Afterburner based on combined pneumatic flame stabilizer

Abstract

In order to solve the problem that an existing afterburner is difficult to give consideration to an efficient flame stabilizing function and low flow resistance loss, the afterburner based on the combined type pneumatic flame stabilizer comprises the combined type pneumatic flame stabilizer and a center cone, the combined type pneumatic flame stabilizer takes a support plate flame stabilizer as a carrier, and the center cone is arranged on the support plate flame stabilizer. And the pneumatic flame stabilizer is borne. Under the non-stress-application working condition, only the supporting plate flame stabilizer and the rear edge sudden-expansion type concave cavity in the center cone work, the supporting plate flame stabilizer serves as an on-duty flame stabilizer, and when the supporting plate flame stabilizer and the rear edge sudden-expansion type concave cavity work under the non-stress-application working condition, the blocking area can be effectively reduced, and the total pressure loss is reduced; and the total pressure recovery performance of the afterburner is improved. Under the stress application working condition, the supporting plate flame stabilizer, the rear edge sudden expansion type concave cavity and the pneumatic flame stabilizer act at the same time, and the low-loss and high-efficiency combustion organization mode of the afterburner is guaranteed. On the premise of meeting flame stability, the total pressure loss can be further reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and particularly to an afterburner. Background Art

[0002] In recent years, with the development of aero-engines, there is a demand for lower flow resistance loss in afterburners. However, due to the characteristics of high inlet speed and low pressure of the inlet gas in advanced afterburners, the flow resistance loss in the afterburner is aggravated, the fuel-air mixing effect is poor, and problems such as easy flameout and difficult combustion organization are likely to occur.

[0003] In view of the harsh working conditions of the afterburner, technicians have designed and developed many new mechanical structures, such as air-cooled fuel injection rods and air-cooled stabilizers, integrated afterburners (such as the integrated design of mixer, diffuser, and stabilizer, and the integrated design of the post-turbine strut, stabilizer, and fuel injection rod, etc.), and the development of pilot stabilizers. Among them, the integrated afterburner is the main research and development direction of the existing afterburner. Through the integrated design, the mechanical mechanism can be combined and streamlined, and the blockage ratio can be reduced to achieve the purpose of reducing the pressure loss along the way. However, excessive reduction of the blockage ratio will cause the flame to be unable to stabilize.

[0004] The working principle of the existing afterburner is to arrange a mechanical structure flame stabilizer (such as a bluff-body flame stabilizer) in the flow channel to form a recirculation zone, and the flame can stably burn in the recirculation zone. If the mechanical structure flame stabilizer is to enable the afterburner to still have an efficient flame stabilization function under the condition of high Mach number incoming flow, a relatively high flow blockage ratio is required, which will cause excessive flow resistance loss in the afterburner, especially the flow resistance loss in the non-afterburning state is unnecessary. To solve the above problems, scholars have proposed another method for flame stabilization in afterburners - using single-hole or multi-hole transverse jets to create a recirculation zone for flame stabilization. Since there is no bluff body and relying on the aerodynamic action between the jet and the mainstream to form an aerodynamic barrier in the mainstream and generate a recirculation zone behind the barrier for flame stabilization, it is called an aerodynamic flame stabilizer. However, due to the small barrier area and narrow recirculation zone formed by the single-hole or multi-hole transverse jets, the stability and reliability of the aerodynamic flame stabilizer cannot meet the design requirements.

[0005] In summary, the existing flame stabilizers and afterburners are difficult to balance a low flow blockage ratio and a high flame stabilization function. Summary of the Invention

[0006] Based on the above background art, in order to solve the technical problem that the existing afterburner is difficult to balance the efficient flame stabilization function and the lower flow resistance loss, the present invention proposes an afterburner based on a combined aerodynamic flame stabilizer, which further reduces the total pressure loss on the premise of meeting the flame stabilization function.

[0007] The technical solution of the present invention is as follows:

[0008] A combined pneumatic flame stabilizer, characterized in that it includes a strut flame stabilizer and a pneumatic flame stabilizer, and the pneumatic flame stabilizer is arranged inside the strut flame stabilizer;

[0009] An internal flow channel is provided inside the strut flame stabilizer. The axial cross-section of the internal flow channel is in a shape of "Ji", and includes a large-area channel and two small-area channels that are connected along the gas flow direction;

[0010] The front end shape of the strut flame stabilizer is designed based on the blade profile curve. A rectangular internal flow channel inlet communicating with the internal flow channel is provided at the outer end on the radial direction. On the two radial side walls, symmetrically arranged at the downstream of the flow path are contraction injection slits that extend radially, communicate with the internal flow channel, have a length matching the height of the internal flow channel, and have the same structure; the contraction injection slit is a flow channel with an inlet width greater than the outlet width and a quadrilateral cross-section, and is used to accelerate the gas in the internal flow channel and enhance the circumferential flame linkage;

[0011] The internal flow channel and the contraction injection slit constitute the pneumatic flame stabilizer;

[0012] At least one L-shaped partition is provided inside the internal flow channel, and the internal flow channel is divided into multiple sub-flow channels arranged from top to bottom. The multiple sub-flow channels are respectively communicated with the contraction injection slit;

[0013] The axial direction and the radial direction are respectively the axial direction and the radial direction of the afterburner where the combined pneumatic flame stabilizer is applied.

[0014] Further, the outlet width of the contraction injection slit is 0.5 - 1 mm, and the contraction ratio is 2.62 - 5.2.

[0015] Further, the upper contraction ratio of the contraction injection slit is greater than the lower contraction ratio.

[0016] Further, the jet inclination angle of the contraction injection slit is 90 - 140°.

[0017] Further, the bottom plane of the lowermost sub-flow channel has an inclination angle to match the profile of the center cone of the afterburner.

[0018] Further, the radial wall surface and the bottom surface of the internal flow channel are connected by an arc surface.

[0019] Further, the distance between the edge of the rectangular internal flow channel inlet and the radial side wall of the strut flame stabilizer, and the distances from the top and bottom of the outlet of the contraction injection slit to the two end faces of the strut flame stabilizer along the radial direction are all determined by simulation to ensure the structural strength of the strut flame stabilizer required by the design.

[0020] The present invention also provides an afterburner, which includes a cylinder body and a center cone; the special feature is that it further includes n of the above-mentioned combined pneumatic flame stabilizers; the n combined pneumatic flame stabilizers are arranged circumferentially and radially evenly on the outer wall of the center cone, and their ends are all connected to the inner wall of the cylinder body; a trailing-edge bulge-expanded cavity is arranged on the rear side wall of the center cone, and the front wall surface of the trailing-edge bulge-expanded cavity is connected to the rear wall surface of the strut flame stabilizer in the combined pneumatic flame stabilizer; the trailing-edge angle of the trailing-edge bulge-expanded cavity should ensure the connection between the cavity recirculation zone and the center cone recirculation zone; n is determined according to the total blockage ratio required by the design and the blockage ratio of a single combined pneumatic flame stabilizer.

[0021] Furthermore, the trailing-edge angle of the trailing-edge bulge-expanded cavity is 0°.

[0022] The present invention also provides a turbofan / turbojet engine, the special feature of which is that it includes the above-mentioned afterburner.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. The afterburner of the present invention is applicable to aeroengines with an afterburner. The combined pneumatic flame stabilizer in the afterburner uses the strut flame stabilizer as a carrier to carry the pneumatic flame stabilizer. Under non-afterburning working conditions, only the strut flame stabilizer and the trailing-edge bulge-expanded cavity work. The strut flame stabilizer serves as the on-duty flame stabilizer, and when working under non-afterburning conditions with the trailing-edge bulge-expanded cavity, it can effectively reduce the blocked area and the total pressure loss, which is beneficial to improving the total pressure recovery performance of the afterburner. Under afterburning working conditions, the strut flame stabilizer, the trailing-edge bulge-expanded cavity and the pneumatic flame stabilizer act simultaneously to ensure a low-loss and high-efficiency combustion organization mode in the afterburner.

[0025] 2. The rear wall surface of the strut flame stabilizer in the afterburner of the present invention is connected to the front wall surface of the trailing-edge bulge-expanded cavity, which can promote the radial propagation of the flame, further making the temperature distribution at the outlet section of the afterburner uniform. Since the trailing-edge inclination angle of the trailing-edge bulge-expanded cavity is 0°, it avoids the potential disconnection at the connection between the cavity recirculation zone and the center cone recirculation zone, which is beneficial to the coupling of the two to form a more compact recirculation zone, promoting the propagation of the flame in the circumferential and axial directions on the basis of stable flame combustion, realizing the flame stabilization and flame linking of the afterburner, and forming a good combustion organization.

[0026] 3. In the afterburner of the present invention, the pneumatic flame stabilizer ejects a gaseous fuel jet through a convergent injection slit, and uses the form of the gaseous fuel jet to create a pneumatic recirculation zone for flame stabilization. Considering that the pneumatic recirculation zone is extremely susceptible to the influence of the inlet flow conditions, when the inlet flow Mach number increases, the range of the pneumatic recirculation zone will decrease. Therefore, in the present invention, through structural design, the pneumatic recirculation zone formed by the pneumatic flame stabilizer is larger than the recirculation zone jointly formed by the strut flame stabilizer and the trailing-edge cavity, and is coupled with the recirculation zone jointly formed by the strut flame stabilizer and the trailing-edge cavity. At this time, the pneumatic recirculation zone plays a major role. When the incoming flow Mach number increases, the presence of the strut flame stabilizer and the trailing-edge cavity can prevent the coupled recirculation zone from further decreasing, so as to avoid the flame being blown out. Therefore, the stability of the combined pneumatic flame stabilizer adopted in the present invention is better than that of the existing simple pneumatic flame stabilizer.

[0027] 4. When the combined pneumatic flame stabilizer in the afterburner of the present invention starts to work, the gaseous fuel flows through the inner flow path. The gas flow direction changes from radial injection to axial flow, and finally sprays out in the circumferential direction from the convergent injection slit. Connecting the turning point of the inner flow path with an arc can reduce the flow loss of the gaseous fuel in the inner flow path. When flowing from a large-area flow path into a small-area flow path, the flow will accelerate due to the area change. After that, when the air flow passes through the convergent injection slit, a greater injection speed can be obtained, improving the penetration distance, and thus forming a larger pneumatic recirculation zone. In addition, the pneumatic recirculation zone is coupled with the recirculation zone jointly generated by the strut flame stabilizer and the trailing-edge cavity to form a more stable recirculation zone, further improving the flame stability.

[0028] 5. The inner flow path of the pneumatic flame stabilizer in the afterburner of the present invention is divided into upper and lower parts by a partition, which can make the radially injected gaseous fuel spray out more evenly in the circumferential direction. In addition, the upper convergent injection slit has a larger contraction ratio than the lower convergent injection slit. The two work together to make the pneumatic recirculation zone more uniform in the radial direction, enhancing the mixing of the gaseous fuel and air in the recirculation zone behind the combined pneumatic flame stabilizer, and can effectively reduce the difficulty of ignition and flame stabilization.

[0029] 6. The convergent injection slit of the pneumatic flame stabilizer in the afterburner of the present invention can continuously eject gaseous fuel in the radial direction, which has better stability compared with the traditional single nozzle or multiple nozzles, and can effectively increase the area of the pneumatic barrier and the size of the pneumatic recirculation zone. At the same time, combined with the strut flame stabilizer and the trailing-edge cavity of the present invention, it ensures that the afterburner can still be stably started and maintain the afterburning working condition under harsh working conditions.

[0030] 7. The combined pneumatic flame stabilizer in the afterburner of the present invention connects the connecting cylinder and the central cone, has a load-bearing function in structure, and can replace the post-turbine fairing in the traditional afterburner; at the same time, the strut flame stabilizer in the present invention also has the functions of fuel injection and flame stabilization, and can replace the fuel injection rod and the flame stabilizer in the traditional afterburner; therefore, after adopting the combined pneumatic flame stabilizer of the present invention, the number of components constituting the afterburner is reduced, the complexity and additional mass of the system are reduced, the structural compactness is improved, and the length of the afterburner is shortened.

[0031] 8. Compared with the existing integrated afterburner, the present invention has a smaller blockage ratio on the premise of ensuring flame anchoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of the overall structure of the afterburner of the present invention.

[0033] Figure 2 is a schematic diagram of the assembly relationship between the central cone and the combined pneumatic flame stabilizer in the present invention.

[0034] Figure 3 is a schematic diagram of the structure of the combined pneumatic flame stabilizer in the present invention.

[0035] Figure 4 is a radial sectional view and an internal flow path display diagram of the combined pneumatic flame stabilizer in the present invention. Diagram a is for illustration Figure 1 , Diagram b is for illustration Figure 2 .

[0036] Figure 5 is a circumferential sectional view and a gaseous fuel injection schematic diagram of the combined pneumatic flame stabilizer in the present invention. Diagram a is for illustration Figure 1 , Diagram b is for illustration Figure 2 .

[0037] Figure 6 is a perspective view of the structure of the afterburner based on the combined pneumatic flame stabilizer of the present invention (one-sixteenth of the afterburner is intercepted).

[0038] Figure 7 is the sectional velocity distribution and streamline diagram of the strut flame stabilizer in the present invention.

[0039] Figure 8 is a schematic diagram of the pneumatic recirculation zone formed by the present invention.

[0040] Figure 9 is the temperature distribution of each cross-section along the length of the afterburner of the present invention.

[0041] Figure 10It is a schematic structural diagram of a plurality of L-shaped partitions arranged in the inner flow path of the afterburner of the present invention. Diagram a is for illustration Figure 1 , Diagram b is for illustration Figure 2 .

[0042] Reference numerals:

[0043] 1 - Cylinder body, 2 - Inner flow path inlet, 3 - Combined pneumatic flame stabilizer, 4 - Central cone, 5 - Rear edge sudden expansion cavity, 6 - Partition, 7 - Contraction injection slit, 8 - Strut flame stabilizer, 9 - Upper inner flow path, 10 - Lower inner flow path, 11 - Inner flow path, 12 - Large area flow path, 13 - Small area flow path, 14 - Gaseous fuel jet, 15 - Pneumatic recirculation zone, 16 - Strut rear edge recirculation zone, 17 - Front wall surface of the rear edge sudden expansion cavity, 18 - Rear wall surface of the combined pneumatic flame stabilizer. Specific embodiments

[0044] The present invention will be further described below with reference to the accompanying drawings.

[0045] Referring to Figure 1 , the afterburner based on the combined pneumatic flame stabilizer provided by the present invention includes a cylinder body 1, a combined pneumatic flame stabilizer 3, and a central cone 4 that are coaxially arranged in sequence from outside to inside.

[0046] The cylinder body 1 is cylindrical.

[0047] The central cone 4 is a typical component in the afterburner, used for decelerating and diffusing the core flow, and is an existing unit. As Figure 2 , 6 shown, a rear edge sudden expansion cavity 5 is provided on the rear end side wall of the central cone 4, and the front wall surface 17 of the rear edge sudden expansion cavity is connected to the rear wall surface 18 of the combined pneumatic flame stabilizer (that is, the rear wall surface of the strut flame stabilizer 8). The smaller the rear edge angle of the rear edge sudden expansion cavity 5 (referring to the angle between the rear wall surface of the cavity and the bottom surface of the cavity), the more conducive it is to the connection between the cavity recirculation zone and the central cone recirculation zone; preferably, the rear edge angle of the rear edge sudden expansion cavity 5 is 0°, which avoids the potential disconnection at the connection between the cavity recirculation zone and the central cone recirculation zone and couples to form a large recirculation zone, which is conducive to forming good combustion organization.

[0048] There are n combined pneumatic flame stabilizers 3, which are evenly distributed in a circumferential and radially radiating manner on the outer wall of the central cone 4, and their ends are all connected to the inner wall of the cylinder body 1; n is determined according to the total blockage ratio required by the design and the blockage ratio of a single combined pneumatic flame stabilizer. In this embodiment, n = 16.

[0049] As Figure 2-5As shown, a single combined pneumatic flame stabilizer 3 includes a strut flame stabilizer 8 and a pneumatic flame stabilizer. The pneumatic flame stabilizer is arranged inside the strut flame stabilizer 8. The strut flame stabilizer 8 is arranged on the center cone 4 and is at a certain distance from the combustor inlet (for example, 140 - 180 mm). The front end shape of the strut flame stabilizer 8 is designed based on the blade profile curve. Specifically, the blade profile curve can be selected according to the afterburner design manual. For example, the C7 blade profile curve can be selected. The tail of the strut flame stabilizer 8 is connected to the front part of the trailing-edge sudden-expansion cavity 5. The recirculation zones of the strut flame stabilizer 8 and the trailing-edge sudden-expansion cavity 5 can be coupled to form a closer recirculation zone, promoting the axial and circumferential propagation of the flame and realizing afterburner flame linking.

[0050] An internal flow passage 11 is arranged inside the strut flame stabilizer 8. A rectangular internal flow passage inlet 2 communicating with the internal flow passage 11 is arranged at the end of the strut flame stabilizer 8 connected to the inner wall of the cylinder 1. The distance between the edge of the internal flow passage inlet 2 and the radial side wall of the strut flame stabilizer 8 is determined according to the structural strength of the strut flame stabilizer 8 required by the design. In this embodiment, it is W is the trailing-edge width of the strut flame stabilizer 8. The radial wall surface and the bottom surface of the internal flow passage 11 are connected by an arc surface to reduce the flow loss of the gaseous fuel in the internal flow passage. Looking at the cross-section perpendicular to the radial direction, the cross-section of the internal flow passage 11 is in a shape like the Chinese character 'ji'. Along the gas flow direction, it includes a large-area passage 12 and two small-area passages 13 that are connected. Through simulation, preferably, the sum of the flow areas of the two small-area passages 13 is 2 / 5 of the flow area of the large-area passage 12, which can further enhance the penetration depth of the jet. After the gaseous fuel enters the internal flow passage, along the gas flow direction, the flow area of the gaseous fuel decreases, changing from one large passage to two small passages, thereby accelerating the flow of the gaseous fuel.

[0051] On the two radial wall surfaces of the strut flame stabilizer 8, symmetrically arranged at the downstream of the gas fuel flow path, there are contraction injection slits 7 that extend radially, communicate with the internal flow passage 11, have a length matching the height (i.e., the radial distance) of the internal flow passage 11, and have the same structure. The internal flow passage 11 and the two contraction injection slits 7 constitute the pneumatic flame stabilizer.

[0052] The contraction injection slit 7 is a flow passage with an inlet width larger than the outlet width and a quadrilateral cross-section, used to accelerate the gas in the internal flow passage and enhance circumferential flame linking.

[0053] Further optimized: The jet inclination angle of the contraction injection slit 7 (the angle between the gas jet injection direction and the radial wall surface) is 90°-140°, which can increase the residence time of the gaseous fuel in the afterburner; the outlet width of the contraction injection slit 7 is 0.5-1 mm, and the contraction ratio (the ratio of the outlet area to the inlet area) is 2.62-5.2. Further preferably, the contraction ratios of the upper and lower parts of the contraction injection slit 7 can be different, and the contraction ratio of the upper part is larger than that of the lower part, making the aerodynamic recirculation zone more uniform in the radial direction; the top of the outlet of the contraction injection slit 7 is spaced from the inner wall of the afterburner cylinder 1 by The bottom of the outlet of the contraction injection slit 7 is spaced from the axis of the afterburner by 12W-13W; the distance from the center line of the contraction injection slit 7 to the trailing edge plane of the strut flame stabilizer 8 is The distance from the center line of the contraction injection slit 7 to the trailing edge plane of the strut flame stabilizer 8 is

[0054] An L-shaped partition 6 is also provided in the internal flow passage 11. The two side walls of the L-shaped partition 6 are connected to the two radial side walls of the internal flow passage 11, dividing both the large-area passage 12 and the small-area passage 13 into an upper internal flow passage 9 and a lower internal flow passage 10. Among them, the bottom surface of the upper internal flow passage 9 is parallel to the axis of the cylinder 1 (it may not be parallel in other embodiments); the L-shaped partition 6 also divides the contraction injection slit 7 into an upper contraction injection slit and a lower contraction injection slit. The upper contraction slit has a larger contraction ratio than the lower contraction slit, which can increase the jet penetration depth and promote circumferential flame linking. In other embodiments, there can be multiple L-shaped partitions 6, which are arranged in parallel in the internal flow passage 11 and divide it into multiple sub-flow passages arranged from top to bottom, as Figure 10 shown. Preferably, the bottom plane of the lower internal flow passage 10 has an inclination angle to match the profile of the center cone 4, and the inclination of the bottom plane of the lower internal flow passage 10 can also increase the length of the contraction injection slit 7 that is matched and connected therewith, which is beneficial to enhancing radial flame linking.

[0055] Referring to Figure 4-5 , under afterburning working conditions, the aerodynamic flame stabilizer starts to work. The gaseous fuel flows through the internal flow passage 11, and the gas flow direction in the internal flow passage 11 changes from radial injection to axial flow, and finally sprays out from the contraction injection slit 7 in the circumferential direction to form a gaseous fuel jet 14.

[0056] The ratio of the flow passage area blocked by the strut flame stabilizer 8 is the blockage ratio of the strut flame stabilizer 8. Under the condition of ensuring the total pressure recovery performance, the blockage ratio of the strut flame stabilizer 8 in the present invention is designed to be 0.14-0.2. The blockage ratio in this range is more appropriate in the benefit trade-off between the total pressure loss and the size of the recirculation zone.

[0057] The principle of the present invention is:

[0058] Under afterburning operating conditions, the strut flame holder 8, the pneumatic flame holder, and the trailing-edge step cavity 5 all operate. At this time, the inlet airflow of the afterburner passes through the front section of the center cone 4 to complete partial pressure increase and deceleration, reaches the front end of the strut flame holder 8, and is rectified along the blade profile surface of the strut flame holder 8. After that, when the pneumatic flame holder starts to operate, gaseous fuel is injected from the inner flow path inlet 2, flows through the inner flow path 11, and the flow direction of the gaseous fuel in the inner flow path 11 changes from radial injection to axial flow, and finally sprays out in the circumferential direction from the convergent injection slit 7. The gaseous fuel jet 14 ejected from the convergent injection slit 7 acts on the mainstream, reduces the axial velocity component of the mainstream, forms a pneumatic recirculation zone 15, and achieves the purpose of pneumatic flame stabilization. Since the injection velocity of the upper convergent injection slit is greater than that of the lower convergent injection slit, the pneumatic recirculation zone 15 presents a form with a wide outer ring and a narrow inner ring, which is beneficial to enhancing circumferential flame linking. Under the action of the mainstream, the gaseous fuel jet 14 changes from circumferential ejection to axial flow. When flowing through the trailing edge of the strut flame holder 8, the shearing action on the side of the strut flame holder 8 causes the airflow to form a strut trailing-edge recirculation zone 16, and the gaseous fuel forms an oil-gas mixing zone suitable for ignition and stable combustion through the entrainment action of the strut trailing-edge recirculation zone 16.

[0059] The trailing-edge step cavity 5 provided on the center cone 4 is connected to the rear wall surface of the strut flame holder 8. When the airflow passes through the trailing-edge step cavity 5, a small recirculation zone connected circumferentially along the center cone 4 will be formed. The rear part of this small recirculation zone is connected to the recirculation zone formed by the center cone 4, which promotes the propagation of the flame along the axial and circumferential directions and realizes afterburning flame linking, as Figure 7 shown. As can be seen from Figure 8 it, the recirculation zone generated by the pneumatic jet is significantly larger than the strut recirculation zone. The recirculation zone generated by the pneumatic jet plays a major role in flame stabilization and is beneficial to reducing the blockage ratio of the strut flame holder. Under non-afterburning operating conditions, only the strut flame holder 8 and the trailing-edge step cavity 5 operate, and the pneumatic flame holder does not operate. Therefore, at this time, only the strut trailing-edge recirculation zone 16 formed by the strut flame holder 8 and the small recirculation zone formed by the trailing-edge step cavity 5 exist. The flow resistance is small, which can reduce the resistance loss of the afterburner.

[0060] Figure 9 The temperature distribution of each cross-section along the way of the afterburner of the present invention is shown. As can be seen from the figure, the flame burns to the boundary of the computational domain at the outlet cross-section basically, indicating that the present invention can meet the requirements of flame stabilization.

Claims

1. Combined pneumatic flame stabilizer, characterized in that: It includes a strut flame stabilizer and a pneumatic flame stabilizer, and the pneumatic flame stabilizer is arranged inside the strut flame stabilizer; An internal flow channel is provided inside the strut flame stabilizer. The axial cross-section of the internal flow channel is in a shape of "ji", and includes a large-area channel and two small-area channels that are connected along the gas flow direction; The front end shape of the strut flame stabilizer is designed based on the blade profile curve. A rectangular internal flow channel inlet communicating with the internal flow channel is provided at the outer end on the radial direction. On the two radial side walls, symmetrically arranged at the downstream of the flow path are contraction injection slits that extend radially, communicate with the internal flow channel, have a length matching the height of the internal flow channel, and have the same structure; the contraction injection slit is a flow channel with an inlet width greater than the outlet width and a quadrilateral cross-section, and is used to accelerate the gas in the internal flow channel and enhance the circumferential flame linkage; The internal flow channel and the contraction injection slit constitute the pneumatic flame stabilizer; At least one L-shaped partition is provided inside the internal flow channel to divide the internal flow channel into multiple sub-flow channels arranged from top to bottom, and the multiple sub-flow channels are respectively communicated with the contraction injection slit; The axial direction and the radial direction are respectively the axial direction and the radial direction of the afterburner to which the combined pneumatic flame stabilizer is applied.

2. The combined pneumatic flame stabilizer according to claim 1, characterized in that: The outlet width of the contraction injection slit is 0.5 - 1 mm, and the contraction ratio is 2.62 - 5.

2.

3. The combined pneumatic flame stabilizer according to claim 2, wherein: The upper contraction ratio of the contraction injection slit is greater than the lower contraction ratio.

4. The combined pneumatic flame stabilizer according to claim 3, characterized in that: The jet inclination angle of the contraction injection slit is 90 - 140°.

5. The combined pneumatic flame stabilizer according to any one of claims 1-4, characterized in that: The bottom plane of the lowermost sub-flow channel has an inclination angle to match the profile of the center cone of the afterburner.

6. The combined pneumatic flame stabilizer according to claim 5, characterized in that: The radial wall surface and the bottom surface of the internal flow channel are connected by an arc surface.

7. The combined pneumatic flame stabilizer according to claim 6, characterized in that: The distances between the edge of the rectangular internal flow channel inlet and the radial side walls of the strut flame stabilizer, and the distances from the top and bottom of the outlet of the contraction injection slit to the two end faces of the strut flame stabilizer in the radial direction are determined by simulation to ensure the structural strength of the strut flame stabilizer required by the design.

8. Afterburner, comprising a cylinder and a center cone; characterized in that: It further includes n combined pneumatic flame stabilizers as described in any one of claims 1 - 7; the n combined pneumatic flame stabilizers are arranged circumferentially and radially symmetrically on the outer wall of the center cone, and the ends are all connected to the inner wall of the cylinder; a trailing-edge bulge-type cavity is provided on the rear side wall of the center cone, and the front wall surface of the trailing-edge bulge-type cavity is connected to the rear wall surface of the strut flame stabilizer in the combined pneumatic flame stabilizer; the trailing-edge angle of the trailing-edge bulge-type cavity should ensure the connection between the cavity recirculation zone and the center cone recirculation zone; n is determined according to the total blockage ratio required by the design and the blockage ratio of a single combined pneumatic flame stabilizer.

9. The afterburner according to claim 8, characterized in that: The trailing-edge angle of the trailing-edge bulge-type cavity is 0°.

10. Turbofan / turbojet engine, characterized in that: It includes the afterburner as described in claim 8 or 9.

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