Flame tube connection structure and combustion chamber

Abstract

The application provides a flame tube connecting structure, which comprises a metal part and a flame tube. The flame tube is made of ceramic matrix composite material. The metal part comprises a groove, and the end of the flame tube is clamped into the groove. The structure further comprises a plurality of flame tube ring grooves and a plurality of metal part ring grooves. The plurality of flame tube ring grooves are arranged at the area of the flame tube in the groove. The plurality of metal part ring grooves are opposite to the flame tube ring grooves to form a radial ring groove. A metal clamping ring is arranged in the radial ring groove with a gap. The flame tube connecting structure has better thermal adaptation performance. The application further provides a combustion chamber adopting the flame tube connecting structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aero-engines, in particular to the field of combustion chamber flame tubes. BACKGROUND

[0002] With the increasingly high performance design index requirements of advanced aero-engines, the inlet and outlet temperatures of the combustion chamber are continuously increasing, and the temperature resistance of traditional high-temperature alloy materials is insufficient, so a complex film cooling system needs to be used to reduce the service temperature. The introduction of a large amount of cooling gas will cause insufficient combustion, resulting in the emission of harmful gases, pollution of the environment, and reduction of the thermal efficiency of the engine.

[0003] Therefore, traditional high-temperature alloys cannot meet the corresponding temperature requirements, so ceramic matrix composites (CMC) are currently used. CMC refers to a type of composite material formed by introducing reinforcing and toughening materials into a ceramic matrix, which has the characteristics of high-temperature resistance, low density, and oxidation resistance, and the long-term permissible temperature can reach 1200 DEG C. For example, SiC / SiC composite material, as a type of ceramic matrix composite material, can enhance the toughness of the ceramic by using SiC fibers, and has higher strength than high-temperature alloys at higher environmental temperatures, to ensure the long service life of the flame tube.

[0004] However, due to the low linear expansion coefficient of CMC materials and the lower strength and plasticity than high-temperature alloys, when connecting with metal parts, the problem of high stress and structural failure caused by the different expansion amounts of the two materials needs to be avoided.

[0005] For example, the CMC flame tube needs to be connected and assembled with a metal head adapter and a metal cap in the combustion chamber to form a flame tube assembly. The flame tube assembly is installed as a flow passage in the combustion chamber case and together forms an engine combustion chamber unit. Generally, the CMC flame tube and the metal component cannot be connected by bolts, and even if bolt fastening is used, due to the large difference in the thermal expansion coefficients of the composite material and the metal material, in the working state, the composite material and the metal part will inevitably have a mismatch in thermal deformation due to the different expansion amounts, which will generate high stress at the connection, the temperature at the connection is low, and the tensile strength and plasticity of the composite material are lower than those of the high-temperature alloy material, which can easily lead to its fracture and damage, thereby causing engine failure. After the ceramic matrix composite material generates microcracks, it will rapidly expand, the flame tube will form a penetrating crack, the flame will spread, and catastrophic consequences will occur. SUMMARY

[0006] An object of the present application is to provide a flame tube connection structure with better thermal adaptation performance.

[0007] The flame tube connecting structure comprises a metal piece and a flame tube, the flame tube is made of ceramic matrix composite material, the metal piece comprises a groove, the end of the flame tube is clamped into the groove, the structure further comprises a plurality of flame tube ring grooves and a plurality of metal piece ring grooves, the plurality of flame tube ring grooves are arranged at the area of the flame tube in the groove, the plurality of metal piece ring grooves are opposite to the flame tube ring grooves to form a radial ring groove, and a metal clamping ring is arranged in the radial ring groove with a gap.

[0008] In one or more embodiments, the metal piece comprises a cap and a head adapter segment, and the cap and the head adapter segment jointly define the groove, which extends in the axial direction.

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

[0010] In one or more embodiments, the metal piece ring grooves comprise cap ring grooves arranged on the cap and / or adapter segment ring grooves arranged on the head adapter segment.

[0011] In one or more embodiments, the metal piece further comprises a plurality of mounting holes which communicate between the outside of the metal piece and the radial ring grooves.

[0012] In one or more embodiments, the mounting holes are arranged in the axial direction.

[0013] In one or more embodiments, the mounting holes are arranged at different radial positions of the metal piece.

[0014] In one or more embodiments, the metal clamping ring is a ring-shaped clamping ring with an opening or a plurality of segmented clamping rings.

[0015] In one or more embodiments, the radial ring grooves are arranged at different axial positions of the groove.

[0016] In one or more embodiments, the central axes of the radial ring grooves are located at different radial heights.

[0017] In one or more embodiments, the metal clamping ring is a resilient member, and is configured to apply a fastening force to the wall of the radial ring groove by means of elastic restoring force.

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

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

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

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

[0022] The above-mentioned flame tube connecting structure solves the problem of thermal deformation mismatch between the CMC flame tube and the metal cap by means of the multiple radial ring grooves and the metal clamps between the CMC flame tube and the metal part, and the floating fit of the metal clamps and the radial ring grooves with gaps. The structure of the floating fit can solve the problem of thermal deformation mismatch between the CMC flame tube and the metal cap, avoid the generation of large stress in the CMC at the connecting part, and solve the problem of thermal deformation mismatch at the connecting part. In addition, the multiple radial ring grooves and the metal clamps can form a labyrinth channel, thereby avoiding the flow of the external airflow of the flame tube from the upstream contact surface of the cap and the flame tube to the inside of the flame tube, and ensuring the effective sealing of the connecting structure. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above-mentioned and other features, properties and advantages of the present application will become more apparent by reference to the following description of embodiments with the aid of the accompanying drawings, wherein:

[0024] Figure 1 is a structural schematic diagram of a combustion chamber;

[0025] Figure 2 is a schematic diagram of a flame tube connecting structure;

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

[0027] Figure 4 is a schematic diagram of the external part of the metal part and the flame tube;

[0028] Figures 5A-5B is a schematic diagram of an embodiment of the metal clamp. DETAILED DESCRIPTION

[0029] The present application will be further described below in conjunction with specific embodiments and the accompanying drawings, and more details are set forth in the following description in order to fully understand the present application, but the present application can be implemented in various ways other than the description, and those skilled in the art can make similar generalizations and deductions according to the actual application without departing from the scope of the present application, and therefore the protection scope of the present application should not be limited by the content of the specific embodiments.

[0030] It should be noted that these and other subsequent drawings are only examples, and are not drawn according to the condition of the same scale, and should not be used as a limitation on the actual protection scope required by the present application.

[0031] As Figure 1As shown, the aero-engine combustion chamber structure is a full-annular combustion chamber structure, and the dashed line S is the axis of the engine. The combustion chamber generally includes a combustion chamber outer casing 3, a combustion chamber inner casing 5, a combustion chamber diffuser 4, a fuel nozzle 1, a head assembly 6, a fuel nozzle outer shell 10, a nozzle stem core 11, a nozzle interstage section 12, and a flame tube assembly 2.

[0032] During engine operation, 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 mixes with the air in the flame tube 2 to burn. The burning will cause the wall surface of the flame tube 2 to be in a high-temperature working environment.

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

[0034] Among them, the head adapter section 23, the cap 21, and the front support 20 are metal materials, and the flame tube 22 is a CMC material. Due to the large difference in the thermal expansion coefficient between the ceramic-based flame tube and the metal piece, the assembly therebetween is prone to thermal adaptation problems.

[0035] Therefore, the flame tube connecting structure of the present disclosure can solve the problem of inconsistent thermal deformation at the connection, while ensuring effective sealing, so as to reduce the stress on the CMC flame tube, reduce the risk of failure, and improve the service life of the CMC flame tube.

[0036] Referring to Figures 2-3 As shown, the flame tube connecting structure includes a metal piece and a flame tube 22, the metal piece includes a groove 32, and the end wall surface of the flame tube is clamped into the groove 32.

[0037] In some embodiments, the metal piece includes a cap 21 and a head adapter section 23, and the cap and the head adapter section together define a groove 32 extending in the axial direction. For example, the cap 21 and the head adapter section 23 are generally connected by welding, and the connection defines the groove 32, which extends in the Figure 2 As shown, the left and right directions. The groove 32 has a bottom wall surface 205 Figure 3 As shown, and a side wall surface 206.

[0038] The CMC flame tube 22 comprises a flame tube inner side wall 227, a flame tube outer side wall 226 and a front end face 225. The head adapter section 23 comprises an adapter section outer side wall 208 and the cap 21 comprises a cap inner side wall 212. It is understood that the adapter section outer side wall 208 and the cap inner side wall 212 are the side walls of the groove 32.

[0039] It is noted that the terms "front" and "rear" in the present application are understood as left and right in the 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" are understood as top and bottom in the drawings, the side radially outward is the outer side, and the side radially inward is the inner side.

[0040] The flame tube connecting structure disclosed in the present application further comprises a plurality of flame tube ring grooves 35 and a plurality of metal ring grooves 36. The plurality of flame tube ring grooves 35 are arranged at the area of the flame tube 22 located in the groove 32, and the plurality of metal ring grooves 36 are arranged opposite to the plurality of flame tube ring grooves 35, and are connected to form the radial ring groove 31.

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

[0042] It is understood that the metal ring groove comprises a cap ring groove arranged on the cap 21 and / or an adapter section ring groove arranged on the head adapter section. That is, the radial ring groove 31 can be arranged on the outer side of the flame tube 22, or can be arranged on the inner side of the flame tube 22.

[0043] As shown in FIG. 1, the CMC flame tube 22 is arranged in the groove 32 of the cap 21, and the metal ring 24 is arranged in the radial ring groove 31 formed by the groove 32 and the cap 21. Figure 3 A specific embodiment of the upstream connecting assembly structure of the CMC flame tube outer ring is shown. Three metal ring grooves 36 and three flame tube ring grooves 35 are respectively machined on the metal cap inner side wall 212 and the CMC flame tube outer side wall 226 along the axial direction, and the two are connected to form the radial ring groove 31, and the radial ring groove 31 is punched along the circumferential direction 360°, that is, a ring groove is formed. The three radial ring grooves 31 respectively form spaces for accommodating the ring metal ring 24. The side wall 241 around the metal ring 24 leaves a certain gap between the side wall of the radial ring groove 31, so that the ring is not stuck during installation, and the installation is facilitated.

[0044] As shown in FIG. 1, the CMC flame tube 22 is arranged in the groove 32 of the cap 21, and the metal ring 24 is arranged in the radial ring groove 31 formed by the groove 32 and the cap 21. Figures 5A-5BAs shown, the metal retaining ring 24 can be a ring-shaped retaining ring with an opening 245, or it can be multiple segmented retaining rings 240 as shown in Figure 5, with the multiple segmented retaining rings 240 forming a ring together.

[0045] Understandably, the segmented multiple-segment 240 rings are easier to install.

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

[0047] A certain gap can be reserved between the inner wall 227 or outer wall 226 of the flame tube and the side wall surface 206 of the groove 32, such as a certain gap 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 surface 205 of the groove 32 to prevent the outward expansion of the cap 21 from exceeding that of the CMC flame tube 22 under high-temperature working conditions, which would cause the cap 21 to press against the wall surface of the flame tube 22 when hot, leading to cracking of the CMC flame tube. Similarly, a certain gap is reserved at the front end face to prevent the bottom wall surface 205 of the groove 32 formed by the metal cap 21 from pressing against the front end face 225 of the CMC flame tube 22 when hot.

[0048] Continue to refer to Figure 3 As shown, the gas P in the casing annular cavity 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 between 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 aforementioned flow area is unreasonable and leakage occurs, a large amount of external gas will enter the internal chamber of the flame tube 22, directly affecting the gas distribution and cooling of the flame tube. The aforementioned axially distributed multiple metal retaining rings 24 and radial annular grooves 31 simultaneously form a labyrinth channel, thereby preventing the external airflow from flowing from the cap 21 and the upstream contact surface of the flame tube 22 into 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 set 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 thus improve the sealing effect.

[0051] To facilitate the installation of the metal retaining ring 24, in some embodiments, the metal component further includes a plurality of mounting holes 39 communicating with the exterior of the metal component and each radial annular groove 31. For example... Figure 4As shown, mounting holes 39 are formed on the outer surface of the cap 21 corresponding to the radial ring grooves 31, and the mounting holes 39 are in communication with the radial ring grooves 31. The mounting holes 39 are used for mounting the metal ring 24. In some embodiments, the radial ring grooves 31 are rectangular ring grooves, and the mounting holes 39 are rectangular through holes.

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

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

[0054] Since there are multiple rings to be installed, the multiple mounting holes 39 for mounting the ring on the outer surface of the cap 21 are distributed in different axial heights in the circumferential direction, that is, the multiple mounting holes 39 are distributed in different upper and lower positions in the left-right direction, which can reduce the damage of the opening to the local cap 21, prevent the local damage from being too large, and avoid the destruction of the metal cap 21 during long-term work. As shown in the figure, when the metal ring 24 is a segmented ring, more mounting holes 39 for mounting the ring are arranged circumferentially on the outer surface of the cap. Figure 4 Figure 5A As shown, when the metal ring 24 is a segmented ring, more mounting holes 39 for mounting the ring are arranged circumferentially on the outer surface of the cap.

[0055] Therefore, the above-mentioned CMC flame tube connecting structure solves the problem of thermal deformation mismatch between the CMC flame tube and the metal cap by floating cooperation of multiple metal rings and radial ring grooves, avoids the generation of large stress on the CMC material at the connection, thereby generating cracks, has better thermal adaptation performance, and multiple structures can realize the labyrinth seal between the CMC flame tube and the metal cap, avoid the external airflow of the flame tube from flowing to the inside of the flame tube from the upstream contact surface of the cap and the flame tube, and affect the air distribution and the cooling of the flame tube.

[0056] In combination with the introduction of the above-mentioned CMC flame tube connecting structure, it can also be understood that a combustion chamber using the above-mentioned flame tube connecting structure has better thermal adaptation performance.

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

[0058] Although the present application has been disclosed in its preferred embodiments with reference to the accompanying drawings, it is not intended to limit the present application thereto, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solutions of the present application, all fall within the protection scope defined by the claims of the present application.

Claims

1. A flame tube connection structure comprising a metal piece and a flame tube, the flame tube being of ceramic matrix composite material, the metal piece comprising a recess into which an end of the flame tube is clamped, characterised in that, The structure further comprises: a plurality of flame tube ring grooves arranged in the area of the flame tube in the recess; a plurality of metal piece ring grooves facing each other with respect to the flame tube ring grooves to form a radial ring groove in abutment; and a metal ring arranged in the radial ring groove with a gap.

2. The flame tube connection structure of claim 1, wherein The metal piece comprises a cap and a head adapter section, which together define the recess, which extends in the axial direction.

3. The flame tube connection structure of claim 2, wherein The cap is fixed to the combustion chamber casing by a connecting piece.

4. The flame tube connection structure of claim 2, wherein The metal piece ring groove comprises a cap ring groove arranged on the cap and / or an adapter section ring groove arranged on the head adapter section.

5. The flame tube connection structure of claim 1, wherein The metal piece further comprises a plurality of mounting holes for communication between the outside of the metal piece and each radial ring groove.

6. The flame tube connection structure of claim 5, wherein Each mounting hole is arranged axially.

7. The flame tube connection structure of claim 5, wherein Each mounting hole is arranged at a different radial position of the metal piece.

8. The flame tube connection structure of claim 1, wherein The metal ring is a ring-shaped ring with an opening, or a plurality of segmented rings.

9. The flame tube connection structure of claim 1, wherein Each radial ring groove is arranged at a different axial position of the recess.

10. The flame tube connection structure of claim 1, wherein The central axis of each radial ring groove is at a different radial height.

11. The flame tube connection structure of claim 1, wherein The metal ring is a resilient member, which exerts a fastening force on the wall of the radial ring groove by virtue of the elastic restoring force.

12. The flame tube connection structure of claim 1, wherein The radial ring groove is a rectangular ring groove.

13. The flame tube connection structure of claim 1, wherein The front end face of the flame tube is arranged with a gap with respect to the bottom wall of the recess.

14. The flame tube connection structure of claim 1, wherein The outer wall or inner wall of the flame tube is arranged with a gap with respect to the side wall of the recess.

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 connecting structure according to any one of claims 1-14.

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