Large-bend structure for high cycle parameter reflow combustion chamber and aero-engine
By setting a complex tongue and retaining ring connection structure between the outer ring of the flame tube and the inner wall of the large bend, the problems of poor sealing and cracking of the split large bend overlapping structure are solved, and good sealing and durability of the combustion chamber under high circulation parameters are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AECC HUNAN AVIATION POWERPLANT RES INST
- Filing Date
- 2024-05-06
- Publication Date
- 2026-05-29
AI Technical Summary
In existing technologies, the gaps in the split-type large bend pipe overlapping structure do not meet the requirements, resulting in total pressure loss in the combustion chamber and performance that does not meet design requirements. At the same time, there is a risk of air leakage and cracking.
A large bend tube structure is designed, which uses a complex tongue and snap ring connection structure between the outer ring of the flame tube and the inner wall of the large bend tube, including radial and axial installation gaps, combined with a limiting structure and air film cavity cooling, to ensure sealing effect and thermal expansion space.
It effectively reduces the processing difficulty of the diffuser, improves the sealing effect, reduces air leakage, prevents cracks at the starting end of the large bend, and meets the usage requirements under high circulation parameters.
Smart Images
Figure CN118310038B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aero-engine technology, and in particular, to a large bend structure for a high-cycle-parameter recirculation combustion chamber. Furthermore, this invention also relates to an aero-engine comprising the aforementioned large bend structure for a high-cycle-parameter recirculation combustion chamber. Background Technology
[0002] With advancements in gas turbine engine technology, engine cycle parameters are becoming increasingly higher, combustion chamber inlet temperatures and temperature rises are continuously increasing, and compressor pressure ratios are gradually rising. This leads to a continuous increase in the aerodynamic and thermal loads on the combustion chamber flame tube, while simultaneously raising the requirements for the combustion chamber's design life. The recirculation combustion chamber is a common structural form in small and medium-sized gas turbine engines, offering advantages such as compact structure and short engine shaft system. The large bend is a crucial component of the recirculation combustion chamber. Due to its design, the increased cycle parameters result in a significant increase in the aerodynamic and thermal stresses experienced by the large bend, potentially leading to deformation and cracking during long-term use, affecting the reliability and durability of the flame tube and even the entire combustion chamber.
[0003] Currently, large bend tube structures are generally divided into two types: One type connects the outer ring of the flame tube and the starting end of the large bend tube by welding, with the outer ring and the large bend tube designed as a single integral part. The outer and inner rings of the flame tube are connected by bolts, and the outlet end of the large bend tube is bolted to the turbine guide vane and diffuser. Because the starting and outlet ends of the large bend tube in this integral connection structure are constrained, there is insufficient space for thermal expansion, making it difficult to release the stress on the large bend tube through elastic deformation. This easily leads to localized high-stress areas in the large bend tube, which are highly susceptible to cracking during use. The other type of structure separates the large bend tube at the connection point between the outer ring of the flame tube and the large bend tube, designing a simple overlapping structure at this separation point. The large bend tube is a separate component, with its starting end attached to the diffuser backplate, and its outlet end bolted to the turbine guide vane and diffuser. This separate design uses a simple overlapping structure; if the clearance is too small, assembly is difficult, and if the clearance is too large, air leakage is likely, resulting in a reduced total pressure loss in the combustion chamber and performance not meeting design requirements.
[0004] On the other hand, the starting end of the split-design large bend is generally attached to the diffuser back plate. A bend structure with a large curvature is designed between the straight section overlap structure and the large bend body surface section, with an included angle much less than 90 degrees. Large stress is prone to occur at this point, leading to cracks. Summary of the Invention
[0005] This invention provides a large bend tube structure for a high-circulation-parameter recirculation combustion chamber and an aero-engine, to solve the technical problems of insufficient total pressure loss and unsatisfactory performance in the combustion chamber caused by non-compliance of the fitting clearance of the split large bend tube overlapping structure in the prior art.
[0006] According to one aspect of the present invention, a large bend structure for a high-cycle-parameter recirculation combustion chamber is provided. The recirculation combustion chamber includes a diffuser, a casing, a flame tube component, a fuel nozzle, and a turbine guide assembly. The flame tube component includes a flame tube outer ring, a flame tube inner ring, a large bend outer wall, a large bend inner wall, and a flame tube head. A connecting structure is provided between the flame tube outer ring and the large bend inner wall, the connecting structure including:
[0007] The first connecting structure is formed at the end of the outer ring of the flame tube, including an outer ring outer tongue, an outer ring inner tongue, and an outer ring U-shaped groove formed axially between the outer ring outer tongue and the outer ring inner tongue;
[0008] The second connection structure is formed at the starting end of the outer wall of the large bend, including an outer tongue of the large bend, an inner tongue of the large bend, and a U-shaped groove of the large bend formed radially between the outer tongue of the large bend and the inner tongue of the large bend.
[0009] The retaining ring has a first mating edge and a second mating edge, which are respectively inserted into the outer ring U-shaped groove and the large bend U-shaped groove. The first mating edge has a radial installation gap with the outer ring U-shaped groove, and the second mating edge has an axial installation gap and a preset radial gap with the large bend U-shaped groove. The large bend outer tongue and the outer ring outer tongue, the first mating edge and the outer ring U-shaped groove, and the large bend inner tongue and the outer ring inner tongue are respectively designed with preset axial gaps.
[0010] As a further improvement to the above technical solution, the design value of the axial clearance between the outer tongue of the large bend pipe and the outer tongue of the outer ring, between the first mating edge and the U-shaped groove of the outer ring, and between the inner tongue of the large bend pipe and the inner tongue of the outer ring gradually increases from the outside to the inside, and the value range is 2-5mm.
[0011] As a further improvement to the above technical solution, the connection structure also includes a large curved pipe rear tongue formed on one side of the large curved pipe inner tongue, and there is a preset radial gap between the large curved pipe rear tongue and the outer ring inner tongue.
[0012] As a further improvement to the above technical solution, the large curved tube structure also includes a Z-ring segment formed at the outer ring end of the flame tube and an outer ring gas film tongue. The first connecting structure is formed on the Z-ring segment. The outer ring inner tongue, the Z-ring segment, and the outer ring gas film tongue surround and form a gas film cavity with an open side. The open side of the gas film cavity faces the starting end. The Z-ring segment has a vent hole that communicates with the gas film cavity.
[0013] As a further improvement to the above technical solution, the included angle between the Z-ring segment and the outer ring surface segment of the outer ring of the flame tube is designed to be 90-150°.
[0014] As a further improvement to the above technical solution, the axial installation gap and the radial installation gap are 0.1-0.5mm.
[0015] As a further improvement to the above technical solution, the large bend structure also includes a limiting structure for axially limiting the outer tongue of the large bend, and the limiting structure and the outer tongue of the large bend have a first axial gap.
[0016] As a further improvement to the above technical solution, the limiting structure includes a limiting member installed on the combustion chamber casing. A plurality of the limiting members are evenly distributed along the circumference of the combustion chamber casing. The limiting member includes an installation section, a transition section, and a limiting section. The installation section is used to connect with the combustion chamber casing. The transition section is designed with a preset size. The limiting section is a plate-shaped structure that matches the position of the outer tongue of the large bend pipe.
[0017] As a further improvement to the above technical solution, the included angle between the large bend profile section of the inner wall of the large bend and the outer tongue of the large bend is designed to be 90°-150°.
[0018] According to another aspect of the invention, an aero-engine is also provided, which includes the large bend structure described above for a high-cycle-parameter recirculation combustion chamber.
[0019] The present invention has the following beneficial effects:
[0020] This large bend tube structure utilizes a first connecting structure on the outer ring of the flame tube and a second connecting structure on the inner wall of the large bend tube. The connection between the inner wall of the large bend tube and the outer ring of the flame tube is achieved by inserting two mating edges of a retaining ring into the U-shaped groove of the outer ring and the U-shaped groove of the large bend tube, respectively. The first mating edge and the U-shaped groove of the outer ring have a radial installation clearance, and the second mating edge and the U-shaped groove of the large bend tube have an axial installation clearance to ensure smooth assembly of the retaining ring. The second mating edge and the bottom of the U-shaped groove of the large bend tube have an axial clearance. Pre-set axial clearances are designed between the outer tongue of the large bend tube and the outer tongue of the outer ring, between the first mating edge and the U-shaped groove of the outer ring, and between the inner tongue of the large bend tube and the inner tongue of the outer ring. Specifically, the end of the outer tongue of the outer ring is located on one side of the outer tongue of the large bend tube, and the inner tongue of the outer ring... The plate is located on one side of the tongue plate inside the large bend. This connection structure changes the limiting structure at the starting end of the large bend from the existing design of hanging on the diffuser back plate to being installed in the combustion chamber casing, thereby reducing the processing difficulty of the diffuser and the stress on the diffuser. Moreover, the outer ring of the flame tube and the inner wall of the large bend are both supported by the combustion chamber casing. In this connection structure, the axial relative position of the mating parts can be better guaranteed, thereby ensuring the sealing effect. This connection structure forms a complex mating and sealing structure through the cooperation of each tongue plate and the retaining ring. The radial installation gap, axial installation gap, preset axial gap and preset radial gap of each overlap are designed to ensure that the large bend has a good sealing effect while having a certain thermal expansion space in both the axial and radial directions.
[0021] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description
[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:
[0023] Figure 1 This is a schematic diagram of the recirculation combustion chamber according to a preferred embodiment of the present invention;
[0024] Figure 2 This is a schematic diagram of the connection structure of a preferred embodiment of the present invention;
[0025] Figure 3 This is a front view of the limiting member according to a preferred embodiment of the present invention;
[0026] Figure 4 This is a bottom view of the limiting member according to a preferred embodiment of the present invention;
[0027] Figure 5 This is a side view of the limiting member according to a preferred embodiment of the present invention.
[0028] Legend:
[0029] 1. Diffuser 2. Combustion chamber casing 21. Mounting base 3. Flame tube components 31. Flame tube outer ring 311. Outer ring outer tongue 312. Outer ring U-groove 313. Outer ring inner tongue 314. Outer ring film tongue 315. Vent hole 316. Z-ring section 317. Film chamber 318. Outer ring profile section 32. Large bend outer wall 33. Large bend inner wall 331. Large bend outer tongue 332. Large bend inner tongue 333. Large bend rear tongue 334. Large bend U-groove 335. Large bend profile section 336. 34. Start end, 35. Flame tube head, 36. Flame tube inner ring, 361. Snap ring, 362. First mating edge, 363. Second mating edge, 4. Bending section, 5. Fuel nozzle, 6. Turbine guide assembly, 61. Limiting component, 62. Limiting section, 63. Mounting cover plate, 64. Mounting section, 621. Transition section, t1. Bolt hole, t2. First axial clearance, t3. Second axial clearance, t4. Third axial clearance, t4. Fourth axial clearance, a. Angle between outer ring profile section and Z-ring section, b. Angle between large bend profile section and large bend outer tongue plate. Detailed Implementation
[0030] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.
[0031] Figure 1 This is a schematic diagram of the recirculation combustion chamber according to a preferred embodiment of the present invention; Figure 2 This is a schematic diagram of the connection structure of a preferred embodiment of the present invention; Figure 3 This is a front view of the limiting member according to a preferred embodiment of the present invention; Figure 4 This is a bottom view of the limiting member according to a preferred embodiment of the present invention; Figure 5 This is a side view of the limiting member according to a preferred embodiment of the present invention.
[0032] like Figures 1 to 5 As shown, this embodiment features a large bend structure for a high-cycle-parameter recirculation combustion chamber. The recirculation combustion chamber includes a diffuser 1, a casing 2, a flame tube component 3, a fuel nozzle 4, and a turbine guide assembly 5. The flame tube component 3 includes an outer flame tube ring 31, an inner flame tube ring 35, a large bend outer wall 32, a large bend inner wall 33, and a flame tube head 34. A connecting structure is provided between the outer flame tube ring 31 and the large bend inner wall 33. The connecting structure includes:
[0033] The first connecting structure is formed at the end of the outer ring 31 of the flame tube, including an outer ring outer tongue 311, an outer ring inner tongue 313, and an outer ring U-shaped groove formed axially between the outer ring outer tongue 311 and the outer ring inner tongue 313.
[0034] The second connection structure is formed at the starting end 336 of the inner wall 33 of the large bend, including the outer tongue 331 of the large bend, the inner tongue 332 of the large bend, and the U-shaped groove of the large bend formed radially between the outer tongue 331 and the inner tongue 332 of the large bend.
[0035] The retaining ring 36 has a first mating edge 361 and a second mating edge 362, which are respectively inserted into the outer ring U-shaped groove and the large bend U-shaped groove. The first mating edge 361 has a radial installation gap with the outer ring U-shaped groove, and the second mating edge 362 has an axial installation gap and a preset radial gap with the large bend U-shaped groove. The large bend outer tongue 331 and the outer ring outer tongue 311, the first mating edge 361 and the outer ring U-shaped groove, and the large bend inner tongue 332 and the outer ring inner tongue 313 are respectively designed with preset axial gaps.
[0036] The retaining ring 36 has an L-shaped cross-section, and the first mating edge 361 and the second mating edge 362 are connected by a bent section 363; the axial installation clearance and the radial installation clearance are 0.1-0.5mm.
[0037] Working principle of the recirculation combustion chamber: The high-temperature and high-pressure air entering from the diffuser 1 enters the flame tube component 3 through the two channels between the casing 2 and the flame tube component 3, and mixes and burns with the fuel injected by the fuel nozzle 4. The resulting high-temperature gas enters the turbine component after passing through the turbine guide assembly 5.
[0038] Understandably, this large bend tube structure utilizes a first connecting structure designed on the outer ring 31 of the flame tube and a second connecting structure designed on the inner wall 33 of the large bend tube. The connection between the inner wall 33 of the large bend tube and the outer ring 31 of the flame tube is achieved by inserting the two mating edges of the retaining ring 36 into the U-shaped groove of the outer ring and the U-shaped groove of the large bend tube, respectively. The first mating edge 361 and the U-shaped groove of the outer ring have a radial installation clearance, and the second mating edge 362 and the U-shaped groove of the large bend tube have an axial installation clearance to ensure smooth assembly of the retaining ring 36. The second mating edge 362 and the bottom of the U-shaped groove of the large bend tube have an axial clearance. Pre-set axial clearances are designed between the outer tongue 331 of the large bend tube and the outer tongue 311 of the outer ring, between the first mating edge 361 and the U-shaped groove of the outer ring, and between the inner tongue 332 of the large bend tube and the inner tongue 313 of the outer ring. That is, the end of the outer tongue 311 of the outer ring is located within the large bend tube. On one side of the outer tongue 331, the inner tongue 313 of the outer ring is located on one side of the inner tongue 332 of the large bend. This connection structure changes the limiting structure of the starting end 336 of the large bend from the existing structure design of hanging on the back plate of the diffuser 1 to being installed on the combustion chamber casing 2, thereby reducing the processing difficulty of the diffuser 1 and reducing the stress borne by the diffuser 1. Moreover, the outer ring 31 of the flame tube and the inner wall 33 of the large bend are both supported by the combustion chamber casing 2. In this connection structure, the axial relative position of the mating part can be better guaranteed, thereby ensuring the sealing effect. This connection structure forms a complex mating and sealing structure through the cooperation of each tongue and the retaining ring 36. The radial installation gap, axial installation gap, preset axial gap and preset radial gap of each overlap are designed to ensure that the large bend has a good sealing effect while having a certain thermal expansion space in both the axial and radial directions.
[0039] In one embodiment, the large bend structure further includes a limiting structure for axially limiting the outer tongue 331 of the large bend. The limiting structure and the outer tongue 331 of the large bend have a first axial gap t1. The limiting structure is used to restrict the axial movement of the outer tongue 331 of the large bend, thereby restricting the rearward deformation of the outer tongue 331 of the large bend, and playing a role in axially limiting the starting end 336 of the large bend. A certain first axial gap t1 is designed to provide rear support force to the large bend under hot conditions, preventing excessive deformation that would cause the retaining ring 36 to axially detach from the outer ring 31 of the flame tube. The value of t1 is 0.5-2mm.
[0040] Specifically, the limiting structure includes limiting members 6 installed on the combustion chamber casing 2. Multiple limiting members 6 are evenly distributed along the circumference of the combustion chamber casing 2, specifically 4-12. Each limiting member 6 includes a mounting section 63, a transition section 64, and a limiting section 61. The mounting section 63 is used to connect with the combustion chamber casing 2. This mounting section 63 is used to pass through the casing 2 and cooperate with the corresponding mounting seat 21. A mounting cover plate 62 is provided on the mounting section 63, and bolt holes 621 are provided on the mounting cover plate 62 to secure the mounting cover plate 62 with bolts. The adapter section 64 is designed with a preset size, and the structural and dimensional design is based on minimizing interference with the outlet flow field of the diffuser 1 while ensuring connection strength. The limiting section 61 is a plate structure that matches the position of the outer tongue 331 of the large bend tube to ensure the contact area with the outer tongue 331 of the large bend tube and to ensure the limiting effect. At least two bolts are provided on the mounting cover plate 62 to limit the installation direction of the limiting member 6, so that the mating surface of the limiting section 61 of the limiting member 6 after installation matches the outer tongue 331 of the large bend tube.
[0041] In this embodiment, the axial clearance design values between the outer tongue plate 331 of the large bend and the outer tongue plate 311 of the outer ring, between the first mating edge 361 and the outer ring U-shaped groove, and between the inner tongue plate 332 of the large bend and the inner tongue plate 313 of the outer ring gradually increase from the outside to the inside. The aforementioned axial clearances are the second axial clearance t2, the third axial clearance t3, and the fourth axial clearance t4, respectively, i.e., the second axial clearance t2 < the third axial clearance t3 < the fourth axial clearance t4. The value range of each axial clearance is 2-5mm. Under extreme use conditions, the outer tongue plate 331 of the large bend and the outer tongue plate 311 of the outer ring are in axial contact. This position is far from the gas in the flame tube and the wall temperature is relatively low. Therefore, no large stress will be generated at this position in this connection structure. Through the reasonable design of each radial clearance and the second axial clearance t2, the third axial clearance t3, and the fourth axial clearance t4, it is ensured that the starting end 336 of the large bend has suitable thermal expansion space in both the axial and radial directions.
[0042] In this embodiment, the connecting structure also includes a large bend pipe rear tongue 333 formed on one side of the large bend pipe inner tongue 332. There is a preset radial gap between the large bend pipe rear tongue 333 and the outer ring inner tongue 313. When the second axial gap t2 is equal to 0, this position can maintain a good sealing effect. When the second axial gap t2 is greater than 0, the first connecting structure, the second connecting structure, and the retaining ring 36 form a labyrinth-type sealing structure to ensure a good sealing effect.
[0043] In this embodiment, the large bend structure also includes a Z-ring segment formed at the end of the outer ring 31 of the flame tube and an outer ring gas film tongue 314. A first connecting structure is formed on the Z-ring segment. The outer ring inner tongue 313, the Z-ring segment, and the outer ring gas film tongue 314 enclose a gas film cavity 317 with an open side. The open side of the gas film cavity 317 faces the starting end 336. The Z-ring segment has a vent hole 315 communicating with the gas film cavity 317. The opening of the preset radial gap between the large bend rear tongue 333 and the outer ring inner tongue 313 faces the gas film cavity 317. The inner wall of the membrane cavity 317 is approximately Ω-shaped, which guides airflow. Cooling air introduced through the vent 315 enters the membrane cavity 317, and a small amount of cooling air entering through the retaining ring 36 can also enter the membrane cavity 317 through the tongue 333 of the large bend, cooling the membrane tongue and the starting end 336 of the large bend, thus enhancing the cooling effect. This connection structure incorporates the possible air leakage into the cooling design, which can effectively reduce the risk of cracks caused by high stress at the starting end 336 of the large bend.
[0044] In this embodiment, the included angle b between the large bend profile section 335 of the inner wall 33 of the large bend and the outer tongue plate 331 of the large bend is designed to be 90°-150°, and a chamfer is designed at the bend to avoid large stress at the starting end 336 of the large bend; similarly, the included angle a between the Z ring section and the outer ring profile section 318 of the outer ring 31 of the flame tube is designed to be 90-150°. By limiting the included angles at the two locations and coordinating with the cooling structure, problems such as cracks caused by large stress can be effectively prevented.
[0045] On the other hand, an aero-engine is provided that uses the above-mentioned connection structure. Numerical simulation and experimental verification show that the connection structure has good assemblability, excellent sealing effect, small part deformation, and good performance. Compared with the existing technology, it solves the problems of easy cracking and excessive air leakage at the separation point of the large bend of the return combustion chamber and the outer ring of the flame tube.
[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A large bend structure for a high-circulation-parameter recirculation combustion chamber, the recirculation combustion chamber comprising a diffuser (1), a combustion chamber casing (2), a flame tube component (3), a fuel nozzle (4), and a turbine guide assembly (5), the flame tube component (3) comprising a flame tube outer ring (31), a flame tube inner ring (35), a large bend outer wall (32), a large bend inner wall (33), and a flame tube head (34), characterized in that, A connecting structure is provided between the outer ring (31) of the flame tube and the inner wall (33) of the large bend, the connecting structure including: The first connecting structure is formed at the end of the outer ring (31) of the flame tube, including an outer ring outer tongue (311), an outer ring inner tongue (313) and an outer ring U-shaped groove formed axially between the outer ring outer tongue (311) and the outer ring inner tongue (313); The second connection structure is formed at the starting end (336) of the inner wall (33) of the large bend pipe, including the outer tongue (331) of the large bend pipe, the inner tongue (332) of the large bend pipe, and the U-shaped groove of the large bend pipe formed radially between the outer tongue (331) and the inner tongue (332) of the large bend pipe. The retaining ring (36) has a first mating edge (361) and a second mating edge (362) for being inserted into the outer ring U-shaped groove and the large bend U-shaped groove respectively. The first mating edge (361) has a radial installation gap with the outer ring U-shaped groove, and the second mating edge (362) has an axial installation gap and a preset radial gap with the large bend U-shaped groove. The large bend outer tongue (331) and the outer ring outer tongue (311), the first mating edge (361) and the outer ring U-shaped groove, and the large bend inner tongue (332) and the outer ring inner tongue (313) are respectively designed with preset axial gaps.
2. The large bend pipe structure for a high-circulation-parameter recirculation combustion chamber according to claim 1, characterized in that, The design value of the axial clearance between the outer tongue plate (331) of the large bend pipe and the outer tongue plate (311) of the outer ring, between the first mating edge (361) and the outer ring U-shaped groove, and between the inner tongue plate (332) of the large bend pipe and the inner tongue plate (313) of the outer ring gradually increases from the outside to the inside, and the value range is 2-5mm.
3. The large bend pipe structure for a high-circulation-parameter recirculation combustion chamber according to claim 1, characterized in that, The connection structure also includes a large curved pipe rear tongue (333) formed on one side of the large curved pipe inner tongue (332), and there is a preset radial gap between the large curved pipe rear tongue (333) and the outer ring inner tongue (313).
4. The large bend pipe structure for a high-circulation-parameter recirculation combustion chamber according to claim 3, characterized in that, The large curved tube structure also includes a Z-ring segment formed at the end of the outer ring (31) of the flame tube and an outer ring air film tongue (314). The first connecting structure is formed on the Z-ring segment. The outer ring inner tongue (313), the Z-ring segment and the outer ring air film tongue (314) surround to form an air film cavity (317) with an open side. The open side of the air film cavity (317) faces the starting end (336). The Z-ring segment has a vent hole (315) that communicates with the air film cavity (317).
5. The large bend pipe structure for a high-circulation-parameter recirculation combustion chamber according to claim 4, characterized in that, The included angle between the Z-ring segment and the outer ring surface segment (318) of the outer ring (31) of the flame tube is designed to be 90-150°.
6. The large bend pipe structure for a high-circulation-parameter recirculation combustion chamber according to claim 1, characterized in that, The axial installation clearance and the radial installation clearance are 0.1-0.5 mm.
7. The large bend pipe structure for a high-circulation-parameter recirculation combustion chamber according to claim 1, characterized in that, The large bend structure also includes a limiting structure for axially limiting the outer tongue (331) of the large bend, and the limiting structure and the outer tongue (331) of the large bend have a first axial gap (t1).
8. The large bend pipe structure for a high-circulation-parameter recirculation combustion chamber according to claim 7, characterized in that, The limiting structure includes a limiting member (6) installed on the combustion chamber casing (2). Multiple limiting members (6) are evenly distributed along the circumference of the combustion chamber casing (2). The limiting member (6) includes an installation section (63), a transition section (64), and a limiting section (61). The installation section (63) is used to connect with the combustion chamber casing (2). The transition section (64) is designed with a preset size. The limiting section (61) is a plate-shaped structure that matches the position of the outer tongue plate (331) of the large bend pipe.
9. The large bend pipe structure for a high-circulation-parameter recirculation combustion chamber according to claim 1, characterized in that, The angle between the large bend profile section (335) of the inner wall (33) of the large bend and the outer tongue (331) of the large bend is designed to be 90°-150°.
10. An aircraft engine, characterized in that, The application has the large bend pipe structure for a high circulation parameter recirculation combustion chamber as described in any one of claims 1-9.