CN116358000A - Double-swirl premixing nozzle with fuel sprayed from blades and single-tube combustion chamber structure - Google Patents

Abstract

The invention discloses a double-cyclone premixing nozzle for injecting fuel from blades and a single-tube combustion chamber structure, wherein the double-cyclone premixing nozzle comprises a nozzle body, a primary cyclone, a secondary cyclone, fuel spray holes and a blowing rod, wherein the primary cyclone is internally provided with a primary cyclone blade, the secondary cyclone is internally provided with a secondary cyclone blade, the primary cyclone blade and the secondary cyclone blade are hollow blades, the windward side of each hollow blade is provided with the fuel spray holes, and the blowing rod, the primary cyclone and the secondary cyclone are sequentially and coaxially arranged from inside to outside. The double-swirl premixing nozzle and the single-tube combustion chamber structure provided by the invention have the advantages that the radial distribution uniformity and the mixing effect after fuel-air mixing are improved, the pollution discharge is low, the spontaneous combustion and tempering problems in the nozzle can be avoided, and the low pollution discharge level of the combustion chamber in the whole working condition range is realized by reasonably arranging the nozzles in the single-tube combustion chamber and matching a reasonable grading mode.

Description

Double-swirl premixing nozzle with fuel sprayed from blades and single-tube combustion chamber structure

Technical Field

The invention relates to the technical field of gas turbines, in particular to a double-swirl premixing nozzle with fuel sprayed from blades and a single-tube combustion chamber structure.

Background

With the continuous development of combustion technology and the continuous improvement of environmental protection consciousness, the pollutant emission requirements of the ground gas turbine and the aeroengine are also more and more strict, especially for the heavy gas turbine for power generation. The related art mainly controls emissions in the following ways: post-combustion reduction treatment, water or steam injection in the combustion chamber, dry low emission technology (DLN). The post-combustion reduction catalysis is to generate NO after combustion _X On the surface of the catalyst with a reducing agent (NH) ₃ ) Nitrogen and water are generated, but the method can influence the flexibility of unit operation, and the catalyst is easy to cause secondary pollution; the water or steam is sprayed into the combustion chamber to reduce the temperature of the combustion zone, thereby reducing NO _X Emission, but this affects the life of the hot side components, increasing the operating and maintenance costs; the dry low emission technology is to blend excessive combustion air and fuel to form premixed gas close to lean limit, avoid local high temperature during combustion, and inhibit NO _X Is generated. At present, the research and development and application directions of the combustion chamber of the gas turbine mainly adopt a multi-nozzle dry low-emission combustion technology, and the nozzle scheme in the related technology is difficult to effectively avoid the problems of spontaneous combustion, tempering and the like in the nozzle while improving the fuel-air mixing uniformity and reducing the emission of nitrogen oxides.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, the embodiment of the invention provides the double-swirl premixing nozzle for injecting fuel from the blades, which has the advantages of high fuel-air mixing uniformity and low pollutant emission, and can avoid the problems of spontaneous combustion and tempering in the nozzle.

According to the double-swirl premixing nozzle for injecting fuel from the blades, the double-swirl premixing nozzle for injecting fuel from the blades comprises a nozzle body, a first-stage swirler, a second-stage swirler, fuel spray holes, a fuel channel and a blowing rod, wherein the nozzle body is provided with a nozzle inlet and a nozzle outlet, a straight section is arranged at the nozzle inlet, a converging section and a diverging section are arranged at the nozzle outlet, first-stage swirl blades are arranged in the first-stage swirler, second-stage swirl blades are arranged in the second-stage swirler, the fuel spray holes are positioned on windward sides of the first-stage swirl blades and the second-stage swirl blades, the fuel channel comprises a first-stage fuel channel and a second-stage fuel channel, the first-stage fuel channel and the second-stage fuel channel are respectively communicated with the corresponding fuel spray holes, one end of the blowing rod is positioned in the center of the first-stage swirler, the first-stage swirler and the second-stage swirler are both positioned at the nozzle inlet, and the blowing rod, and the first-stage swirler and the second-stage swirler are sequentially coaxially arranged from inside to outside.

In some embodiments, the primary and secondary swirl vanes are hollow straight vanes circumferentially fixed to and connected to the inner wall of the primary or secondary cyclone.

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 °

In some embodiments, the number of the fuel spray holes on each primary swirl vane is 1-2, and the aperture is 0.5-3 mm; the number of the fuel spray holes on each secondary swirl vane is 2-4, and the aperture is 1-3 mm.

In some embodiments, the nozzle body sequentially and correspondingly forms a straight channel, a converging channel and a diverging channel along the direction from the nozzle inlet to the nozzle outlet, a throat is arranged between the converging channel and the diverging channel, the end face of one end of the blowing rod, which is far away from the primary cyclone, is flush with the throat, an air spray hole is arranged on the end face, and the included angle between the air spray hole and the axial direction of the nozzle body is 15-45 degrees.

In some embodiments, the expansion section is provided with a cooling hole, an axial direction of the cooling hole is parallel to an axial direction of the nozzle body, and the cooling hole communicates with the converging channel and the expanding channel.

In some embodiments, the dual swirl premix nozzle with fuel injection from the vanes further includes a transition trailing edge located at an end of the outer wall of the primary swirler and the inner wall of the secondary swirler adjacent the converging section.

In some embodiments, the combustion zone equivalence ratio of the dual swirl premix nozzle with fuel injected from the vanes is 0.5 to 0.8.

According to the single-tube combustion chamber structure provided by the embodiment of the invention, the single-tube combustion chamber structure comprises a nozzle mounting flange, a flame tube and a plurality of double-swirl nozzles, wherein the nozzle mounting flange is positioned at one end of the flame tube, the double-swirl nozzles are positioned on the nozzle mounting flange, and a plurality of flange cooling holes are formed in the nozzle mounting flange.

In some embodiments, the flange cooling holes have a pore size of 0.8-2mm and a distribution density of 2-4 per square centimeter.

Compared with the prior art, the invention has the following advantages:

(1) The turbulence in the straight section and the convergence section is increased by adopting a mode of combining two-stage rotational flow, the mixing effect between fuel and air is improved, high-temperature hot spots in the combustion chamber can be effectively eliminated, and the pollutant emission level in the combustion chamber is obviously reduced.

(2) The natural gas is injected from the two-stage swirl vanes to improve the radial distribution uniformity of the mixed fuel-air, thereby further improving the pollutant emission level of the combustion chamber.

(3) Through the combination of the modes of designing the transition tail edge, designing a convergent-divergent structure at the outlet of the nozzle, adding blowing air at the center of the nozzle, and the like, the spontaneous combustion and tempering in the nozzle can be effectively avoided, and the flame stabilizing capability is improved.

(4) The double-cyclone premixing nozzle is simple and compact in structure and easy to process, assemble and maintain in the later period. By reasonably arranging a certain number of double-cyclone premixing nozzles and matching a reasonable fuel grading mode and a reasonable fuel supply mode, the low pollution emission level of the combustion chamber in the whole working condition range can be realized.

Drawings

FIG. 1 is a schematic illustration of a dual swirl premix nozzle with fuel injection from vanes in accordance with an embodiment of the invention.

FIG. 2 is a schematic cross-sectional view of a dual swirl premix nozzle with fuel injection from vanes in accordance with an embodiment of the invention.

FIG. 3 is a schematic diagram of a primary swirler of a dual swirl premix nozzle with fuel injection from vanes in accordance with an embodiment of the invention.

FIG. 4 is a schematic diagram of a two-stage swirler of a dual swirl premix nozzle with fuel injection from vanes in accordance with an embodiment of the invention.

Fig. 5 is a schematic view of a structure of a single tube combustion chamber according to an embodiment of the present invention.

FIG. 6 is a schematic view of nozzle staging for a single tube combustor configuration in accordance with an embodiment of the invention.

Reference numerals: 1. a dual swirl premix nozzle; 2. the inner wall of the primary cyclone; 3. a primary swirl vane; 4. the outer wall of the primary cyclone; 5. the inner wall of the secondary cyclone; 6. a secondary swirl vane; 7. the outer wall of the secondary cyclone; 8. a convergence section; 9. an expansion section; 10. blowing off the air channel; 11. a primary swirl passage; 12. a primary fuel passage; 13. a secondary fuel passage; 14. a secondary swirl passage; 15. a transition trailing edge; 16. a straight channel; 17. converging the channel; 18. expanding the channel; 19. a blow-off lever; 20. an air jet orifice; 21. a cooling hole; 22. a throat; 23. vane fuel channel inlets; 24. a fuel injection hole; 25. a nozzle mounting flange; 26. a flange cooling hole; 27. a flame tube; 28. class number; 29. primary combustion; 30 primary combustion secondary.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

According to the double-swirl premixing nozzle for injecting fuel from blades, as shown in fig. 1 to 4, the double-swirl premixing nozzle 1 comprises a nozzle body, a first-stage swirler, a second-stage swirler, fuel spray holes 24, fuel channels and blowing rods 19, wherein the nozzle body is provided with a nozzle inlet and a nozzle outlet, a straight section is arranged at the nozzle inlet, a converging section 8 and a diverging section 9 are arranged at the nozzle outlet, a first-stage swirl blade 3 is arranged in the first-stage swirler, a second-stage swirl blade 6 is arranged in the second-stage swirler, one end of the blowing rods 19 is positioned in the center of the first-stage swirler, the first-stage swirler and the second-stage swirler are both positioned at the nozzle inlet, the fuel spray holes are positioned on windward sides of the first-stage swirl blade 3 and the second-stage swirl blade 6, the fuel channels comprise a first-stage fuel channel and a second-stage fuel channel, the first-stage fuel channel and the second-stage fuel channel are respectively communicated with the fuel spray holes on the corresponding swirl blades, the first-stage fuel channel and the second-stage fuel channel are positioned between the outer wall 4 of the first-stage swirler and the inner wall 5, and the blowing rods 19, and the first-stage swirler and the second-stage swirler are sequentially coaxially arranged from inside the outside. The first-stage fuel enters the first-stage cyclone blade through the first-stage fuel channel 12 and the blade fuel channel inlet 23 and is mixed with the first-stage cyclone air after being sprayed out through the fuel spray holes 24, the second-stage fuel enters the second-stage cyclone blade through the second-stage fuel channel 13 and the blade fuel channel inlet 23 and is mixed with the second-stage cyclone air after being sprayed out through the fuel spray holes 24, the mixed gas after being mixed in the first-stage cyclone channel 11 of the first-stage cyclone and the mixed gas after being mixed in the second-stage cyclone channel 14 of the second-stage cyclone are further mixed in a premixing channel formed by the straight channel 16 and the convergence channel 17, the cyclone strength of the first-stage cyclone is higher than that of the second-stage cyclone, and the mixing uniformity of the fuel-air is effectively improved under the strong shearing force action of the two-stage cyclone, so that high-temperature hot spots in a combustion chamber are eliminated, and the pollutant emission problem in the combustion chamber can be remarkably reduced. The nozzle outlet is designed into a convergent section 8 and an divergent section 9, the convergent section 8 increases the flow velocity of the mixed gas, which is beneficial to inhibiting spontaneous combustion and tempering, and the divergent section 9 reduces the flow velocity of the mixed gas, promotes the formation of a central backflow area, and is beneficial to improving flame stabilizing capability.

The double-swirl premixing nozzle for injecting fuel from the blades has the advantages of high mixing uniformity and capability of avoiding spontaneous combustion and tempering in the nozzle. The mixed gas flow rate is adjusted through the cooperation of the convergent section and the divergent section of the nozzle outlet, and the two-stage cyclone is arranged to improve the mixing uniformity of the fuel gas and reduce the emission of pollutants.

In some embodiments, the primary swirl vanes 3 and the secondary swirl vanes 6 are hollow straight vanes 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.

Specifically, the first-stage swirl blades 3 are hollow straight blades, the number of the blades is 6-18, and the second-stage swirl blades 6 are hollow straight blades, and the number of the blades is 6-18. In the cyclone channels of the primary cyclone and the secondary cyclone, the air entering the inlet is influenced by the blades to generate cyclone motion.

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

Specifically, the angle of the secondary swirl vane 6 is 30-42 degrees, and weak swirl is adopted, so that on one hand, the turbulent flow pulsation intensity of the air flow is weakened, and the tempering and spontaneous combustion risks are reduced; on the other hand, the residence time of the mixed gas is reduced, and the emission of thermal NOx is reduced. The angle of the primary swirl vane 3 is larger than the angle of the secondary swirl vane 6, so that the swirl strength of the primary swirl vane 3 is larger than the secondary swirl vane 6. The turbulence in the premixing section is increased by adopting a mode of combining strong-weak two-stage rotational flow, the mixing effect between fuel and air is improved, high-temperature hot spots in the combustion chamber can be effectively eliminated, and pollutant emission in the combustion chamber is obviously reduced.

In some embodiments, the windward sides of the primary swirl vane 3 and the secondary swirl vane 6 are respectively provided with fuel spray holes 24, the number of the fuel spray holes 24 on the primary swirl vane 3 is 1-2, and the aperture is 0.5-3 mm; the number of the fuel spray holes 24 on the secondary swirl vane 6 is 2-4, and the aperture is 1-3 mm.

Specifically, fuel enters the primary swirl vanes 3 via the primary fuel passages 12 and vane fuel passage inlets 23, enters the primary swirl passages 11 through fuel nozzles, is mixed with primary swirl air, and the number of fuel nozzles 24 provided on the primary swirl vanes 3 is smaller than the number of fuel nozzles 24 provided on the secondary swirl vanes 6. Fuel enters the secondary swirl vanes 6 via the secondary fuel channels 13 and vane fuel channel inlets 23 and passes through the fuel jets into the secondary swirl channels 14 where it is mixed with the secondary swirl air. The mode of injecting fuel gas from the two-stage swirl vanes can improve the radial distribution uniformity after fuel-air mixing, thereby further improving the pollutant emission level.

In some embodiments, as shown in fig. 2, the nozzle body sequentially and correspondingly forms a straight channel 16, a converging channel 17 and a diverging channel 18 along the direction from the inlet of the nozzle to the outlet of the nozzle, a throat 22 is arranged between the converging channel 17 and the diverging channel 18, the end face of one end of the blowing rod 19, which is far away from the primary cyclone, is flush with the throat 22, an air spray hole 20 is arranged on the end face, and the included angle between the air spray hole 20 and the axial direction of the nozzle body is 15-45 degrees.

Specifically, the included angle between the converging section 8 and the diverging section 9 and the axial direction of the nozzle body is 30-50 degrees, the number of air spray holes 20 on the blowing rod 19 is 4-12, and the aperture is 2-6 mm. The blow-off air channels 10 in the blow-off lever 19 supply air uniformly to the air jet holes 20. The convergent-divergent nozzle outlet structure is adopted, the convergent channel 17 increases the flow velocity of the mixture, which is beneficial to suppressing spontaneous combustion and backfire, and the divergent channel 18 decreases the flow velocity of the mixture, which promotes the formation of a central backflow zone, which is beneficial to improving flame stabilizing capability. In addition, air is easy to gather to the outer sides of the straight channel 16 and the converging channel 17 under the swirling condition, the axial speed of the central position is low, the air is sprayed into the central position of the nozzle through the air spray holes 20 to blow off the air, the flame height is raised, and the occurrence of spontaneous combustion and backfire in the nozzle is avoided.

In some embodiments, as shown in fig. 2, the expansion section 9 is provided with a cooling hole 21, 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 converging passage 17 and the expanding passage 18.

Specifically, the cooling hole 21 penetrates the convergent section 8 and the divergent section 9, the cooling hole 21 introduces swirling air into the divergent section 9, the divergent section 9 can be cooled, and the aperture of the cooling hole 21 is 1 to 3mm.

In some embodiments, as shown in FIG. 2, the dual swirl premix nozzle 1 further includes a transition trailing edge 15, the transition trailing edge 15 being located at an end of the primary swirler outer wall 4 and the secondary swirler inner wall 5 adjacent the converging section 8.

Specifically, the transition tail edge 15 can eliminate step vortex and low-speed area in the straight section, and avoid phenomena of spontaneous combustion, tempering and the like.

In some embodiments, the design equivalence ratio of the dual swirl premix nozzle 1 with fuel injected from the vanes is 0.5-0.8.

In particular, when the equivalent ratio of the combustion area is 0.5-0.8, the mixing effect of fuel and air is good, and the lean premixed combustion can effectively inhibit thermal NO _X Is formed by the steps of (a).

According to the single tube combustion chamber structure of the embodiment of the present invention, as shown in fig. 5 and 6, 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 the vane, the nozzle mounting flange 25 is located at one end of the flame tube 27, the double swirl nozzles are located on the nozzle mounting flange 25, and a plurality of flange cooling holes 26 are provided on the nozzle mounting flange 25.

The single tube combustion chamber may be comprised of a flame tube 27, a nozzle mounting flange 25 and six dual swirl premix nozzles 1, the six dual swirl premix nozzles 1 being divided into three stages according to the operating range. One nozzle is arranged in the center as a value class 28, the other five nozzles are arranged around the value class 28, two of the nozzles are used as a main combustion stage 29, the other three are used as main combustion stages 30, and the double swirl premixing nozzles 1 of the same stage share one set of fuel supply system. When the working condition of the combustion chamber is lower, the valve class 28 nozzle is independently combusted by natural gas, and the equivalent ratio is maintained between 0.7 and 0.8 so as to maintain flame stability. With the continuous improvement of working conditions, the nozzles of the primary combustion stage 29 and the nozzles of the primary combustion stage 30 sequentially enter a working mode, and under 100% load, the nozzles of the duty stage 28, the primary combustion stage 29 and the primary combustion stage 30 work simultaneously, and the equivalent ratio of all the nozzles is maintained at 0.5-0.6, so that lower pollutant emission level is ensured. A multi-point lean premixed low pollution combustion chamber is formed by the reasonable arrangement of a plurality of double swirl premixed nozzles 1.

In some embodiments, the flange cooling holes 26 on the flange have a hole diameter of 0.8-2mm and a distribution density of 2-4 per square centimeter.

Specifically, air forms a layer of air film on the downstream end face of the flange through the flange cooling holes 26, so that the burning of fuel gas to the flange is well avoided, the service life of the combustion chamber is prolonged, and meanwhile, the weight of the nozzle mounting flange 25 can be reduced through the flange cooling holes 26.

The technical advantages of the single-tube combustor structure according to the embodiment of the present invention are the same as those of the above-described dual swirl premix nozzle in which fuel is injected from the vanes, and will not be described in detail herein.

In the description of the present 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", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

For purposes of this disclosure, the terms "one embodiment," "some embodiments," "example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations of the above embodiments may be made by those skilled in the art without departing from the scope of the invention.

Claims (10)

1. A dual swirl premix nozzle for injecting fuel from a vane, comprising:

the nozzle comprises a nozzle body, a nozzle body and a nozzle body, wherein the nozzle body is provided with a nozzle inlet and a nozzle outlet, a straight section is arranged at the nozzle inlet, and a converging section and a diverging section are arranged at the nozzle outlet;

the primary cyclone is internally provided with primary cyclone blades;

the secondary cyclone is internally provided with secondary cyclone blades;

one end of the blowing rod is positioned in the center of the primary cyclone;

the fuel spray holes are positioned on the windward sides of the primary swirl vanes and the secondary swirl vanes;

the fuel channel comprises a primary fuel channel and a secondary fuel channel, and the primary fuel channel and the secondary fuel channel are respectively communicated with the corresponding fuel spray holes;

the primary cyclone and the secondary cyclone are both positioned at the inlet of the nozzle, and the blowing rod, the primary cyclone and the secondary cyclone are sequentially and coaxially arranged from inside to outside.

2. The dual swirl premix nozzle of claim 1 wherein said primary swirl vanes and said secondary swirl vanes are hollow straight vanes circumferentially secured to and connected to either the inner primary or secondary swirler walls.

3. A dual swirl premix nozzle for fuel injection from vanes as set forth in claim 2 wherein said primary swirl vanes have a vane angle of 35 ° to 48 ° and said secondary swirl vanes have a vane angle of 30 ° to 42 °.

4. The dual swirl premix nozzle for injecting fuel from vanes as claimed in claim 1, wherein the number of fuel injection holes on each primary swirl vane is 1-2, and the aperture is 0.5-3 mm; the number of the fuel spray holes on each secondary swirl vane is 2-4, and the aperture is 1-3 mm.

5. The double-swirl premixing nozzle for injecting fuel from blades as claimed in claim 1, wherein said nozzle body is formed with a straight channel, a converging channel and a diverging channel along said nozzle inlet to said nozzle outlet, a throat is provided between said converging channel and said diverging channel, an end face of said blowing rod far from one end of said primary swirler is flush with said throat, said end face is provided with air injection holes, and an angle between said air injection holes and said nozzle body is 15 ° to 45 °.

6. A dual swirl premix nozzle for injecting a fuel from a vane as described in claim 1 wherein said diverging section is provided with cooling holes having an axial direction parallel to an axial direction of said nozzle body, said cooling holes communicating said converging and diverging passages.

7. A dual swirl premix nozzle for fuel injection from a vane as described in claim 1 further comprising a transition trailing edge located at an end of said primary swirler outer wall and said secondary swirler inner wall adjacent to a converging section.

8. A dual swirl premix nozzle for injecting a fuel from a vane as defined in claim 1 wherein the dual swirl premix nozzle has a design equivalence ratio of 0.5 to 0.8.

9. A single tube combustor structure comprising a nozzle mounting flange, a flame tube and a plurality of double swirl nozzles, wherein the nozzle mounting flange is positioned at one end of the flame tube, the double swirl nozzles are positioned on the nozzle mounting flange, a plurality of flange cooling holes are formed in the nozzle mounting flange, and the double swirl nozzles are double swirl premixing nozzles for injecting fuel from a vane according to any one of claims 1-9.

10. The single tube combustor structure of claim 9, wherein the flange cooling holes have a diameter of 0.8-2mm and a distribution density of 2-4 per square centimeter.

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