Burner, burner provided with burner, and gas turbine provided with burner

Abstract

The burner is provided with: a mixing tube in which a mixing space is formed; and a fuel nozzle disposed in the mixing space. The fuel nozzle is provided with: a nozzle body extending in the direction in which the mixing space extends; and a protruding part protruding from the outer peripheral surface of the nozzle body and away from the inner peripheral surface of the mixing tube. The nozzle body is provided with a fuel ejection port capable of ejecting the fuel into the mixing space. The protruding part gradually extends to the downstream side in the extending direction as the protruding part extends in the circumferential direction with respect to the nozzle main body, and the whole protruding part is formed in a spiral shape around the nozzle main body.

Description

Technical Field

[0001] The present invention relates to a burner, a combustor equipped with the burner, and a gas turbine equipped with the combustor.

[0002] This application claims priority based on Japanese Patent Application No. 2022-168852 filed in Japan on October 21, 2022, and the contents are incorporated herein by reference. Background Art

[0003] The gas turbine includes a compressor that compresses air, a combustor that burns fuel using the air compressed by the compressor to generate combustion gas, and a turbine that is driven by the combustion gas from the combustor.

[0004] The following patent document 1 discloses a burner, which comprises: a cylinder, which forms a combustion space for burning fuel containing hydrogen; a plurality of fuel nozzles; and a plate. In the cylinder, openings are formed at the ends of the downstream side and the upstream side in the extension direction of the cylinder. The plate is configured to close the opening at the end of the downstream side of the cylinder. A plurality of air holes are formed on the plate and penetrate the plate along the extension direction. The front ends of the fuel nozzles are inserted into the plurality of air holes. A revolving groove is formed on the inner circumferential surface of the plurality of air holes, which gradually extends toward the downstream side as it extends along the circumferential direction of the hole.

[0005] The gas flow velocity near the inner circumference of the air hole is slower than the gas flow velocity near the central axis of the air hole. Therefore, if the fuel concentration near the inner circumference of the air hole is high, it is easy to cause backfire in which the flame in the combustion space is also transferred to the air hole.

[0006] In the burner described in Patent Document 1, during the process of compressed air passing through the air hole from the compressor, the compressed air becomes a swirling flow through the swirling groove formed on the inner circumferential surface of the air hole. Fuel containing hydrogen is ejected from the fuel nozzle into the swirling flow. Since the density of the compressed air is higher than that of the fuel, it is pressed to the inner circumferential surface side of the air hole by centrifugal force, and on the other hand, the fuel gathers near the central axis of the air hole. That is, in this burner, the separation of fuel and air is achieved by the swirling flow. Therefore, in this burner, the aforementioned backfire can be suppressed.

[0007] Previous technical literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Publication No. 2015-014400 Summary of the invention

[0010] Technical issues to be solved by the invention

[0011] In the burner described in Patent Document 1, although backfire can be suppressed, a region with a high fuel-air ratio (fuel amount / air amount) is generated near the central axis of the air hole, and the amount of NOx generated increases.

[0012] Therefore, an object of the present invention is to provide a technology capable of suppressing the generation of NOx while suppressing backfire.

[0013] Means for solving technical problems

[0014] A burner according to one aspect of the present invention for achieving the above-mentioned object includes:

[0015] A mixing tube extending along a predetermined extension direction to form a mixing space for mixing air and fuel; and a fuel nozzle extending along the extension direction and at least partially arranged in the mixing space. The mixing tube has an air inlet for allowing the air to flow into the mixing space; and a jet outlet for jetting out a premixed gas mixed with the air and fuel from the mixing space. The jet outlet is formed at the downstream end of the mixing tube, one of the upstream side as one side and the downstream side as the other side in the extension direction. The fuel nozzle has a nozzle body extending along the extension direction; and a protrusion protruding from the outer peripheral surface of the nozzle body and away from the inner peripheral surface of the mixing tube. The nozzle body has a fuel jet outlet, and the fuel jet outlet can jet out the fuel into the mixing space from a position closer to the downstream side than the air inlet and closer to the upstream side than the jet outlet. The protrusion gradually extends toward the downstream side as it extends along the circumferential direction based on the nozzle body, and the entire protrusion is formed in a spiral shape around the nozzle body.

[0016] In this mode, in the area around the nozzle body in the imaginary plane perpendicular to the extension direction, a swirling flow of air flowing into the mixing space can be formed by the protrusion, which is the area where the protrusion exists in the extension direction and the area on the downstream side of the protrusion. In addition, the protrusion is far away from the inner peripheral surface of the mixing tube, so if the air crosses the outer peripheral surface of the protrusion, a small turbulence of the air is generated on the downstream side of the air crossing direction in the outer peripheral surface. In addition, a small turbulence of the air is also generated on the downstream side of the downstream end of the protrusion. As described above, in this mode, a swirling flow as a main air flow is formed in the area around the downstream side body, which is the area on the downstream side of the protrusion and is the area around the nozzle body in the imaginary plane perpendicular to the extension direction, and a small turbulence is formed. Therefore, in this mode, in the area around the downstream side body, the mixing of air and the fuel ejected from the nozzle body is promoted. Therefore, in this mode, in the mixing space, the generation of a high fuel-air ratio (fuel amount / air amount) can be suppressed, thereby suppressing the generation of NOx.

[0017] Furthermore, in this embodiment, since the protrusion is away from the inner circumference of the mixing tube, the influence of the swirling flow in the region near the inner circumference of the mixing tube in the region downstream of the protrusion and in the imaginary plane perpendicular to the extension direction can be suppressed. Therefore, in this embodiment, the mixing of air and fuel in the region near the inner circumference can be suppressed. Therefore, in this embodiment, the fuel-air ratio (fuel amount / air amount) in the region near the inner circumference where the gas flow rate is slow can be suppressed to be low, and the backfire caused by the flame being transmitted to the mixing space can be suppressed.

[0018] A burner according to one aspect of the present invention for achieving the above-mentioned object includes:

[0019] The burner as one embodiment; and the cylinder, which can burn the premixed gas ejected from the ejection port of the burner.

[0020] A cluster burner burner according to one embodiment of the present invention for achieving the above-mentioned object comprises a plurality of the burners as the embodiment, and a tube capable of burning the premixed gas ejected from the respective ejection ports of the plurality of burners. The extension direction of each of the plurality of burners is the same direction as each other. The positions of the ejection ports of each of the plurality of burners in the extension direction are aligned with each other.

[0021] A gas turbine according to one aspect of the present invention for achieving the above-mentioned object includes:

[0022] The combustor as one embodiment; a compressor that compresses air to generate compressed air and can supply the compressed air to the burner; and a turbine that can be driven by combustion gas generated by combustion of the premixed gas in the cylinder of the combustor.

[0023] A gas turbine according to another aspect of the present invention for achieving the above-mentioned object includes:

[0024] A cluster burner burner as one of the above methods; a compressor that compresses air to generate compressed air and can supply the compressed air to the plurality of burners; and a turbine that can be driven by combustion gas generated by combustion of the premixed gas in the cylinder of the cluster burner burner.

[0025] Effects of the Invention

[0026] In one aspect of the present invention, it is possible to suppress the generation of NOx while suppressing backfire. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram showing the structure of a gas turbine in one embodiment according to the present invention.

[0028] Figure 2 It is a cross-sectional view of the periphery of a combustor of a gas turbine in one embodiment according to the present invention.

[0029] Figure 3 This is a cutaway perspective view of a burner in one embodiment of the present invention.

[0030] Figure 4 It is a cross-sectional view of a burner in one embodiment according to the present invention.

[0031] Figure 5 This is a cutaway perspective view of a main part of a burner in one embodiment of the present invention.

[0032] Figure 6 It is an explanatory diagram showing the fuel-air ratio distribution in the mixing space in the reference example.

[0033] Figure 7 It is an explanatory diagram showing the fuel-air ratio distribution in the mixing space in one embodiment according to the present invention.

[0034] Figure 8 This is a cutaway perspective view of a main part of a burner in a first modified example according to the present invention.

[0035] Fig. 9 It is a cutaway perspective view of a main part of a burner in a second modified example according to the present invention.

[0036] Fig.10 It is a cross-sectional view of a burner in a third modified example according to the present invention. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of a burner, a combustor including the burner, and a gas turbine including the burner according to the present invention, and modified examples of the burner will be described in detail with reference to the drawings.

[0038] like Figure 1 As shown, the gas turbine in this embodiment includes: a compressor 10 capable of compressing air A to generate compressed air Acom; a plurality of combustors 20 capable of burning fuel F in the compressed air Acom to generate combustion gas G; and a turbine 15 capable of being driven by the combustion gas G.

[0039] The compressor 10 includes a compressor rotor 11 that rotates around a rotor axis Ar, and a compressor housing 12 that covers the compressor rotor 11. The turbine 15 includes a turbine rotor 16 that rotates around a rotor axis Ar, and a turbine housing 17 that covers the turbine rotor 16. In addition, hereinafter, the direction in which the rotor axis Ar extends is referred to as a rotor axis direction Da, one of the two sides of the rotor axis direction Da is referred to as an axis upstream side Dau, and the other side is referred to as an axis downstream side Dad.

[0040] The compressor 10 is arranged on the axial upstream side Dau relative to the turbine 15. The compressor rotor 11 and the turbine rotor 16 are located on the same rotor axis Ar and are connected to each other to form a gas turbine rotor 1. To the gas turbine rotor 1, for example, a rotor of a generator GEN is connected. The gas turbine also includes an intermediate casing 4 arranged between the compressor casing 12 and the turbine casing 17. Compressed air Acom from the compressor 10 flows into the intermediate casing 4. A plurality of burners 20 are arranged in a circumferential direction relative to the rotor axis Ar and are mounted on the intermediate casing 4. The compressor casing 12, the intermediate casing 4 and the turbine casing 17 are connected to each other to form a gas turbine casing 2.

[0041] A fuel line is connected to the combustor 20. The combustor 20 can generate a combustion gas G by burning the fuel F from the fuel line in the compressed air Acom from the compressor 10.

[0042] like Figure 2 As shown, the combustor 20 includes: a cylinder 21 forming a combustion space Sc in which fuel F can be burned; a plurality of burners 30 ejecting a premixed gas Gpm mixed with fuel F and compressed air Acom into the combustion space Sc; and a burner support frame 25 supporting the plurality of burners 30 .

[0043] The tube 21 is sometimes called a tail tube or a combustion tube. The tube 21 is cylindrical with the burner axis Ac as the center. Here, the direction in which the burner axis Ac extends is referred to as the extension direction De. And, one of the two sides of the extension direction De is referred to as the upstream side Deu, and the other side is referred to as the downstream side Ded. The ends of the upstream side Deu and the downstream side Ded of the tube 21 are open. Figure 1 As shown, the opening on the downstream side Ded of the cylinder 21 is formed so that the combustion gas G generated by the combustion of the fuel F can be delivered to the turbine housing 17. On the other hand, the opening 22 on the upstream side Deu of the cylinder 21 is closed by the burner support frame 25. A plurality of burners 30 are arranged in a radial direction and a circumferential direction relative to the burner axis Ac, and are supported by the burner support frame 25. Therefore, the burner 20 of the present embodiment is a cluster burner burner.

[0044] like Figure 3 and Figure 4 As shown, the plurality of burners 30 each have a mixing tube 31 , a fuel nozzle 34 and a plurality of nozzle holders 39 .

[0045] The mixing tube 31 of each of the plurality of burners 30 extends along the extension direction De in which the burner axis Ac extends, and forms a cylindrical mixing space Sm in which the compressed air Acom and the fuel F are mixed. The mixing tube 31 has an air inlet 31i for allowing the compressed air Acom to flow into the mixing space Sm, a jet port 31o for jetting out the premixed gas Gpm mixed with the compressed air Acom and the fuel F from the mixing space Sm, and a fuel flow path 31p. The air inlet 31i is formed at the end of the upstream side Deu of the mixing tube 31, and the jet port 31o is formed at the end of the downstream side Ded of the mixing tube 31. The mixing space Sm has a reduced area portion 33 whose cross-sectional area perpendicular to the extension direction De gradually decreases toward the downstream side Ded. The reduced area portion 33 is formed between the air inlet 31i and the jet port 31o in the extension direction De. The cross-sectional area of ​​the mixing space Sm at the upstream side Deu of the reduced area portion 33 is larger than the cross-sectional area of ​​the mixing space Sm at the downstream side Ded of the reduced area portion 33. The fuel flow path 31p penetrates from the outer peripheral surface of the mixing tube 31 to the inner peripheral surface 32, and allows the fuel F to flow.

[0046] The fuel nozzle 34 is disposed in the mixing space Sm and includes a nozzle body 35 extending in the extending direction De and a plurality of protrusions 37 protruding from an outer peripheral surface 36 of the nozzle body 35 and away from the inner peripheral surface 32 of the mixing tube 31 .

[0047] The nozzle body 35 is arranged on the space center axis Ab which is the center axis of the mixing space Sm. In addition, the space center axis Ab extends along the extension direction De. The nozzle body 35 has: a cylindrical large diameter portion 35a centered on the space center axis Ab; a conical reduced diameter portion 35b centered on the space center axis Ab; and a cylindrical small diameter portion 35c centered on the space center axis Ab. The large diameter portion 35a is formed in a portion on the upstream side Deu of the nozzle body 35. The reduced diameter portion 35b is connected to the end of the downstream side Ded of the large diameter portion 35a. The outer diameter of the reduced diameter portion 35b gradually decreases as it moves toward the downstream side Ded. The small diameter portion 35c is connected to the end of the downstream side Ded of the reduced diameter portion 35b and extends to the end of the downstream side Ded of the nozzle body 35. The outer diameter of the small diameter portion 35c is smaller than the outer diameter of the large diameter portion 35a. The nozzle body 35 further includes a fuel flow path 35p and a fuel ejection port 35o formed at an end portion on the downstream side Ded of the nozzle body 35. The fuel flow path 35p extends along the extension direction De inside the large diameter portion 35a, the reduced diameter portion 35b, and the small diameter portion 35c. The fuel flow path 35p allows the fuel F to flow. The fuel ejection port 35o can eject the fuel F flowing through the fuel flow path 35p toward the downstream side Ded into the mixing space Sm.

[0048] The protrusion 37 gradually extends toward the downstream side Ded as it extends in the circumferential direction based on the nozzle body 35, and the entire protrusion 37 is formed in a spiral shape around the nozzle body 35. In other words, the entire protrusion 37 is formed in a spiral shape with the spatial central axis Ab as the center. Figure 4 In order to facilitate understanding of the protrusion amount of the protrusion 37, the protrusion 37 is drawn in a linear extension along the extension direction De for the convenience of explanation. The protrusion 37 has an upstream end 37u which is closest to the upstream side Deu in the extension direction De and a downstream end 37d which is closest to the downstream side Ded in the extension direction De. The upstream end 37u of each of the plurality of protrusions 37 is located at the boundary between the large diameter portion 35a and the reduced diameter portion 35b in the extension direction De. The downstream end 37d of each of the plurality of protrusions 37 is located at the end of the downstream side Ded of the nozzle body 35 in the extension direction De. The distance from the spatial center axis Ab to the outer peripheral surface 38 of the protrusion 37 is the same as the outer diameter of the large diameter portion 35a at any position in the extension direction De. Therefore, the protrusion amount, which is the distance from the outer peripheral surface 36 of the nozzle body 35 to the outer peripheral surface 38 of the protrusion 37, gradually increases as it moves toward the downstream side Ded. Then, the protrusion amount reaches the maximum protrusion amount pmax at the portion of the protrusion 37 formed in the small diameter portion 35 c of the nozzle body 35 .

[0049] The reduced area portion 33 of the aforementioned mixing space Sm is formed in the region where the protrusion 37 exists in the extension direction De. A portion of the inner peripheral surface 32 of the mixing tube 31 and a portion that is closer to the downstream side Ded than the reduced area portion 33 is radially opposed to the outer peripheral surface 36 of the small diameter portion 35c of the nozzle body 35. Of the distances from a portion of the outer peripheral surface 36 of the nozzle body 35 and a portion where the protrusion 37 exists in the extension direction De to the inner peripheral surface 32 of the mixing tube 31, the distance from the outer peripheral surface 36 of the small diameter portion 35c of the nozzle body 35 to a portion of the inner peripheral surface 32 of the mixing tube 31 and a portion that is closer to the downstream side Ded than the reduced area portion 33 reaches the minimum distance dmin. The maximum protrusion amount pmax of the aforementioned protrusion 37 is less than 20% of the minimum distance dmin.

[0050] The plurality of nozzle holders 39 connect the outer peripheral surface 36 of the nozzle body 35 and the inner peripheral surface 32 of the mixing tube 31 at a position on the downstream side Ded of the region where the protrusion 37 is located in the extension direction De. One nozzle holder 39 among the plurality of nozzle holders 39 has a fuel flow path 39p through which the fuel F can flow. The fuel flow path 39p communicates with the fuel flow path 31p of the mixing tube 31 and the fuel flow path 35p of the nozzle body 35.

[0051] like Figure 2 As shown, the upstream side Deu portion of the cylinder 21 is connected to the end portion on the downstream side Ded of the burner support frame 25, and the opening 22 on the upstream side Deu of the cylinder 21 is closed as described above. The upstream side Deu end portion of the burner support frame 25 is connected to the intermediate casing 4. In the extension direction De, the position of the upstream side Deu end portion of the mixing tube 31 of each of the plurality of burners 30 is substantially consistent with the position of the upstream side Deu end portion of the burner support frame 25. The burner support frame 25 has: a fuel flow path 26 through which the fuel F can flow; and an air flow path 27 through which the compressed air Acom can flow. The fuel flow path 26 has: a main flow path 26m that receives the fuel F from the outside and through which the fuel F can flow; and a plurality of branch flow paths 26b that branch from the main flow path 26m. The plurality of branch flow paths 26b are respectively connected to the fuel flow path 31p of the mixing tube 31 of any one of the plurality of burner combustion furnaces 30. The air flow path 27 is formed so as to allow the compressed air Acom from the compressor 10 to flow into the mixing space Sm of each of the plurality of burners 30 .

[0052] like Figure 1 As shown in FIG. 1 , the compressor 10 compresses the air A to generate compressed air Acom. The compressed air Acom is discharged from the compressor 10 into the intermediate housing 4. Figure 2 As shown, the compressed air Acom discharged into the intermediate casing 4 flows into the mixing space Sm of each of the plurality of burners 30 through the air flow path 27 of the burner support frame 25. Figure 2 and Figure 4 As shown, the fuel F flows into the fuel flow path 35p of the nozzle body 35 of each of the plurality of burners 30 through the fuel flow path 26p of the burner support frame 25, the fuel flow path 31p of the mixing tube 31 of each of the plurality of burners 30, and the fuel flow path 39p of the nozzle holder 39 of each of the plurality of burners 30. The fuel F that flows into the fuel flow path 35p of the nozzle body 35 is ejected from the fuel ejection port 35o formed at the end of the downstream side Ded of the nozzle body 35 to the mixing space Sm. The fuel F ejected into the mixing space Sm is mixed with the compressed air Acom in the mixing space Sm and ejected from the ejection port 31o of the mixing tube 31 into the combustion space Sc of the cylinder 21 as the premixed gas Gpm. The premixed gas Gpm is burned in the combustion space Sc to become the combustion gas G. The combustion gas G is delivered from the burner 20 to the inside of the turbine casing 17. The combustion gas G rotates the turbine rotor 16 while flowing toward the axial downstream side Dad in the turbine casing 17. The rotation of the turbine rotor 16 causes the rotor of the generator GEN connected to the gas turbine rotor 1 to rotate.

[0053] As a result, the generator GEN generates electric power.

[0054] In this embodiment, if Figure 5 As shown, in the area around the nozzle body 35 in the imaginary plane perpendicular to the extension direction De, the protrusion 37 can form a swirling flow Fs of the compressed air Acom flowing into the mixing space Sm. This area is the area where the protrusion 37 is present in the extension direction De and the area on the downstream side Ded of the protrusion 37. In addition, the protrusion 37 is formed in a spiral shape with the space center axis Ab as the center, so the swirling flow Fs is a flow that swirls around the space center axis Ab as the center. In addition, the protrusion 37 is away from the inner peripheral surface 32 of the mixing tube 31, so if the compressed air Acom crosses the outer peripheral surface 38 of the protrusion 37, a small turbulent flow Ft1 of the air is generated on the downstream side Ded of the air crossing direction in the outer peripheral surface 38. In addition, a small turbulent flow Ft2 of the air is also generated on the downstream side Ded of the downstream end 37d of the protrusion 37.

[0055] Assuming that the spiral protrusion 37 is not provided around the nozzle body 35, the mixing of the compressed air Acom and the fuel F ejected from the nozzle body 35 is not promoted, and the area around the nozzle body 35 in the virtual plane perpendicular to the extension direction De, that is, the downstream side body surrounding area Ra ( Figure 4 and Figure 7 As shown in Figure 6 As shown in Figure 1, a region with a high fuel-air ratio (fuel amount / air amount) is formed. Figure 6 and later Figure 7 In the figure, the color becomes darker as the fuel-air ratio becomes higher.

[0056] On the other hand, in the present embodiment, as described above, the swirling flow Fs as the main air flow is formed in the downstream side main body surrounding area Ra, which is the area closer to the downstream side Ded than the protrusion 37 and is the area around the vicinity of the nozzle body 35 in the imaginary plane perpendicular to the extension direction De, and the small turbulent flows Ft1 and Ft2 are formed. Therefore, in the present embodiment, in the downstream side main body surrounding area Ra, the mixing of the compressed air Acom and the fuel F ejected from the nozzle body 35 is promoted. In particular, in the present embodiment, the protrusion 37 is formed in the area including the end of the downstream side Ded of the nozzle body 35. Therefore, in the present embodiment, compared with the case where the downstream end 37d of the protrusion 37 is formed closer to the upstream side Deu than the end of the downstream side Ded of the nozzle body 35, the swirling flow Fs and the turbulent flows Ft1 and Ft2 of the compressed air Acom formed by the protrusion 37 can be strongly applied to the fuel F ejected from the end of the downstream side Ded of the nozzle body 35. Thus, in this embodiment, the compressed air Acom and the fuel F can be effectively mixed in the downstream side main body surrounding area Ra. Figure 7 As shown, in the downstream side main body surrounding area Ra, the generation of a region with a high fuel-air ratio (fuel amount / air amount) can be suppressed, and thus the generation of NOx can be suppressed.

[0057] Furthermore, in the present embodiment, the protrusion 37 is away from the inner circumferential surface 32 of the mixing tube 31. In particular, as described above, the maximum protrusion amount pmax of the protrusion 37 from the outer circumferential surface 36 of the nozzle body 35 is less than 20% of the minimum distance dmin from the outer circumferential surface 36 of the small diameter portion 35c of the nozzle body 35 to the inner circumferential surface 32 of the mixing tube 31. Therefore, in the present embodiment, in the aforementioned downstream side body surrounding area Ra within the imaginary plane perpendicular to the extension direction De, the circumferential component flow velocity Vc ( Figure 7 ) is the area of ​​the region with a flow velocity of at least the first flow velocity. On the other hand, in the present embodiment, the region Rb ( Figure 4 and Figure 7 As shown in FIG. 1 , the area of ​​the region where the circumferential component velocity Vc of the swirling flow Fs is lower than the second velocity slower than the first velocity can be increased. Therefore, in the present embodiment, in the region Rb near the inner circumferential surface where the gas velocity is slow, the mixing of the fuel F and the compressed air Acom flowing along the inner circumferential surface 32 of the mixing tube 31 can be suppressed, and the flame can be prevented from being transmitted to the backfire in the mixing space Sm.

[0058] In the present embodiment, an air flow having a directional component toward the center of the mixing tube 31 is generated in the area along the inner circumferential surface 32 of the mixing tube 31 in the reduced area portion 33. Due to this air flow, in the present embodiment, the swirl flow Fs formed by the protrusion 37 is pushed toward the center side of the mixing tube 31. Therefore, in the present embodiment, in the aforementioned downstream side main body surrounding area Ra within the imaginary plane perpendicular to the extension direction De, the area where the circumferential component flow velocity Vc of the swirl flow Fs is above the first flow velocity is close to the center side of the mixing tube 31. As a result, in the present embodiment, the area of ​​the area where the circumferential component flow velocity Vc of the swirl flow Fs is above the first flow velocity can be reduced. Moreover, the cross-sectional area of ​​the mixing space Sm on the downstream side Ded more than the reduced area portion 33 is smaller than the cross-sectional area of ​​the mixing space Sm on the upstream side Deu more than the reduced area portion 33. Therefore, in the present embodiment, the gas flow velocity in the mixing space Sm on the downstream side Ded more than the reduced area portion 33 in the extension direction De is faster than in the case where the reduced area portion 33 does not exist. Therefore, in the present embodiment, backfire in which the flame is transferred to the mixing space Sm can be effectively suppressed.

[0059] The air flowing into the mixing space Sm generates pressure loss due to the nozzle holder 39. Furthermore, if a part of the mixing space Sm is occupied by the nozzle holder 39, the area in the mixing space Sm for the compressed air Acom to flow becomes narrower, the flow velocity of the compressed air Acom increases, and the pressure loss of the air due to the nozzle holder 39 increases. Therefore, in the present embodiment, in order to suppress the pressure loss of the compressed air Acom caused by the nozzle holder 39, the nozzle holder 39 is arranged in the area with a larger cross-sectional area of ​​the mixing space Sm on the upstream side Deu than the reduced area portion 33.

[0060] The protrusion 37 of this embodiment does not exist radially outside the large diameter portion 35a relative to the space center axis Ab. Therefore, in this embodiment, the pressure loss of the compressed air Acom caused by the collision of the compressed air Acom flowing along the large diameter portion 35a of the nozzle body 35 with the upstream end 37u of the protrusion 37 can be suppressed.

[0061] "Variation"

[0062] In the above embodiment, the maximum protrusion amount pmax of the protrusion 37 is less than 20% of the minimum distance dmin from the outer peripheral surface 36 of the small diameter portion 35c of the nozzle body 35 to the inner peripheral surface 32 of the mixing tube 31. However, according to the flow velocity of the compressed air Acom flowing in the mixing space Sm in the extension direction De, the maximum protrusion amount pmax of the protrusion 37 may be greater than 20% of the minimum distance dmin from the outer peripheral surface 36 of the small diameter portion 35c of the nozzle body 35 to the inner peripheral surface 32 of the mixing tube 31 and less than half of the minimum distance dmin.

[0063] In the above embodiment, the protrusion 37 is formed in a predetermined range from the end of the downstream side Ded of the nozzle body 35 toward the upstream side Deu. Figure 8 As shown, the protrusion 37a can be formed in a predetermined range from a position closer to the upstream side Deu than the end of the downstream side Ded of the nozzle body 35 toward the upstream side Deu.

[0064] In the above embodiment, the protrusion 37 is not formed in the region including the end portion on the upstream side Deu of the nozzle body 35. However, the protrusion may be formed in the region including the end portion on the upstream side Deu of the nozzle body 35.

[0065] In the above embodiment, one protrusion 37 is formed along a spiral imaginary line centered on the space center axis Ab. Fig. 9 As shown, a plurality of protrusions 37b and 37c may be formed along a single imaginary line in a spiral shape with the space central axis Ab as the center.

[0066] In the above embodiment, the nozzle body 35 is entirely contained in the mixing space Sm. Fig.10 As shown, the end of the upstream side Deu of the nozzle body 35 may protrude from the end of the upstream side Deu of the mixing space Sm to the upstream side Deu. In this case, as described above, the protrusion 37 may also be formed in the region including the end of the upstream side Deu of the nozzle body 35. That is, a part of the protrusion 37 may be formed outside the mixing space Sm.

[0067] The burner 20 in the above embodiment is a cluster burner burner in which a plurality of burners 30 are arranged in the circumferential direction and radial direction relative to the burner axis Ac. However, the burner structure of the present invention can also be applied to a premixing burner in a conventional burner in which a plurality of premixing burners are not arranged in the radial direction relative to the burner axis Ac.

[0068] Furthermore, the present invention is not limited to the above-described embodiment and modified examples, and various additions, changes, substitutions, partial deletions, etc. are possible without departing from the conceptual idea and purpose of the present invention derived from the contents specified in the claims and their equivalents.

[0069] "P.S."

[0070] The burner in the above embodiment is explained as follows, for example.

[0071] (1) The burner in the first embodiment has:

[0072] The mixing tube 31 extends along a predetermined extension direction De to form a mixing space Sm for mixing air Acom and fuel F, and a fuel nozzle 34 extends along the extension direction De and is at least partially disposed in the mixing space Sm. The mixing tube 31 includes an air inlet 31i for allowing the air Acom to flow into the mixing space Sm, and a jet outlet 31o for jetting a premixed gas Gpm mixed with the air Acom and fuel F from the mixing space Sm. The jet outlet 31o is formed at an end of the downstream side Ded of the mixing tube 31, one of the upstream side Deu as one side and the downstream side Ded as the other side in the extension direction De. The fuel nozzle 34 includes a nozzle body 35 extending along the extension direction De, and protrusions 37, 37a, 37b, 37c protruding from the outer peripheral surface 36 of the nozzle body 35 and away from the inner peripheral surface 32 of the mixing tube 31. The nozzle body 35 has a fuel ejection port 35o, and the fuel ejection port 35o can eject the fuel F into the mixing space Sm from a position closer to the downstream side Ded than the air inlet 31i and closer to the upstream side Deu than the ejection port 31o. The protrusions 37, 37a, 37b, 37c gradually extend toward the downstream side Ded as they extend along the circumferential direction with the nozzle body 35 as a reference, and the protrusions 37, 37a, 37b, 37c are formed in a spiral shape around the nozzle body 35 as a whole.

[0073] In this embodiment, in the area around the nozzle body 35 in the virtual plane perpendicular to the extension direction De, the swirling flow Fs of the air Acom flowing into the mixing space Sm can be formed by the protrusions 37, 37a, 37b, 37c. The area is the area where the protrusions 37, 37a, 37b, 37c exist in the extension direction De and the area on the downstream side Ded of the protrusions 37, 37a, 37b, 37c. In addition, since the protrusions 37, 37a, 37b, 37c are away from the inner peripheral surface 32 of the mixing tube 31, when the air Acom crosses the outer peripheral surface 38 of the protrusions 37, 37a, 37b, 37c, a small turbulent flow Ft1 of the air Acom is generated on the downstream side Ded of the air crossing direction in the outer peripheral surface 38. In addition, a small turbulent flow Ft1 of the air Acom is also generated on the downstream side Ded of the downstream end 37d of the protrusions 37, 37a, 37b, 37c. As described above, in the present embodiment, the swirling flow Fs as the main air flow is formed in the downstream side main body surrounding area Ra, which is a region closer to the downstream side Ded than the protrusions 37, 37a, 37b, 37c and is a region around the vicinity of the nozzle body 35 in the imaginary plane perpendicular to the extension direction De, and the small turbulent flows Ft1 and Ft2 are formed. Therefore, in the present embodiment, in the downstream side main body surrounding area Ra, the mixing of the air Acom and the fuel F ejected from the nozzle body 35 is promoted. Therefore, in the present embodiment, in the mixing space Sm, the generation of a region with a high fuel-air ratio (fuel amount / air amount) can be suppressed, thereby suppressing the generation of NOx.

[0074] Furthermore, in this embodiment, since the protrusions 37, 37a, 37b, 37c are away from the inner circumferential surface 32 of the mixing tube 31, the influence of the swirling flow Fs in the region Rb near the inner circumferential surface of the mixing tube 31 in the region on the downstream side Ded and in the imaginary plane perpendicular to the extension direction De can be suppressed. Therefore, in this embodiment, the mixing of the air Acom and the fuel F in the region Rb near the inner circumferential surface can be suppressed. Therefore, in this embodiment, the fuel-air ratio (fuel amount / air amount) in the region Rb near the inner circumferential surface where the gas flow rate is slow can be suppressed to be low, and the backfire of the flame being transmitted to the mixing space Sm can be suppressed.

[0075] (2) The burner in the second embodiment is the burner 30 in the first embodiment,

[0076] The maximum protrusion amount pmax of the protrusions 37, 37a, 37b, 37c from the outer peripheral surface 36, 38 of the nozzle body 35 is less than half of the minimum distance dmin from a part of the outer peripheral surface 36 of the nozzle body 35 and the part where the protrusions 37, 37a, 37b, 37c exist in the extension direction De to the inner peripheral surface 32 of the mixing tube 31.

[0077] In this embodiment, in the aforementioned downstream side main body surrounding area Ra within the imaginary plane perpendicular to the extension direction De, the area of ​​the region where the circumferential component flow velocity of the swirling flow Fs is greater than the first flow velocity can be reduced. On the other hand, in the aforementioned inner peripheral surface vicinity area Rb within the imaginary plane perpendicular to the extension direction De, the area of ​​the region where the circumferential component flow velocity of the swirling flow Fs is less than the second flow velocity slower than the first flow velocity can be increased. Therefore, in this embodiment, in the inner peripheral surface vicinity area Rb where the gas flow velocity is slow, the mixing of the fuel F and the air Acom flowing along the inner peripheral surface 32 of the mixing tube 31 can be suppressed, and the backfire in which the flame is transmitted to the mixing space Sm can be suppressed.

[0078] (3) The burner in the third embodiment is the burner 30 in the first embodiment or the second embodiment,

[0079] The maximum protrusion amount pmax of the protrusion 37, 37a, 37b, 37c from the outer peripheral surface 36, 38 of the nozzle body 35 is less than 20% of the minimum distance dmin from a part of the outer peripheral surface 36, 38 of the nozzle body 35 and the part where the protrusion 37, 37a, 37b, 37c exists in the extension direction De to the inner peripheral surface 32 of the mixing tube 31.

[0080] In this embodiment, in the aforementioned downstream side main body surrounding area Ra within the imaginary plane perpendicular to the extension direction De, the area of ​​the region where the circumferential component flow velocity of the swirling flow Fs is greater than the first flow velocity can be reduced. On the other hand, in the aforementioned inner peripheral surface vicinity area Rb within the imaginary plane perpendicular to the extension direction De, the area of ​​the region where the circumferential component flow velocity of the swirling flow Fs is less than the second flow velocity slower than the first flow velocity can be increased. Therefore, in this embodiment, in the inner peripheral surface vicinity area Rb where the gas flow velocity is slow, the mixing of the fuel F and the air Acom flowing along the inner peripheral surface 32 of the mixing tube 31 can be suppressed, and the backfire in which the flame is transmitted to the mixing space Sm can be suppressed.

[0081] (4) A burner in a fourth aspect is the burner 30 in any one of the first aspect to the third aspect,

[0082] The fuel ejection port 35o is formed at the downstream end Ded of the nozzle body 35. The protrusions 37 and 37c are formed on the outer peripheral surface 36 of the nozzle body 35 in a predetermined range from the downstream end Ded of the nozzle body 35 toward the upstream Deu.

[0083] In this embodiment, the protrusions 37 and 37c are formed in the region including the end portion of the downstream side Ded of the nozzle body 35. Therefore, in this embodiment, compared with the case where the downstream end 37d of the protrusions 37 and 37c is formed on the upstream side Deu relative to the end portion of the downstream side Ded of the nozzle body 35, the influence of the swirling flow Fs and turbulent flows Ft1 and Ft2 of the air Acom formed by the protrusions 37 and 37c can be strongly given to the fuel F ejected from the end portion of the downstream side Ded of the nozzle body 35. Therefore, in this embodiment, the air Acom and the fuel F can be effectively mixed in the aforementioned downstream side body surrounding area Ra.

[0084] (5) A burner in a fifth aspect is the burner 30 in any one of the first aspect to the fourth aspect,

[0085] The protrusions 37, 37a, 37b, 37c are formed only in the mixing space Sm.

[0086] (6) A burner according to a sixth aspect is the burner 30 according to the fifth aspect,

[0087] The mixing space Sm has a reduced area portion 33 whose cross-sectional area perpendicular to the extending direction De gradually decreases toward the downstream side Ded. The reduced area portion 33 is formed in a region where the protrusions 37, 37a, 37b, 37c exist in the extending direction De.

[0088] In this embodiment, an air flow having a directional component toward the center of the mixing tube 31 is generated in the region along the inner circumferential surface 32 of the mixing tube 31 in the reduced area portion 33. Due to this air flow, the swirl flow Fs formed by the protrusions 37, 37a, 37b, and 37c is pushed toward the center side of the mixing tube 31. Therefore, in this embodiment, in the aforementioned downstream side main body surrounding region Ra within the imaginary plane perpendicular to the extension direction De, the region where the circumferential component flow velocity Vc of the swirl flow Fs is above the first flow velocity is close to the center side of the mixing tube 31. As a result, in this embodiment, the area of ​​the region where the circumferential component flow velocity Vc is above the first flow velocity can be reduced. Moreover, the cross-sectional area of ​​the mixing space Sm on the downstream side Ded than the reduced area portion 33 is smaller than the cross-sectional area of ​​the mixing space Sm on the upstream side Deu than the reduced area portion 33. Therefore, in this embodiment, the gas flow velocity in the mixing space Sm on the downstream side Ded than the reduced area portion 33 in the extension direction De is faster than in the case where there is no reduced area portion 33. Therefore, in this embodiment, it is possible to effectively suppress backfire in which the flame is transferred to the mixing space Sm.

[0089] (7) A burner according to a seventh aspect is the burner 30 according to the sixth aspect,

[0090] A nozzle holder 39 is provided, and the nozzle holder 39 supports the fuel nozzle 34 in the mixing space Sm. The nozzle holder 39 is located closer to the upstream side Deu than the area where the reduced area portion 33 is formed in the extension direction De, and connects the outer peripheral surfaces 36 and 38 of the nozzle body 35 and the inner peripheral surface 32 of the mixing tube 31.

[0091] The air Acom flowing into the mixing space Sm generates a pressure loss due to the nozzle holder 39. Furthermore, if a part of the mixing space Sm is occupied by the nozzle holder 39, the area in the mixing space Sm where the air Acom flows becomes narrower, the flow velocity of the air Acom increases, and the pressure loss of the air Acom due to the nozzle holder 39 increases. Therefore, in this embodiment, in order to suppress the pressure loss of the air Acom caused by the nozzle holder 39, the nozzle holder 39 is arranged in the area with a larger cross-sectional area of ​​the mixing space Sm on the upstream side Deu than the reduced area portion 33.

[0092] (8) The burner according to the eighth aspect is the burner 30 according to any one of the first to seventh aspects,

[0093] The mixing space Sm is a cylindrical space. The nozzle body 35 is disposed on the spatial center axis Ab of the mixing space Sm.

[0094] (9) A burner according to a ninth aspect is the burner 30 according to the eighth aspect,

[0095] The nozzle body 35 includes: a cylindrical large diameter portion 35a, centered on the spatial central axis Ab; a conical reduced diameter portion 35b, centered on the spatial central axis Ab; and a cylindrical small diameter portion 35c, centered on the spatial central axis Ab. The reduced diameter portion 35b is connected to the end of the large diameter portion 35a on the downstream side Ded, and the outer diameter gradually decreases toward the downstream side Ded. The small diameter portion 35c is connected to the end of the reduced diameter portion 35b on the downstream side Ded. The upstream end 37u of the protrusion 37, 37a, 37b, 37c is located at the boundary between the large diameter portion 35a and the reduced diameter portion 35b in the extension direction De. The downstream end 37d of the protrusion 37, 37a, 37b, 37c is located at the end of the small diameter portion 35c on the downstream side Ded. The distance from the spatial central axis Ab to the outer peripheral surface 38 of the protrusion 37, 37a, 37b, 37c is equal to or less than the outer diameter of the large diameter portion 35a at any position in the extending direction De.

[0096] The protrusions 37, 37a, 37b, 37c of this embodiment do not exist radially outside the large diameter portion 35a relative to the space center axis Ab. Therefore, in this embodiment, it is possible to suppress the pressure loss of the air Acom caused by the air Acom flowing along the large diameter portion 35a of the nozzle body 35 colliding with the upstream end 37u of the protrusions 37, 37a, 37b, 37c.

[0097] The burner in the above embodiment is explained as follows, for example.

[0098] (10) A burner according to the tenth aspect comprises:

[0099] The burner 30 and the cylinder 21 in any one of the first to ninth aspects can burn the premixed gas Gpm ejected from the ejection port 31 o of the burner 30 .

[0100] The cluster burner burner in the above embodiment is explained as follows, for example.

[0101] (11) The cluster burner burner in the eleventh embodiment includes a plurality of burners 30 in any one of the first to ninth embodiments, and includes a tube 21 capable of burning the premixed gas Gpm ejected from the respective ejection ports 31o of the plurality of burners 30. The extension direction De of each of the plurality of burners 30 is the same direction as each other. The positions of the ejection ports 31o of each of the plurality of burners 30 in the extension direction De are aligned with each other.

[0102] The gas turbine in the above embodiment can be understood, for example, as follows.

[0103] (12) A gas turbine according to a twelfth aspect, comprising:

[0104] The burner in the tenth mode; the compressor 10, which compresses the air A to generate compressed air Acom and can supply the compressed air Acom to the burner 30; and the turbine 15, which can be driven by the combustion gas G generated by the combustion of the premixed gas Gpm in the cylinder 21 of the burner.

[0105] (13) A gas turbine according to the thirteenth aspect comprises:

[0106] The cluster burner burner in the eleventh method; a compressor 10, which compresses air A to generate compressed air Acom and can supply the compressed air Acom to the multiple burners 30; and a turbine 15, which can be driven by the combustion gas G generated by the combustion of the premixed gas Gpm in the cylinder of the cluster burner burner.

[0107] Industrial Applicability

[0108] In one aspect of the present invention, it is possible to suppress the generation of NOx while suppressing backfire.

[0109] Explanation of symbols

[0110] 1-gas turbine rotor, 2-gas turbine casing, 4-intermediate casing, 10-compressor, 11-compressor rotor, 12-compressor casing, 15-turbine, 16-turbine rotor, 17-turbine casing, 20-combustor, 21-tube, 22-upstream opening, 25-burner support frame, 26-fuel flow path, 26m-main flow path, 26b-branch flow path, 27-air flow path, 30-burner, 31-mixing tube, 31i-air inlet, 31o-spout, 31p-fuel flow path, 32-inner circumferential surface, 33-reduced area portion, 34-fuel nozzle, 35-nozzle body, 35a-large diameter portion, 35b-reduced diameter portion, 35c-small diameter portion, 35o-fuel spray port, 35p-fuel Material flow path, 36-outer peripheral surface, 37, 37a, 37b, 37c-protrusion, 37u-upstream end, 37d-downstream end, 38-outer peripheral surface, 39-nozzle bracket, 39p-fuel flow path, A-air, Acom-compressed air, F-fuel, G-combustion gas, Gpm: premixed gas, Ar-rotor axis, Ac-burner axis, Ab-space center axis, Da-rotor axis direction, Dau-upstream side of the axis, Dad-downstream side of the axis, De-extension direction, Deu-upstream side, Ded-downstream side, Sc-combustion space, Sm-mixing space, Ra-area around the downstream side main body, Rb-area near the inner peripheral surface, Fs-swirl flow, Ft1, Ft2-turbulent flow.

Claims

1. A burner comprising: a mixing tube extending along a predetermined extending direction to form a mixing space for mixing air and fuel; and a fuel nozzle extending along the extension direction and at least a portion of which is disposed in the mixing space, The mixing tube has an air inlet for allowing the air to flow into the mixing space, and a jet outlet for jetting out a premixed gas mixed with the air and the fuel from the mixing space. The ejection port is formed at an end portion of the mixing tube on the downstream side, one of the upstream side and the downstream side in the extending direction. The fuel nozzle comprises: a nozzle body extending along the extending direction; and a protrusion protruding from the outer peripheral surface of the nozzle body and away from the inner peripheral surface of the mixing tube. The nozzle body has a fuel ejection port, and the fuel ejection port is capable of ejecting the fuel into the mixing space from a position further downstream than the air inlet and further upstream than the ejection port. The protrusion gradually extends toward the downstream side as it extends in the circumferential direction based on the nozzle body, and the entire protrusion is formed in a spiral shape around the nozzle body.

2. The burner according to claim 1, wherein: The maximum protrusion amount of the protrusion from the outer peripheral surface of the nozzle body is less than half of the minimum distance from a portion of the outer peripheral surface of the nozzle body where the protrusion exists in the extending direction to the inner peripheral surface of the mixing tube.

3. The burner according to claim 1, wherein: The maximum protrusion amount of the protrusion from the outer peripheral surface of the nozzle body is less than 20% of the minimum distance from a portion of the outer peripheral surface of the nozzle body where the protrusion exists in the extending direction to the inner peripheral surface of the mixing tube.

4. The burner according to any one of claims 1 to 3, wherein: The fuel ejection port is formed at the downstream end of the nozzle body. The protrusion is formed on the outer peripheral surface of the nozzle body within a predetermined range from the downstream end of the nozzle body toward the upstream side.

5. The burner according to claim 4, wherein: The protrusion is formed only in the mixing space.

6. The burner according to claim 5, wherein: The mixing space has a reduced area portion whose cross-sectional area perpendicular to the extending direction gradually decreases toward the downstream side. The reduced area portion is formed in a region where the protruding portion exists in the extending direction.

7. The burner according to claim 6, comprising a nozzle holder which supports the fuel nozzle in the mixing space, The nozzle holder connects the outer peripheral surface of the nozzle body and the inner peripheral surface of the mixing pipe at a position on the upstream side of a region where the reduced area portion is formed in the extending direction.

8. The burner according to any one of claims 1 to 3, wherein: The mixing space is a cylindrical space. The nozzle body is arranged on the spatial center axis of the mixing space.

9. The burner according to claim 8, wherein: The nozzle body comprises: a cylindrical large diameter portion, centered on the central axis of the space; a conical reduced diameter portion, centered on the central axis of the space; and a cylindrical small diameter portion, centered on the central axis of the space. The reduced diameter portion is connected to the downstream end of the large diameter portion, and the outer diameter thereof gradually decreases toward the downstream side. The small diameter portion is connected to the downstream end of the reduced diameter portion, The upstream end of the protruding portion is located at the boundary between the large diameter portion and the reduced diameter portion in the extending direction. The downstream end of the protruding portion is located at the downstream end of the small diameter portion, The distance from the central axis of the space to the outer peripheral surface of the protruding portion is less than the outer diameter of the large diameter portion at any position in the extending direction.

10. A burner comprising: The burner according to any one of claims 1 to 3; and The cylinder is capable of burning the premixed gas ejected from the ejection port of the burner.

11. A cluster burner burner comprising a plurality of burners according to any one of claims 1 to 3, and comprising a cylinder capable of burning the premixed gas ejected from the respective ejection ports of the plurality of burners, The extension direction of each of the plurality of burners is the same direction as each other, Positions of the ejection ports of each of the plurality of burners in the extending direction are aligned with each other.

12. A gas turbine comprising: The burner according to claim 10; a compressor that compresses air to generate compressed air and is capable of supplying the compressed air to the burner; and The turbine can be driven by combustion gas generated by combustion of the premixed gas in the cylinder of the combustor.

13. A gas turbine comprising: The cluster burner burner according to claim 11; a compressor that compresses air to generate compressed air and is capable of supplying the compressed air to the plurality of burners; and The turbine can be driven by the combustion gas generated by the combustion of the premixed gas in the cylinder of the cluster burner burner.

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