A ceramic-based reflow combustion chamber flame tube based on a flexible connection structure

Abstract

The present invention relates to a ceramic-based reflow combustion chamber flame tube based on a flexible connection structure, which belongs to the technical field of aircraft engine combustion chambers and includes a combustion chamber casing and a diffuser. The combustion chamber casing and the diffuser are respectively fixedly connected to the flame tube. The flame tube includes a ceramic-based flame tube outer ring, a ceramic-based flame tube inner ring and a metal-based flame tube head ring. The metal-based flame tube head ring is connected to the combustion chamber casing through a plurality of circumferentially evenly distributed fixing pins and fixing pin seats; one end of the ceramic-based flame tube outer ring is connected and sealed to the metal-based flame tube head ring through an outer ring sealing ring, and the other end of the ceramic-based flame tube outer ring is fixedly connected to the diffuser through an inner mounting edge. The present invention provides a high-life ceramic-based composite flame tube with good sealing, assembly and maintenance performance for the aircraft engine reflow combustion chamber, provides margin for the axial and radial free expansion of the ceramic-based flame tube under high-temperature working conditions, and has engineering application value.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation engine combustion chambers, and in particular relates to a ceramic-based reflow combustion chamber flame tube based on a flexible connection structure. Background Art

[0002] In aircraft engines, the combustion chamber converts fuel into high-temperature combustion gases through combustion, which propels the turbine to produce power. Recirculating combustion chambers effectively shorten the axial length of the engine's rotor and are widely used in small and medium-sized aircraft engines with high speeds.

[0003] To achieve high performance in aircraft engines, the operating temperatures within the combustion chamber are increasing. Therefore, more heat-resistant materials are needed to ensure stable and high-performance operation. Ceramic-based composites (CMCs) offer higher temperature resistance and lower density than metals, making them internationally recognized as one of the most promising heat-resistant materials for aircraft engines. Therefore, their application in high-temperature components of aircraft engine combustion chambers is an effective means of improving aircraft engine performance.

[0004] The flame tube is the component in the recirculating combustion chamber that withstands the highest temperature. If ceramic-based composite materials are used, the connection method with the casing, diffuser, nozzle, vortex generator, etc. must be considered. The shortcomings of the existing technology for ceramic-based flame tube structures are: First, the aircraft engine will generate a certain degree of vibration during operation. The existing technology cannot avoid the problem of large local stress caused by the main load-bearing points of the ceramic-based flame tube being concentrated on several fixed pin seats, which may cause damage to the outer ring of the ceramic-based flame tube, and cannot ensure the long-term safe and stable operation of the aircraft engine;

[0005] Second, existing technologies cannot simultaneously meet the design requirements for nozzle assembly and sealing. To account for the assembly of the ceramic-based flame tube and the expansion of the ceramic substrate under high-temperature operating conditions, a gap must be designed between the nozzle and the nozzle holder. As a result, there is a large amount of air leakage here, affecting the performance of the aircraft engine.

[0006] Third, the existing technology cannot avoid the problem of excessive stress and damage in the ceramic matrix due to the inconsistent axial or radial expansion of the ceramic-based flame tube outer ring and the metal parts under high-temperature working conditions, and cannot ensure the long-term safe and stable operation of the aircraft engine. Summary of the Invention

[0007] In response to the above problems, the present invention provides a long-life ceramic-based composite flame tube and related connection structures for the recirculation combustion chamber of an aircraft engine, which has good sealing, assembly and maintenance performance and engineering application value.

[0008] In order to overcome the problems existing in the prior art, the present invention provides the following technical solutions:

[0009] A ceramic-based reflow combustion chamber flame liner based on a flexible connection structure includes a combustion chamber casing and a diffuser. The combustion chamber casing and the diffuser are respectively fixedly connected to the flame liner to provide support. The flame liner includes a ceramic-based flame liner outer ring, a ceramic-based flame liner inner ring, and a metal-based flame liner head ring. The metal-based flame liner head ring is connected to the combustion chamber casing via a plurality of fixing pins and fixing pin seats uniformly distributed in the circumferential direction.

[0010] Among them, one end of the outer ring of the ceramic-based flame tube is connected and sealed to the head ring of the metal-based flame tube through an outer ring sealing ring, and the other end of the outer ring of the ceramic-based flame tube is fixedly connected to the diffuser through an inner mounting edge, and the inner mounting edge is provided with an inner mounting edge sealing ring; one end of the inner ring of the ceramic-based flame tube is connected and sealed to the inner ring fixing seat through an inner ring sealing ring, and the inner ring fixing seat is connected to the head ring of the metal-based flame tube, and the other end of the inner ring of the ceramic-based flame tube is connected and sealed to the combustion chamber casing through an inner casing sealing ring; a nozzle holder assembly is installed on the outer ring of the ceramic-based flame tube, and the nozzle holder assembly includes a nozzle movable ring, a nozzle holder, and a cover plate, and the cover plate presses the nozzle movable ring onto the nozzle holder, and the upper edge of the nozzle holder clamps the cover plate.

[0011] Furthermore, an outer ring support plate is provided between the diffuser and the outer ring of the ceramic-based flame tube. One end of the outer ring support plate is fixed on the diffuser, and the other end of the outer ring support plate is bent and contacts the outer side of the ceramic-based flame tube outer ring. The outer ring support plate is an elastic thin sheet structure, and several outer ring support plates are evenly distributed circumferentially on the outer side of the ceramic-based flame tube outer ring to provide flexible unidirectional supporting force.

[0012] Furthermore, the outer ring sealing ring, inner ring sealing ring and inner casing sealing ring are annular thin film structures, which are fixed to the metal-based flame tube head ring, inner ring fixing seat and combustion chamber casing by welding or bolting, and the sealing effect is achieved by applying pre-tightening force through interference fit.

[0013] Furthermore, the metal-based flame tube head ring is provided with a head ring sealing structure at both ends of the metal-based flame tube outer ring and the ceramic-based flame tube inner ring. A W-shaped elastic sealing ring is installed in the head ring sealing structure. The W-shaped elastic sealing ring is an annular structure and is elastic in the axial direction. The two ends of the W-shaped elastic sealing ring are respectively tightly attached to the ceramic-based flame tube outer ring, the head ring sealing structure and the ceramic-based flame tube inner ring, the head ring sealing structure.

[0014] Furthermore, a plurality of inner ring fixing bushings are provided on the inner ring of the ceramic-based flame tube, and inner ring fixing screws are installed in the inner ring fixing bushings. The inner ring of the ceramic-based flame tube is fixedly connected to the inner ring fixing seat through the inner ring fixing bushings and the inner ring fixing screws, and the inner ring sealing ring is arranged between the inner ring fixing bushings and the inner ring fixing seat.

[0015] Furthermore, a plurality of the inner ring fixing bushings are evenly distributed circumferentially on the inner ring of the ceramic-based flame tube.

[0016] Furthermore, the nozzle holder assembly is installed on the end of the outer ring of the ceramic-based flame tube close to the combustion chamber casing.

[0017] Furthermore, the nozzle seat assembly includes a nozzle seat fixing seat, and the nozzle seat and the nozzle seat fixing seat are fixed to the inner and outer surfaces of the ceramic-based flame tube outer ring by welding and docking.

[0018] Furthermore, a gap a is provided between the edge of the nozzle movable ring and the nozzle seat.

[0019] Furthermore, an ignition nozzle is installed on the combustion chamber casing, the ignition nozzle is screwed into the combustion chamber casing through a thread, and the ignition end of the ignition nozzle passes through the nozzle seat and is inserted into the outer ring of the ceramic-based flame tube.

[0020] Furthermore, a circumferentially evenly distributed boss and groove structure is provided between the outer ring of the ceramic-based flame tube and the inner mounting edge, and the boss and groove are fixed to each other in cooperation.

[0021] Beneficial effects of the present invention: The present invention utilizes a metal-based flame tube head ring assembly and a metal elastic support sealing ring to connect the inner and outer rings of the ceramic-based flame tube to the combustion chamber casing, transferring the main load-bearing point of the combustion chamber flame tube to the metal substrate, and at the same time, with a nozzle holder assembly that allows a certain amount of movement, providing a margin for the free axial and radial expansion of the ceramic-based flame tube under high-temperature working conditions, avoiding catastrophic consequences such as ceramic substrate rupture caused by excessive internal stress of the ceramic substrate, and also achieving effective sealing between the metal substrate and the ceramic substrate, ensuring the aerodynamic performance of the combustion chamber, and having engineering application value. A reasonable and feasible ceramic-based flame tube connection structure with engineering application value is designed, and the structure has good sealing, assembly and strength, ensuring the total pressure loss of the combustion chamber and the life of the ceramic-based flame tube.

[0022] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A cross-sectional schematic diagram of a ceramic-based reflow combustion chamber flame tube according to an embodiment of the present invention is shown;

[0025] Figure 2 A schematic cross-sectional view of the installation of a nozzle holder assembly of a ceramic-based reflow combustion chamber flame tube according to an embodiment of the present invention is shown;

[0026] Figure 3 A schematic diagram showing the cooperation between the nozzle and nozzle holder of the ceramic-based reflow combustion chamber flame tube according to an embodiment of the present invention is shown;

[0027] Figure 4 A schematic diagram showing the fixing of the inner ring of the flame tube of a ceramic-based reflow combustion chamber according to an embodiment of the present invention is shown;

[0028] Figure 5 A schematic diagram of the circumferential fixation of the outer ring of the flame tube of the ceramic-based reflow combustion chamber according to an embodiment of the present invention is shown;

[0029] Figure 6 A schematic diagram of the connection between the metal-based flame tube head ring and the W-shaped elastic sealing ring in an embodiment of the present invention is shown.

[0030] In the picture

[0031] 1-combustion chamber casing, 2-diffuser, 3-fixing pin, 4-fixing pin seat, 5-outer ring sealing ring, 6-ceramic-based flame tube outer ring, 7-outer ring support plate, 8-metal-based flame tube head ring, 8-1-head ring sealing structure, 9-ceramic-based flame tube inner ring, 10-inner ring fixing bushing, 11-inner ring sealing ring, 12-inner ring fixing seat, 13-inner casing sealing ring, 14-inner mounting edge sealing ring, 15-inner mounting edge, 16-inner ring fixing screw, 17-ignition nozzle, 18-nozzle seat assembly, 18-1 -nozzle movable ring, 18-2 -nozzle seat, 18-3 -cover plate, 18-4 -nozzle seat fixing seat, 19-W-type elastic sealing ring. DETAILED DESCRIPTION

[0032] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and description are to be considered as illustrative in nature and not restrictive.

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0034] It should be noted that the terms "first", "second" etc. in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the application described herein. In this application, the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "center", "vertical", "horizontal", "lateral", "longitudinal" etc. are based on the directions or positional relationships shown in the accompanying drawings.

[0035] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0036] The existing technology refers to the commonly used structural design of metal-based flame tubes. The inner and outer rings of the flame tube and the head ring are integrally woven and formed. The fixed pin seat, the nozzle seat and the outer ring of the flame tube are connected into one. The vortex generator is clamped and assembled from both sides of the head ring. The flame tube body uses fixed pins and inner mounting edges for axial and circumferential positioning, and a simple overlap structure is used for sealing.

[0037] The ceramic-based reflow combustion chamber flame tube based on a flexible connection structure of this embodiment includes a combustion chamber casing 1 and a diffuser 2, and is characterized in that: a ceramic-based flame tube outer ring 6, a ceramic-based flame tube inner ring 9 and a metal-based flame tube head ring 8 of an annular structure are installed between the combustion chamber casing 1 and the diffuser 2, and the metal-based flame tube head ring 8 is connected to the combustion chamber casing 1 through a fixing pin 3 and a fixing pin seat 4; one end of the ceramic-based flame tube outer ring 6 is connected and sealed to the metal-based flame tube head ring 8 through an outer ring sealing ring 5, and the other end of the ceramic-based flame tube outer ring 6 is fixedly connected to the diffuser 2 through an inner mounting edge 15, and an inner mounting edge sealing ring 14 is provided at the inner mounting edge 15; one end of the ceramic-based flame tube inner ring 9 is connected and sealed to the inner ring fixing seat 12 through an inner ring sealing ring 11, and the inner ring fixing seat 12 is connected to the metal-based flame tube head ring 8, and the other end of the ceramic-based flame tube inner ring 9 is connected and sealed to the combustion chamber casing 1 through an inner casing sealing ring 13.

[0038] The ceramic-based flame tube inner ring 9 and the ceramic-based flame tube outer ring 6 are annular structures, and their cross-section is a multi-segment line connected by straight lines and circular arcs. They are located between the diffuser 2 and the combustion chamber casing 1. To ensure strength, local thickening design is performed at the stress-bearing and positioning positions. The metal-based flame tube head ring 8 is an annular structure, and its cross-section is a C-shaped multi-segment line connected by straight lines and circular arcs. Its function is to fix the vortex finder and assist in positioning the ceramic-based flame tube inner ring 9 and the ceramic-based flame tube outer ring 6. The inner ring fixing seat 12 is an annular structure, and its cross-section is an L-shaped multi-segment line. It is fixed to the inner side of the metal-based flame tube head ring 8 by welding. Its function is to assist in positioning the ceramic-based flame tube inner ring 9.

[0039] An outer ring support sheet 7 is provided between the diffuser 2 and the ceramic-based flame tube outer ring 6. This outer ring support sheet 7 is a flexible thin sheet structure, with multiple outer ring support sheets 7 evenly distributed circumferentially around the outer side of the ceramic-based flame tube outer ring 6. The outer ring support sheets 7 are fan-shaped thin sheets with a fishhook-shaped polyline cross-section, and their function is to provide flexible axial support for the ceramic-based flame tube outer ring 6.

[0040] The outer ring sealing ring 5, the inner ring sealing ring 11 and the inner casing sealing ring 13 are annular thin-sheet structures, which are fixed to the metal-based flame tube head ring 8, the inner ring fixing seat 12 and the combustion chamber casing 1 by welding or bolting. Flexible support and sealing are provided for the ceramic-based flame tube inner ring 9 and the ceramic-based flame tube outer ring 6. The metal-based flame tube head ring 8 is provided with a head ring sealing structure 8-1 at both ends of the metal-based flame tube head ring 8 that are connected to the ceramic-based flame tube outer ring 6 and the ceramic-based flame tube inner ring 9. A W-shaped elastic sealing ring 19 is installed in the head ring sealing structure 8-1. The W-shaped elastic sealing ring 19 is an annular structure and is elastic in the axial direction. When the W-shaped elastic sealing ring 19 is working, its two ends are respectively pressed against the ceramic-based flame tube outer ring 6, the head ring sealing structure 8-1 and the ceramic-based flame tube inner ring 9 and the head ring sealing structure 8-1.

[0041] The ceramic-based flame tube inner ring 9 is provided with a plurality of inner ring fixing bushings 10, and inner ring fixing screws 16 are installed in the inner ring fixing bushings 10. The ceramic-based flame tube inner ring 9 is fixedly connected to the inner ring fixing seat 12 through the inner ring fixing bushings 10 and the inner ring fixing screws 16. The plurality of inner ring fixing bushings 10 are evenly distributed circumferentially on the ceramic-based flame tube inner ring 9. The inner ring fixing bushing 10 is a rectangular parallelepiped structure with a circular hole in the center. It is located in the square groove of the ceramic-based inner ring. Its function is to convert the line contact between the inner ring fixing screws 16 and the ceramic substrate into surface contact, so as to reduce the local stress of the ceramic substrate and at the same time increase the assembly between the metal-based flame tube head ring 8 and the ceramic-based flame tube inner ring 9.

[0042] A nozzle holder assembly 18 is mounted on the ceramic-based flame tube outer ring 6. The nozzle holder assembly 18 comprises a nozzle movable ring 18-1, a nozzle holder 18-2, a cover plate 18-3, and a nozzle holder fixing seat 18-4. The nozzle holder 18-2 and nozzle holder fixing seat 18-4 are welded and fixed to the inner and outer surfaces of the ceramic-based flame tube outer ring 6. The cover plate 18-3 presses the nozzle movable ring 18-1 against the nozzle holder 18-2, with the upper edge of the nozzle holder 18-2 clamping onto the cover plate 18-3. A gap a is provided between the edge of the nozzle movable ring 18-1 and the nozzle holder 18-2. The structure of the nozzle holder assembly 18 ensures the assembly of the ignition nozzle 17, taking into account the expansion of the combustion chamber casing 1 and the ceramic-based flame tube outer ring 6 during operation, while also ensuring the sealing of the nozzle hole and the aerodynamic performance of the combustion chamber.

[0043] An ignition nozzle 17 is installed on the combustion chamber casing 1. The ignition nozzle 17 is screwed into the combustion chamber casing 1 through a thread. The ignition end of the ignition nozzle 17 passes through the nozzle seat 18-2 and is inserted into the ceramic-based flame tube outer ring 6.

[0044] A circumferentially uniformly distributed boss and groove structure is provided between the ceramic-based flame tube outer ring 6 and the inner mounting edge 15, and the boss and groove cooperate with each other to be fixed.

[0045] like Figure 1The metal-based flame liner head ring 8 is connected to the combustion chamber casing 1 through multiple circumferentially distributed fixing pins 3 and fixing pin holders 4 to achieve head fixation. The ceramic-based flame liner outer ring 6 is fixed and sealed using the outer ring sealing ring 5, outer ring support plate 7, inner mounting edge sealing ring 14, and inner mounting edge 15. Among them, the outer ring sealing ring 5 and the inner mounting edge sealing ring 14 are full-ring rotating elastic thin-sheet structures, which achieve sealing by applying preload force through interference fit. The outer ring support plate 7 is a fan-shaped rotating elastic thin-sheet structure. Multiple support plates are evenly distributed around the circumference to provide flexible unidirectional support for the ceramic-based flame tube outer ring under non-combustion chamber operating conditions, and the inner mounting edge 15 provides relative axial positioning. Under combustion chamber operating conditions, the flame tube is subjected to high temperatures and expands in the axial and radial directions. However, the linear expansion coefficient of the ceramic-based material is much smaller than that of metal materials. The flexibility of the outer ring sealing ring 5, outer ring support plate 7, and inner mounting edge sealing ring 14, as well as the gap between the ceramic-based flame tube outer ring 6 and the metal-based flame tube head ring 8, can accommodate the axial and radial thermal expansion of the ceramic-based flame tube outer ring 6, avoiding damage caused by excessive internal stress of the ceramic matrix. The ceramic-based flame tube inner ring 9 is fixed and sealed by the inner ring fixing bushing 10, inner ring sealing ring 11, inner ring fixing seat 12, inner casing sealing ring 13, and inner ring fixing screws 16. Among them, the inner ring seal 11 and the inner casing seal 13 are full-ring rotating elastic thin-sheet structures, which achieve sealing by applying pre-tightening force through interference fit; the ceramic-based flame tube inner ring 9 is fixed to the inner ring fixing seat 12 using a certain number of inner ring fixing bushings 10 and inner ring fixing screws 16 evenly distributed around the circumference, and the ceramic-based substrate at the stress-bearing position is smoothed and thickened to increase the local strength of the substrate. The outer ring seal 5 has slots with a width of 1mm evenly distributed to release stress, reduce the force of the outer ring seal 5 on the ceramic-based flame tube outer ring 6, and improve service life. In addition, the W-shaped elastic seal 19 is installed in the head ring sealing structure 8-1 of the metal-based flame tube head ring 8 to further seal the air leaking from the slot on the outer ring seal 5. Similarly, the inner ring seal 11 and the inner casing seal 13 have slots with a width of 1mm evenly distributed to release stress, and the W-shaped elastic seal 19 is used to strengthen the seal.

[0046] The backflow combustion chamber is usually equipped with multiple ignition nozzles 17 for starting the combustion chamber. Since the ignition nozzle 17 and the fixing pin 3 and the fixing pin seat 4 are not in the same cross section, Figure 2 、 Figure 3 Described separately.

[0047] like Figure 2As shown, after the ignition nozzle 17 is screwed into the combustion chamber casing 1 through a thread, the ignition end passes through the nozzle seat and is inserted into the ceramic-based flame tube outer ring 6, thereby igniting the oil and gas mixture in the flame tube. Due to the difference in material properties between the combustion chamber casing 1 and the ceramic-based flame tube outer ring 6, the linear expansion amounts of the two are inconsistent during working conditions. If a nozzle seat designed as an integral part of the ceramic-based flame tube outer ring 6 is used, a large stress is easily generated in the ceramic matrix, causing the nozzle seat to be damaged and leak. Therefore, the nozzle seat assembly 18 is designed to accommodate this expansion amount, thereby reducing the internal stress of the ceramic matrix.

[0048] like Figure 3 As shown, the nozzle holder assembly 18 consists of 4 parts. A circular flat groove matching the nozzle holder assembly 18 is polished on the wall surface of the ceramic-based flame tube outer ring 6, which facilitates the nozzle holder 18-2 and the nozzle holder fixed seat 18-4 to be docked and fixed on both sides of the ceramic-based flame tube outer ring 6 by spot welding. The docking position is also treated with a smooth transition and thickening. After the nozzle movable ring 18-1 is pressed onto the nozzle holder 18-2 through the cover plate 18-3, the upper end of the nozzle holder 18-2 is bent to prevent the cover plate and the movable ring from falling off. There is a gap a between the nozzle movable ring 18-1 and the nozzle holder 18-2. This gap can ensure that the ignition nozzle 17 has a certain amount of mobility and will not leak.

[0049] like Figure 4 As shown, the inner ring fixing sleeve 10 can transform the original line contact between the metal material and the ceramic material between the ceramic-based flame tube inner ring 9 and the inner ring fixing screw into surface contact, thereby effectively reducing the local stress of the ceramic matrix around the inner ring fixing screw 16 and improving the service life of the ceramic-based flame tube.

[0050] like Figure 5 As shown, there are circumferentially evenly distributed bosses and groove structures between the ceramic-based flame tube outer ring 6 and the inner mounting edge 15, thereby achieving circumferential fixation of the ceramic-based flame tube outer ring 6.

[0051] like Figure 6 As shown, the W-shaped elastic sealing ring 19 is an annular structure with a certain degree of axial elasticity. During operation, it closely adheres to the ceramic-based flame tube outer ring 6, the ceramic-based flame tube inner ring 9, and the head ring sealing structure 8-1 on the metal-based flame tube head ring 8 to ensure sealing. The head ring sealing structure 8-1 has upper and lower ends extending from the end, and a mounting groove is formed between the upper and lower ends. The W-shaped elastic sealing ring 19 is fixed in the mounting groove.

[0052] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A ceramic-based reflow combustion chamber flame tube based on a flexible connection structure, comprising a combustion chamber casing (1) and a diffuser (2), wherein the combustion chamber casing (1) and the diffuser (2) are respectively fixedly connected to the flame tube to provide support, and is characterized in that: The flame tube comprises a ceramic-based flame tube outer ring (6), a ceramic-based flame tube inner ring (9) and a metal-based flame tube head ring (8), wherein the metal-based flame tube head ring (8) is connected to the combustion chamber casing (1) via a plurality of fixing pins (3) and fixing pin seats (4) uniformly distributed in the circumferential direction; One end of the ceramic-based flame tube outer ring (6) is connected and sealed to the metal-based flame tube head ring (8) through the outer ring sealing ring (5); the other end of the ceramic-based flame tube outer ring (6) is fixedly connected to the diffuser (2) through the inner mounting edge (15); the inner mounting edge sealing ring (14) is provided at the inner mounting edge (15); one end of the ceramic-based flame tube inner ring (9) is connected and sealed to the inner ring fixing seat (12) through the inner ring sealing ring (11); the inner ring fixing seat (12) is connected to the metal-based flame tube head ring (8), the other end of the ceramic-based flame tube inner ring (9) is connected and sealed to the combustion chamber casing (1) through the inner casing sealing ring (13); a nozzle seat assembly (18) is installed on the ceramic-based flame tube outer ring (6), and the nozzle seat assembly (18) includes a nozzle movable ring (18-1), a nozzle seat (18-2), and a cover plate (18-3), the cover plate (18-3) presses the nozzle movable ring (18-1) onto the nozzle seat (18-2), and the upper edge of the nozzle seat (18-2) clamps the cover plate (18-3).

2. The ceramic-based reflow combustion chamber flame liner based on a flexible connection structure according to claim 1, characterized in that: An outer ring support sheet (7) is provided between the diffuser (2) and the ceramic-based flame tube outer ring (6), one end of the outer ring support sheet (7) is fixed on the diffuser (2), and the other end of the outer ring support sheet (7) is bent and contacts the outer side of the ceramic-based flame tube outer ring (6). The outer ring support sheet (7) is an elastic thin sheet structure, and a plurality of outer ring support sheets (7) are evenly distributed circumferentially on the outer side of the ceramic-based flame tube outer ring (6) to provide flexible unidirectional supporting force.

3. The ceramic-based reflow combustion chamber flame tube based on a flexible connection structure according to claim 1, characterized in that: The outer ring sealing ring (5), the inner ring sealing ring (11), and the inner casing sealing ring (13) are annular thin sheet structures, which are fixed to the metal-based flame tube head ring (8), the inner ring fixing seat (12) and the combustion chamber casing (1) by welding or bolting, and the sealing effect is achieved by applying a pre-tightening force through interference fit.

4. The ceramic-based reflow combustion chamber flame tube based on a flexible connection structure according to claim 1, characterized in that: The metal-based flame tube head ring (8) is provided with a head ring sealing structure (8-1) at both ends of the metal-based flame tube outer ring (6) and the ceramic-based flame tube inner ring (9), and a W-shaped elastic sealing ring (19) is installed in the head ring sealing structure (8-1). The W-shaped elastic sealing ring (19) is an annular structure and has elasticity in the axial direction. The two ends of the W-shaped elastic sealing ring (19) are respectively in close contact with the ceramic-based flame tube outer ring (6), the head ring sealing structure (8-1) and the ceramic-based flame tube inner ring (9), and the head ring sealing structure (8-1).

5. The ceramic-based reflow combustion chamber flame liner based on a flexible connection structure according to claim 1, characterized in that: The ceramic-based flame tube inner ring (9) is provided with a plurality of inner ring fixing bushings (10), and the inner ring fixing screws (16) are installed in the inner ring fixing bushings (10). The ceramic-based flame tube inner ring (9) is fixedly connected to the inner ring fixing seat (12) through the inner ring fixing bushings (10) and the inner ring fixing screws (16), and the inner ring sealing ring (11) is provided between the inner ring fixing bushings (10) and the inner ring fixing seat (12).

6. The ceramic-based reflow combustion chamber flame tube based on a flexible connection structure according to claim 5, characterized in that: A plurality of inner ring fixing bushings (10) are evenly distributed circumferentially on the ceramic-based flame tube inner ring (9).

7. The ceramic-based reflow combustion chamber flame liner based on a flexible connection structure according to claim 1, characterized in that: The nozzle seat assembly (18) is installed at the end of the ceramic-based flame tube outer ring (6) close to the combustion chamber casing (1), and the nozzle seat assembly (18) includes a nozzle seat fixing seat (18-4). The nozzle seat (18-2) and the nozzle seat fixing seat (18-4) are welded and fixed to the inner and outer surfaces of the ceramic-based flame tube outer ring (6).

8. The ceramic-based reflow combustion chamber flame liner based on a flexible connection structure according to claim 1, characterized in that: A gap a is provided between the edge of the nozzle movable ring (18-1) and the nozzle seat (18-2).

9. The ceramic-based reflow combustion chamber flame tube based on a flexible connection structure according to claim 1, characterized in that: An ignition nozzle (17) is installed on the combustion chamber casing (1). The ignition nozzle (17) is screwed into the combustion chamber casing (1) through a thread, and the ignition end of the ignition nozzle (17) passes through the nozzle seat (18-2) and is inserted into the ceramic-based flame tube outer ring (6).

10. The ceramic-based reflow combustion chamber flame liner based on a flexible connection structure according to claim 1, characterized in that: A circumferentially evenly distributed boss and groove structure is provided between the ceramic-based flame tube outer ring (6) and the inner mounting edge (15), and the boss and groove cooperate with each other and are fixed.

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