipe 69 outlet will decrease at the extension pipe 69 outlet, and the fuel concentration in the central region of the extension pipe 69 outlet will increase, causing the combustion temperature to rise, and NO x There is a risk that this will increase. According to the combustor 4 according to some embodiments, by appropriately setting the direction in which the outer peripheral surface 163o of the eccentric region 163 is eccentric with respect to the inner peripheral surface 165i of the cylindrical portion 165 of the outer body 66B, it is possible to preferentially flow the air from the air flow path 167 to the region where flashback is relatively likely to occur, without increasing the total amount of air from the air flow path 167. x This can reduce flashback while suppressing an increase in

[0036] Furthermore, if the air flow path 167 is provided only in a portion of the circumferential direction centered on the second center axis AX2, an area where the air flow velocity is relatively slow may be created due to unintended vortices being generated as the air flows through the air flow path 167, which may become the starting point for flashback. According to the combustor 4 of some embodiments, the air flow path 167 is provided continuously around the entire circumference of the second central axis AX2, thereby reducing the possibility that the above-mentioned unintended vortex will be generated and become a starting point for flashback.

[0037] According to the gas turbine 1 of some embodiments, since it is equipped with the combustor 4 of some embodiments, the possibility of the above-mentioned unintended vortex being generated and becoming a starting point for flashback can be reduced. Furthermore, according to some embodiments of the gas turbine 1, NO x This can reduce flashback while suppressing an increase in

[0038] In the combustor 4 according to some embodiments, the inner circumferential surface 163i of the eccentric region 163 may be eccentric with respect to the inner circumferential surface 161i of the concentric region 161. If the direction in which the outer peripheral surface 163o of the eccentric region 163 is eccentric relative to the inner peripheral surface 165i of the tubular portion 165 of the outer body 66B is eccentric to the direction in which the inner peripheral surface 163i of the eccentric region 163 is eccentric relative to the inner peripheral surface 161i of the concentric region 161, then in the region in which the outer peripheral surface 163o and the inner peripheral surface 163i of the eccentric region 163 extend along the axial direction of the second center axis AX2, the thickness of the eccentric region 163 defined by the outer peripheral surface 163o and the inner peripheral surface 163i of the eccentric region 163 can be made more uniform in the circumferential direction of the eccentric region 163. This makes it easier to prevent the thickness of the eccentric region 163 from becoming undesirably thick or thin.

[0039] Here, when the inner circumferential surface 66Ai of the main swirler tube 66A, which is centered on the upstream second central axis AX2U, is defined as the upstream first inner circumferential surface 661i, and the inner circumferential surface, which is centered on the downstream second central axis AX2D, is defined as the downstream first inner circumferential surface 662i, the inner circumferential surface 161i of the concentric region 161 is included in the upstream first inner circumferential surface 661i, and the inner circumferential surface 163i of the eccentric region 163 is included in the downstream first inner circumferential surface 662i.

[0040] In the combustor 4 according to some embodiments, the inner circumferential surface 163i of the eccentric region 163 is eccentric radially inward about the first central axis AX1 with respect to the central axis of the inner circumferential surface 161i of the concentric region 161, i.e., the upstream second central axis AX2U. As a result, the direction in which the outer peripheral surface 163o of the eccentric region 163 is eccentric relative to the inner peripheral surface 165i of the tubular portion 165 of the outer body 66B coincides with the direction in which the inner peripheral surface 163i of the eccentric region 163 is eccentric relative to the inner peripheral surface 161i of the concentric region 161, so that in the region in which the outer peripheral surface 163o and the inner peripheral surface 163i of the eccentric region 163 extend along the axial direction of the second center axis AX2, the thickness of the eccentric region 163 defined by the outer peripheral surface 163o and the inner peripheral surface 163i of the eccentric region 163 can be made more uniform in the circumferential direction of the eccentric region 163. This makes it easier to prevent the thickness of the eccentric region 163 from becoming undesirably thick or thin.

[0041] (Regarding the processing of the burner tube 66) The inner peripheral surface of the burner cylinder 66 configured as described above can be obtained by processing, for example, the following method. FIG. 6 is a diagram for explaining the processing of the inner circumferential surface from the concentric region 161 to the transition region 162. As shown in FIG. FIG. 7 is a diagram for explaining the machining of the inner circumferential surface from the eccentric region 163 to the transition region 162. As shown in FIG. In the example shown in Figures 6 and 7, for example, the outer surface of the burner tube 66 has already been processed, but it is not necessarily necessary for the outer surface of the burner tube 66 to be processed prior to processing the inner surface of the burner tube 66.

[0042] 6, the inner circumferential surface 161i of the concentric region 161 is machined to be the inner surface of a cylinder centered on the upstream second central axis AX2U, and the inner circumferential surface 162i of the transition region 162 is machined to be a conical surface centered on the upstream second central axis AX2U. The inner circumferential surface 161i of the concentric region 161 and the inner circumferential surface 162i of the transition region 162 thus formed become the upstream first inner circumferential surface 661i.

[0043] 7, the inner circumferential surface 163i of the eccentric region 163 is machined to have the inner surface of a cylinder centered on the second downstream central axis AX2D, and the inner circumferential surface 162i of the transition region 162 is machined to have the inner surface of a cone centered on the second downstream central axis AX2D. The inner circumferential surface 163i of the eccentric region 163 and the inner circumferential surface 162i of the transition region 162 formed in this way become the first downstream inner circumferential surface 662i. In this case, for example, the area radially outward from the dashed line 91 in Figure 7 and centered on the downstream second center axis AX2D will be removed. However, since the downstream second center axis AX2D is shifted radially inward from the upstream second center axis AX2U and centered on the first center axis AX1, for example, the area radially outward from the two-dot chain line 92 in Figure 7 and centered on the downstream second center axis AX2D will not be removed and will remain as is as the upstream first inner circumferential surface 661i. Therefore, when the inner surface 162i of the transition region 162 is machined to be a conical surface centered on the downstream second center axis AX2D, a ridge line (ridge portion 169) appears at the boundary between the region to be removed and the region that remains unremoved, i.e., at the boundary between the downstream first inner surface 662i and the upstream first inner surface 661i.

[0044] That is, when the inner circumferential surface 66Ai of the main swirler tube 66A, which is centered on the upstream second central axis AX2U, is defined as the upstream first inner circumferential surface 661i, and the inner circumferential surface, which is centered on the downstream second central axis AX2D, is defined as the downstream first inner circumferential surface 662i, the ridge portion 169 is formed at the boundary position between the upstream first inner circumferential surface 661i and the downstream first inner circumferential surface 662i. The ridge line refers to the line on the inner circumferential surface (inner circumferential surface 66Ai) that appears as a result of the difference in the angle between the two inner circumferential surfaces (downstream first inner circumferential surface 662i, upstream first inner circumferential surface 661i) on either side of the boundary position, i.e., the difference in the angle of the tangents to the two inner circumferential surfaces at the boundary position, and the part where this ridge line exists is called the ridge line portion 169.

[0045] The ridge portion 169 is located upstream of the plurality of through holes 166 .

[0046] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0047] The contents described in each of the above embodiments can be understood, for example, as follows. (1) A gas turbine combustor 4 according to at least one embodiment of the present disclosure includes: a pilot burner 50 having a pilot nozzle 54 extending along a first central axis AX1 of the combustor 4; and a main burner (premixed burner 60) disposed radially outward of the pilot burner 50 about the first central axis AX1 and having a main nozzle 64 extending along a second central axis AX2 parallel to the first central axis AX1. The main burner (premixed burner 60) includes a main nozzle cylinder (burner cylinder 66) surrounding the periphery of the main nozzle 64. The main nozzle cylinder (burner cylinder 66) includes a first cylinder (main swirler cylinder 66A), a second cylinder (outer barrel 66B) having a second inner circumferential surface (inner circumferential surface 165i) spaced apart from a first outer circumferential surface (outer circumferential surface 163o) in a downstream region of the first cylinder (main swirler cylinder 66A), and an air flow path 167 defined by the first outer circumferential surface (outer circumferential surface 163o) and the second inner circumferential surface (inner circumferential surface 165i) and provided around the entire circumference centered on a second central axis AX2 so that air can flow toward the downstream side. The first outer circumferential surface (outer circumferential surface 163o) is eccentric with respect to the second inner circumferential surface (inner circumferential surface 165i).

[0048] If the air flow path 167 is provided only in a portion of the circumferential direction around the second center axis AX2, an area where the air flow velocity is relatively slow may be generated due to unintended vortices being generated as the air flows through the air flow path 167, which may become the starting point for flashback. According to the configuration (1) above, the air flow path 167 is provided around the entire circumference of the second central axis AX2, which reduces the possibility that the above-mentioned unintended vortex will be generated and become the starting point for flashback. Furthermore, according to the configuration (1) above, the first outer peripheral surface (outer peripheral surface 163o) is eccentric with respect to the second inner peripheral surface (inner peripheral surface 165i). Therefore, by appropriately setting the direction in which the first outer peripheral surface (outer peripheral surface 163o) is eccentric with respect to the second inner peripheral surface (inner peripheral surface 165i), it is possible to preferentially flow air from the air flow path 167 into an area where flashback is relatively likely to occur, without increasing the total amount of air from the air flow path 167. x This can reduce flashback while suppressing an increase in

[0049] (2) In some embodiments, in the configuration of (1) above, when viewed from the downstream side of the second cylinder (outer barrel 66B), the first outer peripheral surface (outer peripheral surface 163o) may be eccentric with respect to the second inner peripheral surface (inner peripheral surface 165i).

[0050] According to the above configuration (2), air from the air flow path 167 can be preferentially directed to an area where flashback is relatively likely to occur.

[0051] (3) In some embodiments, in the configuration of (2) above, the first outer peripheral surface (outer peripheral surface 163o) may be eccentric radially inward about the first center axis AX1 relative to the second inner peripheral surface (inner peripheral surface 165i).

[0052] According to the configuration (3) above, more air flows from the air flow path 167 in a region radially outward about the first central axis AX1 at the outlet of the main burner (the outlet of the extension pipe 69) than in a region radially inward. This makes it possible to effectively reduce flashback in cases where flashback is more likely to occur in a region radially outward about the first central axis AX1 at the outlet of the main burner (the outlet of the extension pipe 69) than in a region radially inward.

[0053] (4) In some embodiments, in any of the configurations (1) to (3) above, the cross-sectional area of ​​the air flow path 167 may be larger in a radially outer region centered on the first center axis AX1 than in a radially inner region centered on the first center axis AX1.

[0054] According to the configuration (4) above, more air flows from the air flow path 167 in a region radially outward about the first central axis AX1 at the outlet of the main burner (the outlet of the extension pipe 69) than in a region radially inward. This makes it possible to effectively reduce flashback in cases where flashback is more likely to occur in a region radially outward about the first central axis AX1 at the outlet of the main burner (the outlet of the extension pipe 69) than in a region radially inward.

[0055] (5) In some embodiments, in any of the configurations (1) to (4) above, the first inner circumferential surface (inner circumferential surface 66Ai) of the first cylinder (main swirler cylinder 66A) may include an upstream first inner circumferential surface 661i on the upstream side of the first cylinder (main swirler cylinder 66A) and a downstream first inner circumferential surface 662i on the downstream side of the first cylinder (main swirler cylinder 66A). The downstream first inner circumferential surface 662i may be eccentric with respect to the upstream first inner circumferential surface 661i.

[0056] According to the configuration (5) above, if the direction in which the first outer peripheral surface (outer peripheral surface 163o) is eccentric relative to the second inner peripheral surface (inner peripheral surface 165i) is consistent with the direction in which the downstream first inner peripheral surface 662i is eccentric relative to the upstream first inner peripheral surface 661i, in the region (eccentric region 163) in which the first outer peripheral surface (outer peripheral surface 163o) and the downstream first inner peripheral surface 662i extend along the axial direction (extension direction of the second central axis AX2) of the first cylinder (main swirler cylinder 66A), the thickness of the first cylinder (main swirler cylinder 66A) (the thickness of the eccentric region 163) defined by the first outer peripheral surface (outer peripheral surface 163o) and the downstream first inner peripheral surface 662i becomes more easily uniform in the circumferential direction of the first cylinder (main swirler cylinder 66A) (the circumferential direction centered on the second central axis AX2). This makes it easier to prevent the wall thickness (wall thickness of the eccentric region 163) of the first cylinder (main swirler cylinder 66A) from becoming undesirably thick or thin.

[0057] (6) In some embodiments, in the configuration of (5) above, the downstream first inner circumferential surface 662i may be eccentric radially inward about the first central axis AX1 with respect to the central axis (second central axis AX2) of the upstream first inner circumferential surface 661i.

[0058] According to the configuration (6) above, the direction in which the first outer peripheral surface (outer peripheral surface 163o) is eccentric relative to the second inner peripheral surface (inner peripheral surface 165i) coincides with the direction in which the downstream first inner peripheral surface 662i is eccentric relative to the upstream first inner peripheral surface 661i. Therefore, in the region (eccentric region 163) in which the first outer peripheral surface (outer peripheral surface 163o) and the downstream first inner peripheral surface 662i extend along the axial direction (extension direction of the second central axis AX2) of the first tube (main swirler tube 66A), the thickness of the first tube (main swirler tube 66A) defined by the first outer peripheral surface (outer peripheral surface 163o) and the downstream first inner peripheral surface 662i (the thickness of the eccentric region 163) becomes easier to make uniform in the circumferential direction of the first tube (main swirler tube 66A) (the circumferential direction centered on the second central axis AX2). This makes it easier to prevent the wall thickness (wall thickness of the eccentric region 163) of the first cylinder (main swirler cylinder 66A) from becoming undesirably thick or thin.

[0059] (7) In some embodiments, in the configuration of (5) or (6) above, the first inner circumferential surface (inner circumferential surface 66Ai) may have a ridge portion 169 formed at the boundary between the upstream first inner circumferential surface 661i and the downstream first inner circumferential surface 662i.

[0060] Depending on the processing method used to form the upstream first inner circumferential surface 661i and the downstream first inner circumferential surface 662i, a ridge portion 169 will be formed at the boundary between the upstream first inner circumferential surface 661i and the downstream first inner circumferential surface 662i. According to the above configuration (7), a ridge line portion 169 may be formed on the first inner circumferential surface (inner circumferential surface 66Ai).

[0061] (8) In some embodiments, in the configuration of (7) above, the second barrel (outer barrel 66B) may have a plurality of through holes 166 that penetrate the second barrel (outer barrel 66B) in a radial direction (radial direction of the second center axis AX2) and are arranged at intervals in a circumferential direction of the second barrel (outer barrel 66B) (circumferential direction centered on the second center axis AX). The ridge portion 169 may be located upstream of the plurality of through holes 166 in the second barrel (outer barrel 66B).

[0062] According to the above configuration (8), air can be introduced from the outside of the second tube (outer body 66B) to the inner peripheral side of the second tube (outer body 66B), i.e., into the air flow path 167, via the multiple through holes 166. Furthermore, according to the above configuration (8), the ridge portion 169 may be located upstream of the multiple through holes 166 on the second tube (outer body 66B).

[0063] (9) A gas turbine 1 according to at least one embodiment of the present disclosure includes a compressor 2, a gas turbine combustor 4 having any one of the configurations described above in (1) to (8), and a turbine 6 driven by combustion gas FG generated in the gas turbine combustor 4.

[0064] According to the above-mentioned configuration (9), the air flow path 167 is provided around the entire circumference of the second central axis AX2 in the gas turbine combustor 4, so that it is possible to reduce the possibility that the above-mentioned unintended vortex will be generated and become a starting point for flashback. Furthermore, according to the configuration of (9) above, the first outer peripheral surface (outer peripheral surface 163o) is eccentric with respect to the second inner peripheral surface (inner peripheral surface 165i). Therefore, by appropriately setting the direction in which the first outer peripheral surface (outer peripheral surface 163o) is eccentric with respect to the second inner peripheral surface (inner peripheral surface 165i), it is possible to preferentially flow air from the air flow path 167 into an area where flashback is relatively likely to occur, without increasing the total amount of air from the air flow path 167. As a result, NO x This can reduce flashback while suppressing an increase in

[0065] (10) A main nozzle cylinder (burner cylinder 66) of a gas turbine combustor 4 according to at least one embodiment of the present disclosure includes: a first cylinder (main swirler cylinder 66A); a second cylinder (outer barrel 66B) having a first outer peripheral surface (outer peripheral surface 163o) and a second inner peripheral surface (inner circumferential surface 165i) arranged at a distance from each other in a region on one axial side of the first cylinder (main swirler cylinder 66A) (in the axial direction of the first central axis AX1, on the downstream side in a flow direction of combustion gas FG flowing through the combustor 4 along the axial direction); and an air flow path 167 that is defined by the first outer peripheral surface (outer peripheral surface 163o) and the second inner circumferential surface (inner circumferential surface 165i) and is provided continuously around the central axis (second central axis AX2) of the second cylinder so that air flows toward the one side. The first outer peripheral surface (outer peripheral surface 163o) is eccentric with respect to the second inner peripheral surface (inner peripheral surface 165i).

[0066] According to the configuration (10) above, the air flow path 167 is provided continuously around the entire circumference of the second central axis AX2, thereby reducing the possibility that an unintended vortex such as that described above will be generated and become a starting point for flashback. Furthermore, according to the configuration of (10) above, the first outer peripheral surface (outer peripheral surface 163o) is eccentric with respect to the second inner peripheral surface (inner peripheral surface 165i). Therefore, by appropriately setting the direction in which the first outer peripheral surface (outer peripheral surface 163o) is eccentric with respect to the second inner peripheral surface (inner peripheral surface 165i), it is possible to preferentially flow air from the air flow path 167 into an area where flashback is relatively likely to occur, without increasing the total amount of air from the air flow path 167. As a result, NO x This can reduce flashback while suppressing an increase in

[0067] (11) In some embodiments, in the configuration of (10) above, an extension pipe 69 may be provided that is connected to the one side (in the axial direction of the first central axis AX1, the downstream side in the flow direction of the combustion gas FG flowing through the combustor 4 along the axial direction) of the second cylinder (outer barrel 66B). An inner circumferential surface (inner wall surface 69i) of the extension pipe 69 may be eccentric to one side in the radial direction of the first cylinder (main swirler cylinder 66A) (radially outward from the first central axis AX1) as it moves from the other side in the axial direction of the first cylinder (main swirler cylinder 66A) (in the axial direction of the first central axis AX1, the upstream side in the flow direction of the combustion gas FG flowing through the combustor 4 along the axial direction) to the one side (in the axial direction of the first central axis AX1, the downstream side in the flow direction of the combustion gas FG flowing through the combustor 4 along the axial direction). The first outer peripheral surface (outer peripheral surface 163o) may be eccentric to the other radial side (radially inward about the first center axis AX1) relative to the second inner peripheral surface (inner peripheral surface 165i).

[0068] According to the configuration (11) above, more air flows from the air flow path 167 in a region on the radially outer side centered on the first central axis AX1 at the outlet of the extension pipe 69 than in a region on the radially inner side. This makes it possible to effectively reduce flashback in cases where flashback is more likely to occur in a region on the radially outer side centered on the first central axis AX1 at the outlet of the extension pipe 69 than in a region on the radially inner side. [Explanation of symbols]

[0069] 1. Gas turbine 2 Compressor 4 Gas turbine combustor (combustor) 6 Turbine 46 Combustor liner 47 Inner tube (swirler support tube) 50 Pilot Burner 54 Pilot nozzle 60 Premix burner (main burner) 64 Main nozzle 66 Burner tube 66A Main swirler tube 66B Outer body 66Ai inner surface 69 Extension tube 161 Concentric region 162 Transition region 163 Eccentric region 163o outer surface 165i Inner surface 167 Air flow path 169 Ridge 661i Upstream side first inner surface 662i Downstream side first inner surface

Claims

1. a pilot burner having a pilot nozzle extending along a first central axis of the combustor; a main burner disposed radially outward of the pilot burner about the first central axis and having a main nozzle extending along a second central axis parallel to the first central axis; Equipped with The main burner has a main nozzle cylinder surrounding the main nozzle, The main nozzle cylinder is The first cylinder, a second cylinder having a first outer circumferential surface in a downstream region of the first cylinder and a second inner circumferential surface spaced apart from the first outer circumferential surface; an air flow path defined by the first outer peripheral surface and the second inner peripheral surface, the air flow path being provided around the entire circumference of the second central axis so that air flows toward the downstream side; Including, The first outer peripheral surface is eccentric with respect to the second inner peripheral surface. Gas turbine combustor.

2. When viewed from the downstream side of the second cylinder, the first outer peripheral surface is eccentric with respect to the second inner peripheral surface. The gas turbine combustor according to claim 1 .

3. the first outer peripheral surface is eccentric with respect to the second inner peripheral surface in a radially inward direction about the first central axis; The gas turbine combustor according to claim 2 .

4. a flow path cross-sectional area of ​​the air flow path is larger in a region on the outer side in the radial direction centered on the first central axis than in a region on the inner side in the radial direction centered on the first central axis; The gas turbine combustor according to any one of claims 1 to 3.

5. The first inner circumferential surface of the first cylinder is an upstream first inner circumferential surface on the upstream side of the first cylinder; a downstream first inner circumferential surface on the downstream side of the first cylinder; Including, the downstream first inner circumferential surface is eccentric with respect to the upstream first inner circumferential surface; The gas turbine combustor according to any one of claims 1 to 3.

6. the downstream first inner circumferential surface is eccentric to the center axis of the upstream first inner circumferential surface inward in the radial direction about the first center axis, The gas turbine combustor according to claim 5 .

7. The first inner circumferential surface has a ridge portion formed at a boundary position between the upstream first inner circumferential surface and the downstream first inner circumferential surface. The gas turbine combustor according to claim 5 .

8. the second cylinder has a plurality of through holes that penetrate the second cylinder in a radial direction and are arranged at intervals in a circumferential direction of the second cylinder, The ridge portion is located upstream of the second cylinder with respect to the plurality of through holes. The gas turbine combustor according to claim 7.

9. A compressor; The gas turbine combustor according to any one of claims 1 to 3; a turbine driven by combustion gas generated in the gas turbine combustor; Equipped with Gas turbine.

10. A main nozzle cylinder of a gas turbine combustor, The first cylinder, a second cylinder having a first outer peripheral surface and a second inner peripheral surface disposed at a distance from the first outer peripheral surface in an axially one side region of the first cylinder; an air flow path defined by the first outer peripheral surface and the second inner peripheral surface, the air flow path being continuously provided around the entire circumference of the second cylinder centered on the central axis thereof so that air flows toward the one side; Equipped with The first outer peripheral surface is eccentric with respect to the second inner peripheral surface. The main nozzle tube of a gas turbine combustor.

11. an extension tube connected to the one side of the second cylinder; Equipped with an inner circumferential surface of the extension tube is eccentric toward one side in a radial direction of the first cylinder as it moves from the other side in the axial direction to the one side, the first outer peripheral surface is eccentric to the other side in the radial direction with respect to the second inner peripheral surface; The main nozzle case of a gas turbine combustor according to claim 10.

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