Pneumatic auxiliary fuel atomizing device and flame tube head structure having the same

Abstract

The application provides a kind of pneumatic auxiliary fuel atomization device and the flame tube head structure with it, including two-stage axial swirler assembly and pneumatic auxiliary fuel nozzle assembly;Two-stage axial swirler assembly is fixed to the head of flame tube, and is internally provided with hollow cylinder passage, and pneumatic auxiliary fuel nozzle assembly is inserted into the air inlet end of hollow cylinder passage;Two-stage axial swirler assembly includes hub, primary swirler and secondary swirler, which are in multi-stage nested structure from inside to outside, venturi is arranged at the outlet of primary swirler, arc air guide structure is arranged at the air inlet end of hub, and the blade rotation directions of primary swirler and secondary swirler are opposite.The high-speed rotating fuel injected from the secondary oil path fuel swirling chamber or the main oil path fuel swirling chamber by pneumatic auxiliary fuel nozzle assembly and two-stage axial swirler assembly is sheared by high-speed rotating airflow flowing from primary swirler, gas swirling chamber and secondary swirler, and high-quality atomization mixing of low-volatility fuel can be realized.

Description

Pneumatically assisted fuel atomizing device and its flame tube head structure Technical Field

[0001] This application belongs to the field of turbocharger testing systems and gas turbine combustion chambers, and particularly relates to a pneumatically assisted fuel atomizing device and a flame tube head structure having therein. Background Technology

[0002] The turbocharger test system combustion chamber is a single-tube gas turbine combustion chamber that generates high-temperature gas to drive the turbocharger to rotate, thereby conducting turbocharger performance tests.

[0003] The airflow velocity in the combustion chamber of a gas turbine is very high and the fuel residence time is very short. In order to organize stable and efficient combustion in the combustion chamber, high-quality fuel atomization and mixing must be achieved in a very short time. Otherwise, the ignition and shutdown performance, combustion process stability and combustion efficiency will be deteriorated.

[0004] Currently, most advanced gas turbine combustors adopt a dual-swirling combination scheme at the flame tube head. Among them, the air atomizing swirling cup device, which combines a two-stage swirler, a venturi tube, and a fuel injector, has been widely used in combustor design due to its excellent atomization and comprehensive combustion performance.

[0005] Figure 1 shows an air atomizing swirl cup device currently used in combustion chambers. The fuel mist ejected from the injector first splashes onto the venturi tube to form a liquid film, which is then sheared by the high-speed rotating airflow from the first and second swirlers, forming broken fuel droplets. Simultaneously, a large central backflow is formed downstream of the swirlers to achieve efficient and stable combustion. Furthermore, the airflow exiting through the anti-carbon deposit cap helps to remove carbon deposits from the injector tip.

[0006] The currently used air-atomizing swirl cup device has the following problems: First, the central recirculation stable combustion working mode of this air-atomizing swirl cup device limits its air intake volume; otherwise, the velocity in the recirculation zone will be too high, thus worsening the combustion process. However, the low air intake volume limits the shearing effect of the rotating airflow from the first and second stage swirls on fuel droplets, making it difficult to achieve high-quality atomization and mixing of low-volatility fuels. Second, if the airflow through the anti-carbon deposit cap is too high, although it can effectively suppress carbon deposits at the injector tip, the faster airflow has a stronger compression effect on the fuel mist cone, causing the injector spray cone angle to shrink. The shrinkage is even greater at low injection pressures, making it difficult to control the spray cone angle within a small range under different injection pressures, which is not conducive to achieving good fuel atomization and mixing. If the airflow through the anti-carbon deposit cap is too low, the effect on the spray cone angle is weaker, but it is difficult to effectively remove carbon deposits at the injector tip. Summary of the Invention

[0007] In view of this, this application aims to propose a pneumatically assisted fuel atomizing device and a flame tube head structure thereon, in order to solve the technical problems of poor atomization and mixing of low-volatility fuel that rely on the shearing action of two-stage rotating airflow in the existing flame tube head structure, and the difficulty in simultaneously achieving effective removal of carbon deposits at the nozzle tip and small-range changes in the spray cone angle when using an anti-carbon deposit cap structure.

[0008] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0009] In a first aspect, this application provides a pneumatically assisted fuel atomizing device, including a two-stage axial cyclone assembly and a pneumatically assisted fuel nozzle assembly;

[0010] The dual-stage axial swirler assembly is fixed to the head of the flame tube, and the dual-stage axial swirler assembly has a hollow cylindrical channel inside, and the pneumatic auxiliary fuel nozzle assembly is inserted into the air inlet end of the hollow cylindrical channel.

[0011] The dual-stage axial cyclone assembly includes a hub, a first-stage cyclone and a second-stage cyclone arranged in a multi-stage nested structure from the inside to the outside. A venturi tube is provided at the outlet of the first-stage cyclone. The hub is provided with an arc-shaped air guide structure at the air inlet end. The blades in the first-stage cyclone and the second-stage cyclone rotate in opposite directions.

[0012] The pneumatic auxiliary fuel nozzle assembly is provided with a secondary fuel line and a main fuel line, as well as a main fuel line fuel swirl chamber and a secondary fuel line fuel swirl chamber respectively connected to the main fuel line and the secondary fuel line. The pneumatic auxiliary fuel nozzle assembly is also provided with a gas swirl chamber connected to the arc-shaped air guide structure. The gas swirl chamber is located inside the main fuel line fuel swirl chamber, and the main fuel line fuel swirl chamber is located inside the secondary fuel line fuel swirl chamber.

[0013] The gas enters the gas swirl chamber through the arc-shaped gas guide structure, forms a high-speed rotating airflow in the gas swirl chamber, and is then ejected. The high-speed rotating airflow with the opposite direction of rotation to the airflow flowing out from the secondary swirler shears the fuel droplets at the Venturi outlet.

[0014] The high-speed rotating fuel injected through the auxiliary fuel swirl chamber or the main fuel swirl chamber is sheared by the high-speed rotating airflow flowing out from the first-stage swirler, the gas swirl chamber and the second-stage swirler, so as to atomize and mix the fuel.

[0015] Secondly, based on the same inventive concept, this application also provides a flame tube head structure, including:

[0016] The flame tube head is provided with an opening, and a cyclone fixing assembly is fixed at the opening of the flame tube head. The cyclone fixing assembly is a hollow cylindrical structure.

[0017] The pneumatically assisted fuel atomizing device as described in the first aspect is disposed on the cyclone fixing assembly.

[0018] Compared with the prior art, the pneumatically assisted fuel atomizing device and the flame tube head structure having therein described in this application have the following advantages:

[0019] The pneumatically assisted fuel atomizing device and its flame tube head structure described in this application, in a pneumatically assisted fuel atomizing device composed of the pneumatically assisted fuel nozzle assembly and the two-stage axial cyclone assembly, the high-speed rotating fuel injected through the auxiliary fuel cyclone chamber or the main fuel cyclone chamber is sheared by three high-speed rotating airflows flowing from the first-stage cyclone, the gas cyclone chamber, and the second-stage cyclone, which is beneficial for achieving high-quality atomization and mixing of low-volatility fuel. Furthermore, since the high-speed airflow injected from the gas cyclone chamber can prevent the central backflow of high-temperature combustion gas from approaching the end of the pneumatically assisted fuel nozzle assembly, carbon deposits on the end of the pneumatically assisted fuel nozzle assembly can be effectively suppressed, while having minimal impact on the fuel spray cone angle of the pneumatically assisted fuel nozzle assembly. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0021] Figure 1 is a cross-sectional view of the prior art air atomizing swirl cup device described in the embodiment of this application;

[0022] Figure 2 is a cross-sectional view of the pneumatic assisted fuel atomizing device and the flame tube head structure having it, according to an embodiment of this application.

[0023] Figure 3 is a cross-sectional view of the pneumatically assisted fuel atomizing device according to an embodiment of this application;

[0024] Figure 4 is a schematic diagram of the cross-sectional structure along direction AA in Figure 3;

[0025] Figure 5 is a schematic diagram of the cross-sectional structure along the BB direction in Figure 3.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1-Flame tube head; 2-Swamp vortex fixing assembly; 3-Dual-stage axial swamp vortex assembly; 301-Hub; 302-First-stage swamp vortex; 303-Second-stage swamp vortex; 304-Venturi tube; 4-Pneumatic auxiliary fuel nozzle assembly; 401-Secondary fuel passage; 402-Main fuel passage; 403-Air spur hole; 404-Gas swamp chamber; 405-Main fuel passage fuel swamp chamber; 406-Secondary fuel passage fuel swamp chamber; 407-Secondary fuel passage fuel connecting hole; 408-Main fuel passage fuel connecting hole; 409-Gas oblique cut hole; 410-Main fuel passage fuel oblique cut hole; 411-Secondary fuel passage fuel oblique cut hole. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0029] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0030] Please refer to Figures 2 and 3. A pneumatically assisted fuel atomizing device includes a two-stage axial cyclone assembly 3 and a pneumatically assisted fuel nozzle assembly 4.

[0031] The dual-stage axial swirler assembly 3 is fixed to the flame tube head 1, and the dual-stage axial swirler assembly 3 has a hollow cylindrical channel inside, and the pneumatic auxiliary fuel nozzle assembly 4 is inserted into the air inlet end of the hollow cylindrical channel.

[0032] The dual-stage axial cyclone assembly 3 includes a hub 301, a first-stage cyclone 302, and a second-stage cyclone 303 arranged in a multi-stage nested structure from the inside to the outside. A venturi tube 304 is provided at the outlet of the first-stage cyclone 302. An arc-shaped air guide structure is provided at the air inlet end of the hub 301. The blades in the first-stage cyclone 302 and the second-stage cyclone 303 rotate in opposite directions.

[0033] The pneumatic auxiliary fuel nozzle assembly 4 is provided with a secondary fuel passage 401, a main fuel passage 402, and a main fuel passage fuel swirl chamber 405 and a secondary fuel passage fuel swirl chamber 406 that are respectively connected to the main fuel passage 402 and the secondary fuel passage 401. The pneumatic auxiliary fuel nozzle assembly 4 is also provided with a gas swirl chamber 404 that is connected to the arc-shaped air guide structure. The gas swirl chamber 404 is located inside the main fuel passage fuel swirl chamber 405, and the main fuel passage fuel swirl chamber 405 is located inside the secondary fuel passage fuel swirl chamber 406.

[0034] Gas enters the gas swirl chamber 404 through the arc-shaped gas guide structure, and after forming a high-speed rotating airflow in the gas swirl chamber 404, it is ejected. The high-speed rotating airflow with the opposite direction of the rotation from the secondary swirler 303 shears the fuel droplets at the outlet of the venturi tube 304.

[0035] The high-speed rotating fuel injected through the auxiliary fuel swirl chamber 406 or the main fuel swirl chamber 405 is sheared by the high-speed rotating airflow flowing out from the first-stage swirler 302, the gas swirl chamber 404 and the second-stage swirler 303, so as to atomize and mix the fuel.

[0036] Specifically, the dual-stage axial cyclone assembly 3 is matched with the pneumatic auxiliary fuel nozzle assembly 4 as one unit. The gas enters the air intake hole 403 through the arc-shaped air guide structure at the air intake end of the hub 301, and then flows through the gas oblique cut hole 409 and enters the gas cyclone chamber 404. After forming a high-speed rotating airflow in the gas cyclone chamber 404, it is ejected. The high-speed rotating airflow with the opposite direction of the rotation from the secondary cyclone 303 further shears the fuel droplets at the outlet of the venturi tube 304.

[0037] In the pneumatically assisted fuel atomizing device composed of a pneumatically assisted fuel nozzle assembly 4 and a two-stage axial cyclone assembly 3, the high-speed rotating fuel injected through the auxiliary fuel cyclone chamber 406 or the main fuel cyclone chamber 405 is sheared by three high-speed rotating airflows flowing out from the first-stage cyclone 302, the gas cyclone chamber 404 and the second-stage cyclone 303, which is beneficial to achieve high-quality atomization and mixing of low-volatility fuel.

[0038] Downstream of the dual-stage axial cyclone assembly 3, a central backflow will form, causing some of the high-temperature gas to flow back to the vicinity of the end of the pneumatic auxiliary fuel nozzle assembly 4, which can easily lead to carbon buildup at the end of the pneumatic auxiliary fuel nozzle assembly 4. However, the high-speed rotating airflow ejected from the gas cyclone chamber 404 can prevent the central backflow of high-temperature gas from approaching the end of the pneumatic auxiliary fuel nozzle assembly 4, and can effectively suppress carbon buildup at the end of the pneumatic auxiliary fuel nozzle assembly 4.

[0039] The high-speed rotating airflow ejected from the gas swirl chamber 404 has little effect on the fuel spray cone angle of the pneumatic auxiliary fuel nozzle assembly, as it passes inside the fuel mist cone ejected from the auxiliary fuel swirl chamber 406 or the main fuel swirl chamber 405.

[0040] In some embodiments, as shown in Figures 4 and 5, the pneumatic auxiliary fuel nozzle assembly 4 is provided with a connected air intake hole 403 and a gas oblique cut hole 409. The air intake hole 403 is connected to the arc-shaped air guide structure, and the gas oblique cut hole 409 is connected to the gas swirl chamber 404.

[0041] The gas enters the gas inlet 403 through the arc-shaped gas guiding structure, and then flows through the gas oblique cut hole 409 to enter the gas swirl chamber 404.

[0042] In some embodiments, as shown in Figures 4 and 5, the pneumatic auxiliary fuel nozzle assembly 4 is provided with a secondary fuel line connecting hole 407, a main fuel line connecting hole 408, a main fuel line oblique cutting hole 410, and a secondary fuel line oblique cutting hole 411.

[0043] In response to fuel entering the auxiliary fuel passage 401, the fuel flows through the auxiliary fuel passage fuel connecting hole 407, then through the auxiliary fuel passage fuel oblique cutting hole 411, and enters the auxiliary fuel passage fuel swirl chamber 406 to form high-speed rotating fuel. Finally, it is ejected from the outlet of the auxiliary fuel passage fuel swirl chamber 406 and splashed towards the inside of the venturi tube 304.

[0044] In response to the fuel entering the main oil passage 402, the fuel flows through the fuel connecting hole 408 of the main oil passage, then through the fuel oblique cutting hole 410 of the main oil passage, and enters the fuel swirl chamber 405 of the main oil passage to form high-speed rotating fuel. Finally, it is sprayed out from the outlet of the fuel swirl chamber 405 and splashed towards the inside of the venturi tube 304.

[0045] Specifically, when the fuel flow rate required by the pneumatic auxiliary fuel nozzle assembly 4 is low, the fuel flows into the auxiliary fuel passage 401. When the fuel enters the auxiliary fuel passage 401, the fuel first flows through the auxiliary fuel passage fuel connecting hole 407, then through the auxiliary fuel passage fuel oblique cutting hole 411, and then enters the auxiliary fuel passage fuel swirl chamber 406 to form high-speed rotating fuel. Finally, the fuel is sprayed out from the outlet of the auxiliary fuel passage fuel swirl chamber 406 and splashed towards the inside of the venturi tube 304.

[0046] When the fuel flow rate required by the pneumatic auxiliary fuel nozzle assembly 4 is high, the fuel flows into the main fuel passage 402. When the fuel enters the main fuel passage 402, the fuel first flows through the fuel connecting hole 408 of the main fuel passage, then flows through the fuel oblique cutting hole 410 of the main fuel passage, and then enters the fuel swirl chamber 405 of the main fuel passage to form high-speed rotating fuel. Finally, it is sprayed out from the outlet of the fuel swirl chamber 405 and splashed towards the inside of the venturi tube 304.

[0047] The high-speed rotating airflow from the first-stage cyclone separator 302 shears the fuel on the inner wall of the venturi tube 304. At the same time, the swirling direction of the gas flowing out of the first-stage cyclone separator 302 is opposite to the swirling direction of the fuel injected from the auxiliary fuel cyclone chamber 406 or the main fuel cyclone chamber 405, which helps to enhance the shearing effect of the swirling gas on the fuel and form smaller fuel droplets.

[0048] In some embodiments, the diameter of the auxiliary fuel line fuel connection hole 407 is smaller than the diameter of the main fuel line fuel connection hole 408;

[0049] The auxiliary oil passage fuel oblique cut hole 411 is in the same direction as the main oil passage fuel oblique cut hole 410, and the gas passage oblique cut hole 409 is in the opposite direction to the main oil passage fuel oblique cut hole 410.

[0050] The auxiliary oil passage fuel oblique cut hole 411 is tangent to the auxiliary oil passage fuel swirl chamber 406, the main oil passage fuel oblique cut hole 410 is tangent to the main oil passage fuel swirl chamber 405, and the gas passage oblique cut hole 409 is tangent to the gas swirl chamber 404.

[0051] The rotation direction of the gas ejected from the outlet of the gas swirling chamber 404 is the same as the rotation direction of the gas flowing out of the first-stage swirling chamber 302. The rotation direction of the fuel injected from the auxiliary oil circuit fuel swirling chamber 406 and the main oil circuit fuel swirling chamber 405 is the same.

[0052] The gas flowing out of the first-stage cyclone separator 302 rotates in the opposite direction to the gas flowing out of the second-stage cyclone separator 303, and the gas ejected from the outlet of the gas cyclone chamber 404 rotates in the opposite direction to the fuel injected from the auxiliary fuel cyclone chamber 406.

[0053] The direction of gas swirl from the first-stage swirler 302 is opposite to the direction of fuel swirl from the auxiliary fuel swirler 406 or the main fuel swirler 405.

[0054] Specifically, the gas enters the priming hole through the arc-shaped air guide structure at the hub intake end, and then flows through the oblique gas cut hole into the gas swirl chamber. After forming a high-speed rotating airflow in the gas swirl chamber, it is ejected. The high-speed rotating airflow, which is opposite to the swirl direction of the gas flowing out from the secondary swirler, further shears the fuel droplets at the venturi outlet, thereby achieving high-quality shear atomization of low-volatile fuel.

[0055] When implementing this plan:

[0056] When the required fuel flow rate through the pneumatic auxiliary fuel nozzle assembly is low, fuel flows into the secondary fuel passage; when the required fuel flow rate through the pneumatic auxiliary fuel nozzle assembly is high, fuel flows into the main fuel passage. When fuel flows into the secondary or main fuel passage, it first flows through the fuel connection hole of the secondary or main fuel passage, then through the oblique fuel hole of the secondary or main fuel passage, entering the fuel swirl chamber of the secondary or main fuel passage to form high-speed rotating fuel. Finally, it is ejected from the outlet of the fuel swirl chamber of the secondary or main fuel passage and splashed towards the inside of the venturi tube. The fuel then undergoes the following shear atomization process: First, the high-speed rotating airflow from the first-stage cyclone separator shears the fuel on the inner wall of the venturi tube. Simultaneously, the swirling direction of the gas from the first-stage cyclone separator is opposite to the swirling direction of the fuel ejected from the auxiliary or main fuel cyclone chamber, which enhances the shearing effect of the swirling gas on the fuel and forms smaller fuel droplets. Then, the gas enters the bleed-in through the arc-shaped air guide structure at the hub intake end, and then flows through the oblique gas orifice into the gas cyclone chamber. Within the gas cyclone chamber, a high-speed rotating airflow is formed and ejected. This high-speed rotating airflow, with a swirling direction opposite to that from the second-stage cyclone separator, further shears the fuel droplets at the venturi tube outlet, achieving high-quality shear atomization of low-volatile fuel. Furthermore, because the high-speed airflow ejected from the gas cyclone chamber prevents the high-temperature combustion gas from returning to the center and approaching the end of the pneumatic auxiliary fuel nozzle assembly, carbon deposits on the end of the pneumatic auxiliary fuel nozzle assembly are effectively suppressed, while having minimal impact on the fuel spray cone angle of the pneumatic auxiliary fuel nozzle assembly.

[0057] Based on the same inventive concept, corresponding to any of the above-described embodiments, as shown in FIG2, an embodiment of this application also provides a flame tube head structure, including:

[0058] The flame tube head 1 has an opening, and a cyclone fixing component 2 is fixed at the opening of the flame tube head 1. The cyclone fixing component 2 is a hollow cylindrical structure.

[0059] The pneumatically assisted fuel atomizing device, as described in the above embodiment, is installed on the cyclone fixing assembly 2.

[0060] The apparatus of the above embodiments is used to implement the corresponding pneumatically assisted fuel atomizing device in any of the foregoing embodiments, and has the beneficial effects of the corresponding apparatus embodiments, which will not be repeated here.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

[0062] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A pneumatically assisted fuel atomizing device, characterized in that: The system includes a two-stage axial swirler assembly (3) and a pneumatic auxiliary fuel nozzle assembly (4). The two-stage axial swirler assembly (3) is fixed to the head of the flame tube (1), and the two-stage axial swirler assembly (3) has a hollow cylindrical channel inside. The pneumatic auxiliary fuel nozzle assembly (4) is inserted into the air inlet end of the hollow cylindrical channel. The two-stage axial swirler assembly (3) includes a hub (301), a first-stage swirler (302), and a second-stage swirler (303) arranged in a multi-stage nested structure from the inside to the outside. A venturi tube (304) is provided at the outlet of the first-stage swirler (302). The hub (301) has an arc-shaped air guide structure at the air inlet end. The blades of the first-stage cyclone separator (302) rotate in the opposite direction to those of the second-stage cyclone separator (303); the pneumatic auxiliary fuel nozzle assembly (4) is provided with a secondary fuel passage (401), a main fuel passage (402), and a main fuel passage fuel cyclone chamber (405) and a secondary fuel passage fuel cyclone chamber (406) respectively connected to the main fuel passage (402) and the secondary fuel passage (401). The pneumatic auxiliary fuel nozzle assembly (4) is also provided with a gas cyclone chamber (404) connected to the arc-shaped air guide structure. The gas cyclone chamber (404) is located inside the main fuel passage fuel cyclone chamber (405), and the main fuel passage fuel cyclone chamber (405) is located inside the secondary fuel passage fuel cyclone chamber. Inside the flow chamber (406); gas enters the gas swirl chamber (404) through the arc-shaped gas guide structure, forms a high-speed rotating airflow in the gas swirl chamber (404), and is ejected. The high-speed rotating airflow with the opposite rotation direction to that flowing out from the secondary swirler (303) shears the fuel droplets at the outlet of the Venturi tube (304); the high-speed rotating fuel injected through the auxiliary fuel swirl chamber (406) or the main fuel swirl chamber (405) is sheared by the high-speed rotating airflow flowing out from the primary swirler (302), the gas swirl chamber (404), and the secondary swirler (303) to atomize and mix the fuel; the pneumatic The auxiliary fuel nozzle assembly (4) is provided with a connected air intake hole (403) and a gas oblique cut hole (409). The air intake hole (403) is connected to the arc-shaped air guide structure, and the gas oblique cut hole (409) is connected to the gas swirl chamber (404). Gas enters the air intake hole (403) through the arc-shaped air guide structure, and then flows through the gas oblique cut hole (409) and enters the gas swirl chamber (404). The pneumatic auxiliary fuel nozzle assembly (4) is provided with a secondary fuel line fuel connection hole (407), a main fuel line fuel connection hole (408), a main fuel line fuel oblique cut hole (410), and a secondary fuel line fuel oblique cut hole (411).In response to fuel entering the secondary fuel passage (401), the fuel flows through the fuel connecting hole (407) of the secondary fuel passage, then through the fuel oblique hole (411) of the secondary fuel passage, and enters the fuel swirl chamber (406) of the secondary fuel passage to form high-speed rotating fuel. Finally, it is ejected from the outlet of the fuel swirl chamber (406) of the secondary fuel passage and splashed towards the inside of the Venturi tube (304). In response to fuel entering the main fuel passage (402), the fuel flows through the fuel connecting hole (408) of the main fuel passage, then through the fuel oblique hole (410) of the main fuel passage, and enters the fuel swirl chamber (405) of the main fuel passage to form high-speed rotating fuel. Fuel is finally ejected from the outlet of the main fuel swirl chamber (405) and splashed towards the inside of the venturi tube (304); the auxiliary fuel oblique cut hole (411) is in the same direction as the main fuel oblique cut hole (410), and the gas oblique cut hole (409) is in the opposite direction to the main fuel oblique cut hole (410); the auxiliary fuel oblique cut hole (411) is tangent to the auxiliary fuel swirl chamber (406), the main fuel oblique cut hole (410) is tangent to the main fuel swirl chamber (405), and the gas oblique cut hole (409) is tangent to the gas swirl chamber (404).

2. The pneumatically assisted fuel atomizing device according to claim 1, characterized in that: The diameter of the auxiliary oil circuit fuel connection hole (407) is smaller than the diameter of the main oil circuit fuel connection hole (408).

3. The pneumatically assisted fuel atomizing device according to claim 1, characterized in that: The rotation direction of the gas ejected from the outlet of the gas swirling chamber (404) is the same as that of the gas flowing out of the first-stage swirling device (302). The rotation direction of the fuel ejected from the auxiliary oil circuit fuel swirling chamber (406) and the main oil circuit fuel swirling chamber (405) is the same. The rotation direction of the gas flowing out of the first-stage swirling device (302) is opposite to that of the gas flowing out of the second-stage swirling device (303). The rotation direction of the gas ejected from the outlet of the gas swirling chamber (404) is opposite to that of the fuel ejected from the auxiliary oil circuit fuel swirling chamber (406).

4. The pneumatically assisted fuel atomizing device according to claim 1, characterized in that: The direction of gas swirl from the primary swirler (302) is opposite to the direction of fuel swirl from the auxiliary fuel swirler chamber (406) or the main fuel swirler chamber (405).

5. A flame tube head structure, characterized in that, include: The flame tube head (1) is provided with an opening, and a swirler fixing assembly (2) is fixedly provided at the opening of the flame tube head (1). The swirler fixing assembly (2) is a hollow cylindrical structure. The pneumatic assisted fuel atomizing device as described in any one of claims 1-4 is provided on the swirler fixing assembly (2).

Images