Ceramic matrix composite floating wall combustion chamber

Abstract

The invention discloses a ceramic matrix composite floating wall combustion chamber which comprises a casing shell and a flame tube, a diffuser is arranged at one end of the casing shell and provided with an air inlet allowing high-pressure air to be introduced conveniently, the other end of the casing shell is connected with one end of the flame tube, and the other end of the flame tube is arranged in the casing shell. The cartridge receiver shell is connected with a nozzle extending into the flame tube through the other end of the flame tube, a plurality of floating heated assemblies are arranged on the flame tube, each heated assembly comprises a tile which is arranged in the flame tube and can float, and the tiles are made of a ceramic matrix composite material; a plurality of floatable tiles are arranged in the flame tube, the tiles can freely expand towards the periphery from the positioning center when heated, thermal stress is fully released, the service life of the tiles is prolonged, and the problem that thermal expansion of a composite material component and thermal expansion of a metal material component are not matched is solved.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engines, in particular to a ceramic-based composite material floating wall combustion chamber. Background Art

[0002] The demand for engine performance of high-performance aircraft is constantly increasing. Increasing the combustion chamber outlet temperature and reducing the structural weight are the main ways to improve the engine thrust-to-weight ratio. The combustion chamber is the core component of the engine that converts chemical energy into thermal energy. It heats the high-pressure air after the compressor is pressurized to the allowable temperature before the turbine so that it can enter the turbine to expand and do work. In order to increase the combustion chamber outlet temperature, the proportion of combustion air needs to be greatly increased and the proportion of cooling air reduced. At the same time, under the conditions of reduced cooling air distribution and reduced cooling air quality, the combustion chamber is also required to further maintain or even improve the durability of the flame tube.

[0003] At present, the flame tube of the combustion chamber of an aircraft engine is made of high-temperature alloy materials. In order to improve the performance of the engine, the outlet temperature of the combustion chamber needs to be further increased. The existing high-temperature alloy system can no longer meet the urgent needs of the development of advanced aircraft engines. The temperature resistance of the flame tube has become a bottleneck and restrictive factor for the high thrust-to-weight ratio engine to achieve technical indicators. In order to meet the above requirements, the use of new high-temperature resistant, low-density, high-strength and toughness structural materials has become an inevitable trend. This is not only the need for the continuous improvement of engine performance, but also the key to improving the thrust-to-weight ratio of aircraft engines. SiC fiber reinforced ceramic matrix composites (CMC-SiC) have the characteristics of high specific strength, high specific modulus, high temperature resistance, ablation resistance, oxidation resistance and low density. Ceramic matrix composites can become the most promising material for replacing high-temperature alloys in high-temperature engine components. However, the linear expansion coefficient between the composite parts and the connected high-temperature alloy connectors is very different. The thermal expansion coefficient of the ceramic matrix composite material at high temperature is only about 1 / 3 of that of the metal material. During the use of the engine, due to the change in temperature, large residual thermal stress will be generated at the interface of the two materials, which seriously affects the bearing capacity of the composite material. The flame tube is the component with the highest temperature in the engine, and the residual thermal stress caused by the difference in linear expansion coefficient is more obvious. For example, the mismatch between the cold and hot structures can easily lead to component failure. When the ceramic matrix composite component is connected to the metal component, the problem of thermal expansion mismatch between the two materials is a problem that needs to be solved in this application. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above problems and / or problems existing in existing engine combustion chambers, the present invention is proposed.

[0006] Therefore, the purpose of the present invention is to provide a ceramic-based composite floating wall combustion chamber. The present invention arranges a number of floating tiles inside the flame tube. When the tiles are heated, they can expand freely around the positioning center, fully releasing thermal stress, extending the service life of the tiles, and solving the problem of thermal expansion mismatch between composite materials and metal materials.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a ceramic-based composite material A floating wall combustion chamber includes a casing shell and a flame tube. A diffuser is provided at one end of the casing shell. An air inlet for conveniently introducing high-pressure air is provided on the diffuser. The other end of the casing shell is connected to one end of the flame tube. The other end of the flame tube is inside the casing shell. A nozzle is connected to the casing shell and extends into the flame tube through the other end of the flame tube. A plurality of floating heat-receiving components are arranged on the flame tube. The heat-receiving components include floating tiles arranged in the flame tube. The tiles are made of ceramic-based composite materials.

[0008] As a preferred solution of the ceramic-based composite floating wall combustion chamber in the present invention, wherein: a plurality of connecting holes corresponding to the tiles are arranged on the flame tube, the heat-receiving component also includes a plurality of positioning blocks corresponding to the connecting holes, the positioning blocks are made of ceramic-based composite materials, the positioning blocks include a connecting portion fixedly connected to the tiles, a positioning rod is fixed at one end of the connecting portion away from the center of the flame tube, the positioning rod extends out of the flame tube through the corresponding connecting holes, a plurality of fixing blocks corresponding to the connecting holes are arranged on the outside of the flame tube, the positioning rod outside the flame tube passes through the fixing blocks and is connected to the fixing blocks, a nut is threadedly connected to the fixing blocks, and the nut abuts against the outside of the flame tube.

[0009] As a preferred solution of the ceramic-based composite floating wall combustion chamber in the present invention, a ventilation channel is formed between the outer side of the flame tube and the inner side of the casing shell, a plurality of main combustion holes are arranged on the periphery of the flame tube near one end of the nozzle, and a plurality of mixing holes are arranged on the periphery of the flame tube near the other end of the casing shell.

[0010] As a preferred solution of the ceramic-based composite floating wall combustion chamber of the present invention, there is a first gap between two adjacent tiles when viewed in the axial direction.

[0011] As a preferred solution of the ceramic-based composite floating wall combustion chamber in the present invention, a plurality of protrusions are arranged on one side of the tile relative to the inner wall of the flame tube, and a second gap is provided between the protrusions and the inner wall of the flame tube.

[0012] As a preferred solution of the ceramic-based composite floating wall combustion chamber in the present invention, a plurality of impact holes are arranged on the flame tube, and divergent holes inclined along the axial direction are arranged on the tile.

[0013] Compared with the prior art, the present invention has the following technical effects: 1. Through the setting of positioning blocks, fixing blocks and nuts, the indirect connection between the tiles and the flame tube is realized to prevent the damage of the ceramic matrix composite tiles caused by the rigid connection; 2. The linear expansion coefficients between the ceramic-based composite material and the high-temperature alloy connector are very different. Due to temperature changes, large thermal stress will be generated at the interface of the two materials. This application adopts a method of reserving a compensation gap to solve the problem of thermal expansion mismatch between the ceramic-based composite material and the metal material; 3. A double-wall flame tube formed by a heating component and a flame tube is used. The metal shell of the double-wall flame tube mainly bears the mechanical load, and the tile mainly bears the heat load generated by the high-temperature gas in the flame tube, which improves the high temperature resistance and corrosion resistance of the flame tube. The mechanical load and the heat load are separated, which can increase the service life of the flame tube. At the same time, each tile can expand freely around its positioning center when heated, fully releasing the thermal stress, thereby extending the service life of the tile; 4. The combined effect of the impact holes and the divergent holes strengthens the convective heat transfer of the flame tube wall, improves the cooling efficiency of the flame tube cooling air, and reduces the overall temperature of the flame tube wall, making the temperature distribution of the flame tube wall more uniform, thereby reducing the temperature gradient of the flame tube wall and reducing the thermal stress of the flame tube wall, thereby avoiding cracks, falling blocks and other failures caused by excessive thermal stress in the flame tube and extending the service life of the flame tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them: Figure 1 It is a schematic diagram of the internal structure of the present invention.

[0015] Figure 2 It is a partial structural diagram of the heating component and the flame tube connected together in the present invention.

[0016] Figure 3 It is a three-dimensional structural diagram of the tile in the present invention.

[0017] Figure 4 It is a partial enlarged view of a group of heating components and a flame tube connected together in the present invention.

[0018] In the figure: 100 high-pressure turbine guide vane, 200 diffuser, 201 air inlet, 300 nozzle, 400 casing shell, 500 fixing bolt, 600 heat receiving component, 601 nut, 602 tile, 602a diverging hole, 602b protrusion, 603 positioning block, 603a connecting part, 603b positioning rod, 604 fixing block, 605 rivet, 700 flame tube, 701 main combustion hole, 702 mixing hole, 703 impact hole, S first gap, X second gap, W ventilation channel, TCA cooling air. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0020] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0022] Example 1 Reference Figure 1 to Figure 3 , which is the first embodiment of the present invention, provides a ceramic-based composite floating wall combustion chamber, which can extend the service life of the combustion chamber.

[0023] A ceramic-based composite floating wall combustion chamber includes a casing shell 400 and a flame tube 700. A diffuser 200 is provided at one end of the casing shell 400. The diffuser 200 is provided with an air inlet 201 for conveniently introducing high-pressure air. The other end of the casing shell 400 is fixedly connected to one end of the flame tube 700. In this embodiment, a plurality of fixing bolts 500 are used to fix the casing shell 400 and the flame tube 700 together. The other end of the flame tube 700 is inside the casing shell 400. The casing shell 400 is connected to a flame tube 700. The other end of the flame tube 700 extends into the nozzle 300 in the flame tube 700, and a plurality of floating heat-receiving components 600 are arranged on the flame tube 700. The heat-receiving components 600 include floating tiles 602 arranged in the flame tube 700, and the tiles 602 are made of ceramic-based composite materials. An air passage W is formed between the outer side of the flame tube 700 and the inner side of the casing shell 400. A plurality of main combustion holes 701 are arranged on the periphery of the flame tube 700 near one end of the nozzle 300, and a plurality of mixing holes 702 are arranged on the periphery of the flame tube 700 near the other end of the casing shell 400.

[0024] The casing 400, the diffuser 200 and the flame tube 700 are all annular structural parts, and the other end of the flame tube 700 is connected to the high-pressure turbine guide 100; after the high-pressure air entering the combustion chamber is decelerated and diffused by the diffuser 200, the air is divided into two paths, one path enters the flame tube 700 through the main combustion hole 701 and the mixing hole 702 along the ventilation channel W, and the other path enters the flame tube 700 through the other end of the flame tube 700, passes through the swirler at the other end of the flame tube 700 (which is the existing technology and is arranged in the flame tube 700) to form a recirculation zone, and then flows out from the outlet at one end of the flame tube 700 after mixing with the fuel and burning.

[0025] Specifically, a plurality of connection holes corresponding to the tiles 602 are arranged on the flame tube 700, and the heated component 600 also includes a plurality of positioning blocks 603 corresponding to the connection holes. The positioning blocks 603 are made of a ceramic-based composite material and can be deposited as a whole with the positioning blocks 603 during the preparation and molding process of the tiles 602. The positioning blocks 603 include a connection portion 603a fixedly connected to the tiles 602, and a positioning rod 603b is fixed at one end of the connection portion 603a away from the center of the flame tube 700, and the positioning rod 603b extends out of the flame tube through the corresponding connection hole. In addition to 700, a plurality of fixing blocks 604 corresponding to the connecting holes are arranged on the outside of the flame tube 700, and the positioning rod 603b outside the flame tube 700 passes through the fixing block 604 and is connected to the fixing block 604. A nut 601 is threadedly connected to the fixing block 604, and the nut 601 abuts against the outside of the flame tube 700. From the axial direction, there is a first gap S between two adjacent tiles 602, and a plurality of protrusions 602b are arranged on the side of the tile 602 relative to the inner wall of the flame tube 700, and there is a second gap X between the protrusion 602b and the inner wall of the flame tube 700.

[0026] In the present application, any component except the tile 602 and the positioning block 603 is made of a metal high-temperature alloy material; when installing the heated component 600, first, the positioning rod 603b is just passed through the connecting hole on the flame tube 700 and the center hole on the fixing block 604, and the fixing block 604 and the positioning rod 603b are fixed together with a rivet 605 to position the tile 602 and the flame tube 700, and finally the threaded fixing block 604 is fixed with a nut 601; by setting the positioning block 603, the fixing block 604 and the nut 601, an indirect connection between the tile 602 and the flame tube 700 is achieved, preventing the hard connection from causing damage to the ceramic-based composite material tile 602; the problem of difficulty in connecting and fixing the tile 602 and the load-bearing shell is solved.

[0027] In the hot state, the first gap S and the second gap X can be reduced to alleviate the difference in thermal expansion between the tile 602 made of ceramic-based composite material and the metal load-bearing shell (i.e., the flame tube 700), thereby solving the problem of thermal expansion mismatch between two materials with huge thermal expansion differences and preventing the flame tube 700 from being damaged; a double-walled flame tube 700 formed by a heated component 600 and a flame tube 700 is adopted, and the metal shell of the double-walled flame tube 700 mainly bears the mechanical load, and the tile 602 mainly bears the thermal load generated by the high-temperature combustion gas in the flame tube 700, thereby improving the high temperature resistance and corrosion resistance of the flame tube 700, separating the mechanical load from the thermal load, and reducing the demand for cooling air volume of the flame tube 700, thereby obtaining the benefit of extending the service life of the flame tube 700 at high temperature under limited cooling air volume, and at the same time, each tile 602 can freely expand around its positioning center when heated, fully releasing thermal stress, thereby extending the service life of the tile 602, thereby extending the service life of the entire combustion chamber.

[0028] Example 2 Reference Figure 1 to Figure 4 This embodiment provides a ceramic-based composite floating wall combustion chamber, which is different from Embodiment 1 in that it can improve the cooling efficiency of the cooling air TCA of the flame tube 700 and reduce the overall temperature of the wall of the flame tube 700, thereby extending the service life of the flame tube 700.

[0029] Specifically, a plurality of impact holes 703 are arranged on the flame tube 700, and the axis of the impact hole 703 is preferably perpendicular to the central axis of the flame tube 700. The tile 602 is provided with divergent holes 602a which are inclined along the axial direction. When viewed from the other end of the flame tube 700 to the axial direction of one end of the flame tube 700 (corresponding to the direction from left to right), the central axis of the divergent hole 602a is inclined downward from left to right.

[0030] The side of tile 602 away from the center of flame tube 700 is the cold side of tile 602, and the side of tile 602 opposite to the center of flame tube 700 is the hot side of tile 602. Cooling air TCA is ejected from the outside of flame tube 700 through impact hole 703, impacting the cold side of tile 602, forming impact cooling. Impact hole 703 is a straight hole. The existence of impact hole 703 causes strong impact heat exchange on the cold side of diverging hole 602a. Due to the effect of impact, the heat exchange conditions in diverging hole 602a are changed to a certain extent, especially the changes in the inlet area of ​​diverging hole 602a are more significant. The cooling air TCA ejected by the impact hole 703 flows along the wall on all sides and enters the diverging hole 602a. The diverging hole 602a is inclined to increase the area of ​​convective heat exchange, so that the hot side air film of the tile 602 adheres well to the wall, forming full air film protection. The convective heat exchange of the wall of the flame tube 700 is enhanced through the joint action of the impact hole 703 and the diverging hole 602a, thereby improving the cooling efficiency of the cooling air TCA of the flame tube 700 and reducing the overall temperature of the wall of the flame tube 700, making the temperature distribution of the wall of the flame tube 700 more uniform, thereby reducing the temperature gradient of the wall of the flame tube 700, reducing the thermal stress of the wall of the flame tube 700, and thus avoiding cracks, falling blocks and other failures of the flame tube 700 caused by excessive thermal stress, thereby extending the service life of the flame tube 700.

[0031] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A ceramic matrix composite floating wall combustion chamber, characterized in that: The invention comprises a casing shell (400) and a flame tube (700), wherein a diffuser (200) is provided at one end of the casing shell (400), and an air inlet (201) is provided on the diffuser (200) for conveniently introducing high-pressure air, and the other end of the casing shell (400) is connected to one end of the flame tube (700), and the other end of the flame tube (700) is inside the casing shell (400), and the casing shell (400) is connected to a nozzle (300) extending into the flame tube (700) through the other end of the flame tube (700), and a plurality of floating heat-receiving components (600) are arranged on the flame tube (700), and the heat-receiving components (600) include floating tiles (602) arranged in the flame tube (700), and the tiles (602) are made of ceramic-based composite materials.

2. The ceramic matrix composite floating wall combustion chamber according to claim 1, characterized in that: The flame tube (700) is provided with a plurality of connection holes corresponding to the tiles (602) one by one. The heat receiving component (600) further comprises a plurality of positioning blocks (603) corresponding to the connection holes one by one. The positioning blocks (603) are made of a ceramic-based composite material. The positioning blocks (603) comprise a connection portion (603a) fixedly connected to the tiles (602). A positioning rod ( 603b), the positioning rod (603b) extends out of the flame tube (700) through the corresponding connecting hole, a plurality of fixing blocks (604) corresponding to the connecting holes are arranged on the outside of the flame tube (700), the positioning rod (603b) outside the flame tube (700) passes through the fixing block (604) and is connected to the fixing block (604), a nut (601) is threadedly connected to the fixing block (604), and the nut (601) abuts against the outside of the flame tube (700).

3. The ceramic matrix composite floating wall combustion chamber according to claim 1 or 2, characterized in that: An air passage (W) is formed between the outer side of the flame tube (700) and the inner side of the casing shell (400), a plurality of main combustion holes (701) are arranged on the periphery of one end of the flame tube (700) close to the nozzle (300), and a plurality of mixing holes (702) are arranged on the periphery of the other end of the flame tube (700) close to the casing shell (400).

4. The ceramic matrix composite floating wall combustion chamber according to claim 2, characterized in that: Viewed from the axial direction, there is a first gap (S) between two adjacent tiles (602).

5. The ceramic matrix composite floating wall combustion chamber according to claim 2, characterized in that: A plurality of protrusions (602b) are arranged on one side of the tile (602) facing the inner wall of the flame tube (700), and a second gap (X) is provided between the protrusions (602b) and the inner wall of the flame tube (700).

6. The ceramic matrix composite floating wall combustion chamber according to claim 2, characterized in that: The flame tube (700) is also provided with a plurality of impact holes (703), and the tile (602) is provided with divergent holes (602a) arranged obliquely along the axial direction.

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