Combustion chamber, gas turbine engine, combustion organization method

Abstract

The invention provides a combustion chamber, a gas turbine engine, and a combustion organization method. Wherein the combustion chamber comprises a graded fuel nozzle and a main swirler, and the main swirler and the graded fuel nozzle are coaxially arranged in the radial direction; the graded fuel nozzle comprises a central nozzle, a pre-combustion-stage swirler and an oil collecting ring; the main swirler comprises a U-shaped guide plate, a main combustion stage swirler and a main swirler outer ring; wherein the U-shaped guide plate, the main combustion stage cyclone, the main swirler outer ring and the oil collecting ring provide a main combustion stage channel; after air flow is baffled by the U-shaped guide plate, a pneumatic trapped vortex area is formed on the outer side of the main combustion stage channel, and an acceleration area is formed on the inner side of the main combustion stage channel.

Description

Technical Field

[0001] The present invention relates to the field of combustion chambers, and in particular to a combustion chamber, a gas turbine engine, and a combustion organization method. Background Art

[0002] The pollutant emission requirements proposed by the ICAO Committee on Aviation Environmental Protection (CAEP) are becoming increasingly stringent. According to the long-term (20 years later) target requirements set at the 7th CAEP meeting in 2007, the NOx emission index is 60% lower than the emission required by the CAEP / 6 standard, and the possibility of CAEP issuing higher emission standards in the future is not ruled out. Other emissions such as carbon monoxide (CO) and unburned hydrocarbons (UHC) must retain a certain margin compared to the emission indicators specified by ICAO.

[0003] Research shows that controlling the maximum gas temperature in the combustion chamber and the temperature uniformity of the combustion zone are the key to controlling NOx pollution emissions. One of the main technical approaches to controlling the temperature of the combustion zone is to adopt a lean premixed combustion mode. However, under working conditions such as ground slow-running and starting ignition, the combustion zone needs to adopt a diffusion combustion oil-gas matching method close to the chemically appropriate ratio to ensure combustion performance, while also reducing CO and UHC emissions under low power conditions. In order to resolve the contradiction between NOx emissions under high power conditions and CO and UHC emissions under low power conditions, domestic and foreign aviation engine research and development units usually adopt a partitioned or staged combustion mode to ensure that the local area of ​​the combustion chamber burns in the best fuel-air matching mode under different engine powers. For example, the dual-annular combustion chamber developed by GE in the high-efficiency energy-saving engine program adopts a radial partitioned combustion mode; the sequential combustion chamber developed by Alstom for the GT36 gas turbine adopts an axial partitioned combustion mode; the TAPS combustion chamber used in GE's LEAP_X and GEnx engines adopts a staged combustion mode.

[0004] The use of central staged combustion technology has become a trend in the development of low-emission combustion chambers due to its compact structure and good NOx control effect through staged lean combustion. However, the existing staged combustion technology often causes flashback in the main combustion channel when the engine is working under high operating conditions, as the premixed fuel-air mixture is easily disturbed by the airflow pressure, resulting in ablation of the inner wall of the main combustion channel.

[0005] The present application proposes a combustion chamber using a counter-flow main vortex finder, which effectively avoids the flashback and ablation problems of the main combustion stage premixing channel while ensuring the low pollution emission level of the combustion chamber, and at the same time can improve the life of the main vortex finder at the fuel nozzle stage. Summary of the invention

[0006] An object of the present invention is to provide a combustion chamber.

[0007] An object of the present invention is to provide a gas turbine engine.

[0008] An object of the present invention is to provide a method for burning tissue.

[0009] According to one aspect of the present invention, a combustion chamber comprises a staged fuel nozzle and a main vortex finder, wherein the main vortex finder is arranged radially coaxially with the staged fuel nozzle; the staged fuel nozzle comprises a central nozzle, a pre-combustion stage swirler, and an oil collecting ring; the main vortex finder comprises a U-shaped guide plate, a main combustion stage swirler, and a main vortex finder outer ring; wherein the U-shaped guide plate, the main combustion stage swirler, the main vortex finder outer ring, and the oil collecting ring provide a main combustion stage channel; wherein, after the airflow is deflected by the U-shaped guide plate, an aerodynamic trapped vortex area is formed on the outside of the main combustion stage channel, and an acceleration area is formed on the inside of the main combustion stage channel.

[0010] In one or more embodiments of the combustion chamber, the main combustion stage swirler comprises a vane-type swirler with 20 to 60 vanes and a vane installation angle between 20° and 60°.

[0011] In one or more embodiments of the combustion chamber, the main combustion stage swirler comprises a multi-inclined hole swirler, the number of holes being 10 to 30, and the inclination angle of the holes being between 20° and 60°.

[0012] In one or more embodiments of the combustion chamber, the pre-combustion stage swirler includes a pre-combustion stage first swirler and a pre-combustion stage second swirler, wherein the pre-combustion stage first swirler and the pre-combustion stage second swirler are both axial or radial swirlers.

[0013] In one or more embodiments of the combustion chamber, the main combustion stage swirler is an axial swirler.

[0014] In one or more embodiments of the combustion chamber, the staged fuel nozzle is manufactured by welding and / or integral casting and / or 3D printing.

[0015] In one or more embodiments of the combustion chamber, the main vortex finder is formed as a whole by welding and / or integral casting and / or 3D printing, and the staged fuel nozzle and the main vortex finder are radially floatingly matched.

[0016] In one or more embodiments of the combustion chamber, the air flow path of the air flow through the main combustion stage channel includes: after the air flow passes through the main combustion stage swirler, the air flow is guided by the first air flow channel defined by the first part of the U-shaped guide plate and the outer wall of the outer ring of the main vortex flow device to flow in a first direction, and then the air flow is guided by the second part of the U-shaped guide plate to flow in a second direction, and the second direction is perpendicular to the first direction. Then, the air flow is guided by the second air flow channel defined by the inner wall of the outer ring of the main vortex flow device and the outer wall of the oil collecting ring to flow in a third direction, and the third direction is opposite to the first direction, forming an aerodynamic trapped vortex area on the outside of the second air flow channel, and forming an acceleration zone on the inside of the main combustion stage channel.

[0017] A gas turbine engine according to yet another aspect of the present invention comprises the combustion chamber described above.

[0018] According to a combustion organization method according to another aspect of the present invention, in the main combustion stage, the main combustion stage channel is configured as a U-shaped channel aerodynamic trapped vortex structure, and the air flow after being deflected by the U-shaped channel forms an aerodynamic trapped vortex area on the outside of the main combustion stage channel, and forms an acceleration zone on the inside of the main combustion stage channel.

[0019] In one or more embodiments of the combustion organization method, a U-shaped guide plate, a main combustion stage swirler, a main vortex outer ring, and an oil collecting ring provide a main combustion stage channel; after the air flow passes through the main combustion stage swirler, the air flow is guided to flow in a first direction by a first air flow channel defined by the first part of the U-shaped guide plate and the outer wall of the main vortex outer ring, and then the air flow is guided to flow in a second direction by the second part of the U-shaped guide plate, and the second direction is perpendicular to the first direction; then the air flow is guided to flow in a third direction by a second air flow channel defined by the inner wall of the main vortex outer ring and the outer wall of the oil collecting ring, and the third direction is opposite to the first direction, forming an aerodynamic trapped vortex area on the outside of the second air flow channel, and an acceleration area on the inside of the main combustion stage channel; fuel is sprayed from the spray holes on the outer wall of the oil collecting ring to the second air flow channel, and mixed with the air flow in the second air flow channel.

[0020] The beneficial effects of adopting the above embodiment scheme include but are not limited to: the main combustion stage channel adopts a U-shaped channel aerodynamic trapped vortex design, the airflow after the U-shaped channel is deflected forms an aerodynamic trapped vortex area on the outside of the main combustion stage channel with a lower flow velocity, and forms an acceleration area on the inside of the main combustion stage channel with a higher flow velocity. On the basis of ensuring the low pollution emission level of the combustion chamber, the flashback and ablation problems of the main combustion stage premixing channel are effectively avoided, and the life of the main vortex device of the fuel nozzle stage can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments. In the accompanying drawings, the same reference numerals always represent the same features. It should be noted that these drawings are only examples and are not drawn according to the conditions of equal scale, and should not be used as a limitation on the actual scope of protection required by the present invention, wherein:

[0022] Figure 1 It is a schematic diagram of the structure of a gas turbine engine according to an embodiment.

[0023] Figure 2 Schematic diagram of the structure of a combustion chamber according to an embodiment.

[0024] Figure 3 It is a schematic structural diagram of a head portion of a combustion chamber according to an embodiment.

[0025] Figure 4 It is a schematic structural diagram of a main vortex finder of a combustion chamber according to one embodiment. DETAILED DESCRIPTION

[0026] Reference will now be made in detail to various embodiments of the present invention, examples of which are shown in the accompanying drawings and described below. Although the present invention will be described in conjunction with the exemplary embodiments, it should be appreciated that this specification is not intended to limit the present invention to those exemplary embodiments. On the contrary, the present invention is intended to cover not only these exemplary embodiments, but also various alternative forms, modifications, equivalent forms and other embodiments that may be included within the spirit and scope of the present invention as defined by the appended claims.

[0027] In the following description, the directions or positional relationships indicated by "axial", "radial", "circumferential", "upstream", "downstream", "inner", "outer" or other directional terms are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, "upstream" and "downstream" are divided according to the direction of airflow, for example, air flows from "upstream" to "downstream".

[0028] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment" and / or "an embodiment" means a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0029] The combustion chamber introduced below is applicable to gas turbine engines, taking aircraft engines as an example, but is not limited to this. For example, it can also be applicable to ship gas turbines, ground gas turbines and other scenarios.

[0030] like Figure 1 As shown, the gas turbine engine, taking an aircraft engine as an example, includes a low-pressure compressor 1, a high-pressure compressor 2, an annular combustion chamber 3, a high-pressure turbine 4 and a low-pressure turbine 5. After being compressed by the low-pressure compressor 1, the air enters the high-pressure compressor 2, and the high-pressure air enters the annular combustion chamber 3 to burn with the fuel. The high-temperature and high-pressure combustion gas formed after the combustion enters the high-pressure turbine 4 and the low-pressure turbine 5, and the high-pressure compressor 2 and the low-pressure compressor 1 are driven respectively through the turbine work.

[0031] like Figure 2 As shown, in some embodiments, the structure of the combustion chamber can be an annular combustion chamber, Figure 2 An enlarged view of the annular combustion chamber 3 is shown. The annular combustion chamber 3 may include a diffuser 300, an outer combustion chamber casing 302, an inner combustion chamber casing 304, a flame tube outer ring 306, a flame tube inner ring 308, a staged fuel nozzle 310, a primary swirler 320, a splash plate 330, and a head transition section 340.

[0032] A plurality of staged fuel nozzles 310 and main vortex finders 320 are evenly arranged along the circumferential direction of the single-annular cavity structure of the annular combustion chamber 3. For example, the number of the staged fuel nozzles 310 and the main vortex finders 320 is 10 to 30, which are circumferentially distributed in the single-annular cavity. After passing through the diffuser 300, the air flows into the flame tube through the staged fuel nozzles 310 and the main vortex finders 320 to organize combustion. The remaining air cools the flame tube wall and the splash plate through the flame tube outer ring 306, the flame tube inner ring 308, and the splash plate 330. The remaining part of the air flows into the high-pressure turbine 4 through the inner and outer annular cavity channels of the combustion chamber to cool the high-pressure turbine blades.

[0033] Figure 3 The figure shows a combustion chamber center staged nozzle assembly, including a staged fuel nozzle 310 and a main swirler 320. The staged fuel nozzle 310 and the main swirler 320 are arranged coaxially, the staged fuel nozzle 310 is in the center, and the main swirler 320 is arranged on the periphery of the staged fuel nozzle 310. The staged fuel nozzle 310 and the main swirler 320 together constitute the pre-combustion stage 31 and the main combustion stage 32 of the center staged nozzle of the annular combustion chamber.

[0034] The staged fuel nozzle 310 may include a central nozzle 311, a pre-combustion stage primary swirler 312, a pre-combustion stage secondary swirler 313, a venturi tube sandwiched between the swirlers 312 and 313, an outer sleeve 315 of the swirler 313, an interstage section 316, and an oil collecting ring 317. It can be understood that the structure of the pre-combustion stage swirler is not limited to the structure of the two-stage swirler described above. The fuel from the main oil circuit is divided into two stages, one of which is supplied to the central nozzle 311 and sprayed from the centrifugal fuel spray hole 318 at the end of the central nozzle 311 to supply the pre-combustion stage 31; the other stage is supplied to the oil collecting ring 317 and sprayed from the direct spray holes 324 uniformly arranged along the circumference on the oil collecting ring 317 to supply the main combustion stage 32. The fuel sprayed from the centrifugal fuel injection hole 318 forms a conical spray and hits the wall of the venturi 314, and is mixed with the air of the pre-combustion stage first swirler 312 and the pre-combustion stage second swirler 313 to form a pre-combustion stage flame downstream. The sleeve 315 is connected to the interstage 316 and the inner wall 319 of the oil collecting ring 317 to form a cavity. The end 328 of the sleeve 315 is provided with at least one row of cooling holes along the circumference of the center line of the graded fuel nozzle 310. The air from the upstream enters the cavity and impacts the cooling interstage 316 through the cooling holes. The cooled air enters the main combustion stage channel 325 along the inner wall of the interstage 316.

[0035] refer to Figure 3 As shown, the main vortex finder 320 may include a U-shaped guide plate 321, a main combustion stage swirler 322, a main vortex finder outer ring 323, and a mounting seat 327. The internal channel of the main vortex finder is U-shaped. The airflow from the diffuser 3 enters the main combustion stage channel 325 formed by the main vortex finder outer ring 323 and the outer wall 326 of the oil collecting ring 317 after being deflected by the main vortex finder, and mixes with the fuel 38 sprayed from the direct injection holes 324 uniformly arranged along the circumference of the oil collecting ring 317, and forms a main combustion stage flame downstream of the main combustion stage channel 325. The U-shaped guide plate 321 here refers to the ability to form a U-shaped channel, and does not mean that the guide plate itself is U-shaped, such as Figure 3 , Figure 4 As shown, the shape of the U-shaped guide plate itself is closer to an L-shaped structure.

[0036] refer to Figure 4 The enlarged view of the main vortex finder 320 shown in the figure shows that the principle of using the structure of the main vortex finder 320 to achieve beneficial effects is that the airflow after being deflected by the U-shaped channel forms an aerodynamic trapped vortex area 36 in the main combustion stage channel 325 near the main vortex finder outer ring 323, with a relatively low flow velocity, and forms an acceleration area in the main combustion stage channel 325 near the oil collecting ring outer wall 326, with a relatively high flow velocity, which can effectively avoid the problem of flashback in the main combustion stage channel 325 and ablation of the oil collecting ring outer wall 326 due to the low flow velocity inside the main combustion stage channel 325 at high engine operating conditions. On the other hand, Figure 4As shown, the main combustion stage fuel 38 is mainly concentrated on the side of the main combustion stage channel 325 close to the outer wall 326 of the oil collecting ring, and is atomized, evaporated and mixed under the swirl shearing action. The main vortex flow device with the above-mentioned design features has a high flow velocity on this side and a strong swirl shearing action, which is beneficial to the atomization, evaporation and mixing of the main combustion stage fuel 38, thereby helping to reduce the emission of pollutants such as NOx and CO in the combustion chamber. Specifically, the air flow passes through the air flow path of the main combustion stage channel 325, as shown in FIG. Figure 3 The path shown by the dashed line, combined with Figure 4 As shown, the path of the air flow may include: after the air flow passes through the main combustion stage swirler 322, the air flow is guided by the first part 3211 of the U-shaped guide plate 321 and the first air flow channel 3251 defined by the outer wall of the main vortex outer ring 323 to flow in a first direction, and then the air flow is guided by the second part 3212 of the U-shaped guide plate 321 to flow in a second direction, and the second direction is perpendicular to the first direction (it can be understood that the vertical here is approximately vertical, not strictly 90°, and there is a certain error). The second part 3212 can be connected perpendicular to the first part 3211, such as the L-shaped structure described above; and then the air flow is guided by the second air flow channel 3252 defined by the inner wall of the main vortex outer ring 323 and the outer wall 326 of the oil collecting ring to flow in a third direction, and the third direction is opposite to the first direction, for example Figure 3 , Figure 4 As shown in the figure, the first direction is the flow direction from right to left, and the third direction is the flow direction from left to right. An aerodynamic trapped vortex area 36 is formed on the radial outer side of the second air flow channel 2352, and an acceleration area is formed on the radial inner side of the second air flow channel 2352, that is, close to the outer wall 326 of the oil collecting ring.

[0037] In some embodiments, the main combustion stage swirler 322 is a vane-type swirler with 20 to 60 blades and a blade installation angle between 20° and 60°.

[0038] In some embodiments, the main combustion stage swirler 322 adopts a multi-inclined hole swirler with 10 to 30 holes, and the inclination angle of the holes is between 20° and 60°.

[0039] In some embodiments, the pre-combustion stage first swirler and the pre-combustion stage second swirler are axial swirlers, and the main combustion stage swirler is an axial swirler.

[0040] In some embodiments, the graded fuel nozzle 310 is designed to be formed as a whole by welding and / or integral casting and / or 3D printing, and the main vortex finder 320 is also designed to be formed as a whole by welding and / or integral casting and / or 3D printing. The graded fuel nozzle 310 and the main vortex finder 320 are radially floatingly matched, and the matching surface is located between the lower end surface of the guide plate 321 and the outer ring surface 326 of the oil collecting ring 317. During assembly, the main vortex finder 320 is first connected to the splash plate 330 and the head transition section 340 through the mounting seat 327, and then the graded fuel nozzle 310 is inserted into the combustion chamber through the outer casing 302, and matched with the main vortex finder 320, and the graded fuel nozzle 310 is fixed to the outer casing by bolts.

[0041] Combined with the above introduction to the annular combustion chamber staged fuel nozzle 310 and the main vortex finder 320, it is also possible to understand an annular combustion chamber 3. The annular combustion chamber 3 adopts the above-mentioned annular combustion chamber staged fuel nozzle 310 and the main vortex finder 320, which can achieve the effect of reducing pollution emissions and avoiding backfire and ablation of the main combustion stage channel under any operating conditions of the engine. At the same time, the design scheme of the above-mentioned annular combustion chamber staged fuel nozzle 310 and the main vortex finder 320 is simple in structure and easy to manufacture.

[0042] As introduced above, the present application also provides a combustion organization method, including: in the main combustion stage, the main combustion stage channel is set as a U-shaped channel aerodynamic trapped vortex structure, and the air flow after being deflected by the U-shaped channel forms an aerodynamic trapped vortex area on the outside of the main combustion stage channel, and forms an acceleration zone on the inside of the main combustion stage channel.

[0043] Preferably, in some embodiments, the air flow after being deflected by the U-shaped channel forms an aerodynamic trapped vortex area on the outside of the main combustion stage channel, and the specific steps of forming an acceleration zone on the inside of the main combustion stage channel may be: a U-shaped guide plate, a main combustion stage swirler, a main vortex device outer ring, and an oil collecting ring provide a main combustion stage channel; after the air flow passes through the main combustion stage swirler, the air flow is guided to flow in a first direction by a first air flow channel defined by the first part of the U-shaped guide plate and the outer wall of the main vortex device outer ring, and then the air flow is guided to flow in a second direction by the second part of the U-shaped guide plate, and the second direction is perpendicular to the first direction; then the air flow is guided to flow in a third direction by a second air flow channel defined by the inner wall of the main vortex device outer ring and the outer wall of the oil collecting ring, and the third direction is opposite to the first direction, an aerodynamic trapped vortex area is formed on the outside of the second air flow channel, and an acceleration zone is formed on the inside of the main combustion stage channel; fuel is sprayed from the spray hole on the outer wall of the oil collecting ring to the second air flow channel, and mixed with the air flow in the second air flow channel.

[0044] To sum up, the beneficial effects of the combustion chamber, gas turbine engine, and combustion organization method introduced above include but are not limited to: a U-shaped channel aerodynamic trapped vortex design is adopted in the main combustion stage channel, and the airflow after being deflected by the U-shaped channel forms an aerodynamic trapped vortex area on the outside of the main combustion stage channel with a lower flow velocity, and forms an acceleration zone on the inside of the main combustion stage channel with a higher flow velocity. On the basis of ensuring the low pollution emission level of the combustion chamber, the flashback and ablation problems of the main combustion stage premixing channel are effectively avoided, and the life of the main vortex device of the fuel nozzle stage can be improved.

[0045] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A combustion chamber, characterized in that: It comprises a staged fuel nozzle and a main vortex finder, wherein the main vortex finder is arranged radially coaxially with the staged fuel nozzle; The staged fuel nozzle includes a central nozzle, a pre-combustion stage swirler, and an oil collecting ring; The main vortex finder includes a U-shaped guide plate, a main combustion stage swirler, and a main vortex finder outer ring; Among them, the U-shaped guide plate, the main combustion stage swirler, the main vortex outer ring, and the oil collecting ring provide a main combustion stage channel; wherein, after the airflow is deflected by the U-shaped guide plate, an aerodynamic trapped vortex area is formed on the outside of the main combustion stage channel, and an acceleration area is formed on the inside of the main combustion stage channel.

2. The combustion chamber according to claim 1, characterized in that The main combustion stage swirler comprises a blade-type swirler, the number of blades is 20 to 60, and the installation angle of the blades is between 20° and 60°.

3. The combustion chamber according to claim 1, characterized in that The main combustion stage cyclone includes a multi-inclined hole cyclone with 10 to 30 holes and an inclination angle of the holes ranging from 20° to 60°.

4. The combustion chamber according to claim 1, characterized in that The pre-combustion stage swirler comprises a pre-combustion stage primary swirler and a pre-combustion stage secondary swirler, wherein the pre-combustion stage primary swirler and the pre-combustion stage secondary swirler are both axial or radial swirlers.

5. The combustion chamber according to claim 1, characterized in that The main combustion stage swirler is an axial swirler.

6. The combustion chamber according to claim 1, characterized in that The graded fuel nozzle is manufactured by welding and / or integral casting and / or 3D printing.

7. The combustion chamber according to claim 1, characterized in that The main vortex finder is formed into a whole by welding and / or integral casting and / or 3D printing, and the graded fuel nozzle and the main vortex finder are radially floatingly matched.

8. The combustion chamber according to claim 1, characterized in that The air flow path of the air flow through the main combustion stage channel includes: after the air flow passes through the main combustion stage swirler, the air flow is guided by the first air flow channel defined by the first part of the U-shaped guide plate and the outer wall of the outer ring of the main vortex finder to flow in a first direction, and then the air flow is guided by the second part of the U-shaped guide plate to flow in a second direction, and the second direction is perpendicular to the first direction. Then the air flow is guided by the second air flow channel defined by the inner wall of the outer ring of the main vortex finder and the outer wall of the oil collecting ring to flow in a third direction, and the third direction is opposite to the first direction, forming an aerodynamic trapped vortex area on the outside of the second air flow channel, and forming an acceleration zone on the inside of the main combustion stage channel.

9. A gas turbine engine, characterized in that: Comprising a combustion chamber as described in any one of claims 1-8.

10. A method for organizing combustion, characterized in that: include: In the main combustion stage, the main combustion stage channel is set as a U-shaped channel aerodynamic trapped vortex structure. The air flow after being deflected by the U-shaped channel forms an aerodynamic trapped vortex area on the outside of the main combustion stage channel and forms an acceleration area on the inside of the main combustion stage channel.

11. The method for organizing combustion according to claim 10, characterized in that: The U-shaped guide plate, the main combustion stage swirler, the main vortex outer ring and the oil collecting ring provide a main combustion stage channel; after the air flow passes through the main combustion stage swirler, the air flow is guided to flow in a first direction by the first air flow channel defined by the first part of the U-shaped guide plate and the outer wall of the main vortex outer ring, and then the air flow is guided to flow in a second direction by the second part of the U-shaped guide plate, and the second direction is perpendicular to the first direction; then the air flow is guided to flow in a third direction by the second air flow channel defined by the inner wall of the main vortex outer ring and the outer wall of the oil collecting ring, and the third direction is opposite to the first direction, forming an aerodynamic trapped vortex area on the outside of the second air flow channel and an acceleration area on the inside of the main combustion stage channel; fuel is sprayed from the spray holes on the outer wall of the oil collecting ring to the second air flow channel and mixed with the air flow in the second air flow channel.

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