Combustors and Gas Turbines

Abstract

This combustor comprises: a combustor plate that has a mixing tube which extends so as to penetrate the combustor plate upstream end face and downstream end face perpendicular to the combustor axis and into which air is introduced from the upstream end face side; a first fuel injection part that is capable of injecting a first fuel along the center axis of the mixing tube on the inner side of the mixing tube; and a second fuel injection part that is capable of injecting a second fuel within the mixing tube radially outward of the center axis of the mixing tube.

Description

[Technical Field]

[0001] The present disclosure relates to combustors and gas turbines. This application claims priority to Japanese Patent Application No. 2022-56200, filed on March 30, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] For example, Patent Document 1 discloses a cluster combustor as an example of a combustor used in a gas turbine.

[0003] The cluster combustor has a plurality of mixing tubes arranged side by side and into which air is introduced, and a fuel nozzle inserted into the mixing tubes and injecting fuel from the tip thereof. The fuel nozzle injects fuel along the central axis of the mixing tube. As fuel is injected from the fuel nozzle, a mixture of air and fuel flows through the mixing tubes and is ejected downstream. At this time, the mixture ignites, forming multiple small flames at the outlet of each mixing tube. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2013 / 0067926 Summary of the Invention [Problem to be solved by the invention]

[0005] In the combustor described above, it is necessary to suppress the increase in fuel concentration on the inner wall surface of the mixing tube in order to suppress flashback, which is the backward flow of flame along the wall surface inside the mixing tube. This tendency becomes particularly pronounced when a relatively flammable fuel is used. On the other hand, particularly when a relatively difficult-to-burn fuel is used, if the fuel concentration on the inner wall surface is low, there is a risk of misfire, and stable combustion may not be possible.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a combustor and a gas turbine that can avoid misfires while suppressing flashback. [Means for solving the problem]

[0007] In order to solve the above problems, a combustor according to the present disclosure includes: a combustor plate having mixing tubes extending to penetrate upstream end faces and downstream end faces perpendicular to a combustor axis and into which air is introduced from the upstream end face side; a first fuel injection unit capable of injecting a first fuel inside the mixing tube along a central axis of the mixing tube; and a second fuel injection unit capable of injecting a second fuel into the mixing tube, radially outward from the central axis of the mixing tube.

[0008] The gas turbine according to the present disclosure includes a compressor that generates air, the combustor described above that generates combustion gas by burning premixed gas generated by mixing fuel with the air compressed by the compressor, and a turbine driven by the combustion gas. [Effects of the Invention]

[0009] According to the combustor and gas turbine of the present disclosure, it is possible to avoid misfires while suppressing flashback. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a gas turbine according to a first embodiment of the present disclosure. [Figure 2] FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a combustor according to a first embodiment of the present disclosure. [Figure 3] FIG. 2 is a longitudinal cross-sectional view of a main portion of a combustor plate of the combustor according to the first embodiment of the present disclosure. [Figure 4] FIG. 2 is a perspective view of the inside of a mixing tube of a combustor plate of the combustor according to the first embodiment of the present disclosure. [Figure 5] FIG. 10 is a longitudinal cross-sectional view of a main portion of a combustor plate of a combustor according to a second embodiment of the present disclosure. [Figure 6] FIG. 11 is a longitudinal cross-sectional view of a main portion of a combustor plate of a combustor according to a third embodiment of the present disclosure, also illustrating the cross-sectional shape of a strut. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] A first embodiment of the present invention will be described in detail below with reference to Figures 1 to 4. As shown in Figure 1, a gas turbine 1 according to this embodiment includes a compressor 2 that compresses air A, a combustor 3 that generates combustion gas C, and a turbine 4 that is driven by the combustion gas C. A plurality of combustors 3 are provided at intervals in the circumferential direction around the rotary shaft of the gas turbine 1. The combustors 3 mix fuel with air A compressed by the compressor 2 and combust the air, thereby generating high-temperature, high-pressure combustion gas C.

[0012] (Combustor) The configuration of the combustor 3 will be described below with reference to FIGS. The combustor 3 includes an outer casing 10, an end cover 11, an inner casing 15, a support portion 17, a combustor plate 20, a first fuel injection portion 40, and a second fuel injection portion 70.

[0013] (Outer cylinder) The outer casing 10 has a cylindrical shape centered on a combustor axis O1 (hereinafter simply referred to as the axis O1) which is the center of the combustor 3.

[0014] (end cover) The end cover 11 is disk-shaped and closes one end (the left side in FIG. 2) of the outer cylinder 10 in the direction of the axis O1. The end cover 11 abuts against the one end of the outer cylinder 10 in the direction of the axis O1.

[0015] (inner cylinder) The inner cylinder 15 is arranged coaxially inside the outer cylinder 10. The inner cylinder 15 has a cylindrical shape extending in the direction of the axis O1 inside the outer cylinder 10. One end of the inner cylinder 15 in the direction of the axis O1 is spaced apart from the end cover 11 in the direction of the axis O1. The outer diameter of the inner cylinder 15 is smaller than the inner diameter of the outer cylinder 10. As a result, an annular flow path is formed between the outer peripheral surface of the inner cylinder 15 and the inner peripheral surface of the outer cylinder 10. Air A compressed by the compressor 2 flows through this flow path from the other side in the direction of the axis O1 (the right side in FIG. 2) toward the one side in the direction of the axis O1.

[0016] (Support part) The support portions 17 are members extending in the direction of the axis O1, and a plurality of them are provided at intervals in the circumferential direction. An end of each support portion 17 on one side in the direction of the axis O1 is fixed to a surface of the end plate on the inner peripheral side of the outer cylinder 10, facing the other side in the direction of the axis O1. Air A that has circulated between the outer cylinder 10 and the inner cylinder 15 on one side in the direction of the axis O1 reverses its flow direction to the other side in the direction of the axis O1 as it passes between adjacent support portions 17.

[0017] (Combustor plate) The combustor plate 20 has a disk shape centered on an axis O1. The combustor plate 20 is provided so as to be coaxially fitted inside the inner cylinder 15. The combustor plate 20 has an upstream end surface 21 and a downstream end surface 22.

[0018] (Upstream end face) The upstream end surface 21 is an end surface of the combustor plate 20 facing one side in the direction of the axis O1, and has a flat shape perpendicular to the axis O1. The upstream end surface 21 is located at the same position in the direction of the axis O1 as the end surface of the inner cylinder 15 on one side in the direction of the axis O1.

[0019] (Downstream end face) The downstream end surface 22 is an end surface of the combustor plate 20 facing the other side in the direction of the axis O1 and has a flat shape perpendicular to the axis O1. The downstream end surface 22 is located on one side in the direction of the axis O1 with respect to the end surface of the inner cylinder 15 on the other side in the direction of the axis O1. Thus, a space is defined by the inner circumferential surface of the inner cylinder 15 and the downstream end surface 22 of the combustor plate 20. This space serves as a combustion space of the combustor 3.

[0020] (mixing tube) The mixing tube 30 is a tube extending in the direction of the axis O1, into which air A flows from the upstream side (one side in the direction of the axis O1, the left side in FIG. 2 ). The mixing tube 30 of this embodiment is formed as a hole extending in the direction of the axis O1 so as to penetrate from the upstream end face 21 to the downstream end face 22 of the combustor plate 20. The mixing tubes 30 extend linearly in the direction of the axis O1, and a plurality of mixing tubes 30 are arranged side by side at intervals from each other in a direction perpendicular to the axis O1. The opening of the mixing tube 30 on the upstream end face 21 side is an upstream inlet opening 31 into which the air A flows. The opening of the mixing tube 30 on the downstream end face 22 side is a downstream outlet opening 32 from which premixed gas M of air A and fuel is ejected. The flow path cross section of the mixing tube 30 is circular, with the central axis O2 of the mixing tube 30 as its center.

[0021] As shown in detail in FIG. 3, the inner wall surface 33, which is the inner peripheral surface of the mixing tube 30, is composed of three portions: an upstream wall surface 33a, a reduced diameter wall surface 33b, and a downstream wall surface 33c.

[0022] The upstream wall surface 33a is the most upstream portion of the inner wall surface 33 of the mixing tube 30. The upstream wall surface 33a has a circular cross section perpendicular to the axis O1 at any position on the central axis O2. The upstream wall surface 33a has a uniform inner diameter along the central axis O2. The upstream end of the upstream wall surface 33a is the inlet opening 31.

[0023] The reduced diameter wall surface 33b is connected to the downstream end of the upstream wall surface 33a. The reduced diameter wall surface 33b has a tapered shape that gradually reduces in diameter toward the downstream side. The inner diameter of the upstream end of the reduced diameter wall surface 33b is the same as the inner diameter of the downstream end of the upstream wall surface 33a. This allows the upstream wall surface 33a and the reduced diameter wall surface 33b to be smoothly connected without forming a step at their boundary. The reduced diameter wall surface 33b may have a conical surface shape or a convex curved surface that convex toward the inner wall surface 33 of the mixing tube 30. The reduced diameter wall surface 33b has a circular cross section perpendicular to the central axis O2 at any position on the central axis O2.

[0024] The downstream wall surface 33c is connected to the downstream end of the reduced-diameter wall surface 33b. The cross-sectional shape of the downstream wall surface 33c perpendicular to the axis O1 is circular at any position on the central axis O2. The inner diameter of the upstream end of the downstream wall surface 33c is the same as the inner diameter of the downstream end of the reduced-diameter wall surface 33b. As a result, the reduced-diameter wall surface 33b and the downstream wall surface 33c are smoothly connected without forming a step at their boundary. The downstream wall surface 33c has a uniform inner diameter along the central axis O2. The inner diameter of the downstream wall surface 33c is slightly smaller than that of the upstream wall surface 33a. The downstream end of the downstream wall surface 33c is the outlet opening 32.

[0025] (First Plenum, Second Plenum) 2 and 3, a first plenum 35 and a second plenum 36 are formed inside the combustor plate 20 as spaces formed to avoid the mixing tubes 30. The first plenum 35 and the second plenum 36 are isolated from the flow path inside the mixing tube 30 via a wall that forms the inner wall surface 33 of the mixing tube 30. The first plenum 35 and the second plenum 36 are not in communication with each other. In other words, the first plenum 35 and the second plenum 36 are defined within the combustor plate 20 independently of each other so as not to interfere with each other.

[0026] The first fuel F1 is supplied into the first plenum 35 via a first fuel supply system 38 that is passed through a connecting member 37 that connects the outer cylinder 10 and the inner cylinder 15. As a result, the space within the first plenum 35 is filled with the first fuel F1. The second fuel F2 is supplied into the second plenum 36 via a second fuel supply system 39 that is passed through, for example, the support portion 17. As a result, the space within the second plenum 36 is filled with the second fuel F2. The first fuel supply system 38 may be passed through the support portion 17, and the second fuel supply system 39 may be passed through the connecting member 37. Alternatively, the first fuel supply system 38 and the second fuel supply system 39 may be provided at any desired location.

[0027] In this embodiment, the first fuel F1 is a fuel that is more combustible than the second fuel F2. That is, the first fuel F1 has higher combustibility than the second fuel F2. For example, hydrogen is used as the first fuel F1. For example, natural gas is used as the second fuel F2. Hydrogen is a fuel that is more combustible than natural gas.

[0028] (First fuel injection part) The first fuel injection unit 40 injects a first fuel F1 into the mixing tube 30 along a central axis O2 of the mixing tube 30. The first fuel injection unit 40 includes a fuel nozzle 41, a strut 50, and a fuel introduction unit 60.

[0029] The fuel nozzle 41 is an elongated member disposed inside the mixing tube 30 and extending in the direction of the central axis O2 of the mixing tube 30. The fuel nozzle 41 is coaxial with the inner wall surface 33 of the mixing tube 30 and is spaced apart from the inner wall surface 33 in the radial direction of the mixing tube 30.

[0030] The fuel nozzle 41 has a cylindrical shape with a closed end that is closed on the upstream side and open on the downstream side. The upstream end of the fuel nozzle 41 has a tapered shape that decreases in diameter toward the upstream side. That is, the upstream end of the fuel nozzle 41 has a shape that tapers toward the upstream side. The outer peripheral surface of the fuel nozzle 41 that continues downstream from the upstream end of the fuel nozzle 41 has a cylindrical surface shape centered on the central axis O2 along the central axis O2. The outer peripheral surface of the fuel nozzle 41 may have a tapered shape that decreases in diameter toward the downstream side, that is, it may have a shape that tapers toward the downstream side.

[0031] In this embodiment, the upstream end of the fuel nozzle 41 is located at a location on the inner wall surface 33 of the mixing tube 30 where the upstream wall surface 33a is formed. The downstream end of the fuel nozzle 41 is located at the boundary between the reduced diameter wall surface 33b and the downstream wall surface 33c on the inner wall surface 33 of the mixing tube 30.

[0032] The cross-sectional shape of the fuel nozzle 41 perpendicular to the central axis O2 is a circle centered on the central axis O2 at any position along the central axis O2. As a result, an annular flow passage centered on the central axis O2 is formed between the fuel nozzle 41 and the inner wall surface 33.

[0033] The upstream portion of the space inside the fuel nozzle 41 is a cavity 42 that opens into the mixing tube 30 at the downstream end of the fuel nozzle 41. The opening of the cavity 42 is a tip opening 45 of the fuel nozzle 41. The tip opening 45 has a circular shape centered on the central axis O2.

[0034] (Strut) A plurality of struts 50 are provided at circumferential intervals in the flow passage between the inner wall surface 33 of the mixing tube 30 and the fuel nozzle 41. The struts 50 serve to hold the fuel nozzle 41 within the mixing tube 30. The struts 50 have ends on the radially outer side of the central axis O2 connected to the inner wall surface 33 of the mixing tube 30, and ends on the radially inner side of the central axis O2 connected to the fuel nozzle 41.

[0035] The strut 50 has an airfoil-shaped cross section perpendicular to the radial direction of the central axis O2. That is, the strut 50 has a shape obtained by extending an airfoil in the radial direction of the central axis O2. In other words, the strut 50 has an airfoil shape with the radial direction of the central axis O2 as the airfoil height direction.

[0036] The upstream end of the strut 50 is a leading edge 51 that extends in the radial direction. The leading edge 51 extends radially inward from the central axis O2 as it moves downstream. As a result, the upstream end of the leading edge 51 is connected to the inner wall surface 33 of the mixing tube 30, and the downstream end of the leading edge 51 is connected to the fuel nozzle 41.

[0037] The downstream end of the strut 50 is a radially extending trailing edge 52. The trailing edge 52 extends in the radial direction of the center axis O2. The airfoil shape of the strut 50 in a cross section perpendicular to the radial direction of the central axis O2 becomes larger as it moves radially outward, due to the shape of the leading edge 51. The strut 50 has a shape made up of overlapping airfoil shapes that gradually become smaller from the radially outer side to the radially inner side of the central axis O2.

[0038] A pair of surfaces facing in the circumferential direction of the central axis O2 that connect the leading edge 51 and trailing edge 52 of the strut 50 are blade surfaces 53. The pair of blade surfaces 53 are in contact with each other at the leading edge 51, and gradually move apart in the circumferential direction of the central axis O2 as they move downstream. Then, as they move further downstream, they gradually approach each other in the circumferential direction of the central axis O2 and are connected to each other at the trailing edge 52. In this embodiment, such struts 50 are provided at equal intervals in the circumferential direction.

[0039] (Fuel introduction section) The fuel introduction portion 60 introduces the first fuel F1 into the fuel nozzle 41. The fuel introduction portion 60 passes through a wall portion separating the inner wall surface 33 of the mixing tube 30 of the combustor plate 20 from the cavity 42 and through the inside of the strut 50, thereby connecting the first plenum 35 to the cavity 42 inside the mixing tube 30. The fuel introduction portion 60 is a hole extending in a radial direction of the central axis O2 of the mixing tube 30, and has an end portion radially outward from the central axis O2 connected to the first plenum 35 and an end portion radially inward from the central axis O2 connected to the cavity 42. A plurality of fuel introduction portions 60 may be provided corresponding to the plurality of struts 50, or may be provided in only some of the plurality of struts 50.

[0040] (Second fuel injection part) The second fuel injection section 70 supplies the second fuel F2 into the mixing tube 30 at a location radially outward from the central axis O2 of the mixing tube 30. The second fuel injection unit 70 of this embodiment has wall holes 71 that can inject the second fuel F2 into the mixing tube 30 from the inner wall surface 33 of the mixing tube 30. The wall holes 71 are holes that extend linearly in the radial direction of the central axis O2, with an end portion on the inner side in the radial direction of the central axis O2 opening to the inner wall surface 33, and an end portion on the outer side in the radial direction of the central axis O2 opening to the second plenum 36. As a result, the wall holes 71 communicate between the flow passage inside the mixing tube 30 and the second plenum 36.

[0041] The wall holes 71 extend radially inward from the second plenum 36 and then downstream. That is, the wall holes 71 are formed so as to be inclined from the radial direction of the mixing tube 30 and from the central axis O2. The inclination angle of the wall holes 71 with respect to the central axis O2 is set to, for example, 30 to 80°, preferably 40 to 70°, and more preferably 45 to 65°.

[0042] A plurality of second fuel injection portions 70 may be formed spaced apart from one another in the circumferential direction of the central axis O2, or only one second fuel injection portion 70 may be formed. The position of the second fuel injection section 70 in the direction of the central axis O2 is located upstream of the first fuel injection section 40. In other words, the opening of the second fuel injection section 70 into the inner wall surface 33 of the mixing tube 30 is located upstream of the tip opening 45 of the fuel nozzle 41 of the first fuel injection section 40. In this embodiment, the opening of the second fuel injection section 70 into the inner wall surface 33 of the mixing tube 30 is formed on the upstream wall surface 33a of the inner wall surface 33 of the mixing tube 30, in a portion further upstream than the upstream end of the strut 50.

[0043] (Actions and Effects) Next, the operation, function, and effect of the combustor 3 according to this embodiment will be described. As shown in Fig. 3, during operation of the gas turbine 1, air A enters each mixing tube 30 of the combustor plate 20 from the upstream side and flows downstream within the mixing tube 30. In this state, when a first fuel F1 is injected into the mixing tube 30 by the first fuel injection unit 40 or a second fuel F2 is injected into the mixing tube 30 by the second fuel injection unit 70, the air A and the fuel are mixed within the mixing tube 30 to generate premixed gas M. The premixed gas M is injected from the outlet opening 32 of the mixing tube 30 at the downstream end surface 22 of the combustor plate 20 and ignited. As a result, the premixed gas M is combusted to generate combustion gas C, and the combustion gas C is sent to the turbine 4 to rotate the turbine 4.

[0044] Here, when the gas turbine 1 is operated, there are cases where only the first fuel F1, which is a fuel that is relatively easy to combust, is fed into the combustor 3, and cases where only the second fuel F2, which is a fuel that is relatively difficult to combust, is fed into the combustor 3. In other words, there are cases where the type of fuel is switched depending on the operation of the gas turbine 1.

[0045] In this embodiment, the first fuel F1, which is a more flammable fuel, is supplied into the mixing tube 30 via the first fuel injection unit 40. That is, the fuel introduced from the first fuel F1 plenum into the cavity 42 of the fuel nozzle 41 via the fuel introduction unit 60 is supplied into the mixing tube 30 via the tip opening 45. Because the tip opening 45 of the fuel nozzle 41 is disposed along the central axis O2 of the mixing tube 30, the first fuel F1 injected from the tip opening 45 flows inside the mixing tube 30 along the central axis O2.

[0046] Therefore, the first fuel F1 is prevented from diffusing radially outward inside the mixing tube 30, and the first fuel F1 is concentrated in the center of the mixing tube 30. That is, the fuel concentration distribution inside the mixing tube 30 is high radially inside and low radially outside. Therefore, the fuel concentration near the inner wall surface 33 of the mixing tube 30 can be suppressed, making it possible to avoid the occurrence of flashback, in which a flame formed on the downstream end face 22 flows backward along the inner wall surface 33 of the mixing tube 30. Flashback is particularly likely to occur when the fuel is highly flammable. However, by injecting the first fuel F1 along the central axis O2 as in this embodiment, the occurrence of flashback can be appropriately avoided even in such cases.

[0047] On the other hand, when the second fuel F2, which is a relatively hard-to-burn fuel, is injected, the risk of misfire increases if it is injected along the central axis O2 of the mixing tube 30, as with the first fuel F1. That is, at the outlet opening 32 of the mixing tube 30, the outer edge of the opening becomes the starting point of flame stabilization. Therefore, if the hard-to-burn fuel collects at the center of the mixing tube 30, the starting point of flame stabilization in the region with high fuel concentration will be far from the fuel, which will result in insufficient stable flame stabilization and the possibility of misfire.

[0048] In contrast to this, in this embodiment, when the second fuel F2, which is less flammable, is introduced, it is not ejected along the central axis O2 of the mixing tube 30, but is ejected from a location radially spaced from the central axis O2. That is, the second fuel F2 is injected into the mixing tube 30 from the inner wall surface 33 of the mixing tube 30 by the second fuel injection unit 70. Therefore, an extreme decrease in fuel concentration near the wall surface of the mixing tube 30 can be avoided.

[0049] More specifically, the second fuel F2 is injected from the inner wall surface 33 of the mixing tube 30 by the second fuel injection unit 70, thereby increasing the fuel concentration on the inner wall surface 33. Therefore, the fuel concentration near the inner wall surface 33 also increases near the outlet of the mixing tube 30, and the combustion speed at the outer edge of the outlet opening 32 of the mixing tube 30, which is the starting point of flame stabilization, can be increased. As a result, the flame can be continuously stabilized.

[0050] From the above, even when fuels with different combustibility are used, it is possible to perform stable combustion while suppressing flashback.

[0051] When the combustor 3 is operated with the second fuel F2, it is possible to provide a separate combustor nozzle with a high fuel concentration for flame stabilization in order to ensure flame stability. However, in this case, the temperature of the flame may rise locally, which may increase the amount of NOx generated. By adopting the configuration of this embodiment, flame stability can be ensured without providing a separate combustor nozzle, making it possible to suppress the generation of NOx.

[0052] In this embodiment, the second fuel injection unit 70 is disposed upstream within the mixing tube 30, and the first fuel injection unit 40 is disposed downstream within the mixing tube 30. This ensures that the flow path of the second fuel F2 from when it is injected to when it reaches the outlet opening 32 is sufficiently long. This allows the second fuel F2 to be sufficiently diffused and distributed throughout the entire flow path cross section of the mixing tube 30. As a result, the fuel concentration near the inner wall surface 33 of the mixing tube 30 can be ensured, and stable flame stabilization can be achieved while preventing misfires.

[0053] On the other hand, the flow path from when the first fuel F1 is injected from the first fuel injection unit 40 to when it reaches the outlet of the mixing tube 30 is shortened. This ensures that the first fuel F1 travels straight, preventing the first fuel F1 from diffusing and reaching the inner wall surface 33 of the mixing tube 30. As a result, the occurrence of flashback can be suppressed.

[0054] Furthermore, because the struts 50 are wing-shaped, the air A inside the mixing tube 30 can be smoothly circulated, thereby suppressing an increase in pressure loss. Furthermore, in this embodiment, because the second fuel injection section 70 is provided upstream of the strut 50, the injected second fuel F2 also flows smoothly along the airfoil of the strut 50. This makes it possible to prevent an increase in pressure loss due to an unintended vortex being generated by the jet of the second fuel F2. It is also possible to prevent uneven fuel distribution, such as a locally increased fuel concentration.

[0055] Furthermore, a portion of the mixing tube 30 is formed as a reduced diameter wall surface 33b, forming a throttled flow path, which can increase the flow velocity inside the mixing tube 30. This can prevent fuel from accidentally accumulating inside the mixing tube 30 and causing unintended flame stabilization.

[0056] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to Fig. 5. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. The second embodiment differs from the first embodiment in the configuration of the second fuel injection section 70. That is, the second fuel injection section 70 has surface holes 72 that inject the second fuel F2 from the blade surface 53 that is the surface of the strut 50.

[0057] The surface holes 72 have radially inner ends that open into the blade surfaces 53 of the struts 50. The radially outer ends of the surface holes 72 open into the second plenum 36. As a result, the surface holes 72 communicate between the interior of the mixing tube 30 and the second plenum 36 via the blade surfaces 53 of the struts 50. The surface holes 72 may be formed in each of the pair of blade surfaces 53 of the struts 50, or may be formed in only one of the pair of blade surfaces 53. Furthermore, the surface holes 72 may be formed in each of multiple struts 50, or may be formed in only some of the struts 50.

[0058] With this configuration, similar to the first embodiment, the second fuel F2 can be injected into the mixing tube 30 at a position away from the central axis O2 radially outward. Therefore, compared to when the second fuel F2 is injected along the central axis O2, the fuel concentration in the vicinity of the inner wall surface 33 of the mixing tube 30 can be increased, and flame stability can be ensured.

[0059] Furthermore, by injecting the second fuel F2 into the flow of the air A that flows smoothly over the blade surface 53, it is possible to prevent an inadvertent generation of a vortex due to the jet of the second fuel F2. Therefore, it is possible to prevent an increase in pressure loss inside the mixing tube 30 and to avoid uneven fuel distribution. On the other hand, since the second fuel F2 can be appropriately mixed with the air A flowing over the blade surface 53, the mixing of the air A and the second fuel F2 can be promoted, and NOx can be reduced.

[0060] [Third embodiment] Next, a second embodiment of the present invention will be described with reference to Fig. 6. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In the third embodiment, the shape of the mixing tube 30 is different from that in the first embodiment.

[0061] The reduced diameter wall surface 33b of the mixing tube 30 in the third embodiment is formed over a wider area than in the first embodiment. The upstream end of the reduced diameter wall surface 33b is located at the same position along the central axis O2 as the upstream end of the strut 50. As in the first embodiment, the downstream end of the reduced diameter wall surface 33b is located at the same position along the central axis O2 as the tip opening 45 of the fuel nozzle 41 of the first fuel injection unit 40. The reduced diameter wall surface 33b is tapered so that its diameter gradually decreases from the upstream end to the downstream end.

[0062] As described above, in this embodiment, the reduced diameter wall surface 33b of the mixing tube 30 is provided at the position where the strut 50 is formed. This allows the flow path cross-sectional area of ​​the mixing tube 30 to be configured to match the change in shape of the strut 50. Therefore, it is possible to avoid the occurrence of low velocity regions within the mixing tube 30, and to prevent the inadvertent occurrence of flame holding within the mixing tube 30.

[0063] (Other embodiments) Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical idea of ​​the invention.

[0064] For example, in the embodiment, an example has been described in which hydrogen is used as the first fuel F1 and natural gas is used as the second fuel F2, but the present invention is not limited to this. Various fuels can be used as the first fuel F1 and the second fuel F2. Furthermore, at least one of the first fuel F1 and the second fuel F2 may be a mixed fuel of hydrogen and natural gas. In this case, too, the first fuel F1 can have higher combustibility than the second fuel F2 depending on the mixture ratio of hydrogen and natural gas. Therefore, by adopting the configuration of this embodiment, it is possible to realize a configuration of the combustor 3 that is suitable for both the first fuel F1 and the second fuel F2. Furthermore, by adjusting the fuel compositions of the first fuel F1 and the second fuel F2 in this manner, it is possible to ensure flame stability while reducing the occurrence of flashback.

[0065] In the embodiment, the second fuel F2 is injected more upstream of the mixing tube 30 than the first fuel F1, but the present invention is not limited to this. The first fuel F1 may be injected more upstream of the mixing tube 30 than the second fuel F2, or the first fuel F1 and the second fuel F2 may be injected at the same position in the direction of the central axis O2.

[0066] [Note] The combustor 3 and the gas turbine 1 described in each embodiment can be understood, for example, as follows.

[0067] (1) A combustor 3 according to a first aspect includes: a combustor plate 20 having a mixing tube 30 extending to penetrate an upstream end surface 21 and a downstream end surface 22 perpendicular to a combustor axis O1 and into which air A is introduced from the upstream end surface 21 side; a first fuel injection unit 40 capable of injecting a first fuel F1 along a central axis O2 of the mixing tube 30 inside the mixing tube 30; and a second fuel injection unit 70, radially outward from the central axis O2 of the mixing tube 30, capable of injecting a second fuel F2 into the mixing tube 30.

[0068] The first fuel injection unit 40 injects fuel along the central axis O2 of the mixing tube 30, which makes it possible to suppress an increase in the fuel concentration of the first fuel F1 on the wall surface of the mixing tube 30. On the other hand, the second fuel injection unit 70 injects the second fuel F2 at a position away from the central axis O2 of the mixing tube 30, which makes it possible to avoid an extreme decrease in the fuel concentration near the wall surface of the mixing tube 30. This makes it possible to perform stable combustion while suppressing flashback.

[0069] (2) The combustor 3 according to a second aspect is the combustor 3 according to the first aspect, wherein the first fuel injection unit 40 may inject the first fuel F1 downstream of the second fuel injection unit 70 within the mixing tube 30.

[0070] By injecting the second fuel F2 from the second fuel injection unit 70 at a position away from the central axis O2 of the mixing tube 30, the second fuel F2 can be diffused and distributed throughout the entire flow path cross section of the mixing tube 30. The first fuel injection unit 40, which injects the first fuel F1 along the central axis O2 of the mixing tube 30, is located downstream of the second fuel injection unit 70, and therefore the path from when the first fuel F1 is injected to when it reaches the outlet of the mixing tube 30 is short. This prevents the first fuel F1 from diffusing and reaching the inner wall surface 33 of the mixing tube 30.

[0071] (3) The combustor 3 according to a third aspect is the combustor 3 according to the first or second aspect, wherein the second fuel injection unit 70 may have a wall hole 71 capable of injecting the second fuel F2 into the mixing tube 30 from an inner wall surface 33 of the mixing tube 30.

[0072] The second fuel F2 is injected from the inner wall surface 33 of the mixing tube 30 by the second fuel injection unit 70, thereby increasing the fuel concentration on the inner wall surface 33 at the outlet of the mixing tube 30. This increases the combustion speed at the starting point of flame stabilization, and stabilizes the flame.

[0073] (4) A combustor 3 according to a fourth aspect may be the combustor 3 according to any one of the first to third aspects, wherein the first fuel injection unit 40 may include: a fuel nozzle 41 extending in the direction of the central axis O2 inside the mixing tube 30 and having a tip opening 45 through which the first fuel F1 is injected at the downstream end thereof; a strut 50 extending in a radial direction of the central axis O2 between the fuel nozzle 41 and an inner wall surface 33 of the mixing tube 30 and connecting the fuel nozzle 41 and the inner wall surface 33 of the mixing tube 30; and a fuel introduction passage through an interior of the strut 50 to the fuel nozzle 41.

[0074] This allows the first fuel F1 to be appropriately injected by the first fuel injection section 40 along the central axis O2 of the mixing tube 30.

[0075] (5) The combustor 3 according to a fifth aspect is the combustor 3 according to the fourth aspect, wherein the struts 50 may have an airfoil shape with a leading edge 51 at an upstream end and a trailing edge 52 at a downstream end.

[0076] This allows the air A inside the mixing tube 30 to flow smoothly, and an increase in pressure loss can be suppressed.

[0077] (6) A combustor 3 according to a sixth aspect is the combustor 3 according to the fourth or fifth aspect, wherein the inner wall surface 33 of the mixing tube 30 may have: an upstream wall surface 33a connected to the upstream end surface 21 and extending downstream with a uniform inner diameter; a reduced-diameter wall surface 33b connected downstream of the upstream wall surface 33a and having a diameter that reduces downstream; and a downstream wall surface 33c connected downstream of the reduced-diameter wall surface 33b, having a smaller diameter than the upstream wall surface 33a, and extending to the downstream end surface 22 with a uniform inner diameter.

[0078] A part of the mixing tube 30 is made into a reduced diameter wall surface 33b, and a throttled flow path is formed, thereby making it possible to increase the flow velocity inside the mixing tube 30. This makes it possible to prevent flame stabilization at unintended locations inside the mixing tube 30.

[0079] (7) A combustor 3 according to a seventh aspect is the combustor 3 according to the sixth aspect, wherein the reduced diameter wall surface 33b may extend from a position in the direction of the central axis O2 of an upstream end of the strut 50 to a position in the direction of the central axis O2 of the tip opening 45.

[0080] By narrowing the flow path of the mixing tube 30 in accordance with the arrangement position of the struts 50, it is possible to avoid the occurrence of low velocity regions within the mixing tube 30. This makes it possible to further prevent unintended flame holding within the mixing tube 30.

[0081] (8) The combustor 3 according to an eighth aspect is the combustor 3 according to any one of the fourth to seventh aspects, wherein the second fuel injection section 70 may have surface holes 72 capable of injecting the second fuel F2 from a surface of the strut 50 into the mixing tube 30.

[0082] This also makes it possible to inject the second fuel F2 at a position away from the central axis O2 of the mixing tube 30, thereby increasing the fuel concentration on the inner wall surface 33 at the outlet of the mixing tube 30. This increases the combustion speed at the starting point of flame stabilization, making it possible to stabilize the flame.

[0083] (9) The combustor 3 according to a ninth aspect may be the combustor 3 according to any one of the first to eighth aspects, wherein the first fuel F1 has a more combustible component than the second fuel F2.

[0084] When using a flammable first fuel F1, the first fuel F1 can be prevented from reaching the inner wall surface 33 of the mixing tube 30 by being injected along the central axis O2 of the mixing tube 30. This makes it possible to suppress an increase in fuel concentration near the inner wall surface 33 of the mixing tube 30 and to suppress the occurrence of flashback. On the other hand, when using the second fuel F2, which is difficult to burn, it is possible to increase the fuel concentration near the inner wall surface 33 by injecting it from the inner wall surface 33 of the mixing tube 30. This increases the combustion speed at the starting point of flame stabilization at the outlet of the mixing tube 30, making it possible to achieve stable flame stabilization.

[0085] (10) A gas turbine 1 according to a tenth aspect includes a compressor 2 that generates air A, a combustor 3 according to any one of the first to ninth aspects that generates combustion gas C by burning premixed gas M generated by mixing fuel with the air A compressed by the compressor 2, and a turbine 4 that is driven by the combustion gas C. [Industrial Applicability]

[0086] According to the present disclosure, it is possible to provide a combustor and a gas turbine that can avoid misfires while suppressing flashback. [Explanation of symbols]

[0087] 1. Gas turbine 2 Compressor 3 Combustor 4 Turbines 10 outer cylinder 11 End cover 15 Inner cylinder 17 Support part 20 Combustor plate 21 Upstream end face 22 Downstream end face 30 mixing tube 31 Entrance opening 32 Exit opening 33 Inner wall surface 33a Upstream wall 33b Reducing wall 33c Downstream wall 35 First Plenum 36 Second Plenum 37 Connecting member 38 First fuel supply system 39 Second fuel supply system 40 First fuel injection section 41 Fuel nozzle 42 Cavity 45 Tip opening 50 strut 51 leading edge 52 Trailing edge 53 Wing surface 60 Fuel introduction part 70 Second fuel injection section 71 Wall hole 72 Surface pores A. Air M Premixed gas C. Combustion gas O1 Combustor axis O2 center axis F1 Daiichi Fuel F2 secondary fuel

Claims

1. a combustor plate having mixing tubes extending through an upstream end surface and a downstream end surface, with air being introduced from the upstream end surface side; a first fuel injection unit capable of injecting a first fuel inside the mixing tube along a central axis of the mixing tube; a second fuel injection unit that is located radially outward of the central axis of the mixing tube and that is capable of injecting a second fuel into the mixing tube; Equipped with The combustor has a wall hole that can inject the second fuel into the mixing tube from an inner wall surface of the mixing tube, wherein the second fuel injection unit has a wall hole.

2. The combustor according to claim 1 , wherein the first fuel injection unit injects the first fuel downstream of the second fuel injection unit within the mixing tube.

3. a combustor plate having mixing tubes extending through an upstream end surface and a downstream end surface, with air being introduced from the upstream end surface side; a first fuel injection unit capable of injecting a first fuel inside the mixing tube along a central axis of the mixing tube; a second fuel injection unit that is located radially outward of the central axis of the mixing tube and that is capable of injecting a second fuel into the mixing tube; Equipped with The first fuel injection unit is a fuel nozzle extending in the central axis direction inside the mixing tube and having a tip opening formed at a downstream end thereof for injecting the first fuel; a strut extending in a radial direction of the mixing tube between the fuel nozzle and an inner wall surface of the mixing tube, the strut connecting the fuel nozzle and the inner wall surface of the mixing tube; a fuel introduction passage that introduces the first fuel into the fuel nozzle via an interior of the strut; A combustor having

4. 4. The combustor according to claim 3, wherein the strut has an airfoil shape with an upstream end serving as a leading edge and a downstream end serving as a trailing edge.

5. The inner wall surface of the mixing tube is an upstream wall surface connected to the upstream end surface and extending downstream with a uniform inner diameter; a tapered wall surface connected to a downstream side of the upstream wall surface and tapering toward the downstream side; a downstream wall surface connected to the downstream side of the reduced diameter wall surface, having a smaller diameter than the upstream wall surface, and extending to the downstream end surface with a uniform inner diameter; The combustor of claim 3 , comprising:

6. The combustor according to claim 5 , wherein the reduced diameter wall surface extends from a central axial position of the mixing tube at an upstream end of the strut to a central axial position of the tip opening.

7. The combustor according to claim 3 , wherein the secondary fuel injection portion has surface holes that can inject the secondary fuel from a surface of the strut into the mixing tube.

8. The second fuel injection unit is The combustor according to claim 3 , further comprising wall holes through which the second fuel can be injected into the mixing tube from an inner wall surface of the mixing tube.

9. the combustor plate includes a plurality of the mixing tubes; The combustor according to claim 1 or 3, wherein each of the mixing tubes comprises the first fuel injection portion and the second fuel injection portion.

10. 4. The combustor according to claim 1, wherein the first fuel has a more combustible component than the second fuel.

11. a compressor for generating air; the combustor according to claim 1 or 3, wherein the combustion gas is generated by burning premixed gas generated by mixing fuel with air compressed by the compressor; a turbine driven by the combustion gas; A gas turbine comprising:

Images