阅读说明：本技术 一种采用全预混低氮燃烧方式的燃气轮机发电装置 (Gas turbine power generation device adopting full-premixing low-nitrogen combustion mode ) 是由 李晓丰 肖俊峰 胡孟起 王峰 王玮 王致程 于 2021-08-26 设计创作，主要内容包括：本发明公开了一种采用全预混低氮燃烧方式的燃气轮机发电装置,包括进气道、压气机、燃烧室、透平、排气道、转子和发电机；呈喇叭收缩型的进气道布置在燃气轮机的最前端,其下游与压气机相连,燃烧室以设定倾角周向均匀布置在压气机和透平之间,燃烧室出口与透平入口相连,燃气轮机排气道布置在燃气轮机最右侧,压气机和透平通过转子连接,发电机位于发电装置的最左侧,发电机轴与转子相连。本发明解决了在役燃气轮机启机过程冒黄烟问题,同时有助于燃气轮机在稳定负荷运行时进一步降低NOx排放。(The invention discloses a gas turbine power generation device adopting a full-premixing low-nitrogen combustion mode, which comprises an air inlet channel, an air compressor, a combustion chamber, a turbine, an exhaust channel, a rotor and a generator, wherein the air inlet channel is connected with the air compressor; the air inlet channel in a horn contraction type is arranged at the foremost end of the gas turbine, the downstream of the air inlet channel is connected with the air compressor, the combustion chamber is circumferentially and uniformly arranged between the air compressor and the turbine at a set inclination angle, the outlet of the combustion chamber is connected with the inlet of the turbine, the exhaust channel of the gas turbine is arranged at the rightmost side of the gas turbine, the air compressor is connected with the turbine through a rotor, the generator is positioned at the leftmost side of the power generation device, and the generator shaft is connected with the rotor. The invention solves the problem of yellow smoke emission in the startup process of the in-service gas turbine, and is beneficial to further reducing the NOx emission when the gas turbine operates at a stable load.)

1. A gas turbine power generation device adopting a full-premixing low-nitrogen combustion mode is characterized by comprising an air inlet channel, an air compressor, a combustion chamber, a turbine, an exhaust channel, a rotor and a generator;

the air inlet channel in a horn contraction type is arranged at the foremost end of the gas turbine, the downstream of the air inlet channel is connected with the air compressor, the combustion chamber is circumferentially and uniformly arranged between the air compressor and the turbine at a set inclination angle, the outlet of the combustion chamber is connected with the inlet of the turbine, the exhaust channel of the gas turbine is arranged at the rightmost side of the gas turbine, the air compressor is connected with the turbine through a rotor, the generator is positioned at the leftmost side of the power generation device, and the generator shaft is connected with the rotor.

2. The gas turbine power generation device adopting the full-premixing low-nitrogen combustion mode as claimed in claim 1, wherein the combustion chamber of the gas turbine adopts the full-premixing low-nitrogen combustion mode, and the premixing swirl vanes and the on-duty swirl vanes of the fuel nozzle of the combustion chamber are designed into structures capable of adaptively changing and adjusting swirl numbers.

3. The gas turbine power plant employing the fully premixed low NOx combustion mode as claimed in claim 2, wherein the fuel nozzle includes a fuel nozzle outer wall, a premixed fuel outer wall, an on-duty air outer wall, an on-duty fuel outer wall, a purge air outer wall, a premixed swirl vane, an on-duty swirl vane, an annular premixed fuel partition and an annular on-duty fuel partition; the outer wall of the fuel nozzle, the outer wall of the premixed fuel, the outer wall of the on-duty air, the outer wall of the on-duty fuel and the outer wall of the purging air are all of concentric circular section thin-wall structures;

the premixing swirl vane is positioned in an annular channel formed by the outer wall of the fuel nozzle and the outer wall of the premixing fuel and is used for dividing the annular channel formed by the outer wall of the fuel nozzle and the outer wall of the premixing fuel into an upstream main combustion air flow channel and a downstream main fuel premixing cavity;

the on-duty swirl vanes are positioned in an annular channel formed by an on-duty air outer wall and an on-duty fuel outer wall and used for dividing the annular channel formed by the on-duty air outer wall and the on-duty fuel outer wall into an upstream on-duty air flow channel and a downstream on-duty fuel premixing cavity;

the annular premixed fuel partition plate is positioned between the outer wall of the premixed fuel and the outer wall of the on-duty air and is used for dividing an annular channel formed by the outer wall of the premixed fuel and the outer wall of the on-duty air into an upstream premixed fuel flow channel and a downstream premixed combustion cooling air flow channel;

the annular on-duty fuel partition plate is positioned between the outer wall of the on-duty fuel and the outer wall of the purging air and is used for dividing an annular channel formed by the outer wall of the on-duty fuel and the outer wall of the purging air into an upstream on-duty fuel flow channel and a downstream on-duty combustion cooling air flow channel;

the outer wall of the purge air is positioned in the center of the fuel nozzle, and a purge air flow channel is arranged in the outer wall of the purge air.

4. The gas turbine power generation device adopting the full-premixing low-nitrogen combustion mode as claimed in claim 3, wherein the premixing swirl vane is composed of a straight vane section, swirl vanes and a rotary torsion spring, the straight vane section is of a hollow structure, the swirl vanes and the straight vane section are connected through the rotary torsion spring, and the premixing swirl vane can rotate freely according to the variation of aerodynamic force applied to the swirl vane, so that the swirl number of the premixed combustible gas mixture can be changed in a self-adaptive manner.

5. The gas turbine power generation device adopting the full-premixing low-nitrogen combustion mode as claimed in claim 4, wherein the front edge of the straight section of the blade is provided with a premixed fuel injection hole, and the rear part of the straight section of the blade is provided with a premixed combustion cooling air hole.

6. The power generation device of a gas turbine adopting a full-premixing low-nitrogen combustion mode as claimed in claim 3, wherein the on-duty swirl vane is composed of a straight vane section, a swirl vane and a rotary torsion spring, the straight vane section is a hollow structure, the swirl vane and the straight vane section are connected through the rotary torsion spring, the on-duty swirl vane can rotate freely, and the swirl number of the on-duty combustible mixed gas can be changed adaptively.

7. The power generation device of a gas turbine adopting the fully premixed low NOx combustion mode as claimed in claim 6, wherein the front edge of the straight blade section is provided with on-duty fuel injection holes, and the rear portion of the straight blade section is provided with on-duty combustion cooling air holes.

8. The gas turbine power generation device adopting the fully premixed low-nitrogen combustion mode as claimed in claim 3, wherein cooling air injection holes are formed in the downstream cross sections of the premixed combustion cooling air flow passage, the on-duty combustion cooling air flow passage and the purge air flow passage.

9. The gas turbine power generation device adopting the fully premixed low-nitrogen combustion mode as claimed in claim 3, wherein the premixed combustion cooling air flow passage, the on-duty combustion cooling air flow passage and the purge air flow passage are provided with purge air injection holes at downstream sections thereof.

Technical Field

The invention relates to a gas turbine, in particular to a gas turbine power generation device adopting a full-premixing combustion mode, which is applied to the field of thermal power generation of gaseous fuels such as natural gas, hydrogen, synthesis gas and the like.

Background

The diffusion combustion and the premixed combustion are two common modes of gaseous fuel combustion, the temperature of a flame surface of the diffusion combustion is high, the combustion stability is good, but the NOx emission is high, the premixed combustion can adjust the fuel-air ratio to reduce the temperature of the flame surface and control the generation of the NOx emission, but the combustion stability is worse than the diffusion combustion.

The existing gas turbine generally adopts a dry type low-nitrogen staged combustion technology to reduce NOx emission, namely, fuel is divided into main fuel and on-duty fuel which enter a combustion chamber to participate in combustion in a staged manner, the main fuel adopts a premixed combustion mode, and the on-duty fuel adopts a diffusion combustion mode, so that the respective advantages of diffusion combustion and premixed combustion are combined, the combustion stability of the gas turbine can be ensured, and the NOx emission can be effectively controlled. The distribution ratio of the duty fuel and the main fuel of the gas turbine changes along with the load change of the gas turbine, and in the starting process of the gas turbine, in order to ensure the combustion stability of a combustion chamber, the duty fuel which generally participates in diffusion combustion is dominant, which also means that the NOx emission of the gas turbine is difficult to control in the starting process, and the phenomenon of yellow smoke emission is often seen in a chimney. In order to solve the problem that the chimney emits yellow smoke, a gas turbine manufacturer designs a full premix combustion system, namely, an on-duty fuel and a main fuel both adopt a premix combustion mode, the technology reduces the NOx emission of the gas turbine in the starting process to a certain extent, but the problem of yellow smoke emission cannot be completely solved, and weak yellow smoke can still be seen in a part of the starting process of the gas turbine; in addition, a full premix combustion system designed by gas turbine manufacturers adopts a strong rotational flow fuel nozzle structure, a strong rotational flow jet flow is formed by means of rotational flow blades on the fuel nozzle, a high-temperature backflow area for stable ignition is formed at the outlet of the fuel nozzle, the existence of the backflow area can improve the combustion stability, but the residence time of the flue gas after combustion in a combustion chamber is also increased, so that thermal NOx pollutants are generated, certain NOx emission still exists in the gas turbine under the working condition of stable load, the increasingly severe pollutant emission regulation requirements are difficult to directly meet, the problem of high NOx emission can be solved by additionally arranging a denitration device in a waste heat boiler, and the system operation complexity and the operation cost are increased.

Disclosure of Invention

In order to solve the problems of yellow smoke emission and NOx emission under the operation of stable load in the starting process of the in-service gas turbine, the invention provides a gas turbine power generation device adopting a full-premixing low-nitrogen combustion mode. Based on the performance advantage of low NOx emission of a weak swirl fuel nozzle and a strong swirl fuel nozzle, the invention adopts a full-premix staged combustion fuel nozzle structure with the self-adaptive adjustment of swirl number in the gas turbine, and the angle of swirl blades on the fuel nozzle can automatically change along with the load of the gas turbine, so that air compressed by a gas compressor forms rotary jet flows with different strengths after passing through the fuel nozzle and enters a combustion chamber for combustion. When the load of the gas turbine is low, the fuel nozzle works in a strong cyclone fuel nozzle mode to ensure the stable combustion of the gas turbine; as the gas turbine load increases, the fuel nozzles are gradually transitioned from the strong swirl mode to the weak swirl fuel nozzle mode to effectively control NOx emissions.

The invention is realized by adopting the following technical scheme:

a gas turbine power generation device adopting a full-premixing low-nitrogen combustion mode comprises an air inlet channel, an air compressor, a combustion chamber, a turbine, an air exhaust channel, a rotor and a generator;

the air inlet channel in a horn contraction type is arranged at the foremost end of the gas turbine, the downstream of the air inlet channel is connected with the air compressor, the combustion chamber is circumferentially and uniformly arranged between the air compressor and the turbine at a set inclination angle, the outlet of the combustion chamber is connected with the inlet of the turbine, the exhaust channel of the gas turbine is arranged at the rightmost side of the gas turbine, the air compressor is connected with the turbine through a rotor, the generator is positioned at the leftmost side of the power generation device, and the generator shaft is connected with the rotor.

The invention has the further improvement that a full-premixing low-nitrogen combustion mode is adopted in the combustion chamber of the gas turbine, and the premixing swirl blades and the on-duty swirl blades of the fuel nozzle of the combustion chamber are designed into structures with swirl numbers capable of being adaptively changed and adjusted.

The fuel nozzle is further improved in that the fuel nozzle comprises a fuel nozzle outer wall, a premixed fuel outer wall, an on-duty air outer wall, an on-duty fuel outer wall, a purging air outer wall, a premixed swirl vane, an on-duty swirl vane, an annular premixed fuel partition plate and an annular on-duty fuel partition plate; the outer wall of the fuel nozzle, the outer wall of the premixed fuel, the outer wall of the on-duty air, the outer wall of the on-duty fuel and the outer wall of the purging air are all of concentric circular section thin-wall structures;

the premixing swirl vane is positioned in an annular channel formed by the outer wall of the fuel nozzle and the outer wall of the premixing fuel and is used for dividing the annular channel formed by the outer wall of the fuel nozzle and the outer wall of the premixing fuel into an upstream main combustion air flow channel and a downstream main fuel premixing cavity;

the on-duty swirl vanes are positioned in an annular channel formed by an on-duty air outer wall and an on-duty fuel outer wall and used for dividing the annular channel formed by the on-duty air outer wall and the on-duty fuel outer wall into an upstream on-duty air flow channel and a downstream on-duty fuel premixing cavity;

the annular premixed fuel partition plate is positioned between the outer wall of the premixed fuel and the outer wall of the on-duty air and is used for dividing an annular channel formed by the outer wall of the premixed fuel and the outer wall of the on-duty air into an upstream premixed fuel flow channel and a downstream premixed combustion cooling air flow channel;

the annular on-duty fuel partition plate is positioned between the outer wall of the on-duty fuel and the outer wall of the purging air and is used for dividing an annular channel formed by the outer wall of the on-duty fuel and the outer wall of the purging air into an upstream on-duty fuel flow channel and a downstream on-duty combustion cooling air flow channel;

the outer wall of the purge air is positioned in the center of the fuel nozzle, and a purge air flow channel is arranged in the outer wall of the purge air.

The invention is further improved in that the premixing swirl blade is composed of a blade straight section, swirl blades and a rotary torsion spring, wherein the blade straight section is of a hollow structure, the swirl blades are connected with the blade straight section through the rotary torsion spring, and the premixing swirl blades can freely rotate according to the change condition of aerodynamic force borne by the swirl blades, so that the swirl number of premixed combustible mixed gas can be changed in a self-adaptive manner.

The invention has the further improvement that the front edge of the straight section of the blade is provided with a premixed fuel injection hole, and the rear part of the straight section of the blade is provided with a premixed combustion cooling air hole.

The invention is further improved in that the on-duty swirl blade is composed of a blade straight section, swirl blades and a rotary torsion spring, wherein the blade straight section is of a hollow structure, the swirl blades are connected with the blade straight section through the rotary torsion spring, and the on-duty swirl blades can freely rotate and self-adaptively change the swirl number of the on-duty combustible mixed gas.

The invention is further improved in that the front edge of the straight section of the blade is provided with an on-duty fuel injection hole, and the rear part of the straight section of the blade is provided with an on-duty combustion cooling air hole.

The invention has the further improvement that the downstream sections of the premixed combustion cooling air flow passage, the duty combustion cooling air flow passage and the blowing air flow passage are provided with cooling air jet holes.

The invention has the further improvement that the downstream sections of the premixed combustion cooling air flow passage, the duty combustion cooling air flow passage and the purging air flow passage are provided with purging air injection holes.

The invention has at least the following beneficial technical effects:

the invention provides a gas turbine power generation device adopting a full-premixing low-nitrogen combustion mode, which adopts a full-premixing staged combustion fuel nozzle structure with the self-adaptive adjustment of the swirl number, and designs a premixing swirl vane and an on-duty swirl vane into a rotatable part by considering the positive correlation between aerodynamic force borne by the swirl vane on a fuel nozzle and the load of a gas turbine. In the working process of the gas turbine from starting to full load, the swirl number of the fuel nozzle can be adaptively adjusted along with the load of the gas turbine, the strength of the rotary jet flow entering the combustion chamber is changed by adjusting the swirl number, and then the size of the backflow area in the combustion chamber is controlled.

Drawings

FIG. 1 is a schematic diagram of an embodiment of a gas turbine power plant employing fully premixed low NOx combustion;

FIG. 2 is a schematic view of the combustor components of FIG. 1;

FIG. 3 is a schematic view of the fuel nozzle component of FIG. 2;

FIG. 4 is a schematic view of the swirl vane of FIG. 3;

FIG. 5 is a schematic diagram of swirl vane adaptive adjustment.

Description of reference numerals:

1. an air inlet channel; 2. a compressor; 3. a combustion chamber; 4. a turbine; 5. a rotor; 6. an exhaust passage; 7. a turbine bearing; 8. a compressor bearing; 9. a generator; 10. a fuel nozzle end cover; 11. a flame tube; 12. a transition section; 13. an igniter; 14. a spring sealing sheet; 15. a combustion main air intake; 16. a fuel nozzle; 17. a combustion flame high temperature zone; 18. a primary fuel pipe; 19. a purge air tube; 20. a fuel line on duty; 21. the fuel nozzle pre-mixes the combustion air inlet; 22. a fuel nozzle on-duty combustion air inlet; 23. a fuel nozzle outer wall; 24. an outer wall of the premixed fuel; 25. an air outer wall on duty; 26. an outer wall of the fuel on duty; 27. purging the outer wall of the air; 28. premixing swirl vanes; 29. the on-duty swirl vanes; 30. a premix fuel injection orifice; 31. premixing combustion cooling air holes; 32. an on-duty fuel injection hole; 33. burning cooling air holes on duty; 34. an annular pre-mix fuel membrane; 35. an annular on-duty fuel separator plate; 36. a main combustion air flow passage; 37. a primary fuel premix chamber; 38. a premix fuel runner; 39. a premixed combustion cooling air flow channel; 40. a duty fuel runner; 41. a combustion cooling air flow passage on duty; 42. an air flow passage on duty; 43. the fuel on duty mixes the chamber in advance; 44. purging an air flow channel; 45. premixing combustion cooling air injection holes; 46. a combustion cooling air injection hole on duty; 47. a purge air jet; 48. a straight section of the blade; 49. a torsion spring; 50. and (4) swirl vanes.

Detailed Description

The following detailed description of specific embodiments of the invention refers to the accompanying drawings.

Referring to fig. 1, the gas turbine power generation apparatus according to the present embodiment includes an intake passage 1, a compressor 2, a combustion chamber 3, a turbine 4, a rotor 50, an exhaust passage 6, a turbine bearing 7, a compressor bearing 8, and a generator 9, and forms a gas flow path through them as indicated by arrows in fig. 1.

Along the airflow direction of the gas turbine, the air inlet channel 1 is arranged at the foremost end of the gas turbine, the air compressor 2 is connected with the air inlet channel 1, the combustion chamber 3 is circumferentially and uniformly arranged between the air compressor 2 and the turbine 4 at a certain inclination angle, the outlet of the combustion chamber is connected with the inlet of the turbine, the air compressor 2 is connected with the turbine 4 through the rotor 5, the rotor 5 is supported by the turbine bearing 7 and the air compressor bearing 8, the exhaust channel 6 is connected with the outlet of the turbine, the generator 9 is arranged at the leftmost side of the power generation device, and the generator shaft is connected with the rotor 5. The air inlet channel 1, the air compressor 2, the turbine 4, the rotor 5 and the generator 9 are the same as those of a traditional gas turbine.

When the gas turbine power generation device works, air is sucked into the air inlet channel 1 by the air compressor 2 rotating at a high speed, is guided by the air inlet channel 1 and then enters the air compressor 2, is compressed step by the multi-stage air compressor to form high-pressure air, an interlayer space formed by the combustion chamber 3 and the gas turbine shell returns to flow to the head part of the combustion chamber, enters the combustion chamber 3 from the head part of the combustion chamber, the high-temperature high-pressure fuel gas is quickly combusted with fuel in the combustion chamber 3 to form high-temperature high-pressure fuel gas, then the high-temperature high-pressure fuel gas enters the turbine 4 to expand and do work, the turbine 4 converts the energy of the fuel gas into rotary mechanical energy, the rotary mechanical energy is transmitted to the gas compressor 2 and the generator 9 in a shaft power mode to drive the gas compressor 2 to rotate, meanwhile, the mechanical energy is converted into electric energy through the generator 9, the exhausted gas after expansion is exhausted through the exhaust passage 6, in order to fully utilize the residual heat energy of the exhausted gas, a waste heat boiler can be additionally arranged at the downstream of the exhaust passage 6 to form a gas-steam combined cycle generator set.

Referring to fig. 2, the gas turbine combustor 3 according to the present embodiment is composed of a fuel nozzle end cover 10, a liner 11, a transition section 12, an igniter 13, a spring seal piece 14, a combustion main air intake hole 15, and a fuel nozzle 16, and forms a gas flow path therethrough as indicated by arrows in fig. 2. The fuel nozzle end cover 10 is provided with a fuel nozzle 16, the flame tube 11 is connected with the fuel nozzle 16 through a spring sealing sheet 14, and the transition section 12 is connected with the flame tube 11; the head of the flame tube 11 is provided with a combustion main air inlet 15, and the middle part of the flame tube 11 is provided with an igniter 13. When the combustion chamber 3 works, air participating in combustion enters the flame tube 11 in a rotary jet mode through the combustion main air inlet hole 15 and the fuel nozzle 16, the fuel participating in combustion enters the flame tube 11 after being mixed with the air through the fuel nozzle 16, after combustible mixed gas in the flame tube 11 is ignited through the igniter 13, a combustion flame high-temperature region 17 is formed in the flame tube 11 at the downstream of the fuel nozzle 16, after the ignition is successful, the igniter 13 exits the flame tube 11, the combustible fresh mixed gas newly entering the flame tube 11 is continuously ignited through the combustion flame high-temperature region 17, the fuel is combusted in the flame tube 11 to form high-temperature and high-pressure flue gas, and the flue gas is uniformly mixed in the transition section 12 and is sprayed into the downstream turbine 4 at high speed to expand to do work.

Referring to fig. 3, the gas turbine fuel nozzle assembly according to the present embodiment includes a fuel nozzle end cover 10, a main fuel pipe 18, a purge air pipe 19, an on-duty fuel pipe 20, a fuel nozzle premixed combustion air intake hole 21, a fuel nozzle on-duty combustion air intake hole 22, a fuel nozzle outer wall 23, a premixed fuel outer wall 24, an on-duty air outer wall 25, an on-duty fuel outer wall 26, a purge air outer wall 27, premixed swirl vanes 28, and on-duty swirl vanes 29, and forms a gas flow path therethrough as indicated by arrows in fig. 3. The outer wall 23 of the fuel nozzle, the outer wall 24 of the premixed fuel, the outer wall 25 of the on-duty air, the outer wall 26 of the on-duty fuel and the outer wall 27 of the purging air are coaxially arranged; the premixing swirl blades 28 are arranged in an annular flow channel formed by the outer wall 23 of the fuel nozzle and the outer wall 24 of premixing fuel, the number of the blades is 10, the blades are uniformly arranged in the circumferential direction, 7 premixing fuel injection holes 30 with the diameter of 1.5mm are formed in the blade back of the front edge of the straight section of each blade and in equal intervals with the blade basin, and the rear part of the straight section of each blade is provided with a premixing combustion cooling air hole 31 with the square section of 5mm in length and 3mm in width; the on-duty swirl vanes 29 are arranged in an annular flow passage formed by an on-duty air outer wall 25 and an on-duty fuel outer wall 26, the number of the vanes is 6, the vanes are uniformly arranged in the circumferential direction, 4 on-duty fuel injection holes 32 with the diameter of 1.5mm are arranged at equal intervals on the front edge blade back and the blade basin of the straight section of the vane, and the rear part of the straight section of the vane is provided with a square section on-duty combustion cooling air hole 33 with the length of 5mm and the width of 3 mm. An annular premix fuel membrane 34 is disposed within the annular flow passage formed by the premix fuel outer wall 24 and the air-on-duty outer wall 25; an annular on-duty fuel baffle 35 is disposed within the annular flow passage formed by the on-duty fuel outer wall 26 and the purge air outer wall 27. The premixing swirl vanes 28 divide the annular passage formed by the outer wall 23 of the fuel nozzle and the outer wall 24 of the premixing fuel into two parts, namely a main combustion air flow passage 36 located upstream of the premixing swirl vanes 28 and a main fuel premixing chamber 37 located downstream of the premixing swirl vanes 28. The on-duty swirl vane 29 divides an annular passage formed by the on-duty air outer wall 25 and the on-duty fuel outer wall 26 into two parts, namely an on-duty air flow passage 42 positioned at the upstream of the on-duty swirl vane 29 and an on-duty fuel premixing cavity 43 positioned at the downstream of the on-duty swirl vane 29. The annular premix fuel membrane 34 divides the annular passage formed by the outer premix fuel wall 24 and the outer air wall 25 into two portions, namely a premix fuel flow passage 38 located upstream of the annular premix fuel membrane 34 and a premix combustion cooling air flow passage 39 located downstream of the annular premix fuel membrane 34. The annular on-duty fuel partition 35 divides an annular passage formed by the on-duty fuel outer wall 26 and the purge air outer wall 27 into two parts, namely an on-duty fuel flow passage 40 located upstream of the annular on-duty fuel partition 35 and an on-duty combustion cooling air flow passage 41 located downstream of the annular on-duty fuel partition 35. The space surrounded by the outer purge air wall 27 is a purge air flow passage 44. The right end faces of the premixed combustion cooling air flow passage 39, the on-duty combustion cooling air flow passage 41 and the purge air flow passage 44 are respectively provided with a premixed combustion cooling air injection hole 45, an on-duty combustion cooling air injection hole 46 and a purge air injection hole 47 which are 1mm in diameter.

When the fuel nozzle assembly works, after high-pressure air compressed by the air compressor enters from a combustion main air inlet hole 15 at the head of the flame tube 11, most of the air respectively enters into a main combustion air flow passage 36 and an on-duty air flow passage 42 through a fuel nozzle premixed combustion air inlet hole 21 and a fuel nozzle on-duty combustion air inlet hole 22, a small part of the air enters into the fuel nozzle through a premixed combustion cooling air hole 31, and the air exhausted by the air compressor also partially enters into a purging air flow passage 44 of the fuel nozzle through a purging air pipe 19. Fuel participating in combustion flows through the main fuel pipe 18, the on-duty fuel pipe 20, into the premix fuel flow passages 38 and the on-duty fuel flow passages 40, respectively, into the fuel nozzles. The premixed fuel enters the hollow structure inside the premixing swirl vane 28 through the premixing fuel passage 38 and is injected into the main combustion air passage 36 through the premixing fuel injection hole 30 to be mixed with the main combustion air entering the main combustion air passage 36. The main combustion air and the premixed fuel flow through the premixing swirl blades 28 while being mixed, a rotating airflow is formed after passing through the premixing swirl blades 28, the main combustion air and the premixed fuel are further mixed in the main fuel premixing cavity 37, and the mixed combustible mixed gas enters the downstream flame tube 11 for combustion in a rotating jet flow mode. The duty fuel enters the hollow structure inside the duty swirl vanes 29 through the duty fuel flow passage 40, and is injected into the duty air flow passage 42 through the duty fuel injection hole 32 to be mixed with the duty air entering the duty air flow passage 42. The on-duty air and the on-duty fuel flow through the on-duty swirl vanes 29 while being mixed, a rotating airflow is formed after passing through the on-duty swirl vanes 29, the on-duty air and the on-duty fuel are further mixed in the on-duty fuel premixing cavity 43, and the mixed combustible mixed gas enters the downstream flame tube 11 for combustion in a rotating jet flow mode. Cooling air for cooling the fuel nozzle enters the fuel nozzle from the premixed combustion cooling air holes 31 on the premixed swirl vanes 28 and then is divided into two paths, wherein one path of cooling air passes through the premixed combustion cooling air flow passage 39 and is sprayed out from the premixed combustion cooling air spray holes 45 to cool the wall surface between the main fuel premixing cavity 37 and the on-duty fuel premixing cavity 43; the other path enters the on-duty combustion cooling air flow passage 41 through the on-duty combustion cooling air hole 33 of the on-duty swirl vane 29 and is ejected from the on-duty combustion cooling air ejection hole 46 to cool the wall surface between the on-duty fuel premixing chamber 43 and the purge air flow passage 44. The purging air is sprayed into the downstream flame tube 11 through the purging air flow passage 44 by the purging air spraying holes 47, and the axial position of the backflow zone in the combustion chamber can be adjusted by controlling the flow rate of the purging air, so that the fuel nozzle is prevented from being burnt and damaged by the forward movement of the high-temperature backflow zone.

Referring to fig. 4 and 5, the premixing swirl vane 28 and the on-duty swirl vane 29 of the fuel nozzle according to the present embodiment are each composed of a vane straight section 48, a torsion spring 49, and a swirl vane 50. When the gas turbine is started, the premixing swirl blades 28 and the swirl blades 50 of the on-duty swirl blades 29 are both positioned at the minimum position 51, the rotating jet flow formed by the main combustion air and the on-duty air after passing through the premixing swirl blades 28 and the on-duty swirl blades 29 is strongest, and a strong backflow area is formed at the head of the combustion chamber, so that ignition starting of the combustion chamber is facilitated; after ignition is successful, along with the increase of the flow of combustion air and fuel, the temperature of the combustion chamber gradually rises, the stable combustion boundary of the combustion chamber is widened, at the moment, the aerodynamic force borne by the swirl vanes 50 also increases along with the increase of the air flow, under the action of the aerodynamic force, the swirl vanes 50 gradually overcome the elastic force of the torsion springs 49, and the positions of the swirl vanes 50 are adjusted to the positions 52 in the gradually increasing direction in a self-adaptive manner. When the air flow is increased to the maximum, the swirl vanes 50 are adjusted to the maximum position 53 in a self-adaptive manner, at the moment, the swirl number of the fuel nozzle is the minimum, the main combustion air and the on-duty air respectively pass through the premixing swirl vanes 28 and the on-duty swirl vanes 29 to form weaker rotary jet flow, no backflow zone is formed at the head of the combustion chamber, the residence time of high-temperature flue gas in the combustion chamber can be reduced, and the NOx emission is further reduced. At the shutdown of the gas turbine, the workflow is just reversed, and the positions of the swirl vanes 50 of the pre-mix swirl vanes 28 and the on-duty swirl vanes 29 are gradually adaptively adjusted from the maximum position 53 to the minimum position 51.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. The present invention is not limited to the above-described embodiments, which are described in the specification and illustrated only for illustrating the principle of the present invention, but various changes and modifications may be made within the scope of the present invention as claimed without departing from the spirit and scope of the present invention.