Annular flame ring and its aeroengine

Abstract

The application relates to the technical field of aero-engines, and provides a flame-associating ring-vortex precombustion chamber which comprises a first annular wall, a second annular wall and a third annular wall, the first annular wall is provided with first through holes which are uniformly arranged in the circumferential direction, the two sides of the second annular wall are provided with second through holes and third through holes which are uniformly arranged in the circumferential direction, and a contraction-expansion injection hole is arranged between the second through hole and the third through hole; the second annular wall is provided with a first flow guide plate and a second flow guide plate; the first flow guide plate and the second flow guide plate can both guide the airflow to the direction of the first annular wall; a fuel nozzle is arranged in the contraction-expansion injection hole, and the fuel nozzle is provided with a flow gap with the contraction-expansion injection hole. Through the arrangement of the first flow guide plate and the second flow guide plate, a stable central backflow area can be formed at the central position of the precombustion chamber, and the formation of the flow gap makes the overlapping range of the atomization cone angles generated by the fuel nozzles larger, so that effective flame association is realized.

Description

Joint Flame Circular Vortex Pre-combustion Chamber and its Aero-engine Technical Field

[0001] This invention relates to the field of aero-engine technology, and in particular to a combined flame ring vortex pre-combustion chamber. Background Technology

[0002] A vortex pre-combustion chamber typically consists of at least a portion of the entire pre-combustion chamber shell, comprising a first annular wall, a second annular wall, and a third annular wall. A mixing space for fuel and air mixing is formed between the first and third annular walls.

[0003] In related technologies, one method to improve the mixing effect of air and fuel is to use vortex generators. This method requires multiple nozzles and vortex generators, resulting in a large overall weight. Furthermore, each vortex generator creates an independent recirculation zone, making overall flame connection difficult. Another method is to influence the airflow direction by perforating the combustion chamber wall, causing the airflow to automatically form a recirculation zone. This method eliminates the need for vortex generators, but it also suffers from the problem of difficult flame connection. Summary of the Invention

[0004] This invention provides a combined flame annular vortex pre-combustion chamber to solve the problem of difficult combined flame in the pre-combustion chamber in the prior art.

[0005] This invention provides a combined flame vortex pre-combustion chamber, comprising: a first annular wall, a second annular wall, and a third annular wall, wherein the second annular wall is located between the first annular wall and the third annular wall, and a mixing space for mixing fuel and air is formed between the first annular wall and the third annular wall; the first annular wall has a first through hole uniformly arranged circumferentially, the second annular wall has a second through hole and a third through hole uniformly arranged circumferentially on both sides, and the second annular wall between the second through hole and the third through hole has a contraction-expansion nozzle uniformly arranged circumferentially;

[0006] A first guide plate is provided on the second annular wall near the second through hole, and a first guide zone is formed between the first guide plate and the second through hole;

[0007] A second guide plate is provided on the second annular wall near the third through hole, and a second guide zone is formed between the second guide plate and the second through hole;

[0008] Both the first guide zone and the second guide zone can guide the incoming airflow towards the direction of the first annular wall;

[0009] The constriction-expansion nozzle is equipped with a fuel nozzle, and there is a flow gap between the fuel nozzle and the constriction-expansion nozzle so that the incoming airflow can expand the mist cone angle of the fuel nozzle by passing through the flow gap.

[0010] According to the pre-combustion chamber of the tandem vortex provided by the present invention, the contraction-expansion nozzle is constructed as an elliptical structure.

[0011] According to the pre-combustion chamber of the tandem vortex provided by the present invention, the first through hole, the second through hole and the third through hole are provided in a one-to-one correspondence.

[0012] According to the pre-combustion chamber of the tandem vortex provided by the present invention, the second annular wall is configured as an arc-shaped plate structure.

[0013] According to the pre-combustion chamber of the tandem vortex provided by the present invention, the first guide plate has a first guide surface, the second guide plate has a second guide surface, and both the first guide surface and the second guide surface are concentrically arranged with the inner wall surface of the second annular wall.

[0014] According to the pre-combustion chamber of the present invention, the contraction-expansion nozzle is located at the center of the second annular wall in the horizontal direction, so that the output end of the contraction-expansion nozzle is located at the center of the pre-combustion chamber.

[0015] According to the pre-combustion chamber of the vortex ring provided by the present invention, a contraction-expansion tube is sleeved inside the contraction-expansion nozzle, and the diameters of the two ends of the contraction-expansion tube are larger than the diameter of the contraction-expansion nozzle.

[0016] According to the pre-combustion chamber of the tandem vortex provided by the present invention, the inner diameter of the contraction expansion tube gradually increases from the middle to both ends, so as to construct a "trumpet mouth" structure at both ends of the contraction expansion tube.

[0017] According to the pre-combustion chamber of the tandem vortex provided by the present invention, the first guide plate and the second guide plate are integrally formed with the second annular wall.

[0018] The present invention also provides an aero engine, including a flame tube configured as a tandem vortex pre-combustion chamber as described in any of the embodiments above.

[0019] According to any of the above embodiments, the present invention has at least the following beneficial effects:

[0020] The present invention provides a tandem vortex pre-combustion chamber, in which a stable central recirculation zone can be formed at the center of the pre-combustion chamber by setting a first guide plate and a second guide plate. Furthermore, the nozzle is set in a contraction-expansion nozzle, and the contraction-expansion nozzle can expand the atomization cone angle of the fuel nozzle, thereby increasing the overlap range of the atomization cone angles generated by each fuel nozzle, and thus achieving effective tandem flame. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 is a three-dimensional structural schematic diagram of the tandem vortex pre-combustion chamber provided by the present invention;

[0023] Figure 2 is a partial three-dimensional structural schematic diagram of the pre-combustion chamber of the tandem flame ring vortex provided by the present invention;

[0024] Figure 3 is one of the partial cross-sectional structural schematic diagrams of the pre-combustion chamber of the tandem flame ring vortex provided by the present invention;

[0025] Figure 4 is a partial front view of the pre-combustion chamber of the tandem flame ring vortex provided by the present invention;

[0026] Figure 5 is a second partial cross-sectional view of the pre-combustion chamber provided by the present invention;

[0027] Figure 6 is a schematic diagram of a specific embodiment of the tandem vortex pre-combustion chamber provided by the present invention;

[0028] Figure 7 is a schematic diagram of the gas flow direction of each through hole in the pre-combustion chamber of the tandem vortex provided by the present invention when the incoming gas flows;

[0029] Figure 8 shows the test results using the tandem vortex pre-combustion chamber provided by the present invention;

[0030] Figure 9 shows the test results of the pre-combustion chamber in the prior art.

[0031] Figure label:

[0032] 10. First annular wall; 11. First through hole;

[0033] 20. Second annular wall; 21. Second through hole; 22. Third through hole; 23. Contraction-expansion nozzle; 24. Expansion tube; 241. Contraction section; 242. Expansion section;

[0034] 30. The third annular wall;

[0035] 40. First guide vane; 41. First guide surface;

[0036] 50. Second guide vane; 51. Second guide surface;

[0037] 60. Fuel nozzle; 61. Flow clearance;

[0038] 70. Reflux zone. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] In the description of this invention, it should be understood that the terms "axial", "upper", "lower", "circumferential", etc., indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0041] Furthermore, unless otherwise explicitly specified, the terms “first” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or the number of technical features indicated.

[0042] The combustor is an indispensable component of an aero-engine. Due to the complex operating environment of aero-engines, reliable ignition and stable, efficient combustion over a wide fuel-air range are critical issues. The rapid development of the aviation industry has led to various solutions to these problems, one of which is designing the combustor with a ring-vortex structure. This ring-vortex structure offers excellent ignition performance at high altitudes and is suitable for miniaturized aero-engines, reducing overall weight and space requirements. However, traditional ring-vortex combustors suffer from poor air mixing, leading to incomplete combustion, high fuel consumption, high nitrogen oxide emissions, high smoke production, and stringent requirements for evaporator materials and design. Furthermore, the limited flame tube design results in weak flow at the head, causing localized high temperatures and uneven temperature distribution, leading to large outlet temperature distribution coefficients (OTDF and RTDF). Additionally, structural limitations make flame coupling difficult. To address the aforementioned problems, this invention modifies the structure of the combustion chamber wall to resolve the issues of mixing and flame interconnection, as detailed below:

[0043] The following description, in conjunction with Figures 1-2, describes a combined flame vortex pre-combustion chamber of the present invention, comprising: a first annular wall 10, a second annular wall 20, and a third annular wall 30. The second annular wall 20 is located between the first annular wall 10 and the third annular wall 30, and a mixing space for fuel and air is formed between the first annular wall 10 and the third annular wall 30. The first annular wall 10 has first through holes 11 uniformly arranged circumferentially. Second through holes 21 and third through holes 22 are uniformly arranged circumferentially on both sides of the second annular wall 20, and contraction-expansion nozzles 23 are uniformly arranged circumferentially between the second through holes 21 and the third through holes 22. A first guide plate 40 is provided on the second annular wall 20 near the second through hole 21, forming a first guide zone between the first guide plate 40 and the second through hole 21. A second guide plate 50 is provided on the second annular wall 20 near the third through hole 22, forming a second guide zone between the second guide plate 50 and the second through hole 21. Both the first guide zone and the second guide zone can guide the incoming airflow towards the direction of the first annular wall 10. A fuel nozzle 60 is installed inside the contraction-expansion nozzle 23, and a flow gap 61 is provided between the fuel nozzle 60 and the contraction-expansion nozzle 23 so that the incoming airflow can expand the mist cone angle of the fuel nozzle 60 by passing through the flow gap 61.

[0044] The first annular wall 10, the second annular wall 20, and the third annular wall 30 are wall surfaces forming at least a portion of the pre-combustion chamber, and the first annular wall 10, the second annular wall 20, and the third annular wall 30 may be integrally formed. The first through hole 11, the second through hole 21, and the third through hole 22 are located in the direction of gas flow, and the first through hole 11 is located on the first annular wall 10, such that the first through hole 11 is located at the top of the entire pre-combustion chamber. The second through hole 21, the third through hole 22, and the contraction-expansion nozzle 23 are located on the second annular wall 20, such that the second through hole 21, the third through hole 22, and the contraction-expansion nozzle 23 are located on one side wall of the entire pre-combustion chamber.

[0045] The size of the contraction-expansion nozzle 23 is larger than that of the fuel nozzle 60, creating a flow gap 61 between the fuel nozzle 60 body and the inner wall of the contraction-expansion nozzle 23. This allows the incoming gas to pass through the flow gap 61, effectively expanding its atomization cone angle when fuel is injected through the fuel nozzle 60. Specifically, the fuel in this invention is suitable for liquid fuels, such as fuel oil. After the fuel oil is atomized through the fuel nozzle 60, the atomization cone angle expands when the incoming gas flows through the flow gap 61, significantly increasing the overlap area of ​​fuel atomization between adjacent fuel nozzles 60. This enables effective flame fusion after ignition, solving the difficulty of flame fusion in related technologies.

[0046] The first annular wall 10 serves as the upper wall of the pre-combustion chamber in the flame tube, the third annular wall 30 serves as the lower wall of the pre-combustion chamber in the flame tube, and the second annular wall 20 serves as the side wall of the pre-combustion chamber in the flame tube.

[0047] The incoming gas passes through the first through-hole 11 at the top, and the second through-hole 21 and the third through-hole 22 on the second annular wall 20. After passing through the second through-hole 21 and the third through-hole 22, the incoming gas moves towards the upper wall through the guidance of the first guide zone and the second guide zone, respectively. When it approaches the first through-hole 11 at the top, its direction of movement is further changed by the airflow in the first through-hole 11, thereby forming a return flow zone 70 in the region. At this time, the return flow is aligned with the injection direction of the fuel nozzle 60, which improves the mixing effect. Furthermore, the first guide plate 40 and the second guide plate 50 form relatively narrow first and second guide flow zones with the wall surface and the second through-hole 21 and the third through-hole 22 on the wall surface, respectively, which accelerates the movement speed of the incoming gas at the head and improves the uniformity of mixing, thereby making the temperature in the entire combustion chamber uniform.

[0048] It is understood that in the above embodiments, the incoming gas can form a stable recirculation zone 70 in the pre-combustion chamber. The stable recirculation zone 70 is beneficial to stabilizing the flame, and the stable flame enables flame coupling between adjacent fuel nozzles 60. That is, the present invention achieves the formation of a suitable stable recirculation zone 70 by setting the first guide plate 40 and the second guide plate 50, and achieves a stable ignition flame through the stable recirculation zone 70, thereby realizing flame coupling between adjacent fuel injection zones.

[0049] In the specific reference, the diameter of the second through hole 21 is the same as the diameter of the third through hole 22, the diameter of the first through hole 11 is larger than the diameter of the second through hole 21 and the third through hole 22, and the size of the contraction and expansion nozzle 23 is larger than the diameter of the first through hole 11.

[0050] In specific applications, as shown in Figures 3 and 4, the contraction and expansion nozzle 23 is constructed as an elliptical structure.

[0051] The overall configuration of the contraction and expansion nozzle 23 is an elliptical structure. The major axis of the elliptical structure is larger than the size of the fuel nozzle 60 body. The minor axis of the elliptical structure is used to cooperate with the fuel nozzle 60, so that the fuel nozzle 60 can be stably installed on the minor axis of the elliptical structure.

[0052] It is understood that when the expansion nozzle is set to an elliptical structure, the gap between the long half-axis end and the fuel nozzle 60 is a flow gap 61, through which the incoming gas can enter the pre-combustion chamber to expand the atomization cone angle of the fuel nozzle 60.

[0053] In some examples, a contraction-expansion tube 24 is also included, which is fitted inside the contraction-expansion nozzle 23. The diameters of the two ends of the contraction-expansion tube 24 are larger than the diameter of the contraction-expansion nozzle 23. The contraction-expansion tube 24 is used to guide the incoming gas flow.

[0054] The contraction-expansion tube 24 has a tubular structure with large diameters at both ends, exceeding the size of the contraction-expansion nozzle 23. This facilitates the collection of incoming gas and allows it to be ejected through the large-diameter ports, enabling control over the expansion angle of the incoming gas. This further enhances the control over the atomization cone angle expansion of the fuel nozzle 60 and improves the stability of the atomization cone angle expansion effect. In other words, in the above embodiment, the contraction-expansion tube 24 stably expands the atomization cone angle of the fuel nozzle 60, and different atomization cone angles can be achieved by adjusting the angle of the diameter at the ends of the contraction-expansion tube 24.

[0055] Specifically, the inner diameter of the contraction-expansion tube 24 gradually increases from the middle to both ends, so that the two ends of the contraction-expansion tube 24 are constructed as a "trumpet mouth" structure.

[0056] In the above embodiment, the contraction-expansion tube 24 gradually increases in diameter as it approaches both ends, thus forming a funnel-like structure. The diameter is smallest in the middle, and the structure in the middle position is designed to fit into the contraction-expansion nozzle 23 for connection. This structural design ensures that the contraction-expansion tube 24 has stable connection strength after connection, enabling stable introduction and export of incoming gas.

[0057] The arrangement of the two flared mouth structures allows the incoming gas to enter in a generally smooth manner, while its flow velocity is accelerated when passing through the small diameter section in the middle, resulting in a higher initial velocity when ejected from the other flared mouth, thereby accelerating the flow of gas in the pre-combustion chamber.

[0058] In a specific example, as shown in Figure 2, the contraction-expansion tube 24 is an elliptical tubular structure, specifically comprising a contraction section 241 and an expansion section 242. The expansion section 242 is located closer to the pre-combustion chamber, while the contraction section 241 is located further away from the pre-combustion chamber. The length of the expansion section 242 is greater than the length of the contraction section 241, and the inner diameter of the expansion section 242 is greater than the inner diameter of the contraction section 241. That is, the major semi-axis dimension of the expansion section 242 is greater than the major semi-axis dimension of the contraction section 241, and the minor semi-axis dimension of the expansion section 242 is greater than the minor semi-axis dimension of the contraction section 241.

[0059] In some examples, the first through hole 11, the second through hole 21, and the third through hole 22 are set in a one-to-one correspondence.

[0060] As shown in Figure 1, the first through hole 11, the second through hole 21, and the third through hole 22 are distributed in a one-to-one correspondence, that is, the first through hole 11, the second through hole 21, and the third through hole 22 are distributed on the same radial line. This arrangement allows the incoming gas flow to enter through the holes at the same radial position, and the flow direction of the incoming gas can be controlled through the holes in their respective directions, which is beneficial to the stability of the return zone 70.

[0061] In specific applications, the second annular wall 20 is configured as an arc-shaped plate structure.

[0062] As shown in Figure 2, the upper end of the second annular wall 20 is connected to the first annular wall 10, and the lower end of the second annular wall 20 is connected to the third annular wall 30. The whole structure is an arc shape. The second through hole 21 is arranged at the upper end of the arc shape, and the third through hole 22 is arranged at the lower end of the arc shape.

[0063] In this design, the first guide plate 40 at the upper end extends upward along its arc surface, allowing the incoming gas to flow towards the first annular wall 10 after passing through the first guide zone. The second guide plate 50 at the lower end also extends upward along its arc surface, forming a second guide zone between the second guide plate 50 and the second annular wall 20. The incoming gas flows towards the first annular wall 10 through this second guide zone. In other words, the structures of both guide zones direct the incoming gas upward, as indicated by the arrows in Figure 7.

[0064] Furthermore, the contraction-expansion nozzle 23 is positioned at the center of the second annular wall 20 in the horizontal direction, so that the output end of the contraction-expansion nozzle 23 is located at the center of the pre-combustion chamber.

[0065] It is understood that in the above embodiments, under the action of the first through-hole 11, the second through-hole 21, the third through-hole 22, the first guide plate 40, and the second guide plate 50, the incoming gas forms a recirculation central zone slightly below the center of the pre-combustion chamber. The nozzle is positioned in the center, and when atomized fuel is injected, the atomized fuel enters the recirculation zone 70 slightly below the center, allowing it to precisely match the recirculation zone 70 for efficient mixing and increased fuel concentration in the central recirculation zone 70, which is beneficial for ignition and flame stabilization. Furthermore, it ensures complete fuel combustion. See the arrows in Figure 7 for details.

[0066] Specifically, the first guide plate 40 has a first guide surface 41, and the second guide plate 50 has a second guide surface 51. Both the first guide surface 41 and the second guide surface 51 are concentrically arranged with the inner wall surface of the second annular wall 20.

[0067] As shown in Figures 2-5, the second annular wall 20 is configured with an arc-shaped plate structure, and the first guide plate 40 and the second guide plate 50 are also configured with an arc-shaped plate structure to cooperate with the second annular wall 20. The first guide surface 41 and the second guide surface 51 can respectively form a relatively narrow space with the inner wall surface of the second annular wall 20; this narrow space is the flow guiding area in the above example.

[0068] Understandably, when the incoming gas passes through the second through hole 21, it interacts with the first guide surface 41 on the first guide plate 40 and can flow along the first guide surface 41. Similarly, when the incoming gas passes through the third through hole 22, it interacts with the second guide surface 51 on the second guide plate 50, causing it to flow along the second guide surface 51.

[0069] In specific applications, the first guide area and the second guide area have the same size, that is, the distance between the first guide surface 41 and the inner wall surface of the second annular wall 20 is equal to the distance between the second guide surface 51 and the inner wall surface of the second annular wall 20.

[0070] In a more specific example, the first guide vane 40 and the second guide vane 50 are integrally formed with the second annular wall 20.

[0071] In the above example, the integral molding of the first guide plate 40 and the second guide plate 50 makes the connection between the two guide plates and the second annular wall 20 stronger, and the integral connection makes the two guide plates at least part of the flame tube shell.

[0072] The fuel injection effect of the combined flame ring vortex pre-combustion chamber in the above embodiments will be explained below through specific examples and comparative experiments.

[0073] As shown in Figure 6, a vortex pre-combustion chamber with a total axial length L = 66.2054 mm and a height H = 44.8868 mm is described. The diameter of the first through hole 11 is d1 = 9 mm, the diameter of the second through hole 21 is d2 = 6 mm, the diameter of the third through hole 22 is d3 = 6 mm, the semi-major axis of the ellipse of the contraction section 241 in the contraction expansion tube 24 is A1 = 6 mm, the length of the contraction section 241 is C1 = 4.7575 mm, the semi-major axis of the ellipse of the expansion section 242 in the contraction expansion tube 24 is A2 = 8 mm, and the length of the expansion section 242 is C2 = 6.7575 mm.

[0074] Figure 8 shows the overlapping area of ​​adjacent oil mist particles in the above example of the present invention, while Figure 9 shows the overlapping area of ​​oil mist particles in a traditional pre-combustion chamber. It can be clearly seen that the atomizing cone angle of the present invention is approximately 110°, while the atomizing cone angle in a traditional pre-combustion chamber is approximately 90°. This means that the solution of the present invention can significantly increase the overlapping area, improve the flame connection performance of the combustion chamber, and solve the flame connection problem.

[0075] The present invention also provides an aero-engine, including a flame tube configured as a tandem vortex pre-combustion chamber as described in any of the above embodiments.

[0076] The specific structure of the tandem vortex pre-combustion chamber in the above embodiments can be found in the detailed description of the foregoing embodiments. By arranging the tandem vortex pre-combustion chamber in the foregoing embodiments, the tandem flame performance of the aero-engine can be improved. The entire scheme is constructed on the wall of the combustion chamber, resulting in a lighter overall weight and a compact structure, making it particularly suitable for configuration in small aero-engines.

[0077] Through the above description of the embodiments, those skilled in the art can clearly understand that the annular vortex combustor of the present invention, by perforating the wall surface to affect the direction of airflow, automatically forms a recirculation zone 70, which is equivalent to eliminating the weight of the cyclone separator, and has a smaller pressure loss and a more compact structure. Furthermore, the contraction-expansion elliptical structure utilizes airflow to change the shape of the mist cone of the pressure atomizing nozzle, causing the mist cone to widen along the tangential direction, increasing the overlap area of ​​oil mist particles from adjacent injection sources, solving the problem of difficult flame coupling in the absence of a tangential vortex in the annular vortex combustor, and also resulting in a lower total pressure loss, higher combustion efficiency, and the ability to achieve a wider ignition and shutdown range and operating range than existing combustors, thus improving overall performance.

[0078] 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A combined flame annular vortex pre-combustion chamber, comprising: A first annular wall, a second annular wall, and a third annular wall, wherein the second annular wall is located between the first annular wall and the third annular wall, and a mixing space for fuel and air is formed between the first annular wall and the third annular wall. The first annular wall has a first through-hole uniformly arranged circumferentially; the second annular wall has a second through-hole and a third through-hole uniformly arranged circumferentially on both sides; and the second annular wall between the second through-hole and the third through-hole has a contraction-expansion nozzle uniformly arranged circumferentially. A first guide plate is located on the second annular wall near the second through-hole, forming a first guide zone between the first guide plate and the second through-hole; a second guide plate is located on the second annular wall near the third through-hole, forming a second guide zone between the second guide plate and the second through-hole; both the first guide zone and the second guide zone can guide incoming air towards the first annular wall; wherein a fuel nozzle is installed inside the contraction-expansion nozzle. A flow gap exists between the fuel nozzle and the contraction-expansion nozzle, allowing incoming air to pass through the flow gap and expand the atomization cone angle of the fuel nozzle. The contraction-expansion nozzle is located at the center of the second annular wall in the horizontal direction, so that the output end of the contraction-expansion nozzle is located at the center of the pre-combustion chamber. A contraction-expansion tube is sleeved inside the contraction-expansion nozzle. The contraction-expansion tube is an elliptical tube structure with its inner diameter gradually increasing from the middle to both ends, forming a "trumpet mouth" structure at both ends. The middle part of the contraction-expansion tube is fitted with the contraction-expansion nozzle to achieve a sleeve connection. The contraction-expansion nozzle is configured as an elliptical structure. The short half-axis of the elliptical structure is used to cooperate with the fuel nozzle, so that the fuel nozzle is installed at the short half-axis position of the elliptical structure. The major half-axis of the elliptical structure is larger than the size of the fuel nozzle body, and the flow gap is formed between the fuel nozzle body and the inner wall of the contraction-expansion nozzle.

2. The combined flame annular vortex pre-combustion chamber according to claim 1, characterized in that, The first through hole, the second through hole, and the third through hole are provided in a one-to-one correspondence.

3. The combined flame annular vortex pre-combustion chamber according to claim 1, characterized in that, The second annular wall is configured as an arc-shaped plate structure.

4. The combined flame annular vortex pre-combustion chamber according to claim 3, characterized in that, The first guide plate has a first guiding surface, and the second guide plate has a second guiding surface. The first guiding surface and the second guiding surface are concentrically arranged with the inner wall surface of the second annular wall.

5. The combined flame annular vortex pre-combustion chamber according to claim 1, characterized in that, The first guide plate and the second guide plate are integrally formed with the second annular wall.

6. An aircraft engine, comprising a flame tube, characterized in that, The flame tube is configured as a combined flame annular vortex pre-combustion chamber as described in any one of claims 1-5.

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