Burner assembly, gas turbine combustor, and gas turbine

Abstract

To provide a burner assembly that can restrain a flashback.SOLUTION: A burner assembly comprises a plurality of burners for mixing fuel and air. The plurality of burners each include a mixing flow passage to which the air is supplied, and a fuel nozzle extending along a central axis of the mixing flow passage inside the mixing flow passage, and constituted so as to inject the fuel. The fuel nozzle includes an orifice upstream of an outlet of the fuel nozzle.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a burner assembly, a gas turbine combustor, and a gas turbine. Background Art

[0002] As a technique for achieving low NOx emissions while providing flashback resistance for fuels with a high risk of flashback (such as hydrogen), there is a technique of forming a large number of independent small flames using a burner assembly (cluster burner).

[0003] In this technique, a plurality of mixing flow paths for mixing fuel and air are arranged, and the scale of fuel mixing is reduced, whereby high mixing performance can be obtained without actively utilizing a swirling flow for mixing fuel and air.

[0004] The burner described in Patent Document 1 is configured such that a fuel nozzle injects fuel along a central axis of a mixing flow path, and the central axis of the fuel nozzle coincides with the central axis of the mixing flow path, so it is sometimes referred to as a coaxial burner. In the case of such a coaxial burner, the fuel concentration near the wall surface of the mixing flow path is less likely to increase than that of a cross-flow burner that injects fuel from the flow path wall of the mixing flow path in a direction intersecting the air flow, so the risk of flashback can be suppressed.

[0005] The burner assembly described in Patent Document 2 comprises a plurality of burners for mixing fuel and air, each of which includes a fuel nozzle, a mixing channel through which fuel and air are supplied, and a support portion that connects the channel wall of the mixing channel to the fuel nozzle and supports the fuel nozzle. With this configuration, since the fuel nozzle is supported by the support portion connected to the channel wall of the mixing channel in each burner, there is no need to provide a large header like the one described in Patent Document 1, which is provided upstream of the mixing channel and independently of the channel wall of the mixing channel. Therefore, it is possible to eliminate the bias in air flow rate between the plurality of mixing channels caused by the header and reduce the bias in fuel concentration between the plurality of mixing channels. Consequently, it becomes possible to reduce NOx emissions and suppress flashback. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2007-232234 [Patent Document 2] Japanese Patent Publication No. 2021-173190 [Overview of the project] [Problems that the invention aims to solve]

[0007] At least one embodiment of the present disclosure is an improvement over the prior art described in Patent Document 2, and aims to provide a burner assembly capable of suppressing flashback, as well as a gas turbine combustor and gas turbine equipped therewith. [Means for solving the problem]

[0008] To achieve the above objective, a burner assembly according to at least one embodiment of this disclosure is: A burner assembly comprising multiple burners for mixing fuel and air, Each of the aforementioned multiple burners is The mixing channel to which the air is supplied, A fuel nozzle is provided inside the mixing channel, extending along the central axis of the mixing channel and configured to inject the fuel, Includes, The fuel nozzle includes an orifice upstream of the outlet of the fuel nozzle.

[0009] To achieve the above objective, a gas turbine combustor according to at least one embodiment of this disclosure is provided. The above burner assembly, A combustion cylinder forming a space for flame formation downstream of the burner assembly, It is equipped with.

[0010] To achieve the above objective, a gas turbine according to at least one embodiment of this disclosure is: Compressor and, A gas turbine combustor is configured to receive compressed air and fuel from the aforementioned compressor, and to burn the fuel to generate combustion gases, A turbine driven by the combustion gas generated in the gas turbine combustor, Equipped with, The aforementioned gas turbine combustor is the gas turbine combustor described above. [Effects of the Invention]

[0011] According to at least one embodiment of the present disclosure, a burner assembly capable of suppressing flashbacks, and a gas turbine combustor and gas turbine equipped therewith are provided. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing a gas turbine 100 according to one embodiment. [Figure 2] This is a schematic cross-sectional view showing the vicinity of the combustor 4 shown in Figure 1. [Figure 3] This is a schematic cross-sectional view along the central axis L of a burner assembly 32 according to one embodiment. [Figure 4] Figure 3 is a schematic cross-sectional view showing an example of the general configuration of the burner 42. [Figure 5] It is a schematic cross-sectional view enlarging the vicinity of an outlet 49 of a mixing flow path 46 in FIG. 4 [Figure 6] It is a schematic cross-sectional view showing the vicinity of an outlet 060 of a fuel nozzle 043 in a mixing flow path 046 according to a comparative embodiment [Figure 7A] It is a diagram showing an example of the distribution of axial flow velocities of fuel and air in a case where, with respect to the mixing flow path 46 of the burner 42 shown in FIG. 5, an orifice 62 is formed as designed so as to inject fuel along a central axis O [Figure 7B] It is a diagram showing an example of the distribution of axial flow velocities of fuel and air in a case where, with respect to the mixing flow path 46 of the burner 42 shown in FIG. 5, the shape of an orifice 62 deviates from the designed shape and the orifice 62 is formed so as to inject fuel in a direction inclined from the central axis O [Figure 8] It is a diagram showing a distribution C1 of axial flow velocity of fuel at the position of an outlet 60 of a fuel nozzle 43 in FIG. 7A, and a distribution C2 of axial flow velocities of fuel and air at the position of the outlet 60 of the fuel nozzle 43 in the axial direction in FIG. 7B [Figure 9] It is a diagram showing the relationship between L / D and the dimensionless wall fuel-air ratio at the position of a wall surface 63 of a flow path wall 55 in the vicinity of an outlet 49 of a mixing flow path 46, in a case where, with respect to the mixing flow path 46 of the burner 42 shown in FIG. 5, the shape of an orifice 62 deviates from the designed shape and the orifice 62 is formed so as to inject fuel in a direction inclined from the central axis O

Mode for Carrying Out 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 and the like of constituent components described as embodiments or shown in the drawings are not intended to limit the scope of the invention thereto, and are merely illustrative examples For example, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" should not only strictly describe such arrangements, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. For example, expressions such as "identical," "equal," and "homogeneous" that describe things being in an equal state not only describe a state of being strictly equal, but also describe a state in which there is a tolerance or a difference that is sufficient to achieve the same function. For example, expressions describing shapes such as squares or cylinders shall not only represent geometrically precise shapes such as squares or cylinders, but also shapes that include protrusions, chamfers, etc., to the extent that the same effect can be achieved. On the other hand, expressions such as "to possess," "to be equipped with," "to have," "to include," or "to have" a single component are not exclusive expressions that exclude the existence of other components.

[0014] Figure 1 is a schematic diagram showing a gas turbine 100 according to one embodiment of the present disclosure. As shown in Figure 1, the gas turbine 100 according to one embodiment includes a compressor 2 for compressing air as an oxidizer supplied to a combustor 4 (i.e., generating compressed air), a combustor 4 (gas turbine combustor) for generating combustion gas using the compressed air and fuel, and a turbine 6 configured to be driven by the combustion gas discharged from the combustor 4. In the case of a gas turbine 100 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.

[0015] In the combustor 4 of the gas turbine 100, the above-mentioned combustion gas is generated by burning a mixture of fuel and air. Examples of fuels burned in the combustor 4 include hydrogen, methane, diesel fuel, heavy oil, jet fuel, natural gas, or gasified coal, and one or more of these fuels can be burned in any combination.

[0016] The compressor 2 comprises a compressor casing 10, an air intake 12 located 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 the turbine casing 22, and various blades arranged within the compressor casing 10. The various blades include an inlet guide blade 14 located on the air intake 12 side, a plurality of stationary blades 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 blades 16. In such a compressor 2, the air taken in from the air intake 12 is compressed by passing through the plurality of stationary blades 16 and the plurality of rotor blades 18 to become high-temperature, high-pressure compressed air. This high-temperature, high-pressure compressed air is then sent from the compressor 2 to the combustor 4 downstream.

[0017] Multiple combustors 4 are arranged circumferentially around the rotor 8, spaced apart. Fuel and compressed air generated by the compressor 2 are supplied to the combustors 4, and combustion gas, which is the working fluid for the turbine 6, is generated by burning the fuel. The combustion gas is then sent from the combustors 4 to the downstream turbine 6.

[0018] The turbine 6 comprises a turbine casing 22 and various blades arranged within the turbine casing 22. The various blades include a plurality of stator blades 24 fixed to the turbine casing 22 and a plurality of rotor blades 26 mounted on the rotor 8 so as to be alternately arranged with respect to the stator blades 24. In the turbine 6, the rotor 8 is driven to rotate as combustion gases pass through the plurality of stator blades 24 and the plurality of rotor blades 26. This drives a generator (not shown) connected to the rotor 8.

[0019] Furthermore, an exhaust chamber 30 is connected to the downstream side of the turbine casing 22 via an exhaust casing 28. Combustion gases after driving the turbine 6 are discharged to the outside through the exhaust casing 28 and the exhaust chamber 30.

[0020] Figure 2 is a schematic cross-sectional view showing the vicinity of the combustor 4. The combustor 4 includes a burner assembly 32, a bottomed cylindrical casing 20 that houses the burner assembly 32, and a combustion tube 25 that forms a space for flame formation downstream of the burner assembly 32. In Figure 2, the dashed line is the common central axis L of the casing 20, the burner assembly 32, and the combustion tube 25. The burner assembly 32 is located inside the casing 20 of the combustor 4.

[0021] In the illustrated exemplary embodiment, the burner assembly 32 is held inside a cylindrical member 34 located within the casing 20, and the cylindrical member 34 is supported by the casing 20 via a plurality of support portions 35 spaced apart around a central axis L. An air passage 36 is formed between the casing 20 and the outer circumferential surface of the cylindrical member 34 (between the casing 20 and the outer circumferential surface of the burner assembly 32) through which compressed air flowing in from the casing 40 flows.

[0022] Compressed air flowing from the cabin 40 into the air passage 36 passes through the axial gap 23 between the burner assembly 32 and the bottom surface 21 of the casing 20 and flows together with fuel into the multiple mixing passages 46 provided in the burner assembly 32 (described later). The fuel and air mixed in the burner assembly 32 are ignited by an ignition device (not shown), forming a flame in the combustion cylinder 25 and generating combustion gases.

[0023] Figure 3 is a schematic cross-sectional view along the central axis L of a burner assembly 32 according to one embodiment.

[0024] As shown in Figure 3, the burner assembly 32 comprises a plurality of burners 42 for mixing fuel and air.

[0025] Each of the multiple burners 42 includes a fuel nozzle 43 for injecting fuel, a mixing channel 46 (mixing tube) through which fuel and air are supplied, and a plurality of support parts 39 that connect the channel wall 55 (inner circumferential surface of the mixing channel 46) of the mixing channel 46 to the fuel nozzle 43 and support the fuel nozzle 43. Since each of the multiple burners 42 has basically the same configuration except for the part that forms the outer circumferential surface of the burner assembly 32, the configuration common to each of the burners 42 will be described below.

[0026] Figure 4 is a schematic cross-sectional view showing an example of the general configuration of the burner 42. Figure 5 is a schematic cross-sectional view showing an enlarged view of the vicinity of the outlet 49 of the mixing channel 46 in Figure 4.

[0027] For example, as shown in Figure 4, the fuel nozzle 43 is formed in a tubular shape and extends within the mixing channel 46 along the central axis O of the mixing channel 46. A fuel channel 45 is formed inside the fuel nozzle 43 on the central axis O. An outlet 60 of the fuel nozzle 43 (the outlet of the fuel channel 45) is formed at the tip of the fuel nozzle 43. The fuel nozzle 43 also includes an orifice 62 upstream of the outlet 60 of the fuel nozzle 43 in the fuel channel 45. The orifice 62 of the fuel nozzle 43 is located on the central axis O and is configured to inject fuel along the central axis O, as shown by arrow a1 in Figure 5. In the following, unless otherwise specified, "axial direction" means the direction parallel to the central axis O, i.e., the axial direction of the fuel nozzle 43 (the axial direction of the mixing channel 46).

[0028] For example, as shown in Figure 4, the mixing channel 46 is formed in a tubular shape and extends along the central axis O. An air channel 47 is formed on the outer circumferential side of the fuel nozzle 43 in the mixing channel 46, that is, between the channel wall 55 of the mixing channel 46 and the outer circumferential surface 44 of the fuel nozzle 43. The compressed air that flows into the mixing channel 46 from the inlet 51 passes through the air channel 47 as shown by arrow b in Figure 5, and then mixes with the fuel injected from the outlet 60 of the fuel nozzle 43.

[0029] For example, as shown in Figure 4, a fuel passage 48 for supplying fuel to the fuel nozzle 43 is formed inside the support section 39 and the flow path wall 55, and the fuel passage 48 is connected to the fuel passage 45 of the fuel nozzle 43. Fuel supplied to the burner assembly 32 from a fuel supply source (not shown) is supplied to the fuel passage 45 of the fuel nozzle 43 through the fuel passage 48 (i.e., through the inside of the flow path wall 55 and the inside of the support section 39), and is injected into the mixing passage 46 from the outlet 60 of the fuel nozzle 43 through the fuel passage 45 of the fuel nozzle 43.

[0030] For example, as shown in Figure 5, the orifice 62 is configured as an annular projection that protrudes from the flow path wall 58 of the fuel flow path 45 toward the central axis O. Furthermore, if the orifice diameter of the orifice 62 is D, the flow path width of the fuel flow path 45 downstream of the orifice 62 is Wd, and the flow path width of the fuel flow path 45 upstream of the orifice 62 is Wu, then Wd > D and Wu > D are satisfied. Typically, the shape of the flow path cross-section of the fuel flow path 45 and the flow path cross-section of the orifice 62 are circular, in which case the orifice diameter D is the diameter of the orifice 62, and the flow path widths Wu and Wd of the fuel flow path 45 are the diameters of the fuel flow path 45. In the illustrated exemplary embodiment, the flow path widths Wu and Wd of the fuel flow path 45 are constant regardless of their axial position. The flow path wall 55 of the mixing flow path 46 includes constant flow path width sections 74, 78 and a throttling section 76. The flow width H of each of the constant flow width sections 74 and 78 is constant regardless of their axial position. The flow width H of the throttling section 76 narrows as it moves downstream. In the illustrated exemplary configuration, the constant flow width section 74, the throttling section 76 and the constant flow width section 78 are provided in order from the upstream side of the mixing flow path 46, with the throttling section 76 located upstream of the outlet 60 of the fuel nozzle 43 in the axial direction.

[0031] According to the burner assembly 32 described above, as shown in Figure 4, etc., the fuel nozzle 43 is supported by a support part 39 connected to the wall surface 63 of the flow path wall 55 of the mixing flow path 46 in each burner 42. Therefore, there is no need to provide a large header, such as the one described in Patent Document 1, which is configured independently of the flow path wall 55 of the mixing flow path 46, on the upstream side of the mixing flow path 46. As a result, the uneven distribution of air flow between multiple mixing flow paths caused by the header is eliminated, and the uneven distribution of fuel concentration between multiple mixing flow paths 46 can be reduced. Consequently, NOx reduction and suppression of flashback become possible.

[0032] Next, the technical significance of placing the orifice 62 of the fuel nozzle 43 upstream of the outlet 60 of the fuel nozzle 43 will be explained based on a comparison with the comparative configuration. Figure 6 is a schematic cross-sectional view showing the vicinity of the outlet 060 of the fuel nozzle 043 in the mixing channel 046 according to the comparative configuration.

[0033] The fuel nozzle 043 in the comparative configuration shown in Figure 6 has an orifice 062 at the outlet 060 of the fuel nozzle 043. That is, the flow path width of the fuel passage 045 of the fuel nozzle 043 in the comparative configuration is minimized at the outlet 060 of the fuel nozzle 043. In such a configuration, if the shape or dimensions of the orifice 062 deviate from the design point during the manufacturing of the burner assembly (for example, if the orifice 062 is formed to inject fuel in a direction inclined from the central axis O, as shown by arrow a2 in Figure 6), fuel will be injected from the orifice 062 of the fuel nozzle 043 (outlet 060 of the fuel nozzle 043) toward the flow path wall 055 of the mixing passage 046. As a result, the fuel concentration near the flow path wall 055 of the mixing passage 046 becomes locally high, increasing the risk of flashback.

[0034] In contrast, in the embodiments shown in Figures 4 and 5, even if the shape or dimensions of the orifice 62 deviate from the design point during the manufacturing of the burner assembly 32 (for example, if the orifice 62 is formed to inject fuel in a direction inclined from the central axis O, as shown by arrow a2 in Figure 5), the orifice 62 of the fuel nozzle 43 is located upstream of the outlet 60 of the fuel nozzle 43. Therefore, the fuel injected from the orifice 62 is rectified in the fuel flow path 45 inside the fuel nozzle 43 before reaching the outlet 60 of the fuel nozzle 43, thereby suppressing the uneven flow of fuel at the outlet 60 of the fuel nozzle 43. As a result, the diffusion of fuel exiting the outlet 60 of the fuel nozzle 43 towards the flow path wall 55 of the mixing flow path 46 is suppressed, reducing the risk of flashback.

[0035] Figure 7A shows an example of the distribution of axial flow velocity of fuel and air in the mixing channel 46 of the burner 42 described above, when the orifice 62 is formed as designed so that fuel is injected along the central axis O. Figure 7B shows an example of the distribution of axial flow velocity of fuel and air in the mixing channel 46 of the burner 42 described above, when the shape of the orifice 62 deviates from the design shape and the orifice 62 is formed so that fuel is injected in an inclined direction from the central axis O. Figure 8 shows the distribution of axial flow velocity of fuel and air at the outlet 60 of the fuel nozzle 43 in the axial direction C1 in Figure 7A, and the distribution of axial flow velocity of fuel and air at the outlet 60 of the fuel nozzle 43 in the axial direction C2 in Figure 7B.

[0036] Comparing Figure 7A and Figure 7B, in Figure 7A, the axial velocity of the fuel has a distribution that is approximately symmetrical with respect to the central axis O, whereas in Figure 7B, in region A1 showing the fuel jet immediately after injection from the orifice 62, the axial velocity of the fuel is greater on the lower side of the central axis O than on the upper side, indicating a bias in the fuel jet with respect to the central axis O. However, since the orifice 62 is located upstream of the outlet 60 of the nozzle 43, the fuel injected from the orifice 62 is rectified in the fuel flow path 45 inside the fuel nozzle 43 before reaching the outlet 60 of the fuel nozzle 43, and at the position of the outlet 60 of the nozzle 43, the axial velocity of the fuel shows a distribution that is approximately symmetrical with respect to the central axis O. For this reason, as shown in Figure 8, the above distribution C1 and distribution C2 are approximately identical. Thus, with the burner assembly 32 described above, even if the shape of the orifice 62 deviates from the design shape and the orifice 62 is formed to inject fuel in a direction inclined from the central axis O, the uneven flow of fuel at the outlet 60 of the fuel nozzle 43 can be suppressed. This suppresses the diffusion of fuel exiting the outlet 60 of the fuel nozzle 43 towards the flow path wall 55 of the mixing flow path 46, thereby reducing the risk of flashback.

[0037] In some embodiments, as shown in Figure 5, for example, if the distance between the outlet 60 and the orifice 62 in the fuel nozzle 43 is L and the orifice diameter of the orifice 62 is D, the fuel nozzle 43 may satisfy L / D > 5, and more preferably, L / D ≥ 7.5. That is, the value obtained by dividing the distance L between the outlet 60 and the orifice 62 in the fuel nozzle 43 by the orifice diameter D of the orifice 62 may be greater than 5, and more preferably 7.5 or greater. The technical significance of satisfying L / D > 5 and the technical significance of satisfying L / D ≥ 7.5 will be explained below with reference to Figure 9.

[0038] Figure 9 shows the relationship between the above L / D and the dimensionless wall fuel-air ratio at the position of the wall surface 63 of the flow path wall 55 near the outlet 49 of the mixing flow path 46 of the burner 42 described above, when the shape of the orifice 62 deviates from the design shape and the orifice 62 is formed to inject fuel in a direction b (see Figure 5) that is inclined from the central axis O. The fuel-air ratio is the reciprocal of the air-fuel ratio and is a dimensionless quantity obtained by dividing the fuel mass by the air mass, and the dimensionless wall fuel-air ratio is a dimensionless quantity calculated by dividing the fuel-air ratio at the position of the wall surface 63 by the average fuel-air ratio of the entire flow path cross-section including that position.

[0039] As shown in Figure 9, in the range where L / D ≤ ​​5, the dimensionless wall fuel-air ratio at the wall surface 63 of the flow channel wall 55 near the outlet 49 of the mixing flow channel 46 is approximately constant regardless of the value of L / D. In contrast, in the range where L / D > 5, the dimensionless wall fuel-air ratio decreases as L / D increases. Furthermore, in the range where L / D ≥ 7.5, the dimensionless wall fuel-air ratio at the wall surface 63 of the flow channel wall 55 near the outlet 49 of the mixing flow channel 46 is significantly and substantially smaller compared to the range where L / D ≤ ​​5.

[0040] Therefore, even if the shape or dimensions of the orifice 62 deviate from the design point during the manufacturing of the burner assembly 32, satisfying L / D > 5 allows the fuel injected from the orifice 62 to be rectified inside the fuel nozzle 43 before reaching the outlet 60 of the fuel nozzle 43, thereby suppressing fuel misflow at the outlet 60 of the fuel nozzle 43 and suppressing the rise in the fuel-air ratio at the wall surface 63 of the flow path wall 55 near the outlet 49 of the mixing flow path 46. Furthermore, satisfying L / D ≥ 7.5 allows the fuel injected from the orifice 62 to be well rectified inside the fuel nozzle 43 before reaching the outlet 60 of the fuel nozzle 43, significantly suppressing fuel misflow at the outlet 60 of the fuel nozzle 43, and thus significantly and substantially suppressing the rise in the fuel-air ratio at the wall surface 63 of the flow path wall 55 near the outlet 49 of the mixing flow path 46, thereby effectively reducing the risk of flashback. Furthermore, when L / D > 5 or L / D ≥ 7.5 is satisfied, L / Wd < 25 may also be satisfied in order to suppress the decrease in flow velocity on the inner wall side of the fuel nozzle 43 due to the complete development of the flow inside the fuel nozzle 43.

[0041] In some embodiments, for example, in the configuration shown in Figures 4 and 5, if the flow path area of ​​the outlet 60 of the fuel nozzle 43 is Af and the flow path area of ​​the air passage 47 at the position of the outlet 60 in the axial direction is Aa, then the ratio of the flow path area Af to the flow path area Aa may satisfy Af / Aa ≥ 0.1.

[0042] In this configuration, the Af / Aa ratio is significantly larger than in conventional burner assemblies. By actively reducing the fuel flow velocity at the outlet 60 in the axial direction of the fuel nozzle 43 relative to the air flow velocity, the uneven flow of fuel remaining at the outlet 60 of the fuel nozzle 43 can be effectively straightened by the air in the air passage 47, thereby suppressing the fuel injected from the fuel nozzle 43 from reaching the flow path wall 55 of the mixing passage 46. This suppresses the increase in the fuel-air ratio at the wall surface 63 of the flow path wall 55 near the outlet 49 of the mixing passage 46, thereby effectively reducing the risk of flashback. When Af / Aa ≥ 0.1 is satisfied, Af / Aa < 0.65 may also be satisfied from the viewpoint of suppressing an increase in the pressure loss of the air passage 47.

[0043] In some embodiments, during rated operation of the gas turbine, if the fuel density at the outlet 60 of the fuel nozzle 43 is ρf, the fuel velocity at the outlet 60 of the fuel nozzle 43 is Vf, the air density in the air passage 47 at the position of the outlet 60 of the fuel nozzle 43 in the axial direction is ρa, and the air velocity in the air passage 47 at the position of the outlet 60 of the fuel nozzle 43 in the axial direction is Va, then ρf × (Vf) 2 <ρa×(Va) 2 The following condition may also be met: In other words, during rated operation of the gas turbine, the momentum of the air in the air passage 47 at the position of the outlet 60 of the fuel nozzle 43 in the axial direction may be greater than the momentum of the fuel at the outlet 60 of the fuel nozzle 43.

[0044] In this configuration, the uneven flow of fuel remaining at the outlet 60 of the fuel nozzle 43 can be effectively straightened by the air in the air passage 47, and the fuel injected from the fuel nozzle 43 can be prevented from reaching the passage wall 55 of the mixing passage 46. As a result, the increase in the fuel-air ratio at the wall surface 63 of the passage wall 55 near the outlet 49 of the mixing passage 46 can be suppressed, thereby effectively reducing the risk of flashback.

[0045] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0046] For example, in the exemplary embodiment shown in Figure 5, the flow path wall 55 of the mixing flow path 46 had a throttling section 76 upstream of the outlet 60 of the fuel nozzle 43. However, the flow path wall 55 of the mixing flow path 46 does not have to have a throttling section 76, and the flow path width of the mixing flow path 46 may be constant from the inlet 51 to the outlet 49.

[0047] As shown in Figure 5, the flow width of the fuel passage 45 formed inside the fuel nozzle 43 was constant regardless of the axial position downstream of the orifice 62. However, the fuel passage 45 may have a section downstream of the orifice 62 where the flow width of the fuel passage 45 increases as it moves downstream.

[0048] The contents described in each of the above embodiments can be understood, for example, as follows:

[0049] (1) A burner assembly according to at least one embodiment of the present disclosure (for example, the burner assembly 32 described above) A burner assembly comprising multiple burners (for example, the burner 42 described above) for mixing fuel and air, Each of the aforementioned multiple burners is The mixing channel through which the air is supplied (for example, the mixing channel 46 described above), A fuel nozzle (for example, the fuel nozzle 43 described above) is configured to extend along the central axis of the mixing channel and inject the fuel inside the mixing channel, Includes, The fuel nozzle includes an orifice (for example, the orifice 62 described above) upstream of the outlet of the fuel nozzle.

[0050] According to the burner assembly described in (1) above, even if the shape or dimensions of the orifice deviate from the design point during the manufacturing of the burner assembly, the orifice of the fuel nozzle is located upstream of the outlet of the fuel nozzle. Therefore, the fuel injected from the orifice is rectified inside the fuel nozzle before reaching the outlet of the fuel nozzle, suppressing uneven flow of fuel at the outlet of the fuel nozzle. As a result, the diffusion of fuel exiting the outlet of the fuel nozzle towards the flow path wall of the mixing channel is suppressed, reducing the risk of flashback.

[0051] (2) In some embodiments, in the burner assembly described in (1) above, If L is the distance between the outlet and the orifice in the fuel nozzle, and D is the orifice diameter, then L / D > 5 is satisfied.

[0052] According to the burner assembly described in (2) above, even if the shape and dimensions of the orifice deviate from the design point during the manufacturing of the burner assembly, satisfying L / D > 5 allows the fuel injected from the orifice to be rectified to some extent inside the fuel nozzle before reaching the outlet of the fuel nozzle, thereby suppressing the uneven flow of fuel at the outlet of the fuel nozzle. This suppresses the rise in the fuel-air ratio at the wall surface of the flow path wall of the mixing channel, thereby reducing the risk of flashback.

[0053] (3) In some embodiments, in the burner assembly described in (1) or (2) above, The L / D ratio must be ≥ 7.5.

[0054] According to the burner assembly described in (3) above, even if the shape and dimensions of the orifice deviate from the design point during the manufacturing of the burner assembly, by satisfying L / D ≥ 7.5, the fuel injected from the orifice is properly rectified inside the fuel nozzle before reaching the outlet of the fuel nozzle, thereby significantly suppressing the uneven flow of fuel at the outlet of the fuel nozzle. As a result, the increase in the fuel-air ratio at the wall surface of the flow path wall of the mixing channel can be significantly and substantially suppressed, thereby effectively reducing the risk of flashback.

[0055] (4) In some embodiments, in the burner assembly described in any of (1) to (3) above, The mixing channel includes an air channel (for example, the air channel 47 described above) on the outer circumference side of the fuel nozzle. If Af is the flow path area at the outlet of the fuel nozzle, and Aa is the flow path area of ​​the air passage at the outlet position in the axial direction of the fuel nozzle, then Af / Aa ≥ 0.1 is satisfied.

[0056] According to the burner assembly described in (4) above, the Af / Aa ratio is significantly larger than that of conventional burner assemblies. By actively reducing the fuel flow velocity at the outlet position in the axial direction of the fuel nozzle relative to the air flow velocity, the uneven flow of fuel remaining at the outlet of the fuel nozzle can be effectively straightened by the air in the air passage, and the fuel injected from the fuel nozzle can be prevented from reaching the flow passage wall of the mixing passage. As a result, the increase in the fuel-air ratio at the wall surface of the flow passage wall near the outlet of the mixing passage can be suppressed, thereby effectively reducing the risk of flashback.

[0057] (5) A gas turbine combustor according to at least one embodiment of the present disclosure (e.g., combustor 4 described above) A burner assembly as described in any of (1) to (4) above, A combustion cylinder (for example, the combustion cylinder 25 described above) that forms a space for flame formation downstream of the burner assembly, A gas turbine combustor equipped with a gas turbine combustor.

[0058] According to the burner assembly described in (5) above, since it is equipped with any of the burner assemblies described in (1) to (4) above, the risk of flashback can be reduced.

[0059] (6) A gas turbine according to at least one embodiment of the present disclosure (e.g., the gas turbine 100 described above) A compressor (for example, compressor 2 mentioned above) and A gas turbine combustor (for example, the combustor 4 described above) is configured to receive compressed air and fuel from the compressor and burn the fuel to generate combustion gases, A turbine (for example, the turbine 6 described above) driven by the combustion gas generated in the gas turbine combustor, Equipped with, The aforementioned gas turbine combustor is the gas turbine combustor described in (5) above.

[0060] According to the burner assembly described in (6) above, since it is equipped with the gas turbine combustor described in (5) above, the risk of flashback can be reduced.

[0061] (7) In some embodiments, in the gas turbine described in (6) above, The mixing channel includes an air channel (for example, the air channel 47 described above) on the outer circumference side of the fuel nozzle. During rated operation of the gas turbine, if the density of the fuel at the outlet of the fuel nozzle is ρf, the flow velocity of the fuel at the outlet of the fuel nozzle is Vf, the density of the air in the air passage at the position of the outlet of the fuel nozzle in the axial direction of the fuel nozzle is ρa, and the flow velocity of the air in the air passage at the position of the outlet of the fuel nozzle in the axial direction of the fuel nozzle is Va, ρf × (Vf) 2 <ρa×(Va) 2 It satisfies the condition.

[0062] According to the gas turbine described in (7) above, the momentum of the air at the outlet position in the axial direction of the fuel nozzle (ρa × (Va) 2) is the momentum of the fuel at the outlet of the fuel nozzle (ρf × (Vf) 2 Because it is larger than the airflow spurt remaining at the fuel nozzle outlet, the airflow in the air passage straightens the spurt, preventing the spurt remaining at the fuel nozzle outlet from reaching the flow path wall of the mixing passage. Therefore, the risk of flashback can be effectively reduced. [Explanation of Symbols]

[0063] 2 Compressor 4 Combustor 6 Turbines 8 rotors 10 Compressor compartment 12,51 Entrance 14 Entrance Information Wing 16,24 Stationary Wing 18,26 Moving blade 20 Casing 21 Bottom 22 Turbine casing 23 gaps 25 Combustion chamber 28 Exhaust chamber 30 Exhaust chamber 32 burner assemblies 34 Cylindrical member 35,39 Support part 36,47 Airflow channels 49,60 exit 40 Cabin 42 burners 43 Fuel nozzle 44 Outer surface 45,48 Fuel passage 46 Mixing channel 55,58 Flow channel wall 62 Orifice 63 Wall surface 74,78 Channel width constant part 76 Aperture section 100 Gas Turbine

Claims

1. A burner assembly comprising multiple burners for mixing fuel and air, Each of the aforementioned multiple burners is The mixing channel to which the air is supplied, A fuel nozzle is provided inside the mixing channel, extending along the central axis of the mixing channel and configured to inject the fuel, Includes, The fuel nozzle includes an orifice upstream of the outlet of the fuel nozzle. A burner assembly satisfying L / D > 5, where L is the distance between the outlet and the orifice in the fuel nozzle, and D is the orifice diameter of the orifice.

2. A burner assembly according to claim 1, satisfying L / D ≥ 7.

5.

3. The aforementioned mixing channel includes an air channel on the outer circumference side of the fuel nozzle. The burner assembly according to claim 1, wherein Af is the flow path area at the outlet of the fuel nozzle, and Aa is the flow path area of ​​the air passage at the outlet position in the axial direction of the fuel nozzle, and Af / Aa ≥ 0.

1.

4. A burner assembly according to any one of claims 1 to 3, A combustion cylinder forming a space for flame formation downstream of the burner assembly, A gas turbine combustor equipped with a gas turbine combustor.

5. Compressor and, A gas turbine combustor is configured to receive compressed air and fuel from the aforementioned compressor, and to burn the fuel to generate combustion gases, A turbine driven by the combustion gas generated in the gas turbine combustor, Equipped with, The gas turbine is a gas turbine combustor as described in claim 4.

6. The aforementioned mixing channel includes an air channel on the outer circumference side of the fuel nozzle. During rated operation of the gas turbine, if the density of the fuel at the outlet of the fuel nozzle is ρf, the flow velocity of the fuel at the outlet of the fuel nozzle is Vf, the density of the air in the air passage at the position of the outlet of the fuel nozzle in the axial direction of the fuel nozzle is ρa, and the flow velocity of the air in the air passage at the position of the outlet of the fuel nozzle in the axial direction of the fuel nozzle is Va, then ρf × (Vf) ２ <ρa × (Va) ２ A gas turbine according to claim 5, satisfying the requirements.

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