A double swirl premixing nozzle and single tube combustion chamber structure for injecting fuel from blades

Abstract

The present invention discloses a double swirl premixing nozzle and a single tube combustion chamber structure in which fuel is sprayed from blades. The double swirl premixing nozzle includes a nozzle body, a primary swirler, a secondary swirler, a fuel spray hole and a blow-off rod. A primary swirl blade is arranged in the primary swirler, and a secondary swirl blade is arranged in the secondary swirler. The primary swirl blade and the secondary swirl blade are hollow blades, and a fuel spray hole is arranged on the windward surface of each hollow blade. The blow-off rod, the primary swirler and the secondary swirler are coaxially arranged in sequence from the inside to the outside. The double swirl premixing nozzle and the single tube combustion chamber structure provided by the invention have the advantages of improving the radial distribution uniformity and mixing effect of fuel-air mixing, low pollution emissions, and avoiding the generation of spontaneous combustion and flashback problems in the nozzle. In the single tube combustion chamber, the nozzle is reasonably arranged and matched with a reasonable grading method to achieve a low pollution emission level of the combustion chamber in the full range of working conditions.

Description

Technical Field

[0001] The invention relates to the technical field of gas turbines, and in particular to a double swirl premixing nozzle and a single-tube combustion chamber structure for injecting fuel from blades. Background Art

[0002] With the continuous development of combustion technology and the continuous improvement of environmental awareness, the requirements for pollutant emissions from ground-based gas turbines and aircraft engines are becoming more and more stringent, especially for heavy-duty gas turbines used for power generation. There are several main ways to control emissions in related technologies: post-combustion reduction treatment, water or steam injection in the combustion chamber, and dry low emission technology (DLN). Post-combustion reduction catalysis is the process of converting the NO generated after combustion into X On the catalyst surface, the reducing agent (NH 3 ) to generate nitrogen and water, but this method will affect the flexibility of the unit operation, and the catalyst is prone to secondary pollution; spraying water or steam in the combustion chamber is to reduce the temperature of the combustion zone, thereby reducing NO X However, this will affect the life of the hot end components and increase operation and maintenance costs; dry low-emission technology uses excess combustion air and fuel to mix to form a premixed gas close to the lean combustion limit, avoiding local high temperatures during combustion, thereby suppressing NO X At present, the research and development and application of gas turbine combustion chambers are mainly based on multi-nozzle dry low-emission combustion technology. The nozzle scheme in the relevant technology is difficult to effectively avoid the occurrence of problems such as spontaneous combustion and flashback in the nozzle while improving the fuel-air mixing uniformity and reducing nitrogen oxide emissions. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, an embodiment of the present invention provides a double swirl premixing nozzle in which fuel is injected from a blade, and the double swirl premixing nozzle has the advantages of high fuel-air mixing uniformity, low pollutant emissions, and can avoid the problems of spontaneous combustion and flashback in the nozzle.

[0004] According to an embodiment of the present invention, a double swirl premixing nozzle for injecting fuel from a blade comprises a nozzle body, a primary swirler, a secondary swirler, a fuel spray hole, a fuel channel and a blow-off rod, the nozzle body comprises a nozzle inlet and a nozzle outlet, a straight section is arranged at the nozzle inlet, a convergent section and an expansion section are arranged at the nozzle outlet, a primary swirler is arranged in the primary swirler, a secondary swirler is arranged in the secondary swirler, the fuel spray hole is located on the windward surface of the primary swirler and the secondary swirler, the fuel channel comprises a primary fuel channel and a secondary fuel channel, the primary fuel channel and the secondary fuel channel are respectively connected to the corresponding fuel spray hole, one end of the blow-off rod is located in the center of the primary swirler, the primary swirler and the secondary swirler are both located at the nozzle inlet, and the blow-off rod, the primary swirler and the secondary swirler are coaxially arranged in sequence from the inside to the outside.

[0005] In some embodiments, the primary swirl blades and the secondary swirl blades are hollow straight blades, which are circumferentially fixed to the inner wall of the primary swirler or the secondary swirler and connected to the outer wall of the primary swirler or the secondary swirler.

[0006] In some embodiments, the blade angle of the primary swirl blade is 35° to 48°, and the blade angle of the secondary swirl blade is 30° to 42°.

[0007] In some embodiments, the number of fuel injection holes on each primary swirl blade is 1 to 2, and the hole diameter is 0.5 to 3 mm; the number of fuel injection holes on each secondary swirl blade is 2 to 4, and the hole diameter is 1 to 3 mm.

[0008] In some embodiments, the nozzle body forms a straight channel, a convergent channel and an expansion channel in sequence along the nozzle inlet toward the nozzle outlet, a throat is arranged between the convergent channel and the expansion channel, an end face of the blow-off rod away from the primary cyclone is flush with the throat, an air nozzle hole is arranged on the end face, and an angle between the air nozzle hole and the axial direction of the nozzle body is 15° to 45°.

[0009] In some embodiments, a cooling hole is provided on the expansion section, an axial direction of the cooling hole is parallel to the axial direction of the nozzle body, and the cooling hole connects the convergent channel and the expansion channel.

[0010] In some embodiments, the double swirl premixing nozzle in which the fuel is injected from the vanes further includes a transition trailing edge located at one end of the outer wall of the primary swirler and the inner wall of the secondary swirler adjacent to the convergent section.

[0011] In some embodiments, the combustion zone equivalence ratio of the double swirl premixing nozzle in which the fuel is injected from the blades is 0.5 to 0.8.

[0012] According to the single-tube combustion chamber structure of an embodiment of the present invention, the single-tube combustion chamber structure includes a nozzle mounting flange, a flame tube and a plurality of double swirl nozzles, the nozzle mounting flange is located at one end of the flame tube, the double swirl nozzle is located on the nozzle mounting flange, and a plurality of flange cooling holes are provided on the nozzle mounting flange.

[0013] In some embodiments, the diameter of the flange cooling holes is 0.8 to 2 mm, and the distribution density is 2 to 4 per square centimeter.

[0014] The advantages of the present invention compared with the prior art are as follows:

[0015] (1) The combination of two-stage swirl increases the turbulence in the straight section and the convergent section, improves the mixing effect between fuel and air, can effectively eliminate high-temperature hot spots in the combustion chamber, and significantly reduce the level of pollutant emissions in the combustion chamber.

[0016] (2) The natural gas is injected from two-stage swirl blades to improve the radial distribution uniformity of the fuel-air mixture, thereby further improving the level of pollutant emissions in the combustion chamber.

[0017] (3) By designing the transition trailing edge, designing a "convergent-divergent" structure at the nozzle outlet, and adding purge air at the center of the nozzle, the occurrence of spontaneous combustion and flashback in the nozzle can be effectively avoided and the flame stability capability can be improved.

[0018] (4) The dual swirl premixing nozzle of the present application has a simple and compact structure and is easy to process, assemble and maintain. By properly arranging a certain number of dual swirl premixing nozzles and matching a reasonable fuel grading method and fuel supply method, a low pollution emission level of the combustion chamber can be achieved in the full range of operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of a double swirl premixing nozzle in which fuel is injected from blades according to an embodiment of the present invention.

[0020] Figure 2 It is a cross-sectional schematic diagram of a double swirl premixing nozzle in which fuel is injected from blades according to an embodiment of the present invention.

[0021] Figure 3 The diagram is a schematic structural diagram of a primary swirler of a double swirling premixing nozzle in which fuel is injected from blades according to an embodiment of the present invention.

[0022] Figure 4The figure is a schematic structural diagram of a secondary swirler of a double swirling premixing nozzle in which fuel is injected from blades according to an embodiment of the present invention.

[0023] Figure 5 Schematic diagram of the structure of a single-tube combustion chamber according to an embodiment of the present invention.

[0024] Figure 6 Schematic diagram of nozzle classification of a single-tube combustion chamber structure according to an embodiment of the present invention.

[0025] Figure numerals: 1. double swirl premixing nozzle; 2. first-stage swirler inner wall; 3. first-stage swirl blade; 4. first-stage swirler outer wall; 5. second-stage swirler inner wall; 6. second-stage swirler blade; 7. second-stage swirler outer wall; 8. convergent section; 9. expansion section; 10. blow-off air channel; 11. first-stage swirl channel; 12. first-stage fuel channel; 13. second-stage fuel channel; 14. second-stage swirl channel; 15. transition trailing edge; 16. straight channel; 17. convergent channel; 18. expansion channel; 19. blow-off rod; 20. air spray hole; 21. cooling hole; 22. throat; 23. blade fuel channel inlet; 24. fuel spray hole; 25. nozzle mounting flange; 26. flange cooling hole; 27. flame tube; 28. duty class; 29. ​​main combustion level one; 30 main combustion level two. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0027] According to an embodiment of the present invention, a double swirl premixing nozzle in which fuel is injected from a blade is provided. Figures 1 to 4As shown, the double swirl premixing nozzle 1 includes a nozzle body, a primary swirler, a secondary swirler, a fuel spray hole 24, a fuel channel and a blow-off rod 19. The nozzle body has a nozzle inlet and a nozzle outlet. A straight section is arranged at the nozzle inlet, and a convergent section 8 and an expansion section 9 are arranged at the nozzle outlet. A primary swirl blade 3 is arranged in the primary swirler, and a secondary swirl blade 6 is arranged in the secondary swirler. One end of the blow-off rod 19 is located in the center of the primary swirler. The primary swirler and the secondary swirler are both located at the nozzle inlet. The fuel spray hole is located on the windward surface of the primary swirler blade 3 and the secondary swirler blade 6. The fuel channel includes a primary fuel channel and a secondary fuel channel. The primary fuel channel and the secondary fuel channel are respectively connected to the fuel spray holes on the corresponding swirler blades. The primary fuel channel and the secondary fuel channel are located between the outer wall 4 of the primary swirler and the inner wall 5 of the secondary swirler. The blow-off rod 19, the primary swirler and the secondary swirler are coaxially arranged in sequence from the inside to the outside. The first-stage fuel enters the first-stage swirler blades through the first-stage fuel channel 12 and the blade fuel channel inlet 23, and is mixed with the first-stage swirling air after being ejected through the fuel nozzle hole 24. The second-stage fuel enters the second-stage swirler blades through the second-stage fuel channel 13 and the blade fuel channel inlet 23, and is mixed with the second-stage swirling air after being ejected through the fuel nozzle hole 24. The fuel-air mixed mixture in the first-stage swirling channel 11 of the first-stage swirler and the fuel-air mixed mixture in the second-stage swirling channel 14 of the second-stage swirler are further mixed in the premixing channel composed of the straight channel 16 and the convergent channel 17. The swirling intensity of the first-stage swirler is higher than that of the second-stage swirler. Under the strong shear force of the two-stage swirling, the fuel-air mixing uniformity is effectively improved, thereby eliminating the high-temperature hot spots in the combustion chamber, and can significantly reduce the pollutant emission problem in the combustion chamber. The nozzle outlet is designed to be a convergent section 8 and an expansion section 9. The convergent section 8 increases the flow rate of the mixed gas, which is beneficial to suppressing spontaneous combustion and flashback. The expansion section 9 reduces the flow rate of the mixed gas, prompting the formation of a central reflow zone, which is beneficial to improving the flame stabilization ability.

[0028] According to an embodiment of the present invention, a double swirl premixing nozzle in which fuel is injected from a blade has the advantages of high mixing uniformity and avoiding the problems of spontaneous combustion and flashback in the nozzle. The present application sets a convergent section and an expansion section at the nozzle outlet to adjust the mixed gas flow rate, and sets a two-stage swirler to improve the mixing uniformity of the gas and reduce pollutant emissions.

[0029] In some embodiments, the primary swirl blades 3 and the secondary swirl blades 6 are hollow straight blades, which are circumferentially fixed to the primary cyclone inner wall 2 or the secondary cyclone inner wall 5 and connected to the primary cyclone outer wall 4 or the secondary cyclone outer wall 7.

[0030] Specifically, the primary swirl blades 3 are hollow straight blades with 6 to 18 blades, and the secondary swirl blades 6 are also hollow straight blades with 6 to 18 blades. In the swirl channels of the primary swirler and the secondary swirler, the air entering the inlet is affected by the blades to generate swirl motion.

[0031] In some embodiments, the blade angle of the primary swirl blade 3 is 35° to 48°, and the blade angle of the secondary swirl blade 6 is 30° to 42°.

[0032] Specifically, the angle of the secondary swirl blade 6 is 30° to 42°, which is a weak swirl. On the one hand, it weakens the turbulent pulsation intensity of the airflow and reduces the risk of flashback and spontaneous combustion; on the other hand, it reduces the residence time of the mixed gas and reduces thermal NOx emissions. The angle of the primary swirl blade 3 is greater than that of the secondary swirl blade 6, so that the swirl intensity of the primary swirl blade 3 is greater than that of the secondary swirl blade 6. The combination of strong and weak two-stage swirl increases the turbulence in the premixing section, improves the mixing effect between fuel and air, can effectively eliminate high-temperature hot spots in the combustion chamber, and significantly reduce pollutant emissions in the combustion chamber.

[0033] In some embodiments, fuel spray holes 24 are provided on the windward surfaces of the primary swirl blade 3 and the secondary swirl blade 6. The number of the fuel spray holes 24 on the primary swirl blade 3 is 1 to 2, and the aperture diameter is 0.5 to 3 mm; the number of the fuel spray holes 24 on the secondary swirl blade 6 is 2 to 4, and the aperture diameter is 1 to 3 mm.

[0034] Specifically, the fuel enters the primary swirl blade 3 through the primary fuel channel 12 and the blade fuel channel inlet 23, enters the primary swirl channel 11 through the fuel nozzle and is mixed with the primary swirl air, and the number of fuel nozzles 24 provided on the primary swirl blade 3 is less than the number of fuel nozzles 24 provided on the secondary swirl blade 6. The fuel enters the secondary swirl blade 6 through the secondary fuel channel 13 and the blade fuel channel inlet 23, enters the secondary swirl channel 14 through the fuel nozzle and is mixed with the secondary swirl air. The way of injecting the fuel gas from the two-stage swirl blades can improve the uniformity of the radial distribution of the fuel-air mixture, thereby further improving the level of pollutant emissions.

[0035] In some embodiments, Figure 2 As shown, the nozzle body forms a straight channel 16, a convergent channel 17 and an expansion channel 18 in sequence along the nozzle inlet toward the nozzle outlet, a throat 22 is arranged between the convergent channel 17 and the expansion channel 18, an end face of the blow-off rod 19 away from the primary cyclone is flush with the throat 22, an air nozzle hole 20 is arranged on the end face, and an angle between the air nozzle hole 20 and the axial direction of the nozzle body is 15° to 45°.

[0036] Specifically, the angle between the convergent section 8 and the divergent section 9 and the axial direction of the nozzle body is 30° to 50°, and the number of the air nozzle holes 20 on the blow-off rod 19 is 4 to 12, and the aperture is 2 to 6 mm. The blow-off air channel 10 in the blow-off rod 19 evenly supplies air to the air nozzle holes 20. The convergent-divergent nozzle outlet structure is adopted, and the convergent channel 17 increases the flow rate of the mixed gas, which is beneficial to suppress spontaneous combustion and flashback. The divergent channel 18 reduces the flow rate of the mixed gas, prompting the formation of a central recirculation zone, which is beneficial to improve the flame stabilization ability. In addition, under the swirl condition, the air tends to gather outside the straight channel 16 and the convergent channel 17, and the axial velocity at the center is relatively low. The blow-off air is sprayed into the center of the nozzle through the air nozzle holes 20 to raise the flame height and avoid the occurrence of spontaneous combustion and flashback in the nozzle.

[0037] In some embodiments, Figure 2 As shown, a cooling hole 21 is provided on the expansion section 9 , the axial direction of the cooling hole 21 is parallel to the axial direction of the nozzle body, and the cooling hole 21 communicates with the convergent channel 17 and the expansion channel 18 .

[0038] Specifically, the cooling hole 21 penetrates the convergent section 8 and the expansion section 9. The cooling hole 21 introduces the swirl air into the expansion section 9, which can cool the expansion section 9. The diameter of the cooling hole 21 is 1 to 3 mm.

[0039] In some embodiments, Figure 2 As shown, the double swirl premixing nozzle 1 further comprises a transition trailing edge 15 , which is located at one end of the primary swirler outer wall 4 and the secondary swirler inner wall 5 adjacent to the convergent section 8 .

[0040] Specifically, the provision of the transition trailing edge 15 can eliminate the step vortex and the low-speed area in the straight section, and avoid the occurrence of spontaneous combustion, backfire and the like.

[0041] In some embodiments, the design equivalence ratio of the double swirl premixing nozzle 1 in which the fuel is injected from the blades is 0.5 to 0.8.

[0042] Specifically, when the combustion zone equivalence ratio is 0.5-0.8, the fuel and air mixing effect is good, and the lean premixed combustion can effectively suppress the thermal NO X formation.

[0043] According to the single tube combustion chamber structure of the embodiment of the present invention, Figure 5 and Figure 6 As shown, the single-tube combustion chamber structure includes a nozzle mounting flange 25, a flame tube 27 and a plurality of double swirl nozzles for injecting fuel from blades. The nozzle mounting flange 25 is located at one end of the flame tube 27, the double swirl nozzle is located on the nozzle mounting flange 25, and a plurality of flange cooling holes 26 are provided on the nozzle mounting flange 25.

[0044] The single-tube combustion chamber can be composed of a flame tube 27, a nozzle mounting flange 25 and six double swirl premixing nozzles 1, and the six double swirl premixing nozzles 1 are divided into three levels according to the working condition range. A nozzle is arranged at the center as the duty class 28, and the remaining five nozzles are arranged around the duty class 28 nozzle, of which two nozzles are used as the main combustion level 1 29, and the remaining three are used as the main combustion level 2 30. The double swirl premixing nozzles 1 of the same level share a fuel supply system. When the combustion chamber working condition is low, the duty class 28 nozzle is burned by natural gas alone, and the equivalence ratio is maintained between 0.7 and 0.8 to maintain flame stability. As the working condition continues to improve, the nozzles of the main combustion level 1 29 and the main combustion level 2 30 enter the working mode in turn. Under 100% load, the nozzles of the duty class 28, the main combustion level 1 29 and the main combustion level 2 30 work simultaneously, and the equivalence ratio of all nozzles is maintained at 0.5 to 0.6, ensuring a low level of pollutant emissions. Through the reasonable arrangement of multiple double swirl premixing nozzles 1, a multi-point lean premixing and low-pollution combustion chamber is formed.

[0045] In some embodiments, the diameter of the flange cooling holes 26 on the flange is 0.8-2 mm, and the distribution density is 2-4 per square centimeter.

[0046] Specifically, air forms an air film on the downstream end face of the flange through the flange cooling holes 26 , which effectively avoids the erosion of the flange by the gas and improves the service life of the combustion chamber. At the same time, the flange cooling holes 26 can reduce the weight of the nozzle mounting flange 25 .

[0047] The technical advantages of the single-tube combustion chamber structure according to the embodiment of the present invention are the same as the technical advantages of the double-swirl premixing nozzle in which the fuel is injected from the blades, and will not be repeated here.

[0048] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0049] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0050] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0052] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0053] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A double swirl premixing nozzle in which fuel is injected from blades, characterized in that: include: A nozzle body, wherein the nozzle body has a nozzle inlet and a nozzle outlet, a straight section is arranged at the nozzle inlet, and a convergent section and an expansion section are arranged at the nozzle outlet; A primary cyclone, wherein a primary cyclone is provided with a primary cyclone blade; A secondary cyclone, wherein the secondary cyclone is provided with secondary cyclone blades; A blow-off rod, one end of which is located at the center of the primary cyclone; A fuel injection hole, wherein the fuel injection hole is located on the windward surface of the primary swirl blade and the secondary swirl blade; A fuel channel, wherein the fuel channel includes a primary fuel channel and a secondary fuel channel, and the primary fuel channel and the secondary fuel channel are respectively connected to corresponding fuel injection holes; The primary cyclone and the secondary cyclone are both located at the nozzle inlet, and the blow-off rod, the primary cyclone and the secondary cyclone are coaxially arranged in sequence from the inside to the outside.

2. A double swirl premixing nozzle for injecting fuel from blades according to claim 1, characterized in that: The primary swirl blades and the secondary swirl blades are hollow straight blades, which are circumferentially fixed to the inner wall of the primary cyclone or the inner wall of the secondary cyclone and connected to the outer wall of the primary cyclone or the outer wall of the secondary cyclone.

3. A double swirl premixing nozzle for injecting fuel from blades according to claim 2, characterized in that: The blade angle of the first-stage swirl blade is 35° to 48°, and the blade angle of the second-stage swirl blade is 30° to 42°.

4. A double swirl premixing nozzle for injecting fuel from blades according to claim 1, characterized in that: The number of the fuel injection holes on each of the first-stage swirl blades is 1 to 2, and the hole diameter is 0.5 to 3 mm; the number of the fuel injection holes on each of the second-stage swirl blades is 2 to 4, and the hole diameter is 1 to 3 mm.

5. A double swirl premixing nozzle for injecting fuel from blades according to claim 1, characterized in that: The nozzle body forms a straight channel, a convergent channel and an expansion channel in sequence along the nozzle inlet toward the nozzle outlet, a throat is arranged between the convergent channel and the expansion channel, an end face of the blow-off rod away from the primary cyclone is flush with the throat, an air spray hole is arranged on the end face, and an angle between the air spray hole and the axial direction of the nozzle body is 15° to 45°.

6. A double swirl premixing nozzle for injecting fuel from blades according to claim 5, characterized in that: A cooling hole is arranged on the expansion section, the axial direction of the cooling hole is parallel to the axial direction of the nozzle body, and the cooling hole communicates with the convergent channel and the expansion channel.

7. A double swirl premixing nozzle for injecting fuel from blades according to claim 1, characterized in that: It also includes a transition trailing edge, which is located at one end of the convergent section adjacent to the outer wall of the primary cyclone and the inner wall of the secondary cyclone.

8. A double swirl premixing nozzle for injecting fuel from blades according to claim 1, characterized in that: The design equivalence ratio of the double swirl premixing nozzle is 0.5 to 0.

8.

9. Single tube combustion chamber structure, characterized in that: It includes a nozzle mounting flange, a flame tube and a plurality of double swirl nozzles, wherein the nozzle mounting flange is located at one end of the flame tube, the double swirl nozzles are located on the nozzle mounting flange, a plurality of flange cooling holes are provided on the nozzle mounting flange, and the double swirl nozzle is a double swirl premixing nozzle for injecting fuel from blades as described in any one of claims 1 to 8.

10. The single-tube combustion chamber structure according to claim 9, wherein the diameter of the flange cooling holes is 0.8-2 mm, and the distribution density is 2-4 per square centimeter.

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