CN114688562A

CN114688562A - Combustion chamber with ceramic matrix composite flame tube

Info

Publication number: CN114688562A
Application number: CN202210393720.3A
Authority: CN
Inventors: 迟雪; 张成凯
Original assignee: AECC Shenyang Engine Research Institute
Current assignee: AECC Shenyang Engine Research Institute
Priority date: 2022-04-14
Filing date: 2022-04-14
Publication date: 2022-07-01
Anticipated expiration: 2042-04-14
Also published as: CN114688562B

Abstract

The application belongs to the field of aircraft engines, in particular to a combustion chamber with a ceramic matrix composite flame tube. As a novel high-temperature resistant material, the ceramic matrix composite is used as a novel high-temperature resistant material, the positioning and fixing problem is firstly solved in engineering application, the positioning mode of a ceramic matrix component cannot be designed by adopting the traditional rigid fixing mode of a metal component due to the material particularity of the ceramic matrix composite, and meanwhile, the thermal expansion coefficient of the ceramic matrix composite is only about 1/3 of the metal material at high temperature, so that the component is easy to lose efficacy if the cold and hot structures are not matched, and the problems that the thermal expansion is not matched when the ceramic matrix composite is connected with the metal material and the flame tube is positioned are solved.

Description

Combustion chamber with ceramic matrix composite flame tube

Technical Field

The application belongs to the field of aero-engines, and particularly relates to a combustion chamber with a ceramic matrix composite flame tube.

Background

The high thrust-weight ratio aircraft engine is the basis for developing advanced military aircraft, the improvement of the turbine inlet temperature of the engine and the reduction of the structural weight are main ways for improving the thrust-weight ratio, in order to ensure the combustion performance, the combustion air ratio needs to be greatly increased, and the cooling air ratio is reduced. Meanwhile, the high-temperature-rise combustion chamber is also required to further maintain and even improve the durability of the flame tube under the conditions of reduced cooling gas distribution and reduced cooling gas quality. In order to meet the requirements, besides the advanced flame tube wall surface cooling technology, a novel high-temperature-resistant, low-density and high-strength and high-toughness structural material is required, which is not only the requirement for continuously improving the performance of the engine, but also the key for improving the thrust-weight ratio of the aircraft engine. The SiC fiber reinforced ceramic matrix composite (CMC-SiC) has the characteristics of high specific strength, high specific modulus, high temperature resistance, ablation resistance, oxidation resistance, low density and the like, the density of the CMC-SiC fiber reinforced ceramic matrix composite is 2-2.5 g/cm3, the CMC-SiC fiber reinforced ceramic matrix composite is only 1/3-1/4 of high-temperature alloy and niobium alloy, and 1/9-1/10 of tungsten alloy, and the weight of a component can be effectively reduced by adopting the material, so that the thrust-weight ratio of an engine is improved. The long-term use temperature of the material is 1350 ℃ which can be improved by 150-350 ℃ compared with high-temperature alloy at present, and the material is one of the most potential thermal structure materials.

The adoption of ceramic matrix composite material for the flame tube of the combustion chamber has the following advantages:

a) the weight of the combustion chamber is reduced. The density of the CMC-SiC is only 2-2.5 g/cm3, the existing flame tube is mostly made of high-temperature alloy, the density of the ceramic matrix composite is only 1/3-1/4, and the same component can be reduced in weight; secondly, the CMC-SiC material has higher temperature resistance, and the complex structure which is needed to be adopted due to cooling when high-temperature alloy is adopted originally is simplified, and the weight of the combustion chamber can be reduced.

b) The temperature rise of the main combustion chamber is improved. The thrust-weight ratio of the engine is improved to a great extent by means of the improvement of the temperature rise of the combustion chamber, and the temperature of the flame tube and the temperature restrict the temperature rise of the combustion chamber. The use temperature of the CMC-SiC is 1350 ℃, which is 150-350 ℃ higher than that of the high-temperature alloy, so that the temperature rise potential of the combustion chamber can be improved.

c) The cooling air volume of the combustion chamber is reduced, because the CMC-SiC material has higher temperature resistance, the air volume for cooling the combustion chamber can be greatly reduced, and the residual cooling air volume can be used for head tissue combustion or mixed air volume, thereby improving the combustion performance.

The temperature of the outlet of the combustion chamber of the current high thrust-weight ratio engine reaches above 2100K, the flame tube of the current combustion chamber is made of high-temperature alloy materials, the current high-temperature alloy combined with high-efficiency cooling and thermal barrier coating technology cannot meet the design requirements of the flame tube of the main combustion chamber of the high thrust-weight ratio aircraft engine, and the temperature resistance of the flame tube becomes the bottleneck and the restriction factor of the realization technical index of the high thrust-weight ratio engine.

Disclosure of Invention

In order to achieve the purpose of the invention, the invention adopts the following technical scheme:

as a novel high-temperature resistant material, the ceramic matrix composite is used for solving the problem of positioning and fixing in engineering application. Due to the brittle nature of ceramic matrix composites, the positioning of ceramic matrix components cannot be designed using the traditional rigid attachment of metal components. In this patent, the adoption runs through the indirect positioning mode of pin + metal locating piece and is fixed in the combustor casing with ceramic matrix composite flame tube on, make the flame tube have certain free space in the axial with radially, prevent that its rigid connection from resulting in the destruction of flame tube, the mode of fixing before simultaneously also is favorable to the centering nature in the homogeneity of combustor oil-gas mixture and nozzle.

The coefficient of linear expansion difference between ceramic matrix composite and the superalloy connector is very big, because the change of temperature can produce great thermal stress in the interface department of two kinds of materials, the unmatched problem of the thermal expansion of ceramic matrix composite and metal material has been solved to the mode that this patent adopted reservation expansion gap, prevents that the flame tube from taking place to destroy.

Because the ceramic matrix composite and the metal material can not be fixed by adopting a welding method, the ceramic matrix composite component and the metal component are fixed in a non-welding way by adopting a mode that the metal rivet penetrates through the ceramic matrix composite component and is in spot welding with the metal component.

The scheme of this application specifically is, includes:

the flame tube comprises a casing, a positioning rod and a flame tube; the casing and the flame tube are both annular; the casing is provided with a ring groove, the bottom of the ring groove is provided with an air channel, airflow at the front end of the aircraft engine flows into the ring groove through the air channel, the flame tube is inserted into the large ring groove through a notch of the ring groove, the front end of the flame tube is provided with an opening, a fuel nozzle extends into the opening, and the rear end of the flame tube is lapped with a turbine component of the engine;

the flame tube comprises an annular inner wall and an annular outer wall, wherein the inner wall and the outer wall are made of ceramic matrix composite materials; the gap between the inner wall and the outer wall forms an annular combustion cavity for aircraft fuel combustion, a metal outer wall positioning block is mounted at the front end of the outer wall through a first rivet, a metal inner wall positioning block is mounted at the front end of the inner wall through a second rivet, the positioning rod penetrates through a through hole of the outer wall positioning block and a through hole of the inner wall positioning block respectively, two ends of the positioning rod are fixed on the casing, an outer air guide sleeve is mounted at the front end of the outer wall, and an inner air guide sleeve is mounted at the front end of the inner wall.

Preferably, the specific mounting structure of the outer wall and the outer wall positioning block is as follows: the outer wall positioning block is connected to the wall surface of the outer wall close to the annular combustion cavity through a rivet, the outer wall is provided with a mounting hole at the through hole of the outer wall positioning block, the outer air guide sleeve is provided with a through hole at the through hole of the outer wall positioning block, the positioning rod sequentially penetrates through the through hole of the outer air guide sleeve, the mounting hole of the outer wall and the through hole of the outer wall positioning block; the inner wall positioning block is connected to the inner wall through a rivet and is close to the wall surface of the annular combustion cavity, the inner wall is provided with a mounting hole at the through hole of the inner wall positioning block, the inner air guide sleeve is provided with a through hole at the through hole of the inner wall positioning block, the positioning rod sequentially penetrates through the through hole of the inner wall positioning block, the mounting hole of the inner wall and the through hole of the inner air guide sleeve.

Preferably, the diameter of the through hole of the inner wall positioning block is smaller than the diameter of the mounting hole of the inner wall, and the diameter of the through hole of the outer wall positioning block is smaller than the diameter of the mounting hole of the outer wall.

Preferably, the specific structure that both ends of locating lever and machine casket are fixed is: the outer wall of quick-witted casket the outer wall of annular has the screw hole, and the screw hole runs through the outer wall of annular, the quick-witted casket the inner wall of annular has the locating hole, and the locating lever inserts through the screw hole the annular falls into in the locating hole, the locating lever has the external screw thread in the position department with the screw hole contact, and the locating lever passes through external screw thread and screw hole threaded connection.

Preferably, a gap is formed between adjacent rivet holes of the inner wall positioning block and the outer wall positioning block, and the gap is used for eliminating thermal stress.

Preferably, the width of the gap is 0.8-1.2 mm.

Preferably, the first rivet connected with the outer wall positioning block is a rivet with a 120-degree countersunk head, the 120-degree countersunk head faces the annular combustion chamber, and the tail end of the first rivet is fixed by spot welding; the second rivet connected with the inner wall positioning block is a rivet with a 120-degree countersunk head, and the tail end of the second rivet is fixed through spot welding.

Preferably, the positioning rods are uniformly arranged along the circumferential direction of the casing.

Preferably, the casing has a mounting seat at a position corresponding to the threaded hole to extend the length of the threaded hole, and the casing has a boss at a position corresponding to the positioning hole to extend the length of the positioning hole.

Preferably, the fuel nozzle is arranged between two adjacent positioning rods

The advantages of the present application include: 1. as a novel high-temperature resistant material, the ceramic matrix composite is firstly required to be positioned and fixed in engineering application. This patent has designed a combustion chamber ceramic matrix composite flame holder fixed knot and has constructed, adopts the fixed ceramic matrix composite flame holder of the indirect positioning mode who runs through pin + metal locating piece, makes the flame holder have certain free space in axial and radial, prevents that its rigid connection from leading to the destruction of flame holder.

2. The coefficient of linear expansion difference between ceramic matrix composite and the superalloy connector is very big, because the change of temperature can produce great thermal stress in the interface department of two kinds of materials, the unmatched problem of the thermal expansion of ceramic matrix composite and metal material has been solved to the mode that this patent adopted reservation expansion gap.

3. Because the ceramic matrix composite and the metal material can not be fixed by adopting a welding method, the ceramic matrix composite component and the metal component are fixed in a non-welding way by adopting a mode that the metal rivet penetrates through the ceramic matrix composite component and is in spot welding with the metal component.

4. Compared with a metal flame tube, the weight of the designed ceramic-based flame tube structure is reduced by 30%, and the ceramic-based flame tube structure has a remarkable effect on reducing the weight of an engine combustion chamber and is beneficial to improving the thrust-weight ratio of an engine.

Drawings

FIG. 1 is a schematic view of a mounting structure for a ceramic matrix composite liner;

FIG. 2 is a schematic view of a structure of a casing;

FIG. 3 is a schematic view of a positioning rod configuration;

FIG. 4 is a schematic view of a flame tube configuration;

FIG. 5 is a schematic view of the connection between the positioning rod and the flame tube;

FIG. 6 is a schematic view of the outer spacer structure;

FIG. 7 is a schematic view of the structure of the outer positioning block

FIG. 8 is a schematic diagram of an inner positioning block structure;

FIG. 9 is a schematic diagram of an inner positioning block structure

FIG. 10 is a schematic view of the connection structure of the outer positioning block and the outer wall of the flame tube;

FIG. 11 is a schematic view of the connection structure between the outer positioning block and the outer wall of the flame tube

FIG. 12 is a schematic view of the connection structure of the inner positioning block and the inner wall of the flame tube;

FIG. 13 is a schematic view of the connection structure of the inner positioning block and the inner wall of the flame tube;

wherein, 1-a casing; 2-positioning a rod; 3-a flame tube; 1 a-an outer wall outer cavity mounting base; an inner cavity mounting base of the outer wall of the casing; 1 c-a threaded hole; 1 e-mounting holes; 1 d-a mounting seat for the inner wall of the casing; 2 a-a thread; 2 b-terminal; 3 b-flame tube outer wall; 3 g-inner wall of flame tube; 3 a-an outer pod; 3 f-inner dome; 3 d-an outer wall positioning block; 3 e-inner wall positioning blocks; 3 c-a liner head; 3h, 3 g-riveting; 3k, 3 l-counter bore, 310-first through hole, 311-first mounting hole; 312 — a first via; 313-a second via; 314-second mounting hole, 315-second through hole.

Detailed Description

In order to make the implementation objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all embodiments of the present application. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application, and should not be construed as limiting the present application. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application. Embodiments of the present application will be described in detail below with reference to the drawings.

A ceramic matrix composite flame tube fixing structure is divided into three components: the flame tube comprises a casing 1, a positioning rod 2 and a ceramic matrix composite flame tube 3.

The casing 1 comprises an outer wall outer cavity mounting seat 1a, a casing outer wall inner cavity mounting seat 1b and a casing inner wall mounting seat 1d, and the casing 1 is made of high-temperature alloy materials.

The positioning rod 2 is provided with threads 2a and is made of high-temperature alloy materials.

The flame tube 3 comprises a flame tube outer wall 3b, a flame tube inner wall 3g, an outer air guide sleeve 3a, an inner air guide sleeve 3f, an outer wall positioning block 3d, an inner wall positioning block 3e and a flame tube head 3 c. Wherein the outer wall 3b and the inner wall 3g of the flame tube are made of ceramic matrix composite materials, and the outer air guide sleeve 3a, the inner air guide sleeve 3f, the outer wall positioning block 3d, the inner wall positioning block 3e and the flame tube head 3c are made of high-temperature alloy materials.

Flame tube 3 is fixed with machine casket 1 through the fixed locating lever 2 of circumference equipartition through, set up outer wall locating piece 3d and inner wall locating piece 3e on the flame tube 3, be metal material, the distance of locating lever 2 and ceramic matrix composite flame tube outer wall 3b and inner wall 3g is far greater than with metal locating piece 3d, 3 e's distance, locating lever 2 is through locating piece 3d promptly, 3e is indirect to be connected with flame tube outer wall 3b and inner wall 3g, play indirect fixed effect, make the flame tube have certain free space in axial and radial, prevent that its rigid connection leads to the destruction of flame tube, machine casket and flame tube all can freely expand under the hot state simultaneously, can prevent that the flame tube that ceramic matrix composite flame tube 2 inflation size discordance leads to destroys. The specific operation is as follows: the casing 1 is provided with a casing outer wall outer cavity mounting seat 1a, a casing outer wall inner cavity mounting seat 1b, a casing inner wall mounting seat 1d, a threaded hole 1c on the casing outer wall outer cavity mounting seat 1a,

the screw thread 2a is matched and screwed with a screw hole 1c of an outer cavity mounting seat 1a of the outer wall of the casing, the screw thread respectively penetrates through a first through hole 310 on an outer guide cover 3a of the flame tube, a first mounting hole 311 on an outer wall 3b, a first through hole 312 of an outer wall positioning block 3d, a second through hole 313 on an inner wall positioning block 3e, a second mounting hole 314 on an inner wall 3g and a second through hole 315 on an inner guide cover 3f, finally the tail end 2b of the positioning rod 2 is inserted into the inner wall mounting seat 1d of the casing 1, and the inner wall mounting seat 1d is provided with a positioning hole 1e matched with the positioning rod 2.

Because the ceramic matrix composite and the metal material can not be fixed by adopting a welding method, the problem of fixing the outer wall positioning block 3d and the inner wall positioning block 3e with the outer wall 3b of the flame tube and the inner wall 3g of the flame tube needs to be solved, and the non-welding type fixing of the ceramic matrix composite component and the metal component is realized by adopting a mode that the first metal rivet 3h and the second metal rivet 3j penetrate through the outer wall 3b of the flame tube and the inner wall 3g of the flame tube and are fixed with the outer wall positioning block 3d and the inner wall positioning block 3 e. The specific operation is as follows: the outer wall positioning block 3d is connected with the outer wall 3b of the flame tube through a first rivet 3h, the inner wall positioning block 3e is connected with the inner wall 3g of the flame tube through a second rivet 3j, the first rivet 3h and the second rivet 3j are rivets with 120-degree countersunk heads respectively, countersunk holes 3k and 3l matched with the first rivet 3h and the second rivet 3j are formed in the outer wall 3b of the flame tube and the inner wall positioning block 3e respectively, the first rivet 3h and the second rivet 3j penetrate through the countersunk holes 3k and 3l to be connected with the outer wall positioning block 3d and the inner wall positioning block 3e, and spot welding is carried out at the tail ends 3m and 3n of the first rivet 3h and the second rivet 3 j.

Because the linear expansion coefficient difference between flame tube outer wall 3b, flame tube inner wall 3g and superalloy outer wall locating piece 3d, inner wall locating piece 3e is very big, reserved 1 mm's slot 3r in the middle of outer wall locating piece 3d, inner wall locating piece 3e, the slot can diminish in the hot state in order to alleviate the difference of thermal expansion, solved the unmatched problem of ceramic matrix composite and metal material's thermal expansion, prevent that the flame tube from taking place to destroy.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A combustor with a ceramic matrix composite liner, comprising:

the device comprises a casing (1), a positioning rod (2) and a flame tube (3); the casing (1) and the flame tube (3) are both annular; the casing (1) is provided with a ring groove, an air channel is arranged at the bottom of the ring groove, airflow at the front end of the aircraft engine flows into the ring groove through the air channel, the flame tube (3) is inserted into the large ring groove through a notch of the ring groove, the front end of the flame tube (3) is provided with an opening, a fuel nozzle extends into the opening, and the rear end of the flame tube (3) is lapped with a turbine assembly of the engine;

the flame tube (3) comprises an annular inner wall (3g) and an annular outer wall (3b), and the inner wall (3g) and the outer wall (3b) are both made of ceramic matrix composite materials; the clearance between inner wall (3g) and outer wall (3b) forms aircraft fuel combustion's annular combustion chamber, outer wall locating piece (3d) of metal are installed through first rivet (3h) to the front end of outer wall (3b), inner wall locating piece (3e) of metal are installed through second rivet (3j) to the front end of inner wall (3g), locating lever (2) pass the through-hole of outer wall locating piece (3d) and the through-hole of inner wall locating piece (3e) respectively, the both ends of locating lever (2) are fixed on machine casket (1), outer kuppe (3a) are installed to the front end of outer wall (3b), interior kuppe (3f) are installed to the front end of inner wall (3 g).

2. The ceramic matrix composite flame tube fixing structure according to claim 1, wherein the specific mounting structure of the outer wall (3b) and the outer wall positioning block (3d) is as follows: the outer wall positioning block (3d) is connected to the wall surface, close to the annular combustion cavity, of the outer wall (3b) through rivets, a mounting hole is formed in the through hole of the outer wall positioning block (3d) of the outer wall (3b), a through hole is formed in the through hole of the outer wall positioning block (3d) of the outer air guide sleeve (3a), the positioning rod (2) sequentially penetrates through the through hole of the outer air guide sleeve (3a), the mounting hole of the outer wall (3b) and the through hole of the outer wall positioning block (3 d); inner wall locating piece (3e) are close to through rivet connection in inner wall (3g) the wall in annular combustion chamber, inner wall (3g) have the mounting hole in the through-hole department of inner wall locating piece (3e), and interior kuppe (3f) have the perforation in the through-hole department of inner wall locating piece (3e), and locating lever (2) pass the through-hole of inner wall locating piece (3e) in proper order, the mounting hole of inner wall (3g) and the perforation of interior kuppe (3 f).

3. The ceramic matrix composite torch fixing structure according to claim 2, wherein the diameter of the through hole of the inner wall positioning block (3e) is smaller than the diameter of the mounting hole of the inner wall (3g), and the diameter of the through hole of the outer wall positioning block (3d) is smaller than the diameter of the mounting hole of the outer wall (3 b).

4. The ceramic matrix composite flame tube fixing structure according to claim 1, wherein the specific structure for fixing the two ends of the positioning rod (2) and the casing (1) is as follows: the outer wall of quick-witted casket (1) the annular has screw hole (1c), and screw hole (1c) run through the outer wall of annular, quick-witted casket (1) the inner wall of annular has locating hole (1e), and locating lever (2) insert through screw hole (1c) the annular falls into in locating hole (1e), and locating lever (2) have the external screw thread in the position department of contacting with screw hole (1c), and locating lever (2) pass through external screw thread and screw hole (1c) threaded connection.

5. The ceramic matrix composite flame tube fixing structure according to claim 1, wherein a gap is provided between adjacent rivet holes of the inner wall positioning block (3e) and the outer wall positioning block (3d), and the gap is used for eliminating thermal stress.

6. The ceramic matrix composite liner retaining structure of claim 5 wherein said gap has a width of 0.8 to 1.2 mm.

7. The ceramic matrix composite torch fixing structure according to claim 1, wherein the first rivet (3h) connecting the outer wall (3b) and the outer wall positioning block (3d) is a rivet with a 120 ° countersunk head, the 120 ° countersunk head faces the annular combustion chamber, and the end of the first rivet (3h) is fixed by spot welding; the second rivet (3j) connected with the inner wall (3g) and the inner wall positioning block (3e) is a rivet with a 120-degree countersunk head, and the tail end of the second rivet (3j) is fixed through spot welding.

8. The ceramic matrix composite liner attachment structure of claim 1, wherein the retaining rods (2) are arranged uniformly in the circumferential direction of the casing (1).

9. The ceramic matrix composite liner fixing structure according to claim 1, wherein the casing (1) has a mounting seat for extending the length of the threaded hole (1c) at a position corresponding to the threaded hole (1c), and the casing (1) has a boss for extending the length of the positioning hole (1e) at a position corresponding to the positioning hole (1 e).

10. The ceramic matrix composite liner fixture structure of claim 8, wherein said fuel nozzle is arranged between two adjacent positioning rods (2).