Flame tube connecting structure and combustion chamber

Abstract

The flame tube connecting structure comprises a metal piece and a flame tube, the flame tube is made of a ceramic-based composite material, the metal piece comprises a groove, the end of the flame tube is clamped into the groove, the flame tube connecting structure further comprises a plurality of flame tube annular grooves and a plurality of metal piece annular grooves, and the flame tube annular grooves are formed in the area, located in the groove, of the flame tube; the multiple metal piece ring grooves are opposite to the flame tube ring grooves so as to be in butt joint to form a radial ring groove. The metal clamping ring is arranged in the radial annular groove in a clearance mode. The flame tube connecting structure has better thermal adaptation performance. The invention further provides a combustion chamber adopting the flame tube connecting structure.

Description

Technical Field

[0001] The invention relates to the field of aviation engines, and in particular to the field of combustion chamber flame tubes. Background Art

[0002] As the performance design index requirements of advanced aircraft engines become higher and higher, the inlet and outlet temperatures of the combustion chamber continue to increase. Traditional high-temperature alloy materials have insufficient heat resistance and need to adopt a complex air film cooling system to reduce their service temperature. The introduction of a large amount of cooling gas will lead to incomplete combustion, resulting in the emission of harmful gases, polluting the environment and reducing the thermal efficiency of the engine.

[0003] Therefore, traditional high-temperature alloys can no longer meet the corresponding use temperature requirements, so ceramic matrix composites (CMC) are mostly used at this stage. CMC refers to a type of composite material formed by introducing reinforcing and toughening materials into a ceramic matrix. It has the characteristics of high temperature resistance, low density, and oxidation resistance, and the long-term allowable temperature can reach 1200°C. For example, SiC / SiC composite material is a ceramic matrix composite material. Its SiC fiber can enhance the toughness of ceramics. At higher ambient temperatures, it has higher strength than high-temperature alloys to ensure the long life of the flame tube.

[0004] However, since the linear expansion coefficient of CMC materials is low, and its strength and plasticity are lower than those of high-temperature alloys, when connecting them with metal parts, it is necessary to avoid problems such as high stress and structural failure caused by the different expansion amounts of the two materials.

[0005] For example, the CMC flame tube needs to be connected and assembled with the metal head adapter section and the metal cap in the combustion chamber to form a flame tube assembly. The flame tube assembly is installed inside the combustion chamber casing as a flow channel component, and together they form the engine combustion chamber unit. Generally, it is difficult to fasten the CMC flame tube with metal components by bolts. Even if bolts are used, the thermal expansion coefficients of composite materials and metal materials are very different. Under working conditions, the composite materials and metal parts will inevitably have different expansion amounts and mismatched thermal deformation, resulting in high stress at the joints. The temperature at the joints is low, and the tensile strength and plasticity of the composite materials are worse than those of high-temperature alloy materials, which can easily lead to their fracture and damage, thereby causing engine failure. After microcracks are generated in ceramic-based composite materials, they will expand rapidly, forming through cracks in the flame tube, and the flame will spread, resulting in catastrophic consequences. Summary of the invention

[0006] An object of the present invention is to provide a flame tube connection structure having better thermal adaptability.

[0007] To achieve the above-mentioned purpose, the flame tube connection structure includes a metal part and a flame tube, the flame tube is made of a ceramic-based composite material, the metal part includes a groove, and the end of the flame tube is inserted into the groove. The structure also includes multiple flame tube annular grooves and multiple metal part annular grooves, and the multiple flame tube annular grooves are arranged in the area where the flame tube is located in the groove; multiple metal part annular grooves are opposite to each of the flame tube annular grooves to form radial annular grooves; a metal clamp ring is arranged in the radial annular groove with a gap.

[0008] In one or more embodiments, the metal part includes a cap and a head transition segment, the metal cap and the head transition segment jointly define the groove, and the groove extends in the axial direction.

[0009] In one or more embodiments, the cap cover is fixed to the combustion chamber casing by a connecting piece.

[0010] In one or more embodiments, the metal part annular groove includes a cap annular groove of the cap and / or a transition segment annular groove on the head transition segment.

[0011] In one or more embodiments, the metal component further includes a plurality of mounting holes connecting the outside of the metal component and each of the radial annular grooves.

[0012] In one or more embodiments, each of the mounting holes is axially arranged.

[0013] In one or more embodiments, each of the mounting holes is disposed at a different radial position of the metal component.

[0014] In one or more embodiments, the metal collar is an annular collar with an opening, or a plurality of segmented collars.

[0015] In one or more embodiments, each of the radial annular grooves is arranged at a different axial position of the groove.

[0016] In one or more embodiments, the central axis of each of the radial annular grooves is located at a different radial height.

[0017] In one or more embodiments, the metal clamping ring is an elastic member for applying a tightening force to the wall surface of the radial annular groove by means of an elastic restoring force.

[0018] In one or more embodiments, the radial annular groove is a rectangular annular groove.

[0019] In one or more embodiments, a front end surface of the flame tube and a bottom wall surface of the groove are arranged to have a gap.

[0020] In one or more embodiments, an outer wall surface or an inner wall surface of the flame tube and a side wall surface of the groove are arranged to have a gap.

[0021] Another object of the present invention is to provide a combustion chamber, comprising a combustion chamber casing, a fuel nozzle and a flame tube, wherein the flame tube adopts the above-mentioned flame tube connection structure.

[0022] The flame tube connection structure mentioned above makes use of multiple radial annular grooves and metal clamping rings between the flame tube of the composite material and the metal part. The metal clamping ring and the radial annular groove have a floating fit with a gap. The floating fit structure can solve the problem of mismatched thermal deformation of the CMC flame tube and the metal cap, avoid large stress on the CMC at the connection, and solve the problem of uncoordinated thermal deformation at the connection; and multiple radial annular grooves and metal clamping rings can form a maze channel, thereby preventing the external airflow of the flame tube from flowing from the upstream contact surface of the cap and the flame tube to the flame tube, ensuring the effective sealing of the connection structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0024] Figure 1 It is a schematic diagram of the structure of the combustion chamber;

[0025] Figure 2 It is a schematic diagram of the flame tube connection structure;

[0026] Figure 3 It is a schematic diagram of the matching structure between the radial ring groove and the metal clamp ring;

[0027] Figure 4 It is a schematic diagram of the exterior of the metal parts and the flame tube;

[0028] Figure 5A-5B is a schematic diagram of an embodiment of a metal collar. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0030] It should be noted that these and other subsequent drawings are only examples and are not drawn to scale, and should not be used to limit the actual scope of protection required by the present invention.

[0031] like Figure 1As shown, the combustion chamber structure of the aircraft engine is a full-ring combustion chamber structure, and the dot-dash line S is the axis of the engine. The combustion chamber generally includes an outer combustion chamber casing 3, an inner combustion chamber casing 5, a combustion chamber diffuser 4, a fuel nozzle 1, a head assembly 6, a fuel nozzle housing 10, a nozzle rod core 11, a nozzle interstage section 12 and a flame tube assembly 2.

[0032] When the engine is working, high-temperature compressed air E enters the flame tube 2 from the diffuser 4, and the fuel nozzle 1 sprays fuel into the flame tube 2, and the fuel and air are mixed and burned in the flame tube 2. During combustion, the wall surface of the flame tube 2 is in a relatively high temperature working environment.

[0033] Continue to refer to Figure 2 As shown, the flame tube assembly 2 includes a flame tube 22, a head transition section 23, a cap 21 and a front support member 20. The CMC flame tube 22 specifically includes a flame tube outer ring 201 and a flame tube inner ring 202. Figure 1 It is understood that the flame tube assembly 2 is fixed to the combustion chamber outer casing 3 through the front support member 20 through connecting members such as bolts, so as to achieve the installation and fixation of the entire flame tube assembly.

[0034] The head adapter section 23, the cap 21 and the front support member 20 are all made of metal, and the flame tube 22 is made of CMC. Due to the huge difference in thermal expansion coefficients between the ceramic-based flame tube and the metal parts, thermal adaptation problems are easily encountered in the assembly between the two.

[0035] Therefore, the flame tube connection structure disclosed in the present invention can solve the problem of thermal deformation inconsistency at the connection point, while ensuring effective sealing to reduce the stress on the CMC flame tube, reduce the risk of failure, and increase the service life of the CMC flame tube.

[0036] Reference Figures 2 to 3 As shown, the flame tube connection structure includes a metal piece and a flame tube 22 , the metal piece includes a groove 32 , and the end wall of the flame tube is inserted into the groove 32 .

[0037] In some embodiments, the metal part includes a cap cover 21 and a head transition section 23, and the cap cover and the head transition section together define a groove 32 extending in the axial direction. For example, the cap cover 21 and the head transition section 23 are generally connected by welding, and the connection defines a groove 32, and the groove 32 extends along the axial direction. Figure 2 The bottom surface of the groove 32 is Figure 3 The bottom wall surface is shown as 205 and the side wall surface is 206.

[0038] The CMC flame tube 22 includes a flame tube inner wall 227, a flame tube outer wall 226 and a front end face 225. The head transition section 23 includes a transition section outer wall 208, and the cap cover 21 includes a cap cover inner wall 212. It can be understood that the transition section outer wall 208 and the cap cover inner wall 212 are the side wall surface 206 of the groove 32.

[0039] It should be noted that the terms "front" and "rear" in this application can be understood from the left and right sides in the accompanying drawings. The side close to the fuel flow is the front side, and the side close to the combustion chamber is the rear side; the terms "outer" and "inner" can be understood from the upper and lower sides in the accompanying drawings. Relative to the engine axis, the radially outward side is called the outer side, and the radially inward side is called the inner side.

[0040] The flame tube connection structure disclosed in the present invention also includes a plurality of flame tube annular grooves 35 and a plurality of metal part annular grooves 36. The plurality of flame tube annular grooves 35 are arranged in the area where the flame tube 22 is located in the groove 32. The plurality of metal part annular grooves 36 are opposite to each flame tube annular groove 35 and are connected to form radial annular grooves 31.

[0041] The metal collar 24 is arranged in the radial annular groove 31 with a gap, so that the metal collar 24 and the radial annular groove 31 form a floating matching structure. Preferably, the metal collar 24 is an elastic member, which is used to apply a tightening force to the wall surface of the radial annular groove 31 by means of elastic restoring force, so as to expand and tighten between the flame tube annular groove 35 and the metal member annular groove 36. Thus, the CMC flame tube 22 is fixed on the cap 21, and further fixed on the combustion chamber casing 3 through the front support member 20 and the bolt structure.

[0042] It is understandable that the metal ring groove includes a cap ring groove provided on the cap 21 and / or a transition section ring groove provided on the head transition section. That is, the radial ring groove 31 can be provided on the outside of the flame tube 22 or on the inside of the flame tube 22.

[0043] like Figure 3 A specific embodiment of the upstream connection assembly structure of the outer ring of the CMC flame tube is shown. Three metal ring grooves 36 and flame tube ring grooves 35 are processed axially on the inner side wall 212 of the metal cap and the outer side wall 226 of the CMC flame tube, respectively. The two are connected to form a radial ring groove 31, and the radial ring groove 31 is opened 360 degrees along the circumferential direction, that is, an annular groove is formed. The three radial ring grooves 31 respectively form a space for accommodating the annular metal clamp ring 24. A certain gap is left between the side walls 241 around the metal clamp ring 24 and the side walls of the radial ring groove 31, so that the clamp ring will not get stuck during installation, which is convenient for installation.

[0044] like Figure 5A-5BAs shown, the metal collar 24 may be an annular collar with an opening 245, or may be a plurality of segmented collars 240 as shown in FIG. 5, wherein the plurality of segmented collars 240 together form an annular ring.

[0045] It can be appreciated that the segmented plurality of segmented collars 240 are easier to install.

[0046] By controlling a certain gap between the CMC flame tube 22, the metal cap cover 21 and the metal clamp ring 24, when the engine is working, the thermal mismatch deformation caused by the large difference in thermal expansion coefficient can be released, preventing the problem of high stress caused by the inability to release the deformation.

[0047] A certain gap can be reserved between the inner wall 227 or the outer wall 226 of the flame tube and the side wall 206 of the groove 32, such as a certain gap is reserved between the inner wall 227 of the flame tube and the outer wall 208 of the transition section; a certain gap is also reserved between the front end face 225 of the CMC flame tube and the bottom wall 205 of the groove 32 to prevent the cap 21 from expanding outwards more than the CMC flame tube 22 under high-temperature working conditions, so that the cap 21 squeezes the wall of the flame tube 22 when hot, causing the CMC flame tube to crack. Similarly, a certain gap is reserved at the front end face to prevent the bottom wall 205 of the groove 32 formed by the metal cap 21 from squeezing the front end face 225 of the CMC flame tube 22 when hot.

[0048] Continue to refer to Figure 3 As shown, the casing annular cavity gas P can enter the interior of the flame tube 22 from the contact point between the outer wall 226 of the CMC flame tube and the inner wall 212 of the cap along the direction of the arrow through the gap of the front end face 225 and the gap between the inner wall 227 of the CMC flame tube and the outer wall 208 of the transition section.

[0049] If the sealing design of the above-mentioned flow area is unreasonable and leakage occurs, a large amount of gas outside the flame tube 22 will enter the internal chamber of the flame tube 22, which will directly affect the gas distribution and cooling of the flame tube. The aforementioned multiple metal collars 24 distributed along the axial direction and the radial annular grooves 31 simultaneously form a labyrinth channel, thereby blocking the external airflow of the flame tube from flowing from the cap cover 21 and the upstream contact surface of the flame tube 22 to the flame tube, resulting in a better sealing effect.

[0050] Preferably, in order to achieve a better labyrinth sealing effect, each radial annular groove 31 is arranged at a different axial position of the groove 32, and the central axis of each radial annular groove 31 can also be located at a different radial height, so as to extend the airflow path and thereby improve the sealing effect.

[0051] To facilitate the installation of the metal collar 24, in some embodiments, the metal member further includes a plurality of installation holes 39 connecting the outside of the metal member and each radial annular groove 31. Figure 4As shown, a mounting hole 39 is provided on the outer surface of the cap cover 21 at a location corresponding to the radial annular groove 31, and the mounting hole 39 is connected to the radial annular groove 31. The mounting hole 39 is used to mount the metal collar 24. In some embodiments, the radial annular groove 31 is a rectangular annular groove, and the mounting hole 39 is a rectangular through hole.

[0052] In some embodiments, the mounting holes 39 are axially distributed and communicate with the radial annular grooves 31 .

[0053] The side wall width of the mounting hole 39 is slightly larger than the width of the radial annular groove 31. Since the metal collar 24 is an open circular ring, it can be greatly expanded and tightened in the radial annular groove 31 due to elasticity during installation. The collar 24 is installed in the radial annular groove 31 by inserting one end of the opening into the mounting hole 39 and continuously pushing the other end forward.

[0054] Since there are multiple collars to be installed, multiple mounting holes 39 for mounting collars on the outer surface of the cap 21 are distributed at different axial heights along the circumferential direction, that is, multiple mounting holes 39 are arranged along the circumferential direction. Figure 4 The holes are distributed at different upper and lower positions in the middle and left directions, which can reduce the damage of the opening to the cap cover 21, prevent excessive local damage, and avoid the damage of the metal cap cover 21 during long-term work. Figure 5A As shown, when the metal collar 24 is a segmented collar, more mounting holes 39 for mounting the collar need to be arranged circumferentially on the outer surface of the cap.

[0055] Therefore, the above-mentioned CMC flame tube connection structure is simple to assemble through the floating cooperation of multiple metal clamps and radial ring grooves, and can solve the problem of thermal deformation mismatch between the CMC flame tube and the metal cap cover, avoid the CMC material from generating large stress at the connection point, thereby generating cracks, and has better thermal adaptability; and the multi-channel structure can realize the labyrinth seal between the CMC flame tube and the metal cap cover, avoiding the external airflow of the flame tube from the upstream contact surface of the cap cover and the flame tube to flow into the flame tube, affecting the gas distribution and flame tube cooling.

[0056] Combined with the introduction to the above-mentioned CMC flame tube connection structure, it can also be understood that a combustion chamber adopting the above-mentioned flame tube connection structure has better thermal adaptability.

[0057] The present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0058] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A flame tube connection structure, comprising a metal part and a flame tube, wherein the flame tube is made of a ceramic-based composite material, the metal part comprises a groove, and the end of the flame tube is inserted into the groove, characterized in that: The structure also includes: A plurality of flame tube annular grooves are arranged in the region where the flame tube is located in the groove; A plurality of metal ring grooves facing each of the flame tube ring grooves to form radial ring grooves by abutting against each other; and The metal collar is arranged in the radial annular groove with a gap.

2. The flame tube connection structure according to claim 1, characterized in that: The metal part comprises a cap cover and a head transition section. The metal cap cover and the head transition section jointly define the groove, and the groove extends in the axial direction.

3. The flame tube connection structure according to claim 2, characterized in that: The cap cover is fixed on the combustion chamber casing through a connecting piece.

4. The flame tube connection structure according to claim 2, characterized in that: The metal part annular groove includes a cap cover annular groove arranged on the cap cover and / or a transition section annular groove on the head transition section.

5. The flame tube connection structure according to claim 1, characterized in that: The metal component further comprises a plurality of mounting holes communicating with the outside of the metal component and each of the radial annular grooves.

6. The flame tube connection structure according to claim 5, characterized in that: Each of the mounting holes is arranged axially.

7. The flame tube connection structure according to claim 5, characterized in that: The mounting holes are arranged at different radial positions of the metal component.

8. The flame tube connection structure according to claim 1, characterized in that: The metal clamp ring is an annular clamp ring with an opening, or a plurality of segmented clamp rings.

9. The flame tube connection structure according to claim 1, characterized in that: Each of the radial annular grooves is arranged at a different axial position of the groove.

10. The flame tube connection structure according to claim 1, characterized in that: The central axis of each radial annular groove is located at a different radial height.

11. The flame tube connection structure according to claim 1, characterized in that: The metal clamping ring is an elastic member, which is used to apply a fastening force to the wall surface of the radial annular groove by means of elastic restoring force.

12. The flame tube connection structure according to claim 1, characterized in that: The radial annular groove is a rectangular annular groove.

13. The flame tube connection structure according to claim 1, characterized in that: The front end surface of the flame tube and the bottom wall surface of the groove are arranged to have a gap.

14. The flame tube connection structure according to claim 1, characterized in that: An outer wall surface or an inner wall surface of the flame tube and a side wall surface of the groove are arranged so as to have a gap.

15. A combustion chamber, comprising a combustion chamber casing, a fuel nozzle and a flame tube, characterized in that: The flame tube adopts the flame tube connection structure as described in any one of claims 1-14.

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