Dual fuel lean premixed swirl nozzle

Abstract

The present application relates to gas turbine technology field and disclose a kind of dual-fuel lean premixed swirled nozzle, the dual-fuel lean premixed swirled nozzle includes nozzle body, blow rod and swirled vane, nozzle body has premixing passage through in its length direction;Blow rod is arranged in premixing passage and extends from feed end to discharge end, blow rod is spaced apart from the inner wall surface of nozzle body to form annular cavity, the free end of blow rod is spaced apart from the end surface of discharge end in the length direction of nozzle body, blow rod has blow channel for air inlet, blow hole is arranged on the free end of blow rod and is communicated with blow channel;Swirled vane is arranged in annular cavity, and swirled flow passage is formed between swirled vane, nozzle body and blow rod, and swirled vane is located between feed end and the free end of blow rod in the length direction of nozzle body.The dual-fuel lean premixed swirled nozzle can pass air into premixing passage by blow rod, and the risk of spontaneous combustion and backfire can be effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, and more specifically, to a dual-fuel lean premixed swirl nozzle. Background Technology

[0002] With the continuous development of combustion technology, improving the adaptability of gas turbine combustors to multiple fuels is an important direction for ground gas turbine combustors. Dual-fuel combustors can effectively broaden the range of fuel adaptability, solve the dependence on a single energy source, improve market competitiveness, and ensure the maintenance and repair of fuel pipelines without shutting down the gas turbine, thereby improving the working efficiency and service life of ground gas turbines.

[0003] Compared to single-fuel combustors, dual-fuel combustors need to meet the operating requirements of both gaseous and liquid fuels. (1) Pollutant emissions: For dual-fuel combustors, when using natural gas, the pollutant emission requirements for gaseous fuels must be met, i.e., NO at an O2 concentration of 15%. X <25ppm, CO <50ppm. When using fuel oil, the pollutant emission levels for liquid fuels must be met, i.e., NO <15% O2 concentration. X <65ppm, CO <100ppm. Additionally, the gas turbine is required to simultaneously meet NO<100ppm requirements within 50% to 100% load. X (2) Combustion stability: Ensure that there is no spontaneous combustion or backfire problem when gaseous fuels and liquid fuels are used alone, and there is no serious oscillating combustion. This requires that when using gaseous fuels or liquid fuels, the combustion chamber has similar fuel-air mixture distribution, main combustion zone location, heat release distribution and flame structure.

[0004] In related technologies, the technical problem of backfire easily occurring in the nozzles of the combustion chamber urgently needs to be solved. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a dual-fuel lean premixed swirl nozzle, which can introduce air into the premixing channel through a purge rod, effectively reducing the risks of spontaneous combustion and backfire.

[0006] The dual-fuel lean premixed swirl nozzle of the present invention comprises:

[0007] The nozzle body has a premixing channel extending through its length and an inlet end and an outlet end disposed opposite each other in its length.

[0008] A blow-off rod is disposed within the premixing channel and extends from the feed end toward the discharge end. The blow-off rod is spaced apart from the inner wall surface of the nozzle body to form an annular cavity. The free end of the blow-off rod is spaced apart from the end face of the discharge end along the length direction of the nozzle body. The blow-off rod has a blow-off channel for introducing air. The free end of the blow-off rod is provided with a blow-off hole communicating with the blow-off channel. The blow-off direction of the blow-off hole forms an angle with the length direction of the nozzle body, and the angle is greater than or equal to 0 degrees and less than 90 degrees.

[0009] A swirling blade is disposed within the annular cavity, and a swirling flow channel is formed between the swirling blade, the nozzle body, and the blow-off rod. The swirling blade is located between the feed end and the free end of the blow-off rod in the longitudinal direction of the nozzle body.

[0010] Optionally, the angle between the blowing direction of the blow-off orifice and the longitudinal direction of the nozzle body is greater than or equal to 15 degrees and less than 45 degrees; and / or

[0011] The blow-off holes are provided in multiple locations, and the multiple blow-off holes are arranged at intervals along the circumference of the nozzle body; and / or

[0012] In a projection plane orthogonal to the length direction of the nozzle body, the blow-off rod is generally located at the center of the premixing channel.

[0013] Optionally, the swirl blades are provided in multiples, and the multiple swirl blades are arranged at circumferential intervals along the nozzle body.

[0014] Optionally, the inner wall surface of the nozzle body is provided with an annular converging protrusion located between the free end of the swirl blade and the blow-off rod in the length direction of the nozzle body, and the protrusion distance of the annular converging protrusion gradually increases in the direction from the feed end to the discharge end.

[0015] Optionally, the position of the annular convergent protrusion with the maximum protrusion distance is set as the minimum premixing channel cross section, and the end face of the free end of the blow-off rod is flush with the minimum premixing channel cross section in the length direction of the nozzle body.

[0016] Optionally, the inner wall surface of the nozzle body is provided with an annular expansion protrusion located between the free end of the blow-off rod and the end face of the discharge end in the length direction of the nozzle body. The protrusion distance of the annular expansion protrusion gradually decreases in the direction from the feed end to the discharge end. The annular expansion protrusion is connected to the annular convergence protrusion.

[0017] Optionally, the annular converging protrusion is provided with a first through hole extending in the length direction of the nozzle body;

[0018] The annular expansion protrusion is provided with a second through hole extending in the length direction of the nozzle body;

[0019] The first through hole is connected to the second through hole to form a cooling through hole.

[0020] Optionally, multiple first through holes and multiple second through holes are provided, with each of the first and second through holes corresponding to one another to form multiple cooling through holes.

[0021] Optionally, the blow-off rod and / or the nozzle body have a liquid channel, and the blow-off rod and / or the nozzle body are provided with a liquid nozzle that communicates with the liquid channel, and the liquid nozzle communicates with the swirling flow channel;

[0022] The blow-off rod and / or the nozzle body have a gas channel, and the blow-off rod and / or the nozzle body are provided with a gas nozzle that communicates with the gas channel and the gas nozzle communicates with the swirling flow channel.

[0023] Optionally, the liquid nozzles are provided in multiple portions, and the multiple liquid nozzles are arranged at circumferential intervals along the nozzle body; and / or

[0024] The gas nozzles are provided in multiple locations, and the multiple gas nozzles are arranged at intervals along the circumference of the nozzle body. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a swirling nozzle according to a specific embodiment of the present invention.

[0026] Figure 2 This is a cross-sectional view of a swirling nozzle according to a specific embodiment of the present invention.

[0027] Figure 3 yes Figure 1 AA view in the middle.

[0028] Figure 4 yes Figure 1 BB view in the middle.

[0029] Reference numerals: 1000-Swirl nozzle, 100-Nozzle body, 110-Premixing channel, 120-Infeed end, 130-Outlet end, 140-Converging protrusion, 150-Annular expansion protrusion, 200-Blowout rod, 210-Free end, 220-Blowout channel, 230-Blowout hole, 300-Swirl blade, a-Annular cavity, b-Swirl channel, c-Minimum premixing channel cross-section, d-Straight section, e-Cooling through hole, f-Liquid nozzle, g-Liquid channel, h-Gas nozzle, i-Gas channel. Detailed Implementation

[0030] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] The following description, with reference to the accompanying drawings, describes an embodiment of the dual-fuel lean premixed swirl nozzle 1000 of the present invention, such as... Figures 1 to 4 As shown, the dual-fuel lean premixed swirl nozzle 1000 of the present invention includes a nozzle body 100, a blow-off rod 200, and swirl blades 300. The nozzle body 100 has a premixing channel 110 extending through its length and an inlet end 120 and an outlet end 130 disposed opposite each other in its length direction. The blow-off rod 200 is disposed within the premixing channel 110 and extends from the inlet end 120 toward the outlet end 130. The blow-off rod 200 is spaced apart from the inner wall surface of the nozzle body 100 to form an annular cavity a. The free end 210 of the blow-off rod 200 is perpendicular to the outlet end 130 in the length direction of the nozzle body 100. The nozzle body 100 is arranged at intervals on its end faces. The blow-off rod 200 has a blow-off channel 220 for introducing air. The free end 210 of the blow-off rod 200 is provided with a blow-off hole 230 communicating with the blow-off channel 220. The blow-off direction of the blow-off hole 230 forms an angle with the length direction of the nozzle body 100, and the angle is greater than or equal to 0 degrees and less than 90 degrees. The swirling blade 300 is provided in the annular cavity a. The swirling blade 300, the nozzle body 100 and the blow-off rod 200 form a swirling flow channel b. The swirling blade 300 is located between the feed end 120 and the free end 210 of the blow-off rod 210 in the length direction of the nozzle body 100.

[0032] According to the dual-fuel lean premixed swirl nozzle 1000 of the present invention, the purge rod 200 in the swirl nozzle 1000 can introduce air at the center position of the premixing channel 110, thereby increasing the air pressure at the center position of the premixing channel 110 and effectively suppressing backfire within the swirl nozzle 1000. Simultaneously, when the gas turbine ignition fails or the gas turbine shuts down, the purge rod 200 can blow unburned mixture out of the gas turbine combustion chamber by introducing air, preventing spontaneous combustion of the mixture in the combustion chamber or deflagration of the mixture during the next combustion chamber ignition. In summary, the purge rod 200 in the swirl nozzle 1000 can reduce the risks of spontaneous combustion and backfire.

[0033] like Figures 1 to 4 As shown, to make the technical solution of this application easier to understand, the technical solution of this application will be described in more detail below using a specific embodiment of the dual-fuel lean premixed swirl nozzle 1000. It should be noted that the nozzle body 100 is parallel to the length direction of... Figure 2 The left and right directions shown are consistent.

[0034] In some specific embodiments, the swirling nozzle 1000 of the present invention injects fuel oil or natural gas. The swirling nozzle 1000 is one of the main components of the turbine combustion chamber. Its main function is to mix the gaseous fuel, liquid fuel, and air, and then inject the mixed gas into the combustion chamber to improve the combustion efficiency of the gaseous and liquid fuels and reduce the generation of nitrogen oxides.

[0035] In some specific embodiments, such as Figures 1 to 4 As shown, the nozzle body 100 is generally cylindrical in shape. Preferably, the nozzle body 100 in this invention is cylindrical. The nozzle body 100 has a premixing channel 110 extending through its length, which can mix gaseous fuel, liquid fuel, and air, thereby improving the combustion efficiency of the gaseous and liquid fuels and reducing the generation of nitrogen oxides. The nozzle body 100 has an inlet end 120 and an outlet end 130 arranged opposite to each other in its length direction.

[0036] In some specific embodiments, such as Figures 1 to 4 As shown, a blow-off rod 200 is disposed within the premixing channel 110 and extends from the feed end 120 toward the discharge end 130. The free end 210 of the blow-off rod 200 is spaced apart from the end face of the discharge end 130 along the length of the nozzle body 100. That is, the blow-off rod 200 is located within the premixing channel 110, and extends from the feed end 120 toward the discharge end 130 to the middle of the premixing channel 110, with a distance between the free end 210 of the blow-off rod 200 and the end face of the discharge end 130. The blow-off rod 200 is spaced apart from the inner wall surface of the nozzle body 100 to form an annular cavity a.

[0037] In some specific embodiments, such as Figures 1 to 4 As shown, the blow-off rod 200 has a blow-off channel 220 for introducing air. Specifically, one end of the blow-off channel 220 is flush with the end face of the feed end 120.

[0038] In some specific embodiments, such as Figures 2 to 4As shown, the free end 210 of the blow-off rod 200 is provided with a blow-off hole 230 communicating with the blow-off channel 220. Specifically, air with a certain pressure enters the nozzle body 100 through the blow-off channel 220, and then enters the middle of the premixing channel 110 through the blow-off hole 230, thereby increasing the air pressure at the center of the premixing channel 110 and effectively suppressing backfire in the swirling nozzle 1000. That is to say, in the premixing channel 110, the mixed gas continuously accumulates towards the inner wall of the nozzle body 100 under swirling conditions, causing the air pressure at the inner wall of the nozzle body 100 to continuously increase, while the air pressure at the center of the premixing channel 110 to continuously decrease. Consequently, the axial velocity of the mixed gas at the center of the premixing channel 110 decreases, making it easier for backfire to occur at the discharge end 130. Meanwhile, when ignition fails or the combustion chamber is extinguished, there will be some premixed gas. The blow-off rod 200 continuously introduces air through the blow-off hole 230. This air can blow the unburned mixture out of the combustion chamber, preventing deflagration when igniting in the combustion chamber next time.

[0039] In some specific embodiments, such as Figure 2 As shown, the blowing direction of the blow-off hole 230 forms an angle with the length direction of the nozzle body 100, and the angle is greater than or equal to 0 degrees and less than 90 degrees. Specifically, the air flowing from the blow-off hole 230 into the premixing channel 110 generally flows towards the discharge end 130.

[0040] Optionally, such as Figure 2 As shown, the angle between the blowing direction of the blow-out hole 230 and the length direction of the nozzle body 100 is greater than or equal to 15 degrees and less than 45 degrees.

[0041] In some specific embodiments, such as Figure 2 As shown, in a projection plane orthogonal to the length direction of the nozzle body 100, the blow-off rod 200 is approximately located at the center of the premixing channel 110. That is, the blow-off rod 200 is located at the centerline of the premixing channel 110.

[0042] It should be noted that the projection plane orthogonal to the length direction of the nozzle body 100 can be understood as the radial section of the nozzle body 100.

[0043] In some specific embodiments, such as Figure 2 As shown, multiple blowout holes 230 are provided, and the multiple blowout holes 23 are arranged at intervals along the circumference of the nozzle body 100. Specifically, the blowout holes 23 can uniformly purge the air in the premixing channel 110, thereby making the air pressure in the premixing channel 110 more uniform, that is, making the air pressure in the premixing channel 110 more stable.

[0044] Optionally, the number of blow-out holes 23 is 4-12.

[0045] Optionally, the diameter of the blow-out hole 23 is 2-6 mm.

[0046] In some specific embodiments, such as Figures 1 to 4 As shown, the swirl vane 300 is disposed in the annular cavity a, and a swirl channel b is formed between the swirl vane 300, the nozzle body 100, and the blow-off rod 200. The swirl vane 300 is located between the feed end 120 and the free end 210 of the blow-off rod 210 in the longitudinal direction of the nozzle body 100. Specifically, air with a certain pressure is guided by the swirl vane 300, causing the air to form a swirl in the annular cavity a.

[0047] In some specific embodiments, such as Figures 1 to 4 As shown, multiple swirl blades 300 are provided, and the multiple swirl blades 300 are arranged at intervals along the circumference of the nozzle body 100.

[0048] Optionally, the swirl blade 300 is a straight blade.

[0049] Optionally, the blade angle of the swirl blade 300 is 30°-45°.

[0050] Optionally, the number of swirl blades 300 is 6-18.

[0051] In some specific embodiments, such as Figure 2 As shown, the inner wall of the nozzle body 100 is provided with an annular converging protrusion 140 located between the swirl vane 300 and the free end 230 of the blow-off rod 200 along the length of the nozzle body 100. The protrusion distance of the annular converging protrusion 140 gradually increases from the feed end 120 to the discharge end 130. It should be noted that the protrusion distance of the annular converging protrusion 140 can be understood as the height of the protrusion. The greater the protrusion distance of the annular converging protrusion 140, the smaller the radial cross-section of the premixing channel 110, that is, the radial cross-section of the premixing channel 110 gradually decreases from the feed end 120 to the discharge end 130. The annular converging protrusion 140 can converge the swirling gas flowing out from the swirl channel b, thereby accelerating the swirling gas and making the swirling speed of the swirling gas faster, thus making the mixed gas more thoroughly mixed. At the same time, the swirling gas continuously converges to the central axis of the premixing channel 110, thereby increasing the gas pressure at the central axis of the premixing channel 110, which can effectively suppress backfire within the swirling nozzle 1000.

[0052] In some specific embodiments, such as Figure 2 As shown, the inner surface of the annular converging protrusion 140 is a conical surface, which is more conducive to guiding the swirling gas.

[0053] Optionally, the inner surface of the annular converging protrusion 140 is a conical surface, and the generatrix of the conical surface forms an angle of 30 to 50 degrees with the central axis of the premixing channel 110.

[0054] In some specific embodiments, such as Figure 2 As shown, the position of the annular convergent protrusion 140 with the maximum protrusion distance is set as the minimum premixing channel section c, and the end face of the free end 210 of the blow-off rod 200 is flush with the minimum premixing channel section c in the length direction of the nozzle body 100.

[0055] In some specific embodiments, such as Figure 2 As shown, the premixing channel 110 has a straight section d, which is located between the swirl vane 300 and the annular converging protrusion 140 in the longitudinal direction of the nozzle body 100. The swirling gas flowing out of the swirl channel b can be fully mixed in the straight section d.

[0056] In some specific embodiments, such as Figure 2 As shown, the inner wall of the nozzle body 100 is provided with an annular expansion protrusion 150 located between the free end 210 of the blow-off rod 200 and the end face of the discharge end 130 along the length of the nozzle body 100. The protrusion distance of the annular expansion protrusion 150 gradually decreases from the feed end 120 to the discharge end 130. The annular expansion protrusion 150 is connected to the annular convergence protrusion 140. Specifically, the smaller the protrusion distance of the annular expansion protrusion 150, the larger the radial cross-section of the premixing channel 110, that is, the radial cross-section of the premixing channel 110 gradually increases from the feed end 120 to the discharge end 130. The annular expansion protrusion 150 can decelerate the swirling gas passing through the annular convergence protrusion 140, thereby promoting the formation of a central recirculation zone in the swirling gas located in the annular expansion protrusion 150, which is beneficial to improving the flame stability of the combustion chamber.

[0057] In some specific embodiments, such as Figure 2 As shown, the inner surface of the annular expansion protrusion 150 is a conical surface, which is more conducive to guiding the swirling gas.

[0058] Optionally, the inner surface of the annular expansion protrusion 150 is a conical surface, and the generatrix of the conical surface forms an angle of 30 to 50 degrees with the central axis of the premixing channel 110.

[0059] In summary, the use of annular expansion protrusions 150 and annular convergence protrusions 140 allows for more thorough mixing of the gas mixture, effectively suppressing backfire and spontaneous combustion. It also promotes the formation of a central recirculation zone, which improves flame stability. The swirl nozzle 1000 has a combustion equivalence ratio of 0.5-0.8 to achieve the design goal of low emissions.

[0060] In some specific embodiments, such as Figure 2As shown, the annular converging protrusion 140 has a first through hole 141 extending in the length direction of the nozzle body 100, and the annular expanding protrusion 150 has a second through hole 151 extending in the length direction of the nozzle body 100. The first through hole 141 and the second through hole 151 communicate to form a cooling through hole e. Specifically, the mixed gas can pass through the cooling through hole e to cool the annular expanding protrusion 150, thereby effectively preventing the temperature of the annular expanding protrusion 150 from becoming too high.

[0061] Optionally, the diameter of the cooling through-hole e is 1-3 mm.

[0062] Optionally, the central axis of the cooling through-hole e is parallel to the central axis of the premixing channel 110.

[0063] In some specific embodiments, such as Figure 2 As shown, there are multiple first through holes 141 and multiple second through holes 151. The first through holes 141 and the second through holes 151 correspond one-to-one to form multiple cooling through holes e.

[0064] In some specific embodiments, such as Figure 2 As shown, the blow-off rod 200 and / or nozzle body 100 have a liquid channel g, and the blow-off rod 200 and / or nozzle body 100 are provided with a liquid nozzle f communicating with the liquid channel g. The liquid nozzle f is connected to the swirling channel b, and liquid fuel can be injected into the swirling channel b through the liquid channel g from the liquid nozzle f, so that the liquid fuel and air are fully mixed.

[0065] In some specific embodiments, such as Figure 2 As shown, there are multiple liquid nozzles f, which are arranged at intervals along the circumference of the nozzle body 100.

[0066] Optionally, the number of liquid nozzles f is 6-18.

[0067] Optionally, the diameter of the liquid nozzle f is 1-5 mm.

[0068] Optionally, the central axis of the liquid nozzle f is orthogonal to the central axis of the premixing channel 110.

[0069] In some specific embodiments, such as Figure 2 As shown, the blow-off rod 200 and / or nozzle body 100 have a gas passage i, and the blow-off rod 200 and / or nozzle body 100 are provided with a gas nozzle h that communicates with the gas passage i. The gas nozzle h is connected to the swirling channel b, and the gaseous fuel can be injected into the swirling channel b through the gas passage i from the gas nozzle h, so that the gaseous fuel and air are fully mixed.

[0070] In some specific embodiments, such as Figure 2As shown, there are multiple gas nozzles h, which are arranged at intervals along the circumference of the nozzle body 100.

[0071] Optionally, the number of gas nozzles h is 6-18.

[0072] Optionally, the diameter of the gas nozzle h is 1-5 mm.

[0073] Optionally, the central axis of the gas nozzle h is orthogonal to the central axis of the premixing channel 110.

[0074] The swirl nozzle 1000 of the present invention can achieve separate operation of gaseous fuel and liquid fuel, or it can achieve mixed operation of gaseous fuel and liquid fuel. The swirl nozzle 1000 of the present invention simplifies the structure, optimizes the fuel-air mixing process, improves the mixing uniformity of the mixture, effectively avoids the occurrence of hot spots in the main combustion zone, thereby reducing the generation of nitrogen oxides.

[0075] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0076] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0077] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0078] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0079] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0080] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A dual-fuel lean premixed swirl nozzle, characterized in that, include: The nozzle body has a premixing channel extending through its length and an inlet end and an outlet end disposed opposite each other in its length. A blow-off rod is disposed within the premixing channel and extends from the feed end toward the discharge end. The blow-off rod is spaced apart from the inner wall surface of the nozzle body to form an annular cavity. The free end of the blow-off rod is spaced apart from the end face of the discharge end along the length direction of the nozzle body. The blow-off rod has a blow-off channel for introducing air. The free end of the blow-off rod is provided with a blow-off hole communicating with the blow-off channel. The blow-off direction of the blow-off hole forms an angle with the length direction of the nozzle body, and the angle is greater than or equal to 0 degrees and less than 90 degrees. A swirl vane is disposed within the annular cavity, and a swirl channel is formed between the swirl vane, the nozzle body, and the blow-off rod. The swirl vane is located between the feed end and the free end of the blow-off rod in the longitudinal direction of the nozzle body. The inner wall of the nozzle body is provided with an annular converging protrusion located between the swirl blade and the free end of the blow-off rod along the length of the nozzle body. The protrusion distance of the annular converging protrusion gradually increases in the direction from the feed end to the discharge end. The position of the annular converging protrusion with the maximum protrusion distance is set as the minimum premixing channel cross-section. The end face of the free end of the blow-off rod is flush with the minimum premixing channel cross-section along the length of the nozzle body. The inner wall of the nozzle body is provided with an annular expanding protrusion located between the end face of the free end of the blow-off rod and the end face of the discharge end along the length of the nozzle body. The protrusion distance of the annular expanding protrusion gradually decreases in the direction from the feed end to the discharge end. The annular expanding protrusion is connected to the annular converging protrusion. The blow-off rod and / or the nozzle body have independent liquid channels and gas channels. The blow-off rod and / or the nozzle body are provided with liquid nozzles communicating with the liquid channels and gas nozzles communicating with the gas channels. Both the liquid nozzles and the gas nozzles are connected to the swirling flow channel.

2. The dual-fuel lean premixed swirl nozzle according to claim 1, characterized in that, The angle between the blowing direction of the blow-off orifice and the longitudinal direction of the nozzle body is greater than or equal to 15 degrees and less than 45 degrees; and / or The blow-off holes are provided in multiple locations, and the multiple blow-off holes are arranged at intervals along the circumference of the nozzle body; and / or In a projection plane orthogonal to the length direction of the nozzle body, the blow-off rod is generally located at the center of the premixing channel.

3. The dual-fuel lean premixed swirl nozzle according to claim 1, characterized in that, The nozzle body has multiple swirl blades, which are arranged at circumferential intervals along the nozzle body.

4. The dual-fuel lean premixed swirl nozzle according to claim 1, characterized in that, The annular converging protrusion is provided with a first through hole extending in the length direction of the nozzle body; The annular expansion protrusion is provided with a second through hole extending in the length direction of the nozzle body; The first through hole is connected to the second through hole to form a cooling through hole.

5. The dual-fuel lean premixed swirl nozzle according to claim 4, characterized in that, The first through hole is provided in multiple ways, and the second through hole is provided in multiple ways. The first through hole and the second through hole correspond one-to-one to form multiple cooling through holes.

6. The dual-fuel lean premixed swirl nozzle according to any one of claims 1-4, characterized in that, - The liquid nozzles are provided in multiple portions, and the multiple liquid nozzles are arranged at intervals along the circumference of the nozzle body; and / or The gas nozzles are provided in multiple locations, and the multiple gas nozzles are arranged at intervals along the circumference of the nozzle body.

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