Gas turbine combustion chamber nozzle structure and working method thereof

Abstract

The present invention relates to the field of gas turbine technology, and in particular to a gas turbine combustion chamber nozzle structure and a working method thereof. The gas turbine combustion chamber nozzle structure comprises: a first cylinder wall, a second cylinder wall, a third cylinder wall, a fourth cylinder wall and a fifth cylinder wall arranged coaxially; wherein the second cylinder wall and the third cylinder wall are spaced apart to form a hydrogen flow path; the third cylinder wall and the fourth cylinder wall are spaced apart to form a secondary natural gas flow path; the fourth cylinder wall and the fifth cylinder wall are spaced apart to form a secondary air flow path; a first step is provided at the end of the secondary natural gas flow path and the secondary air flow path; a second step is provided at the end of the hydrogen flow path; a natural gas high-speed jet hole and a second strip-shaped air supply hole are provided on the first step; and a hydrogen high-speed jet hole is provided on the second step. The gas turbine combustion chamber nozzle structure provided by the present invention can improve the flexibility of the natural gas / hydrogen mixed combustion of the gas turbine.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbines, and in particular to a gas turbine combustion chamber nozzle structure and a working method thereof. Background Art

[0002] Gas turbines used for ground power generation often use natural gas as fuel. Combustion releases large amounts of carbon dioxide, significantly increasing carbon emissions. Given current environmental protection policies and the need for energy conservation and emission reduction, finding a clean alternative to traditional hydrocarbon fuels is essential. Currently, some gas turbine power plants use a blend of natural gas and hydrogen to reduce carbon emissions. In the future, as burners gradually increase the proportion of hydrogen, the carbon reduction effect will be even more significant.

[0003] To ensure stable combustion and gas turbine safety, the natural gas / hydrogen mixture should be evenly mixed. Existing gas turbines that use natural gas mixed with hydrogen for combustion require a hydrogen mixing device, i.e., a natural gas / hydrogen mixing device, to be built outside the gas turbine body. The natural gas and hydrogen are evenly mixed before being introduced into the nozzle of the gas turbine combustion chamber. Moreover, once the hydrogen mixing ratio is determined, it cannot be changed during the operation of the gas turbine and cannot be adjusted in real time. The gas turbine can only continue to operate at the current hydrogen mixing ratio until it is shut down.

[0004] Therefore, the flexibility of existing gas turbine natural gas / hydrogen mixed combustion is low, which is not conducive to the normal operation of the gas turbine. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect of low flexibility of natural gas / hydrogen mixed combustion in existing gas turbines in the prior art, thereby providing a gas turbine combustion chamber nozzle structure and its working method that can improve the flexibility of natural gas / hydrogen mixed combustion.

[0006] In order to solve the above technical problems, the present invention provides a gas turbine combustion chamber nozzle structure, comprising:

[0007] A first cylinder wall, a second cylinder wall, a third cylinder wall, a fourth cylinder wall and a fifth cylinder wall are coaxially arranged;

[0008] The outer circumferential wall of the second cylinder wall and the inner circumferential wall of the third cylinder wall are spaced radially to form a hydrogen flow path; the outer circumferential wall of the third cylinder wall and the inner circumferential wall of the fourth cylinder wall are spaced radially to form a secondary natural gas flow path; and the outer circumferential wall of the fourth cylinder wall and the inner circumferential wall of the fifth cylinder wall are spaced radially to form a secondary air flow path.

[0009] a first step, provided at the ends of the secondary natural gas flow path and the secondary air flow path; a second step, provided at the end of the hydrogen flow path; a premixing zone formed by the first step, which is axially close to the downstream side, and the outer peripheral wall of the fourth cylinder wall, and the second step, which is axially close to the downstream side, and the outer peripheral wall of the second cylinder wall and the inner peripheral wall of the fifth cylinder wall;

[0010] A natural gas high-speed jet hole and a second strip-shaped air supply hole are provided on the first step. The natural gas high-speed jet hole is suitable for connecting the secondary natural gas flow path with the premixing zone, and the second strip-shaped air supply hole is suitable for connecting the secondary air flow path with the premixing zone; a hydrogen high-speed jet hole is provided on the second step. The hydrogen high-speed jet hole is suitable for connecting the hydrogen flow path with the premixing zone.

[0011] Optionally, the fifth cylinder wall includes a rectifying wall surface, the rectifying wall surface includes a first contraction section and a second contraction section, the first contraction section is located in a downstream area of the first step, and the second contraction section is located in a downstream area of the second step;

[0012] The radius of the first contraction section is r2, r2 satisfies r2<r1, wherein r1 is the radius of the first step; the radius of the second contraction section is r4, r4 satisfies r4<r3, wherein r3 is the radius of the second step, r3<r1.

[0013] Optionally, a natural gas mixing hole is further provided on the first step, and the natural gas mixing hole is located on a side of the natural gas high-speed jet hole radially away from the third cylinder wall; one end of the natural gas mixing hole is connected to the secondary natural gas flow path, and the other end is connected to the premixing zone;

[0014] A hydrogen mixing hole is also provided on the secondary step, and the hydrogen mixing hole is located on a side of the hydrogen high-speed jet hole radially away from the second cylinder wall; one end of the hydrogen mixing hole is connected to the hydrogen flow path, and the other end is connected to the premixing zone.

[0015] Optionally, the angle between the central axis of the natural gas mixing hole and / or the hydrogen mixing hole and the central axis of the gas turbine combustion chamber nozzle structure is α, and α satisfies 15°≤α≤60°.

[0016] Optionally, first air holes are opened on the second cylinder wall, and the distribution of the first air holes covers the premixing zone close to the downstream of the secondary step along the axial direction;

[0017] The fifth cylinder wall is provided with second air holes, and the distribution of the second air holes covers the premixing zone of the first step close to the downstream in the axial direction.

[0018] Optionally, the inner diameter of the first air hole and / or the second air hole is d, and d satisfies 0.2mm≤d≤1.0mm.

[0019] Optionally, the central axes of the natural gas high-speed jet hole and the hydrogen high-speed jet hole are both parallel to the central axis of the gas turbine combustion chamber nozzle structure;

[0020] The natural gas high-speed jet hole and the hydrogen high-speed jet hole are both contraction holes, and the radial cross-sectional areas of the natural gas high-speed jet hole and the hydrogen high-speed jet hole gradually decrease along the jet direction;

[0021] The contraction ratio of the natural gas high-speed jet hole and / or the hydrogen high-speed jet hole is γ, and γ satisfies γ<3.

[0022] Optionally, a primary air flow path is formed between the outer peripheral wall of the first tube wall and the inner peripheral wall of the second tube wall along the radial direction;

[0023] A swirler is provided at the outlet of the end of the primary air flow path, and the swirler is suitable for causing the gas to generate a swirling flow;

[0024] A flow stabilizing portion is provided at one end of the primary air flow path close to the cyclone in the axial direction. A first strip-shaped air supply hole is opened on the flow stabilizing portion. The first strip-shaped air supply hole is suitable for stabilizing the air flow.

[0025] Optionally, the inner peripheral wall of the first cylinder wall encloses a primary natural gas flow path;

[0026] A blocking portion is provided at the end of the first cylinder wall. A natural gas jet hole is opened on the blocking portion. The jet port of the natural gas jet hole is located between two adjacent blades of the cyclone.

[0027] The operating method of the gas turbine combustor nozzle structure provided by the present invention is applied to the gas turbine combustor nozzle structure as described above, and the operating method of the gas turbine combustor nozzle structure includes:

[0028] A natural gas supply source supplies diffusion natural gas to the primary natural gas flow path, causing the diffusion natural gas to be ejected through the natural gas jet holes to the blade passages of the swirler. Simultaneously, a compressor supplies diffusion air to the primary air flow path, causing the diffusion air to flow steadily through the first strip-shaped air supply holes and then be ejected to the blade passages of the swirler. The diffused air is rapidly mixed with the diffusion natural gas and then passed into the flame tube to be ignited by the igniter, forming a diffusion combustion flame, i.e., a service flame. A stable recirculation zone is formed under the action of the swirler, serving as a stable ignition source.

[0029] The compressor supplies premixed air to the secondary air flow path, and the natural gas supply source supplies premixed natural gas to the secondary natural gas flow path. This causes the premixed air to steadily flow through the second strip-shaped air supply holes, generating a recirculation zone, i.e., a step vortex, in the downstream area of the primary step. Simultaneously, the premixed natural gas is discharged from the natural gas mixing holes and the natural gas high-speed jet holes, rapidly mixed with the air in the step vortex, and flows downstream. When the premixed air and premixed natural gas flow to the secondary step, a step vortex is generated in the area immediately downstream of the secondary step.

[0030] Hydrogen is supplied to the hydrogen flow path from a hydrogen supply source, so that the hydrogen is transmitted from the hydrogen mixing hole and the hydrogen high-speed jet hole to the step vortex near the secondary step, and is quickly mixed with the premixed gas of natural gas and air to form a premixed gas of natural gas, hydrogen and air, and propagates downstream of the nozzle until it reaches the flame tube and is ignited by the on-duty flame.

[0031] The technical solution of the present invention has the following advantages:

[0032] 1. The gas turbine combustor nozzle structure provided by the present invention forms a first sudden expansion structure and a second sudden expansion structure by providing a first step and a second step, respectively. As a result, when gas flows through, a recirculation zone, i.e., a step vortex, is generated near the first step and the second step. The turbulence within the step vortex is relatively high. After natural gas and hydrogen are transmitted from the step, they are continuously mixed with air within the step vortex. Due to the high internal turbulence and gas recirculation, the three can be quickly and evenly mixed and propagated downstream to the flame tube for combustion. The provision of high-speed natural gas jet holes and high-speed hydrogen jet holes improves the penetration of natural gas and hydrogen. In addition, the high jet velocity attracts the surrounding gas to converge into the jet beam based on the Bernoulli effect, which is conducive to rapid and even mixing. The above-mentioned arrangement of the nozzle structure of the gas turbine combustion chamber of the present invention can achieve rapid and uniform mixing of natural gas, hydrogen and air without the need to construct a hydrogen mixing device outside the gas turbine body. Moreover, the hydrogen mixing ratio can be adjusted in real time during the operation of the gas turbine, thereby improving the flexibility of the natural gas / hydrogen mixed combustion of the gas turbine. In addition, the combustion of natural gas mixed with hydrogen can significantly reduce carbon emissions.

[0033] 2. In the gas turbine combustor nozzle structure provided by the present invention, the angle α between the central axis of the natural gas mixing hole and / or the hydrogen mixing hole and the central axis of the gas turbine combustor nozzle structure satisfies 15°≤α≤60°, thereby improving the gas mixing efficiency and ensuring higher gas fluidity.

[0034] 3. The gas turbine combustion chamber nozzle structure provided by the present invention provides a first air hole on the second cylinder wall so that the first air holes are densely distributed and cover the premixing zone axially close to the downstream of the second step; and provides a second air hole on the fifth cylinder wall so that the second air holes are densely distributed and cover the premixing zone axially close to the downstream of the first step, so that an air film is formed by the jets of the first air hole and the second air hole to prevent the combustible mixture from directly contacting the wall surface, thereby increasing the flow velocity of the mixture boundary layer to make it greater than the flame propagation velocity, preventing the boundary layer from backfire, and at the same time cooling the wall surface to extend its service life.

[0035] 4. The gas turbine combustion chamber nozzle structure provided by the present invention has a natural gas high-speed jet hole that is a contraction hole, and its radial cross-sectional area gradually decreases along the jet direction. The contraction ratio γ of the natural gas high-speed jet hole satisfies γ<3, which is beneficial to improving the natural gas jet speed and penetration strength. On the one hand, it can enhance the mixing effect, and on the other hand, it can enhance the overall average flow rate of the mixed gas and prevent the center flow from flashing back. The hydrogen high-speed jet hole is a contraction hole, and its radial cross-sectional area gradually decreases along the jet direction. The contraction ratio γ of the hydrogen high-speed jet hole satisfies γ<3, which is beneficial to improving the hydrogen jet speed and penetration strength. On the one hand, it can enhance the mixing effect, and on the other hand, it can enhance the overall average flow rate of the mixed gas and prevent the center flow from flashing back.

[0036] 5. The working method of the gas turbine combustion chamber nozzle structure provided by the present invention can quickly and evenly mix natural gas / hydrogen and air by providing steps to generate step vortices. Therefore, natural gas and hydrogen can be supplied separately to the combustion chamber of the gas turbine and mixed while flowing in the nozzle, rather than being mixed evenly before the mixed gas is delivered to the combustion chamber. This method enables the gas turbine to separately adjust the natural gas flow rate and hydrogen flow rate during operation, so that the gas turbine can maintain stable operation despite dynamic changes in fuel flow rate, thereby improving the flexibility of gas turbine combustion and ensuring safe and stable combustion of the gas turbine. Moreover, the combustion of a mixture of natural gas and hydrogen by the gas turbine can reduce carbon emissions, and the environmental protection effect becomes more significant as the hydrogen blending ratio increases. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 Schematic diagram of the cross-sectional structure of the nozzle structure of the combustion chamber of a gas turbine according to the present invention;

[0039] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0040] Figure 3 Dimensional drawings of the first contraction section and the second contraction section of the gas turbine combustion chamber nozzle structure of the present invention;

[0041] Figure 4 It is an isometric structural diagram of the nozzle structure of the combustion chamber of a gas turbine according to the present invention;

[0042] Figure 5 It is a front view schematic diagram of the structure of the nozzle of the combustion chamber of the gas turbine according to the present invention;

[0043] Figure 6 for Figure 5 Cross-sectional view of the middle BB section;

[0044] Figure 7 for Figure 5 Cross-sectional view of the middle CC section;

[0045] Figure 8 for Figure 6 Enlarged view of point D in the middle;

[0046] Figure 9 for Figure 5 Right view;

[0047] Figure 10 This is a schematic diagram of the working principle of the gas turbine combustion chamber nozzle structure generating step vortices according to the present invention.

[0048] Description of reference numerals:

[0049] 10. First cylinder wall; 100. Primary natural gas flow path; 11. Blocking portion; 110. Natural gas jet hole;

[0050] 20, second cylinder wall; 200, primary air flow path; 201, first air hole; 21, cyclone; 22, flow stabilizing portion; 220, first strip-shaped air supply hole;

[0051] 30. Third cylinder wall; 300. Hydrogen flow path;

[0052] 40. Fourth cylinder wall; 400. Secondary natural gas flow path;

[0053] 50, fifth cylinder wall; 500, secondary air flow path; 501, second air hole; 51, rectifying wall surface; 511, first contraction section; 512, second contraction section;

[0054] 60, first step; 600, premixing zone; 601, natural gas high-speed jet hole; 602, natural gas mixing hole; 603, second strip air supply hole;

[0055] 70. Second step; 701. Hydrogen high-speed jet hole; 702. Hydrogen mixing hole. DETAILED DESCRIPTION

[0056] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0057] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0058] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0059] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0060] Example 1

[0061] Combine Figures 1-10 As shown, the gas turbine combustion chamber nozzle structure provided in this embodiment includes:

[0062] A first cylinder wall 10, a second cylinder wall 20, a third cylinder wall 30, a fourth cylinder wall 40 and a fifth cylinder wall 50 are coaxially arranged;

[0063] A hydrogen flow path 300 is formed radially between the outer circumferential wall of the second cylinder wall 20 and the inner circumferential wall of the third cylinder wall 30; a secondary natural gas flow path 400 is formed radially between the outer circumferential wall of the third cylinder wall 30 and the inner circumferential wall of the fourth cylinder wall 40; and a secondary air flow path 500 is formed radially between the outer circumferential wall of the fourth cylinder wall 40 and the inner circumferential wall of the fifth cylinder wall 50.

[0064] A first step 60 is provided at the end of the secondary natural gas flow path 400 and the secondary air flow path 500; a second step 70 is provided at the end of the hydrogen flow path 300; the first step 60, on the downstream side in the axial direction, and the outer peripheral wall of the fourth cylinder wall 40, and the second step 70, on the downstream side in the axial direction, and the outer peripheral wall of the second cylinder wall 20 and the inner peripheral wall of the fifth cylinder wall 50, together enclose a premixing zone 600;

[0065] The first step 60 is provided with a natural gas high-speed jet hole 601 and a second strip-shaped air supply hole 603. The natural gas high-speed jet hole 601 is suitable for connecting the secondary natural gas flow path 400 with the premixing zone 600, and the second strip-shaped air supply hole 603 is suitable for connecting the secondary air flow path 500 with the premixing zone 600. The second step 70 is provided with a hydrogen high-speed jet hole 701. The hydrogen high-speed jet hole 701 is suitable for connecting the hydrogen flow path 300 with the premixing zone 600.

[0066] It should be noted that the gas turbine combustor nozzle structure of the present invention is axially divided into an intake section, a premixing section, and a diffuser section. The premixing section of the gas turbine combustor nozzle structure is generally converging. The primary natural gas flow path 100, the primary air flow path 200, the hydrogen flow path 300, the secondary natural gas flow path 400, and the secondary air flow path 500 are located in the intake section of the gas turbine combustor nozzle structure. The primary step 60, the straightening wall 51, the secondary step 70, the first air hole 201, the second air hole 501, the natural gas high-speed jet hole 601, the natural gas mixing hole 602, the second strip-shaped air supply hole 603, the hydrogen high-speed jet hole 701, and the hydrogen mixing hole 702 are located in the premixing section of the gas turbine combustor nozzle structure. The first strip-shaped air supply hole 220, the swirler 21, and the natural gas jet hole 110 are located in the diffuser section of the gas turbine combustor nozzle structure.

[0067] Please note that, see Figure 1 and Figure 4As shown, the gas turbine combustion chamber nozzle structure includes a first cylinder wall 10, a second cylinder wall 20, a third cylinder wall 30, a fourth cylinder wall 40 and a fifth cylinder wall 50 arranged coaxially, and any two adjacent ones of the first cylinder wall 10, the second cylinder wall 20, the third cylinder wall 30, the fourth cylinder wall 40 and the fifth cylinder wall 50 are spaced apart in the radial direction. Figure 1 As shown, a hydrogen flow path 300 is formed between the outer circumferential wall of the second cylinder wall 20 and the inner circumferential wall of the third cylinder wall 30 along the radial direction, a secondary natural gas flow path 400 is formed between the outer circumferential wall of the third cylinder wall 30 and the inner circumferential wall of the fourth cylinder wall 40 along the radial direction, and a secondary air flow path 500 is formed between the outer circumferential wall of the fourth cylinder wall 40 and the inner circumferential wall of the fifth cylinder wall 50 along the radial direction.

[0068] Please note that, see Figure 1 and Figure 2 As shown, the first-level step 60 is arranged at the end of the secondary natural gas flow path 400 and the secondary air flow path 500; one radial side of the first-level step 60 is connected to the inner circumferential wall of the fifth cylinder wall 50, and the other side is connected to the outer circumferential wall of the third cylinder wall 30, and one axial side of the first-level step 60 is connected to the end of the fourth cylinder wall 40; the first-level step 60 forms a 90-degree angle with the central axis of the gas turbine combustion chamber nozzle structure to form a first sudden expansion structure, so that the air flows through the first sudden expansion structure after being transmitted out, and generates a recirculation zone, i.e., a step vortex, in the downstream area immediately adjacent to the first-level step 60. The turbulence in the step vortex is relatively high, and the gas therein has a reverse velocity, which helps to mix the air and natural gas and improve the gas mixing efficiency. The secondary step 70 is provided at the end of the hydrogen flow path 300; one radial side of the secondary step 70 is connected to the outer peripheral wall of the second cylinder wall 20, and the other side is connected to the end of the third cylinder wall 30; the secondary step 70 forms a 90-degree angle with the central axis of the gas turbine combustion chamber nozzle structure to form a second sudden expansion structure, so that air and natural gas flow through the second sudden expansion structure and generate a recirculation zone, i.e., a step vortex, in the downstream area immediately adjacent to the secondary step 70. The turbulence in the step vortex is high, and the gas therein has a reverse velocity, which further helps to mix the air, natural gas and hydrogen, further improving the gas mixing efficiency. The axially downstream side of the primary step 60 and the outer peripheral wall of the fourth cylinder wall 40, the axially downstream side of the secondary step 70 and the outer peripheral wall of the second cylinder wall 20 and the inner peripheral wall of the fifth cylinder wall 50 together enclose a premixing zone 600, which is suitable for mixing natural gas, air and hydrogen.

[0069] Optionally, the number of the second strip-shaped air supply holes 603 is eight, and the eight second strip-shaped air supply holes 603 are evenly arranged on the first step 60 along the circumferential direction, which is beneficial to improving the uniformity of the air jet, thereby improving the mixing uniformity and mixing efficiency of air and natural gas.

[0070] It should be noted that, see Figure 1 and Figure 2 As shown, a natural gas high-speed jet hole 601 is provided on the first step 60, so that one end of the natural gas high-speed jet hole 601 is connected to the second-level natural gas flow path 400 and the other end is connected to the premixing zone 600, thereby increasing the jet velocity and penetration strength of the natural gas. On the one hand, it can enhance the mixing effect of natural gas and air, and on the other hand, it can increase the overall average flow rate of the mixed gas and prevent the center flow from flashing back. A hydrogen high-speed jet hole 701 is provided on the second step 70, so that one end of the hydrogen high-speed jet hole 701 is connected to the hydrogen flow path 300 and the other end is connected to the premixing zone 600, thereby increasing the jet velocity and penetration strength of the hydrogen. On the one hand, it can enhance the mixing effect of natural gas, air and hydrogen, and on the other hand, it can increase the overall average flow rate of the mixed gas and prevent the center flow from flashing back.

[0071] In this embodiment, a first step 60 and a second step 70 are provided to form a first sudden expansion structure and a second sudden expansion structure respectively, so that when the gas flows through, a recirculation zone, namely a step vortex, is generated near the first step 60 and the second step 70. The turbulence in the step vortex is relatively high. After the natural gas and hydrogen are transmitted from the step, they are continuously mixed with the air in the step vortex. Due to the high internal turbulence and the gas recirculation, the three can be quickly mixed and evenly mixed and propagated downstream to the flame tube for combustion; by providing a natural gas high-speed jet hole 601 and a hydrogen high-speed jet hole 701, the penetrability of the natural gas and hydrogen is improved. In addition, the jet velocity is high, and based on the Bernoulli effect, the surrounding gas can be attracted to gather towards the jet beam, which is conducive to rapid and even mixing. The above-mentioned arrangement of the nozzle structure of the gas turbine combustion chamber of the present invention can achieve rapid and uniform mixing of natural gas, hydrogen and air without the need to construct a hydrogen mixing device outside the gas turbine body. Moreover, the hydrogen mixing ratio can be adjusted in real time during the operation of the gas turbine, thereby improving the flexibility of the natural gas / hydrogen mixed combustion of the gas turbine. In addition, the combustion of natural gas mixed with hydrogen can significantly reduce carbon emissions.

[0072] Specifically, the fifth cylinder wall 50 includes a rectifying wall surface 51, and the rectifying wall surface 51 includes a first contraction section 511 and a second contraction section 512. The first contraction section 511 is located in the downstream area of the first step 60, and the second contraction section 512 is located in the downstream area of the second step 70.

[0073] The radius of the first contraction section 511 is r2, r2 satisfies r2<r1, where r1 is the radius of the first step 60; the radius of the second contraction section 512 is r4, r4 satisfies r4<r3, where r3 is the radius of the second step 70, r3<r1.

[0074] Specifically, a natural gas mixing hole 602 is further formed on the first step 60. The natural gas mixing hole 602 is located on a side of the natural gas high-speed jet hole 601 radially away from the third cylinder wall 30. One end of the natural gas mixing hole 602 is connected to the secondary natural gas flow path 400, and the other end is connected to the premixing zone 600.

[0075] A hydrogen mixing hole 702 is also provided on the secondary step 70 , and the hydrogen mixing hole 702 is located on a side of the hydrogen high-speed jet hole 701 radially away from the second cylinder wall 20 ; one end of the hydrogen mixing hole 702 is connected to the hydrogen flow path 300 , and the other end is connected to the premixing zone 600 .

[0076] Please note that, see Figure 3As shown, the rectifying wall surface 51 is arranged on the fifth cylinder wall 50 in a contraction shape along the airflow direction, and the rectifying wall surface 51 includes a first contraction section 511 and a second contraction section 512 . The first constriction section 511 is located downstream of the first step 60. The radius r2 of the first constriction section 511 is smaller than the radius r1 of the first step 60. After the premixed air exits the second strip-shaped air supply holes 603, it rapidly diffuses. Some of the premixed air flows near the first step 60, generating a step vortex. The remainder flows downstream of the nozzle. Upon reaching the rectifying wall corresponding to the first constriction section 511, it collides with it, causing this portion of the premixed air to generate a more significant radially inward velocity component along the nozzle. Meanwhile, the natural gas exiting the natural gas mixing holes 602 has a radially outward velocity component along the nozzle. These two velocities have opposite radial velocities but the same axial velocities, facilitating rapid mixing of air and natural gas. Otherwise, if the radius r2 of the first constriction section 511 were larger than the radius r1 of the first step 60, the premixed air exiting the second strip-shaped air supply holes 603 would not collide with the rectifying wall corresponding to the first constriction section 511. Even if such collision occurs, this portion of the premixed air would not generate a significant radially inward velocity component along the nozzle. Similarly, the second contraction section 512 is located in the downstream area of the secondary step 70. The radius r4 of the second contraction section 512 is smaller than the radius r3 of the secondary step 70. During the movement of the air-natural gas mixture toward the nozzle end, part of the mixture flows to the vicinity of the secondary step 70 to generate a step vortex, while the remaining part flows downstream of the nozzle. When it flows to the rectifying wall surface corresponding to the second contraction section 512, it collides with it, causing this part of the mixture to generate a more significant component velocity along the radial inward direction of the nozzle. The hydrogen transmitted from the hydrogen mixing hole 702 has a component velocity along the radial outward direction of the nozzle. The radial velocities of the two are opposite, but the axial velocities are the same, which is conducive to the rapid mixing of air, natural gas and hydrogen.

[0077] Please note that, see Figure 1 As shown, since hydrogen diffuses faster and the required premixing distance is shorter, in this embodiment, the axial length of the hydrogen flow path 300 is greater than the axial length of the secondary natural gas flow path 400, that is, the premixing length of hydrogen is shorter than the premixing length of natural gas.

[0078] Optionally, the inner and outer curved portions of the rectifying wall 51 are rounded to reduce gas flow loss.

[0079] Specifically, the angle between the central axis of the natural gas mixing hole 602 and / or the hydrogen mixing hole 702 and the central axis of the gas turbine combustion chamber nozzle structure is α, and α satisfies 15°≤α≤60°.

[0080] Please note that, see Figure 2 As shown, the central axis of the gas turbine combustion chamber nozzle structure refers to Figure 1-Figure 3 The middle line "L" points to the axis, where Figure 2 The central axis L of the gas turbine combustion chamber nozzle structure at the two angles shown in can be obtained according to the parallel principle, which will not be repeated here; the central axis of the natural gas mixing hole 602 refers to Figure 2 The axis indicated by the middle lead "P" is the central axis of the hydrogen mixing hole 702. Figure 2 The axis indicated by the middle lead "Q" is the angle between the central axis of the natural gas mixing hole 602 and / or the hydrogen mixing hole 702 and the central axis of the gas turbine combustion chamber nozzle structure. Figure 2 The angle "α" in the figure cannot be too small, otherwise it will easily cause the radial component velocity of the jet from the natural gas mixing hole 602 and / or the hydrogen mixing hole 702 to be too small, while the axial component velocity is too large, which is not conducive to mixing. In addition, the jet penetration is low, which is also not conducive to mixing. Therefore, the angle α must satisfy α≥15°. The angle α must also not be too large, otherwise it will easily cause the radial component velocity of the jet from the natural gas mixing hole 602 and / or the hydrogen mixing hole 702 to be too large, while the axial component velocity is too small. The large radial flow velocity will decelerate the other fluid being mixed with it, which is not conducive to flow and is also not conducive to mixing. Therefore, the angle α must satisfy α≤60°. The angle α between the central axis of the natural gas mixing hole 602 and / or the hydrogen mixing hole 702 and the central axis of the gas turbine combustor nozzle structure satisfies 15°≤α≤60°, thereby improving the gas mixing efficiency and ensuring high gas fluidity.

[0081] Optionally, the angle α between the central axis of the natural gas mixing hole 602 and the central axis of the gas turbine combustion chamber nozzle structure is α=30°, so that the natural gas is obliquely injected into the air flow, which is conducive to uniform mixing; the angle α between the central axis of the hydrogen mixing hole 702 and the central axis of the gas turbine combustion chamber nozzle structure is α=30°, so that the hydrogen is obliquely injected into the mixture of natural gas and air, which is conducive to uniform mixing.

[0082] Specifically, the second cylinder wall 20 is provided with first air holes 201 , and the distribution of the first air holes 201 covers the premixing zone 600 close to the downstream of the secondary step 70 in the axial direction;

[0083] The fifth cylinder wall 50 is provided with second air holes 501 , and the second air holes 501 are distributed to cover the premixing zone 600 axially close to the downstream of the first step 60 .

[0084] Please note that, see Figure 1As shown, the second cylinder wall 20 and the fifth cylinder wall 50 are the walls that contact the natural gas, hydrogen, and air during premixed flow. By providing first air holes 201 in the second cylinder wall 20, the first air holes 201 are densely distributed and cover the premixing zone 600 axially downstream of the secondary step 70. Furthermore, by providing second air holes 501 in the fifth cylinder wall 50, the second air holes 501 are densely distributed and cover the premixing zone 600 axially downstream of the primary step 60. As a result, the jets from the first and second air holes 201, 501, form an air film, preventing direct contact between the combustible mixture and the wall surface. This increases the flow velocity of the mixture boundary layer, making it greater than the flame propagation velocity, preventing boundary layer flashback, and simultaneously cooling the wall surface, extending its service life. Furthermore, because the premixing section of the gas turbine combustor nozzle structure is generally contracting, and both the natural gas high-speed jet hole 601 and the hydrogen high-speed jet hole 701 are contracting holes, the average flow velocity of the mixture can be significantly increased, exceeding the flame propagation velocity, preventing flashback of the center flow.

[0085] Specifically, the inner diameter of the first air hole 201 and / or the second air hole 501 is d, and d satisfies 0.2 mm ≤ d ≤ 1.0 mm.

[0086] It should be noted that the inner diameter of the first air hole 201 and / or the second air hole 501 is d (not shown in the figure), and the inner diameter d cannot be too small, otherwise it will easily lead to a too small air circulation area, limiting the air flow rate, therefore, the inner diameter d needs to satisfy d≥0.2mm; the inner diameter d cannot be too large, otherwise it will easily lead to a decrease in air jet speed and weakened penetration, which is not conducive to mixing, therefore, the inner diameter d needs to satisfy d≤1.0mm; in summary, the inner diameter d of the first air hole 201 and / or the second air hole 501 satisfies 0.2mm≤d≤1.0mm, thereby ensuring that the air jet speed is at a faster level, enhancing the penetration of the jet and the average flow rate of the mixed air, and ensuring sufficient air flow, thereby improving the mixing efficiency.

[0087] Specifically, the central axes of the natural gas high-speed jet hole 601 and the hydrogen high-speed jet hole 701 are parallel to the central axis of the gas turbine combustion chamber nozzle structure;

[0088] The natural gas high-speed jet hole 601 and the hydrogen high-speed jet hole 701 are both contraction holes, and the radial cross-sectional areas of the natural gas high-speed jet hole 601 and the hydrogen high-speed jet hole 701 gradually decrease along the jet direction;

[0089] The contraction ratio of the natural gas high-speed jet hole 601 and / or the hydrogen high-speed jet hole 701 is γ, and γ satisfies γ<3.

[0090] Please note that, see Figure 2 As shown, the central axis of the natural gas high-speed jet hole 601 is parallel to the central axis of the gas turbine combustor nozzle structure. The natural gas high-speed jet hole 601 is a contraction hole, and its radial cross-sectional area gradually decreases along the jet direction. The contraction ratio γ of the natural gas high-speed jet hole 601 satisfies γ<3, which is beneficial to improving the natural gas jet velocity and penetration strength. On the one hand, it can enhance the mixing effect, and on the other hand, it can increase the overall average flow rate of the mixed gas and prevent center flow flashback. Similarly, the central axis of the hydrogen high-speed jet hole 701 is parallel to the central axis of the gas turbine combustor nozzle structure. The hydrogen high-speed jet hole 701 is a contraction hole, and its radial cross-sectional area gradually decreases along the jet direction. The contraction ratio γ of the hydrogen high-speed jet hole 701 satisfies γ<3, which is beneficial to improving the hydrogen jet velocity and penetration strength. On the one hand, it can enhance the mixing effect, and on the other hand, it can increase the overall average flow rate of the mixed gas and prevent center flow flashback.

[0091] It is worth noting that, compared with the gas turbine combustion chamber nozzle currently in service, the premixing section in the present invention has no swirl components, and the overall structure is more compact and simple, which significantly reduces the production and processing costs and is more convenient for maintenance and replacement.

[0092] Specifically, a primary air flow path 200 is formed between the outer peripheral wall of the first tube wall 10 and the inner peripheral wall of the second tube wall 20 along the radial direction;

[0093] A cyclone 21 is provided at the outlet of the end of the primary air flow path 200, and the cyclone 21 is suitable for causing the gas to generate a swirl;

[0094] A flow stabilizing portion 22 is provided at one end of the primary air flow path 200 axially close to the cyclone 21 . A first strip-shaped air supply hole 220 is provided on the flow stabilizing portion 22 . The first strip-shaped air supply hole 220 is suitable for stabilizing the air flow.

[0095] Please note that, see Figure 1 As shown, the end face of the primary air flow path 200 is chamfered, which is conducive to the flow of fresh premixed gas to the recirculation zone formed downstream of the swirler 21, so that it is easy to be ignited and burned by the on-duty flame.

[0096] Optionally, the number of the first strip-shaped air supply holes 220 is four, and the four first strip-shaped air supply holes 220 are evenly arranged around the flow stabilizing portion 22 to stabilize the air flow.

[0097] Specifically, the inner peripheral wall of the first cylinder wall 10 encloses and forms a primary natural gas flow path 100;

[0098] A sealing portion 11 is provided at the end of the first cylinder wall 10 . A natural gas jet hole 110 is formed on the sealing portion 11 . The jet port of the natural gas jet hole 110 is located between two adjacent blades of the swirler 21 .

[0099] Example 2

[0100] Different from the first embodiment, in this embodiment, the axial length of the hydrogen flow path 300 is made equal to the axial length of the secondary natural gas flow path 400, that is, only one step is provided to form a single sudden expansion structure, thereby forming a step vortex, and the rectifying wall surface also corresponds to only one contraction section. This can simplify the nozzle structure without affecting the mixing effect, making the nozzle structure more compact.

[0101] Example 3

[0102] The operating method of the gas turbine combustor nozzle structure provided in this embodiment is applied to the gas turbine combustor nozzle structure as described above. The operating method of the gas turbine combustor nozzle structure includes:

[0103] A natural gas supply source supplies diffused natural gas to the primary natural gas flow path 100, causing the diffused natural gas to be ejected through the natural gas jet holes 110 to the blade passages of the swirler 21. Simultaneously, a compressor supplies diffused air to the primary air flow path 200, causing the diffused air to flow steadily through the first strip-shaped air supply holes 220 and then be ejected to the blade passages of the swirler 21. The diffused air is rapidly mixed with the diffused natural gas and then passed into the flame tube to be ignited by the igniter, forming a diffused combustion flame, i.e., a service flame. A stable recirculation zone is formed under the action of the swirler 21, serving as a stable ignition source.

[0104] The compressor supplies premixed air to the secondary air flow path 500, and the natural gas supply source supplies premixed natural gas to the secondary natural gas flow path 400. This causes the premixed air to steadily flow through the second linear air supply holes 603, generating a recirculation zone, i.e., a step vortex, in the downstream region of the primary step 60. Simultaneously, the premixed natural gas is discharged through the natural gas mixing holes 602 and the natural gas high-speed jet holes 601, where it rapidly mixes with the air within the step vortex and flows downstream. When the premixed air and premixed natural gas reach the secondary step 70, a step vortex is generated in the region immediately downstream of the secondary step 70.

[0105] Hydrogen is supplied to the hydrogen flow path 300 from a hydrogen supply source, so that the hydrogen is transmitted from the hydrogen mixing hole 702 and the hydrogen high-speed jet hole 701 to the step vortex near the secondary step 70, and is quickly mixed with the premixed gas of natural gas and air to form a premixed gas of natural gas, hydrogen and air, and propagates downstream of the nozzle until it is transmitted to the flame tube and ignited by the duty flame.

[0106] It should be noted that the fuel used for on-duty combustion, i.e., diffusion combustion, in the present invention is natural gas, rather than hydrogen or a mixture of natural gas and hydrogen. This is because diffusion combustion, unlike premixed combustion, cannot adjust the flame surface temperature. If the fuel contains hydrogen, the flame surface temperature will increase significantly, which can easily lead to a significant increase in the emission of thermal nitrogen oxides. Therefore, when pure natural gas is used, the flame surface temperature can be maintained at a low level, which can effectively control the generation of thermal nitrogen oxides.

[0107] The working method of the gas turbine combustion chamber nozzle structure of the present invention is described below in a unified manner:

[0108] During operation, the gas turbine combustor nozzle structure injects diffused natural gas through the natural gas jet holes 110 into the blade passages of the swirler 21. Simultaneously, diffused air flows steadily through the first strip-shaped air supply holes 220 and into the blade passages of the swirler 21. Rapidly mixed with the diffused natural gas, it is then conveyed into the flame tube and ignited by the igniter, forming a diffuse combustion flame, or the duty flame. Under the action of the swirler 21, a stable recirculation zone is formed, serving as a stable ignition source. Simultaneously, premixed air flows steadily out through the second strip-shaped air supply holes 603. Due to the presence of the first step 60, the air, after exiting, flows through the sudden expansion structure, generating a recirculation zone, or step vortex, immediately downstream of the first step 60. (See [1] for details.) Figure 10As shown, the turbulence within the step vortex is high, and the gas therein has a reverse velocity. At the same time, the premixed natural gas is transmitted from the natural gas mixing hole 602 and the natural gas high-speed jet hole 601, rapidly mixed with the air within the step vortex, and flows downstream. The high turbulence and reverse velocity within the step vortex facilitate gas mixing. Since the angle α between the central axis of the natural gas mixing hole 602 and the central axis of the gas turbine combustor nozzle structure is, the natural gas is obliquely injected into the air flow, which is conducive to uniform mixing. The central axis of the natural gas high-speed jet hole 601 is parallel to the central axis of the gas turbine combustor nozzle structure, and the natural gas high-speed jet hole 601 is a contracting hole, which is conducive to increasing the natural gas jet velocity and penetration strength. On the one hand, it can enhance the mixing effect, and on the other hand, it can increase the overall average flow rate of the mixed gas and prevent center flow backfire. Air and natural gas continue to flow downstream of the nozzle within the rectifying wall 51. When they reach the secondary step 70, a step vortex is generated in the area immediately downstream of the secondary step 70, similar to the above. Simultaneously, hydrogen is transmitted through the hydrogen mixing hole 702 and the hydrogen high-speed jet hole 701 into the step vortex near the secondary step 70, where it is rapidly mixed with the premixed gas of natural gas and air to form a premixed gas of natural gas, hydrogen, and air. The premixed gas then propagates downstream of the nozzle until it reaches the flame tube and is ignited by the service flame. The angle α between the central axis of the hydrogen mixing hole 702 and the central axis of the gas turbine combustor nozzle structure allows hydrogen to be injected obliquely into the natural gas and air mixture, facilitating uniform mixing. The central axis of the hydrogen high-speed jet hole 701 is parallel to the central axis of the gas turbine combustor nozzle structure, and the hydrogen high-speed jet hole 701 is a contracting hole, which facilitates increasing the jet velocity and penetration strength of the hydrogen. This not only enhances the mixing effect, but also increases the overall average flow velocity of the mixture, preventing center flow flashback.

[0109] It should be noted that the natural gas-hydrogen blending combustion scheme used in previous gas turbines required the blending of natural gas and hydrogen before delivery to the combustion chamber. Once the hydrogen blending ratio was determined, the gas turbine could not be changed during operation and could only operate at the current hydrogen blending ratio. Otherwise, if the hydrogen blending ratio changed for some reason while the natural gas flow rate remained unchanged, the gas turbine could easily cause unstable combustion or even a trip. The operating method of the gas turbine combustor nozzle structure of the present invention creates a step vortex by providing a step, which allows for rapid and uniform blending of natural gas / hydrogen and air. Therefore, natural gas and hydrogen can be supplied separately to the gas turbine combustion chamber and blended while flowing in the nozzle, rather than being blended thoroughly before delivery to the combustion chamber. This method enables the natural gas and hydrogen flow rates to be adjusted independently during gas turbine operation, allowing the gas turbine to maintain stable operation despite dynamic changes in fuel flow rate, thereby improving the combustion flexibility of the gas turbine and ensuring safe and stable combustion. Furthermore, the combustion of a natural gas-hydrogen mixture by the gas turbine reduces carbon emissions, and the environmental benefits become increasingly significant as the hydrogen blending ratio increases.

[0110] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A gas turbine combustion chamber nozzle structure, characterized in that: include: A first cylinder wall (10), a second cylinder wall (20), a third cylinder wall (30), a fourth cylinder wall (40) and a fifth cylinder wall (50) are coaxially arranged; A hydrogen flow path (300) is formed between the outer peripheral wall of the second cylinder wall (20) and the inner peripheral wall of the third cylinder wall (30) along the radial direction; a secondary natural gas flow path (400) is formed between the outer peripheral wall of the third cylinder wall (30) and the inner peripheral wall of the fourth cylinder wall (40) along the radial direction; and a secondary air flow path (500) is formed between the outer peripheral wall of the fourth cylinder wall (40) and the inner peripheral wall of the fifth cylinder wall (50) along the radial direction. A first step (60) is provided at the end of the secondary natural gas flow path (400) and the secondary air flow path (500); a second step (70) is provided at the end of the hydrogen flow path (300); the first step (60) and the outer peripheral wall of the fourth cylinder wall (40) are enclosed together along the axial downstream side, and the second step (70) and the outer peripheral wall of the second cylinder wall (20) and the inner peripheral wall of the fifth cylinder wall (50) form a premixing zone (600); The first step (60) is provided with a natural gas high-speed jet hole (601) and a second strip-shaped air supply hole (603), wherein the natural gas high-speed jet hole (601) is suitable for connecting the second-level natural gas flow path (400) with the premixing zone (600), and the second strip-shaped air supply hole (603) is suitable for connecting the second-level air flow path (500) with the premixing zone (600); the second step (70) is provided with a hydrogen high-speed jet hole (701), wherein the hydrogen high-speed jet hole (701) is suitable for connecting the hydrogen flow path (300) with the premixing zone (600).

2. The gas turbine combustion chamber nozzle structure according to claim 1, characterized in that: The fifth cylinder wall (50) includes a rectifying wall surface (51), and the rectifying wall surface (51) includes a first contraction section (511) and a second contraction section (512), wherein the first contraction section (511) is located in a downstream area of the first step (60), and the second contraction section (512) is located in a downstream area of the second step (70); The radius of the first contraction section (511) is r2, r2 satisfies r2<r1, wherein r1 is the radius of the first step (60); the radius of the second contraction section (512) is r4, r4 satisfies r4<r3, wherein r3 is the radius of the second step (70), r3<r1.

3. The gas turbine combustion chamber nozzle structure according to claim 1, characterized in that: A natural gas mixing hole (602) is further provided on the first step (60), and the natural gas mixing hole (602) is located on a side of the natural gas high-speed jet hole (601) radially away from the third cylinder wall (30); one end of the natural gas mixing hole (602) is connected to the secondary natural gas flow path (400), and the other end is connected to the premixing zone (600); A hydrogen mixing hole (702) is also provided on the secondary step (70), and the hydrogen mixing hole (702) is located on a side of the hydrogen high-speed jet hole (701) radially away from the second cylinder wall (20); one end of the hydrogen mixing hole (702) is connected to the hydrogen flow path (300), and the other end is connected to the premixing zone (600).

4. The gas turbine combustion chamber nozzle structure according to claim 3, characterized in that: The angle between the central axis of the natural gas mixing hole (602) and / or the hydrogen mixing hole (702) and the central axis of the gas turbine combustion chamber nozzle structure is α, and α satisfies 15°≤α≤60°.

5. The gas turbine combustion chamber nozzle structure according to claim 1, characterized in that: The second cylinder wall (20) is provided with first air holes (201), and the distribution of the first air holes (201) covers the premixing zone (600) close to the downstream of the secondary step (70) in the axial direction; The fifth cylinder wall (50) is provided with second air holes (501), and the distribution of the second air holes (501) covers the premixing zone (600) close to the downstream of the first step (60) in the axial direction.

6. The gas turbine combustion chamber nozzle structure according to claim 5, characterized in that: The inner diameter of the first air hole (201) and / or the second air hole (501) is d, and d satisfies 0.2 mm ≤ d ≤ 1.0 mm.

7. The gas turbine combustor nozzle structure according to claim 1, characterized in that: The central axes of the natural gas high-speed jet hole (601) and the hydrogen high-speed jet hole (701) are both parallel to the central axis of the gas turbine combustion chamber nozzle structure; The natural gas high-speed jet hole (601) and the hydrogen high-speed jet hole (701) are both contraction holes, and the radial cross-sectional areas of the natural gas high-speed jet hole (601) and the hydrogen high-speed jet hole (701) gradually decrease along the jet direction; The contraction ratio of the natural gas high-speed jet hole (601) and / or the hydrogen high-speed jet hole (701) is γ, and γ satisfies γ<3.

8. The gas turbine combustion chamber nozzle structure according to any one of claims 1 to 7, characterized in that: A primary air flow path (200) is formed between the outer peripheral wall of the first cylinder wall (10) and the inner peripheral wall of the second cylinder wall (20) along a radial distance; A cyclone (21) is provided at the outlet of the end of the primary air flow path (200), and the cyclone (21) is suitable for causing the gas to generate a swirling flow; A flow stabilizing portion (22) is provided at one end of the primary air flow path (200) close to the cyclone (21) in the axial direction. A first strip-shaped air supply hole (220) is provided on the flow stabilizing portion (22). The first strip-shaped air supply hole (220) is suitable for stabilizing the air flow.

9. The gas turbine combustion chamber nozzle structure according to claim 8, characterized in that: The inner peripheral wall of the first cylinder wall (10) encloses a primary natural gas flow path (100); A sealing portion (11) is provided at the end of the first cylinder wall (10), and a natural gas jet hole (110) is opened on the sealing portion (11). The injection port of the natural gas jet hole (110) is located between two adjacent blades of the cyclone (21).

10. A method for operating a gas turbine combustion chamber nozzle structure, applied to the gas turbine combustion chamber nozzle structure according to any one of claims 1 to 9, characterized in that: The working method of the gas turbine combustion chamber nozzle structure includes: A natural gas supply source supplies diffusion natural gas to the primary natural gas flow path (100), so that the diffusion natural gas is injected into the blade passages of the swirler (21) through the natural gas injection holes (110). Simultaneously, a compressor supplies diffusion air to the primary air flow path (200), so that the diffusion air is injected into the blade passages of the swirler (21) after a steady flow through the first strip-shaped air supply holes (220). The diffusion air is rapidly mixed with the diffusion natural gas and then transmitted to the flame tube and ignited by the igniter, forming a diffusion combustion flame, i.e., a duty flame. A stable recirculation zone is formed under the action of the swirler (21), serving as a stable ignition source. The compressor supplies premixed air to the secondary air flow path (500), and the natural gas supply source supplies premixed natural gas to the secondary natural gas flow path (400), so that the premixed air flows steadily through the second strip-shaped air supply hole (603) and generates a recirculation zone, i.e., a step vortex, in the downstream area of the primary step (60). At the same time, the premixed natural gas is discharged from the natural gas mixing hole (602) and the natural gas high-speed jet hole (601), and is quickly mixed with the air in the step vortex and flows downstream. When the premixed air and the premixed natural gas flow to the secondary step (70), a step vortex is generated in the downstream area immediately adjacent to the secondary step (70). Hydrogen is supplied from a hydrogen supply source to the hydrogen flow path (300), so that the hydrogen is transferred from the hydrogen mixing hole (702) and the hydrogen high-speed jet hole (701) to the step vortex near the secondary step (70), and is quickly mixed with the premixed gas of natural gas and air to form a premixed gas of natural gas, hydrogen and air, and propagates downstream of the nozzle until it is transferred to the flame tube and ignited by the duty flame.

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