Burner, combustor, and gas turbine

Abstract

This burner is provided with a plate in which is formed an air-fuel mixture forming portion including at least one mixing flow passage which is configured so that air is supplied to the inside thereof and which extends along the axial direction, and at least one fuel injection hole which is configured to inject fuel into the at least one mixing flow passage, wherein: the air-fuel mixture forming portion includes a downstream side part positioned on the downstream side of the fuel injection hole in the axial direction, and an upstream side part positioned on the upstream side of the downstream side part in the axial direction; and the surface roughness of the inner wall surface of the downstream side part is less than the surface roughness of the inner wall surface of the upstream side part.

Description

Burner, Combustor, and Gas Turbine

[0001] The present disclosure relates to a burner, a combustor, and a gas turbine. This application claims priority based on Japanese Patent Application No. 2024-232592 filed with the Japan Patent Office on December 27, 2024, and incorporates its content herein by reference.

[0002] As a burner for a combustor such as a gas turbine, there is sometimes used a burner including one or more mixing channels (holes) extending along the axial direction of the burner, configured to mix air supplied to each mixing channel and fuel injected into the mixing channel and eject the mixture into a combustion chamber.

[0003] Patent Document 1 describes a burner including a plurality of mixing channels to which air is supplied, a plurality of fuel nozzles for injecting fuel, and a plurality of support portions respectively connecting the plurality of fuel nozzles and the channel walls of the mixing channels. The plurality of fuel nozzles are provided such that the central axis of each fuel nozzle coincides with the central axis of the mixing channel. In the mixing channel, the fuel ejected from the fuel nozzle and the air are mixed, and the air-fuel mixture flow formed thereby is ejected from the mixing channel into the combustion chamber of the combustor.

[0004] Japanese Unexamined Patent Application Publication No. 2021-173190

[0005] By the way, a burner may be manufactured by additive manufacturing. Generally, additively manufactured products have a larger surface roughness than machined products. When a burner including a mixing channel is formed by additive manufacturing, the surface roughness of the wall surface of the mixing channel increases, so that the flow velocity of air or the air-fuel mixture in the vicinity of this wall surface tends to decrease. When the flow velocity in the vicinity of the wall surface of the mixing pipe decreases, it is considered that flashback (backflow of flame along the inner wall surface of the mixing pipe, backfire) is likely to occur.

[0006] In view of the above circumstances, at least one embodiment of the present invention aims to provide a burner, a combustor, and a gas turbine capable of suppressing the occurrence of flashback in a burner formed by additive manufacturing.

[0007] A burner according to at least one embodiment of the present invention comprises: a plate having a mixture forming section formed therein, which includes at least one mixing channel configured to supply air internally and extending along the axial direction; and at least one fuel injection hole, each configured to inject fuel into the at least one mixing channel, wherein the mixture forming section includes a downstream portion located downstream of the at least one fuel injection hole in the axial direction, and an upstream portion located upstream of the downstream portion in the axial direction, wherein the surface roughness of the inner wall surface of the downstream portion is smaller than the surface roughness of the inner wall surface of the upstream portion.

[0008] Furthermore, a combustor according to at least one embodiment of the present invention comprises the burner described above and a combustion cylinder provided downstream of the burner.

[0009] Furthermore, a gas turbine according to at least one embodiment of the present invention comprises the above-described combustor and a turbine configured to be driven by the combustion gas from the combustor.

[0010] According to at least one embodiment of the present invention, a burner, a combustor, and a gas turbine are provided that can suppress the occurrence of flashback in a burner formed by additive manufacturing.

[0011] This is a schematic diagram of a gas turbine according to one embodiment. This is a schematic cross-sectional view showing the combustor of a gas turbine according to one embodiment. This is a schematic cross-sectional view along the axial direction of a burner according to one embodiment. This is a schematic cross-sectional view along the axial direction of a burner according to one embodiment. This is a diagram showing a cross-section perpendicular to the axial direction of the burner shown in Figure 3. This is a diagram for explaining the manufacturing method of a burner according to one embodiment.

[0012] Hereinafter, several embodiments of the present invention will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0013] First, a gas turbine, which is an example of an application for burners and combustors according to several embodiments, will be described with reference to Figure 1. Figure 1 is a schematic configuration diagram of a gas turbine according to one embodiment. As shown in Figure 1, the gas turbine 100 includes a compressor 2 for generating compressed air, a combustor 4 for generating combustion gas using compressed air and fuel, and a turbine 6 configured to be rotationally driven by the combustion gas. In the case of a gas turbine 100 for power generation, a generator (not shown) is connected to the turbine 6.

[0014] The compressor 2 includes a plurality of stationary vanes 16 fixed to the compressor casing 10 side, and a plurality of rotor blades 18 mounted on the rotor 8 so as to be alternately arranged with respect to the stationary vanes 16. Air taken in from the air intake 12 is supplied to the compressor 2, and this air is compressed by passing through the plurality of stationary vanes 16 and the plurality of rotor blades 18 to become high-temperature, high-pressure compressed air.

[0015] The combustor 4 is supplied with fuel and compressed air generated by the compressor 2. In the combustor 4, the fuel is burned, and combustion gas, which is the working fluid for the turbine 6, is generated. As shown in Figure 1, the gas turbine 100 has a plurality of combustors 4 arranged circumferentially around the central axis O of the rotor 8 within the casing 20.

[0016] The turbine 6 includes a plurality of stator blades 24 and rotor blades 26 provided in the combustion gas passage formed by the turbine casing 22. The stator blades 24 and rotor blades 26 of the turbine 6 are located downstream of the combustor 4 with respect to the flow of combustion gases. The stator blades 24 are fixed to the turbine casing 22 side, and a plurality of stator blades 24 arranged along the circumferential direction of the rotor 8 constitute a stator blade row. The rotor blades 26 are embedded in the rotor 8, and a plurality of rotor blades 26 arranged along the circumferential direction of the rotor 8 constitute a rotor blade row. The stator blade row and the rotor blade row are arranged alternately in the axial direction of the rotor 8.

[0017] In the turbine 6, combustion gas from the combustor 4 flows into the combustion gas passage and passes through multiple stationary blades 24 and multiple rotor blades 26, thereby driving the rotor 8 to rotate. This drives a generator connected to the rotor 8, generating electricity. After driving the turbine 6, the combustion gas is discharged to the outside through the exhaust chamber 30.

[0018] Figure 2 is a schematic cross-sectional view showing a combustor 4 of a gas turbine 100 according to one embodiment. As shown in Figure 2, the combustor 4 includes a burner 48 for burning fuel and a combustion cylinder 36 provided downstream of the burner 48 (i.e., closer to the turbine 6 than the burner 48).

[0019] The burner 48 includes a cylindrical member 34 provided along the axial direction (the direction of the central axis Q of the burner 48 or the combustion cylinder 36), a plate 50 supported by the cylindrical member 34 and having a plurality of mixing passages 56 formed inside, and a plurality of fuel nozzles 60 for injecting fuel into the plurality of mixing passages 56. The cylindrical member 34 is supported by the casing 20 by a support member 46 provided around the cylindrical member 34. The plurality of mixing passages 56 constitute a mixture forming section 90 for forming a mixture of air and fuel.

[0020] The plate 50 has an upstream end face 52 and a downstream end face 54, which are both ends in the axial direction. Each of the multiple mixing channels 56 is provided so as to extend axially through the interior of the plate 50. The upstream and downstream sides in the axial direction of the burner 48 refer to the upstream and downstream sides, respectively, in the direction of airflow through the multiple mixing channels 56 provided in the plate 50.

[0021] An air chamber 35 is formed between the casing 20 and the plate 50 in the axial direction, and compressed air from the compressor 2 is supplied to a plurality of mixing channels 56 via an air passage 40 and air chamber 35 formed on the outer circumference of the cylindrical member 34, and through an inlet opening (such as the upstream end 56a of the mixing channel 56; see Figure 3) provided on the upstream end face 52 of the plate 50.

[0022] Inside each mixing channel 56, air supplied from the compressor 2 and fuel ejected from the fuel nozzle 60 are mixed as they flow downstream (i.e., toward the combustion cylinder 36), generating a premixed gas. The premixed gas generated in each mixing channel 56 is injected into the combustion chamber 38 formed by the combustion cylinder 36 from an outlet opening (downstream end 56b of the mixing channel 56; see Figure 3) provided on the downstream end face 54 of the plate 50, and is ignited by a pilot light (not shown) to begin combustion. Fuel may also be supplied to each fuel nozzle 60 from the fuel port 44.

[0023] Several embodiments of the burner 48 will be described in more detail below. The burner 48 described below is applied, for example, to the gas turbine 100 and combustor 4 described above.

[0024] Figures 3 and 4 are schematic cross-sectional views along the axial direction of a burner 48 according to one embodiment, respectively. Figure 5 is a cross-section perpendicular to the axial direction of the burner 48 shown in Figure 3. Note that Figure 4 corresponds to the A-A cross-section in Figure 5.

[0025] A burner 48 according to several embodiments comprises a plate 50 having a mixture forming section 90 configured to receive air internally and including at least one mixing passage 56 extending along the axial direction, and at least one fuel injection hole 78, each configured to inject fuel into at least one mixing passage 56. The burner 48 may also include a mixture forming section 90 with a plurality of mixing passages 56, and a plurality of fuel injection holes 78, each configured to inject fuel into the plurality of mixing passages 56.

[0026] In the exemplary embodiment shown in Figure 3, the mixture forming section 90 includes at least one mixing channel 56 having an upstream end 56a that opens to the upstream end face 52 of the plate 50 and a downstream end 56b that opens to the downstream end face 54 of the plate 50. The upstream end 90a of the mixture forming section 90 coincides with the upstream end 56a of the at least one mixing channel 56, and the downstream end 90b of the mixture forming section 90 coincides with the downstream end 56b of the at least one mixing channel 56.

[0027] In the exemplary embodiments shown in Figures 4 and 5, the mixture forming section 90 includes a groove 80 provided in the plate 50 so as to be recessed in the axial direction from the upstream end face 52 of the plate 50, and a plurality of mixing channels 56 located downstream of the groove 80 in the axial direction. The groove 80 has an upstream end 80a that opens to the upstream end face 52 of the plate 50, a bottom surface 84 that extends along a plane intersecting in the axial direction, and an inner wall surface 82 that extends along the axial direction. The upstream end 56a of each of the plurality of mixing channels 56 opens to the bottom surface 84 of the groove 80. The downstream end 56b of each of the plurality of mixing channels 56 opens to the downstream end face 54 of the plate 50. The upstream end 90a of the mixture forming section 90 coincides with the upstream end 80a of the groove 80, and the downstream end 90b of the mixture forming section 90 coincides with the downstream end 56b of the plurality of mixing channels 56.

[0028] As shown in Figure 5, the multiple mixing channels 56 may be arranged circumferentially with respect to a center line P that extends along the direction of the central axis Q of the burner 48. In this case, the groove 80 is provided to extend circumferentially. The groove 80 may be a circumferential groove extending within a certain angular range around the center line P, or it may be an annular groove extending around the entire circumference of the center line P.

[0029] In the embodiments shown in Figures 4 and 5, a common groove 80 is provided on the upstream side of the multiple mixing channels 56, and the fuel nozzle 60 is supported on the inner wall surface 82 of the groove via a support portion 62. This suppresses the reduction in the flow channel area at one of the support portions 62, thereby suppressing the increase in pressure loss in the mixture forming section 90.

[0030] In some embodiments, as shown in Figures 3 to 5, for example, the fuel injection port 78 may be provided in the fuel nozzle 60 and have an outlet 60a that opens at the tip of the fuel nozzle 60. Alternatively, although not specifically shown, in some embodiments, the fuel injection port 78 may have an outlet that opens at the inner wall surface 57 of the mixing passage 56.

[0031] In the exemplary embodiments shown in Figures 3 to 5, the burner 48 includes a fuel nozzle 60 having fuel injection holes 78 extending along the axial direction. The fuel nozzle 60 may be provided coaxially with the mixing passage 56 in which the fuel nozzle 60 is located (i.e., the central axis of the fuel nozzle 60 coincides with the central axis L of the mixing passage 56).

[0032] As shown in Figures 3 to 5, the fuel nozzle 60 may be supported on the plate 50 via a support portion 62.

[0033] In the exemplary embodiments shown in Figures 3 to 5, the support portion 62 includes a strut connecting the fuel nozzle 60 and the plate 50. As shown in Figure 3, the strut (support portion 62) may be provided to connect the inner wall surface 57 of the mixing channel 56 and the fuel nozzle 60. Alternatively, as shown in Figures 4 and 5, the strut (support portion 62) may be provided to connect at least one of the inner wall surface 82a or the outer wall surface 82b of the inner wall surface 82 of the groove 80 and the fuel nozzle 60. In the exemplary embodiments shown in Figures 4 and 5, each of the multiple support portions 62 is connected to the outer wall surface 82b of the groove 80. As shown in Figures 3 to 5, the strut may be provided to extend radially with respect to the central axis L of the mixing channel 56.

[0034] Fuel from the fuel port 44 (see Figure 2) may be supplied to the fuel injection hole 78 via a fuel passage 72 formed inside the plate 50.

[0035] In the exemplary embodiments shown in Figures 3 to 5, a fuel passage 76 is formed inside the support portion 62, and an axial passage 74 extending axially is formed inside the plate 50 as part of the fuel passage 72. Fuel from the fuel port 44 (see Figure 2) is supplied to the fuel injection hole 78 in the fuel nozzle 60 via the fuel passage 72 and fuel passage 76, including the axial passage 74. The fuel supplied to the fuel injection hole 78 is ejected into the mixing passage 56 from the nozzle 60a at the tip of the fuel nozzle 60.

[0036] The fuel supplied to the fuel nozzle 60 may be, for example, a gaseous fuel containing hydrocarbons, hydrogen, ammonia, or carbon monoxide (including, for example, natural gas or coal gasification gas).

[0037] In some embodiments, as shown in Figures 4 and 5, for example, the mixture forming section 90 includes a downstream portion 90D located downstream of the fuel injection hole 78 (or downstream of the outlet 60a of the fuel nozzle 60) in the axial direction, and an upstream portion 90U located upstream of the downstream portion 90D in the axial direction. The surface roughness of the inner wall surface 91D of the downstream portion 90D is smaller than the surface roughness of the inner wall surface 91U of the upstream portion 90U. In Figures 4 and 5, the region occupied by the downstream portion 90D in the axial direction is indicated by R1, and the region occupied by the upstream portion 90U is indicated by R2.

[0038] In the exemplary embodiments shown in Figures 4 and 5, the downstream portion 90D includes a part of the downstream side of the mixing channel 56. Also, in the exemplary embodiment shown in Figure 4, the upstream portion 90U includes a part of the upstream side of the mixing channel 56. In the exemplary embodiment shown in Figure 5, the upstream portion 90U includes a part of the upstream side of the mixing channel 56 and the groove 80.

[0039] Figure 6 is a diagram illustrating a method for manufacturing a burner 48 according to one embodiment, and corresponds to the burner 48 shown in Figure 3. To manufacture the burner 48 including the downstream portion 90D and the upstream portion 90U described above, for example, first, the burner 48 shown in Figure 6 is formed by additive molding. In the burner shown in Figure 6, an excess material portion 94 is provided in the region R1 corresponding to the downstream portion 90D, where the flow channel wall is thicker than in the region R2 corresponding to the upstream portion 90U. Then, by removing the excess material portion 94 by machining (cutting or grinding, etc.), a burner 48 according to one embodiment (i.e., a burner 48 having a downstream portion 90D with a smaller surface roughness than the upstream portion 90U) can be manufactured.

[0040] As described above, the inner wall surface 91U of the upstream portion 90U of the burner 48 is an additively formed surface (a surface obtained by additive forming), and the inner wall surface 91D of the downstream portion 90D is a machined surface (a machined surface).

[0041] In the burner 48 according to the above-described embodiment, in the air-fuel mixture formation portion 90 formed in the burner 48, the surface roughness of the downstream portion 90D located on the downstream side of the fuel injection hole 78 is smaller than the surface roughness of the upstream portion 90U. Therefore, the decrease in the flow velocity near the wall surface at the outlet portion of the mixing channel 56 (that is, the outlet portion of the air-fuel mixture formation portion 90) is suppressed. Thus, it is possible to suppress the occurrence of flashback in the burner 48 formed by additional shaping.

[0042] In some embodiments, the arithmetic mean roughness Ra of the inner wall surface 91D of the downstream portion 90D is 1 / 2 or less of the arithmetic mean roughness Ra of the inner wall surface 91U of the upstream portion 90U. In some embodiments, the arithmetic mean roughness Ra of the inner wall surface 91D of the downstream portion 90D may be 1 / 3 or less or 1 / 4 or less of the arithmetic mean roughness Ra of the inner wall surface 91U of the upstream portion 90U.

[0043] The arithmetic mean roughness Ra can be obtained by the method defined in JIS B 0601.

[0044] According to the above-described embodiment, since the arithmetic mean roughness Ra of the inner wall surface 91D of the downstream portion 90D is 1 / 2 or less, 1 / 3 or less, or 1 / 4 or less of the arithmetic mean roughness Ra of the inner wall surface 91U of the upstream portion 90U, the decrease in the flow velocity near the wall surface at the outlet portion of the mixing channel 56 is effectively suppressed. Thus, it is possible to effectively suppress the occurrence of flashback in the burner 48 formed by additional shaping.

[0045] In some embodiments, the arithmetic mean roughness Ra of the inner wall surface 91D of the downstream portion 90D is 1.6 μm or less.

[0046] In the above-described embodiment, since the arithmetic mean roughness Ra of the inner wall surface 91D of the downstream portion 90D is 1.6 μm or less and is relatively small, the decrease in the flow velocity near the wall surface at the outlet portion of the mixing channel 56 is effectively suppressed. Thus, it is possible to effectively suppress the occurrence of flashback in the burner 48 formed by additional shaping.

[0047] In some embodiments, the arithmetic mean roughness Ra of the inner wall surface 91D of the downstream portion 90D is 1.6 μm or less, and the arithmetic mean roughness Ra of the inner wall surface 91U of the upstream portion 90U is 10 μm or more.

[0048] In the above-described embodiment, since the arithmetic mean roughness Ra of the inner wall surface 91U of the upstream portion 90U is 10 µm or more, the surface roughness of the inner wall surface 91D of the downstream portion 90D is significantly smaller than the surface roughness of the inner wall surface 91U of the upstream portion 90U. Therefore, the decrease in the flow velocity near the wall surface at the outlet of the mixing flow path 56 is effectively suppressed. Thus, the occurrence of flashback in the burner 48 formed by additional shaping can be effectively suppressed.

[0049] The content described in each of the above embodiments is understood as follows, for example.

[0050] [1] A burner (48) according to at least one embodiment of the present invention includes a plate (50) in which a mixture formation portion (90) including at least one mixing flow path (56) configured to supply air therein and extending along the axial direction is formed, and at least one fuel injection hole (78) each configured to eject fuel into the at least one mixing flow path. The mixture formation portion includes a downstream portion (90D) located downstream of the at least one fuel injection hole in the axial direction and an upstream portion (90U) located upstream of the downstream portion in the axial direction. The surface roughness of the inner wall surface (91D) of the downstream portion is smaller than the surface roughness of the inner wall surface (91U) of the upstream portion.

[0051] In the configuration of the above [1], among the mixture formation portions formed in the burner, the surface roughness of the downstream portion located downstream of the fuel injection hole is smaller than the surface roughness of the upstream portion. Therefore, the decrease in the flow velocity near the wall surface at the outlet of the mixing flow path is suppressed. Thus, according to the configuration of the above [1], the occurrence of flashback in the burner formed by additional shaping can be suppressed. The burner including the downstream portion and the upstream portion described in the above [1] can be manufactured, for example, by machining (such as cutting or grinding) the wall surface of the portion corresponding to the downstream portion of the mixing flow path after forming the burner by additional shaping.

[0052] [2] In some embodiments, in the configuration of [1] above, the inner wall surface of the upstream portion is an additively formed surface, and the inner wall surface of the downstream portion is a machined surface.

[0053] According to the configuration in [2] above, the inner wall surface of the upstream portion is an additively formed surface, and the inner wall surface of the downstream portion is a machined surface. Therefore, the surface roughness of the downstream portion can be made smaller than that of the upstream portion. Thus, as described in [1] above, the occurrence of flashback can be suppressed in the burner formed by additive manufacturing.

[0054] [3] In some embodiments, in the configuration of [1] or [2] above, the arithmetic mean roughness Ra of the inner wall surface of the downstream portion is 1 / 2 or less of the arithmetic mean roughness Ra of the inner wall surface of the upstream portion.

[0055] According to the configuration described in [3] above, the arithmetic mean roughness of the inner wall surface of the downstream portion is less than or equal to half the arithmetic mean roughness of the inner wall surface of the upstream portion, so that the decrease in flow velocity near the wall surface at the outlet of the mixing channel is effectively suppressed. Therefore, the occurrence of flashback can be effectively suppressed in the burner formed by additive molding.

[0056] [4] In some embodiments, in any of the configurations [1] to [3] above, the arithmetic mean roughness Ra of the inner wall surface of the downstream portion is 1.6 μm or less.

[0057] According to the configuration described in [4] above, the arithmetic mean roughness Ra of the inner wall surface of the downstream portion is 1.6 μm or less, which is relatively small, so the decrease in flow velocity near the wall surface at the outlet of the mixing channel is effectively suppressed. Therefore, the occurrence of flashback can be effectively suppressed in the burner formed by additive manufacturing.

[0058] [5] In some embodiments, in the configuration of [4] above, the arithmetic mean roughness Ra of the inner wall surface of the upstream portion is 10 μm or more.

[0059] According to the configuration described in [5] above, the arithmetic mean roughness Ra of the inner wall surface of the upstream portion is 10 μm or more. Therefore, the surface roughness of the inner wall surface of the downstream portion is significantly smaller than that of the inner wall surface of the upstream portion. As a result, the decrease in flow velocity near the wall surface at the outlet of the mixing channel is effectively suppressed. Thus, the occurrence of flashback can be effectively suppressed in the burner formed by additive manufacturing.

[0060] [6] In some embodiments, in any of the configurations of [1] to [5] above, the mixture forming section is provided in the plate so as to be recessed in the axial direction from the upstream end face of the plate in the axial direction and includes a groove (80) having a bottom surface and an inner wall surface extending along the axial direction, the at least one mixing passage includes a plurality of mixing passages formed in the plate, the at least one fuel injection hole includes a plurality of fuel injection holes each configured to inject fuel into the plurality of mixing passages, the burner comprises a plurality of fuel nozzles (60) each having the plurality of fuel injection holes, and a plurality of support sections (62) for each of the plurality of fuel nozzles on the inner wall surface (82) of the groove, and the upstream end of each of the plurality of mixing passages opens to the bottom surface (84) of the groove.

[0061] When a fuel nozzle is supported on the inner wall surface of a mixing channel with a constant diameter, the area of ​​the mixing channel is reduced at the position of the support, increasing the flow velocity and pressure loss. In this respect, according to the configuration of [6] above, a common groove is provided on the upstream side of multiple mixing channels, and the fuel nozzle is supported on the inner wall surface of the groove via a support. This suppresses the reduction of the flow channel surface at the position of the support, thereby suppressing the increase in pressure loss in the mixture forming section. Therefore, in a burner formed by additive molding, it is possible to suppress the occurrence of flashback while suppressing the increase in pressure loss.

[0062] [7] A combustor (4) according to at least one embodiment of the present invention comprises a burner (48) described in any one of the above [1] to [6], and a combustion cylinder (36) provided downstream of the burner.

[0063] In the configuration described in [7] above, the surface roughness of the downstream portion of the mixture forming section formed in the burner, which is located downstream of the fuel injection hole, is smaller than the surface roughness of the upstream portion. Therefore, the decrease in flow velocity near the wall at the outlet of the mixing channel is suppressed. Thus, according to the configuration described in [7] above, the occurrence of flashback can be suppressed in a burner formed by additive molding.

[0064] [8] A gas turbine (100) according to at least one embodiment of the present invention comprises a combustor (4) as described in [7] above, and a turbine (6) configured to be driven by combustion gas from the combustor.

[0065] In the configuration described in [8] above, the surface roughness of the downstream portion of the mixture forming section formed in the burner, which is located downstream of the fuel injection hole, is smaller than that of the upstream portion. Therefore, the decrease in flow velocity near the wall at the outlet of the mixing channel is suppressed. Accordingly, according to the configuration described in [7] above, the occurrence of flashback can be suppressed in a burner formed by additive molding.

[0066] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0067] In this specification, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" shall not only describe such arrangements strictly, but also describe states of relative displacement with tolerances or angles or distances sufficient to achieve the same function. For example, expressions describing things being in an equal state such as "identical," "equal," and "homogeneous" shall not only describe states of being strictly equal, but also describe states where tolerances or differences exist to the extent that the same function is achieved. Furthermore, in this specification, expressions describing shapes such as quadrilaterals or cylindrical shapes shall not only describe geometrically precise quadrilaterals or cylindrical shapes, but also describe shapes including concave and concave parts, chamfered parts, etc., to the extent that the same effect is achieved. In addition, in this specification, expressions such as "equipment," "includes," or "possesses" a component are not exclusive expressions that exclude the existence of other components.

[0068] 2 Compressor 4 Combustor 6 Turbine 8 Rotor 10 Compressor casing 12 Air intake 16 Stationary blades 18 Rotor blades 20 Casing 22 Turbine casing 24 Stationary blades 26 Rotor blades 30 Exhaust chamber 34 Cylindrical member 35 Air chamber 36 Combustion cylinder 38 Combustion chamber 40 Air passage 44 Fuel port 46 Support member 48 Burner 50 Plate 52 Upstream end face 54 Downstream end face 56 Mixing passage 56a Upstream end 56b Downstream end 57 Inner wall surface 60 Fuel nozzle 60a Outlet 62 Support part 72 Fuel passage 74 Axial passage 76 Fuel passage 78 Fuel injection hole 80 Groove 80a Upstream end 82 Inner wall surface 82a Inner wall surface 82b Outer wall surface 84 Bottom surface 90 Mixture forming section 90D Downstream section 90U Upstream section 90a Upstream end 90b Downstream end 91D Inner wall surface 91U Inner wall surface 94 Excess material 100 Gas turbine L Central axis O Central axis P Centerline Q Central axis

Claims

1. A burner comprising: a plate having a mixture forming section formed thereon, which includes at least one mixing channel configured to supply air to the interior and extending along the axial direction; and at least one fuel injection hole, each configured to inject fuel into the at least one mixing channel, wherein the mixture forming section includes a downstream portion located downstream of the at least one fuel injection hole in the axial direction, and an upstream portion located upstream of the downstream portion in the axial direction, wherein the surface roughness of the inner wall surface of the downstream portion is less than the surface roughness of the inner wall surface of the upstream portion.

2. The burner according to claim 1, wherein the inner wall surface of the upstream portion is an additively formed surface, and the inner wall surface of the downstream portion is a machined surface.

3. The burner according to claim 1 or 2, wherein the arithmetic mean roughness of the inner wall surface of the downstream portion is 1 / 2 or less of the arithmetic mean roughness of the inner wall surface of the upstream portion.

4. The burner according to claim 1 or 2, wherein the arithmetic mean roughness Ra of the inner wall surface of the downstream portion is 1.6 μm or less.

5. The burner according to claim 4, wherein the arithmetic mean roughness Ra of the inner wall surface of the upstream portion is 10 μm or more.

6. The burner according to claim 1 or 2, comprising: a mixture forming section provided in the plate so as to be recessed in the axial direction from the upstream end face of the plate in the axial direction, and including a groove having a bottom surface and an inner wall surface extending along the axial direction; at least one mixing passage includes a plurality of mixing passages formed in the plate; at least one fuel injection hole includes a plurality of fuel injection holes each configured to inject fuel into the plurality of mixing passages; a plurality of fuel nozzles each having the plurality of fuel injection holes; and a plurality of support sections for each supporting the plurality of fuel nozzles on the inner wall surface of the groove, wherein the upstream end of each of the plurality of mixing passages opens to the bottom surface of the groove.

7. A combustor comprising: a burner according to claim 1 or 2; and a combustion cylinder provided downstream of the burner.

8. A gas turbine comprising: a combustor according to claim 7; and a turbine configured to be driven by combustion gas from the combustor.

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