Combustion chamber casing of small aero-engine

Abstract

The invention provides a small aero-engine combustion chamber casing, which belongs to the technical field of aero-engines, and comprises a combustion chamber shell, a combustion chamber inner ring and a front support plate, the air inlet end of the combustion chamber shell and the near end of the combustion chamber inner ring are connected with the front support plate, and the combustion chamber shell surrounds the periphery of the combustion chamber inner ring; the ends, close to the front supporting plate, of the combustion chamber inner ring and the combustion chamber outer ring are provided with annular supporting plates, and a containing cavity is defined by the annular supporting plates, the combustion chamber inner ring and the front supporting plate and filled with a supporting structure. The combustion chamber inner ring, the combustion chamber shell, the front supporting plate, the annular supporting plate and the supporting structure are manufactured through additive printing, the annular supporting plate and the supporting structure are used for supporting the front supporting plate when the front supporting plate is printed, the added supporting structure does not need to be removed after forming, the capacity of bearing external loads can be enhanced, the supporting structure is utilized, and the manufacturing cost is reduced. And resource waste is reduced.

Description

Technical Field

[0001] The present application relates to the field of aircraft engines, and in particular to a combustion chamber casing of a small aircraft engine. Background Art

[0002] At present, small aircraft engines are developing in the direction of lightweight and low cost. The main structures of the engine include the air intake, compressor, combustion chamber and turbine. The casing outside the combustion chamber is a load-bearing component, which mainly bears radial force, axial force, torque, bending moment, inertia force and vibration. The current manufacturing method is mainly forging and turning and milling, and the structure is not optimal. In addition, it is limited by fixtures, etc., with a long construction period and high manufacturing cost.

[0003] Laser selective melting in additive manufacturing is a near-net-shape forming technology that uses laser as energy source, digital model as basis, and material layer-by-layer accumulation principle. It is a key development direction of aviation manufacturing and has good efficiency and cost advantages in realizing model production, single-piece or small-batch complex component production. The use of additive manufacturing technology to form the combustion chamber casing can shorten the manufacturing cycle and reduce manufacturing costs.

[0004] In order to meet the economic requirements of small aircraft engines, the combustion chamber casing is prepared using additive manufacturing technology. Since additive manufacturing technology often requires additional support structures when printing planar structures, these supports are not only difficult to remove, but also increase the amount of powder material used, resulting in a waste of resources. Summary of the invention

[0005] In view of this, the present application provides a small aircraft engine combustion chamber casing, which solves the problems in the prior art. The structure of the original casing is optimized to provide self-support for planar printing during the additive manufacturing process. The added support structure does not need to be removed after molding, which can enhance the ability to bear external loads, utilize the support structure, and reduce resource waste.

[0006] The present application provides a small aircraft engine combustion chamber casing adopting the following technical solution:

[0007] A combustion chamber casing of a small aircraft engine, comprising a combustion chamber outer shell, a combustion chamber inner ring and a front support plate, wherein the air inlet end of the combustion chamber outer shell and the proximal end of the combustion chamber inner ring are connected to the front support plate, the combustion chamber outer shell surrounds the outer circumference of the combustion chamber inner ring, the combustion chamber inner ring and the combustion chamber outer ring are provided with an annular support plate at the end close to the front support plate, the inner ring of the annular support plate is connected to the combustion chamber inner ring, the outer ring of the annular support plate is connected to the front support plate, the outer ring of the annular support plate is closer to the front support plate than the inner ring, the annular support plate, the combustion chamber inner ring and the front support plate form a accommodating chamber, and the accommodating chamber is filled with a supporting structure;

[0008] Among them, the combustion chamber inner ring, combustion chamber outer shell, front support plate, annular support plate and support structure are manufactured by additive printing, and the annular support plate and support structure are used to provide support for the front support plate when printing the front support plate.

[0009] Optionally, the combustion chamber inner ring, combustion chamber outer shell, annular support plate and support structure are made of the same material.

[0010] Optionally, the annular support plate includes an annular inclined plate, the inner ring of the annular inclined plate is connected to the inner ring of the combustion chamber, the outer ring of the annular inclined plate is connected to the front support plate, and the outer ring of the annular inclined plate is closer to the front support plate than the inner ring.

[0011] Optionally, the annular support plate includes an annular inclined plate and an annular connecting plate, the annular connecting plate is perpendicular to the axial direction of the inner ring of the combustion chamber, the inner ring of the annular connecting plate is connected to the inner ring of the combustion chamber, the outer ring of the annular connecting plate is connected to the inner ring of the annular inclined plate, the outer ring of the annular inclined plate is connected to the front support plate, and the outer ring of the annular inclined plate is closer to the front support plate than the inner ring.

[0012] Optionally, the angle between the annular inclined plate and the central axis of the combustion inner ring is greater than 20°.

[0013] Optionally, the support structure is a porous structure.

[0014] Optionally, the support structure is formed by stacking a plurality of lattice units, the lattice units comprising a plurality of support rods, one end of each support rod of a lattice unit being interconnected as the center of the lattice unit, all support rods of the lattice unit presenting a body-centered cubic structure, the support rods of adjacent lattice units of the support structure being interconnected, and the support rods outside the lattice units of the outermost layer of the support structure in the accommodating chamber are connected to the inner wall of the accommodating chamber.

[0015] Optionally, the ends of the support rods in the lattice unit that are aligned with each other along the axis direction of the combustion inner ring are connected by columns.

[0016] Optionally, the length and / or diameter of the support rods of the lattice units in the accommodating chamber gradually decreases from the inside to the outside.

[0017] Optionally, a straight line passing through the center of the lattice unit and parallel to the axial direction of the inner ring of the combustion chamber is a first straight line, and an acute angle between the support rod of the lattice unit and the first straight line is less than 45° and greater than 20°.

[0018] In summary, this application includes the following beneficial technical effects:

[0019] The combustion chamber casing of the present application combines the characteristics of additive manufacturing and optimizes the structure of the original casing. An annular support plate and a support structure are added in the combustion chamber area near the front support plate. The annular support plate is located between the combustion chamber outer shell and the combustion chamber inner ring to form a accommodating chamber. The support structure is located in the accommodating chamber. A conical structure is designed inside the casing structure at one end of the compressor, and the thickness of the original plane is reduced. Not only can it provide support for the flat printing of the front support plate during the additive manufacturing process and play a self-supporting role, but the added annular support plate and support structure are part of the combustion chamber casing. The support structure does not need to be removed after the combustion chamber casing is formed without affecting the normal operation of the combustion chamber. The support structure is used to enhance the ability of the combustion chamber casing to bear external loads.

[0020] The present application changes the size of the lattice unit in the boundary area, reduces the length and / or rod diameter of the lattice unit, performs dense filling at the boundary, changes the relative size of the lattice unit at different spatial positions according to the accommodating chamber, performs variable density filling from the boundary to the inside, and analyzes the strength and rigidity of the casing at the same time. If the preset requirements are not met, the rod diameter and density distribution of the filled lattice unit are further modified, and finally the lattice unit arrangement is made close to the shape of the filling domain. This can effectively reduce the phenomenon of incomplete lattice units at the irregular structural boundaries, so that the lattice units and the structure will not be separated and damaged at the boundaries when bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is a schematic diagram of the structure of the combustion chamber casing of a small aircraft engine in this application;

[0023] Figure 2 A schematic diagram of the structure of the chamber and the support structure for this application;

[0024] Figure 3 A schematic diagram of a lattice unit of the present application in a body-centered cubic structure;

[0025] Figure 4 This is a schematic diagram of the structure of a lattice unit with columns added to a body-centered cubic structure in the present application.

[0026] Explanation of the accompanying drawings: 1. Combustion chamber casing; 2. Combustion chamber inner ring; 3. Front support plate; 4. Oil pipeline; 5. Combustion chamber area; 6. Accommodating chamber; 61. Annular inclined plate; 62. Annular connecting plate; 63. Support structure; 7. Support rod; 71. Column. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0028] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0029] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0030] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0031] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0032] An embodiment of the present application provides a combustion chamber casing of a small aircraft engine.

[0033] like Figure 1 As shown, a combustion chamber casing of a small aircraft engine includes a combustion chamber outer shell 1, a combustion chamber inner ring 2 and a front support plate 3. The air inlet end of the combustion chamber outer shell 1 and the proximal end of the combustion chamber inner ring 2 are connected to the front support plate 3. The combustion chamber outer shell 1 surrounds the outer periphery of the combustion chamber inner ring 2, and a combustion chamber area 5 is formed between the combustion chamber outer shell 1 and the combustion chamber inner ring 2. The compressor rotor is installed at the front support plate 3 of the combustion chamber casing, and the turbine stator is installed at the other end of the combustion chamber casing for connection with the tail nozzle. At the same time, the combustion chamber casing also includes an oil pipeline 4 for supplying fuel to the combustion chamber. The combustion chamber casing is the load-bearing shell of the engine. The front section of the combustion chamber outer shell 1 and the combustion chamber inner ring 2 constitute a diffuser to reduce the compressor airflow velocity. The combustion chamber outer shell 1 and the combustion chamber inner ring 2 form an annular airflow channel to ensure the stability of the airflow.

[0034] The combustion chamber inner ring 2 and the combustion chamber outer ring are provided with an annular support plate at the end close to the front support plate 3, the inner ring of the annular support plate is connected to the combustion chamber inner ring 2, the outer ring of the annular support plate is connected to the front support plate 3, the outer ring of the annular support plate is closer to the front support plate 3 than the inner ring, the annular support plate, the combustion chamber inner ring 2 and the front support plate 3 form a accommodating chamber 6, and the accommodating chamber 6 is filled with a supporting structure 63; wherein, the combustion chamber inner ring 2, the combustion chamber outer shell 1, the front support plate 3, the annular support plate and the supporting structure 63 are manufactured by additive printing, and the annular support plate and the supporting structure 63 are used to provide support to the front support plate 3 when printing the front support plate 3.

[0035] like Figure 1 and Figure 2 As shown, in view of the requirements of the economy of small aircraft engines, the combustion chamber casing is prepared using additive manufacturing technology. Since additive manufacturing technology often requires additional support structures when printing planar structures, these supports are not only difficult to remove, but also increase the amount of powder material used, resulting in a waste of resources. Therefore, the combustion chamber casing of the present application is optimized on the structure of the original casing in combination with the characteristics of additive manufacturing, and an annular support plate and a support structure 63 are added near the front support plate 3 in the combustion chamber area 5. The annular support plate is located between the combustion chamber outer shell 1 and the combustion chamber inner ring 2, and forms a accommodating chamber 6. The support structure 63 is located in the accommodating chamber 6. A conical structure is designed inside the casing structure at one end of the compressor, and the thickness of the original plane is reduced at the same time, which can not only provide support for the plane printing of the front support plate 3 during the additive manufacturing process, but also play a self-supporting role. In addition, the added annular support plate and support structure 63 are part of the combustion chamber casing, which will not affect the normal operation of the combustion chamber. After the combustion chamber casing is formed, the support structure 63 does not need to be removed, and the support structure 63 is used to enhance the ability of the combustion chamber casing to bear external loads.

[0036] In one embodiment, the combustion chamber inner ring 2, the combustion chamber outer shell 1, the annular support plate and the support structure 63 are made of the same material.

[0037] like Figure 1 As shown, regarding the annular support plate, in one embodiment, the annular support plate includes an annular inclined plate 61, the inner ring of the annular inclined plate 61 is connected to the combustion chamber inner ring 2, the outer ring of the annular inclined plate 61 is connected to the front support plate 3, and the outer ring of the annular inclined plate 61 is closer to the front support plate 3 than the inner ring. Figure 2 As shown, in another embodiment, the annular support plate includes an annular inclined plate 61 and an annular connecting plate 62, the annular connecting plate 62 is perpendicular to the axial direction of the combustion chamber inner ring 2, the inner ring of the annular connecting plate 62 is connected to the combustion chamber inner ring 2, the outer ring of the annular connecting plate 62 is connected to the inner ring of the annular inclined plate 61, the outer ring of the annular inclined plate 61 is connected to the front support plate 3, and the outer ring of the annular inclined plate 61 is closer to the front support plate 3 than the inner ring. The angle between the annular inclined plate 61 and the central axis of the combustion inner ring is greater than 20°.

[0038] Regarding the support structure 63, in this embodiment, the support structure 63 is a porous structure, and the use of a porous structure can reduce the weight of the engine. In other embodiments, the support structure 63 can be a solid filler.

[0039] like Figure 3 As shown, in the embodiment of the present application, the support structure 63 is formed by stacking a plurality of lattice units, the lattice unit includes a plurality of support rods 7, one end of each support rod 7 of a lattice unit is interconnected as the center of the lattice unit, all the support rods 7 of the lattice unit are in a body-centered cubic structure, that is, a BBC type lattice unit, the support rods 7 of adjacent lattice units of the support structure 63 are interconnected, and the support rods 7 on the outer side of the lattice units of the outermost layer of the support structure 63 in the accommodating chamber 6 are connected to the inner wall of the accommodating chamber 6.

[0040] The specific description of the lattice unit is as follows: a straight line passing through the center of the lattice unit and parallel to the axial direction of the combustion chamber inner ring 2 is a first straight line, and a plane passing through the center of the lattice unit and perpendicular to the first straight line is a first plane. Some of the supporting rods 7 of all the supporting rods 7 of a lattice unit are recorded as first rods, and the other supporting rods 7 are recorded as second rods. The first rods extend from the center of the lattice unit toward the side close to the front support plate 3, and the second rods extend from the center of the lattice unit to the side away from the front support plate 3. Figure 3 The upward support rod 7 is the first rod, and the downward support rod 7 is the second rod; all the first rods in one lattice unit are evenly distributed around the first straight line, and all the second rods in one lattice unit are evenly distributed around the first straight line, and the lattice unit is plane-symmetrical about the first plane.

[0041] like Figure 4 As shown, in one embodiment, the ends of the support rods 7 aligned with each other along the axis direction of the combustion inner ring in the lattice unit can be connected by a column 71. That is, the aligned first rod and the second rod are connected by a column 71, and the lattice unit is a BBCZ type structure. BCCZ adds columns 71 at the upper and lower corresponding nodes of BCC to enhance the rigidity and strength of its structural unit. The BBCZ type lattice unit has firm connection of rods, good structural stability, and good bending and compression resistance. At the same time, there is no horizontal rod inside the lattice unit, which meets the machinability of additive manufacturing technology. Other lattice units with good mechanical properties can also be selected. The support structure 63 is formed into a hollow structure composed of multiple lattice units, which can effectively reduce the weight of the casing.

[0042] For the annular support plate and the support structure 63 in the combustion chamber casing, on the premise of calculating the strength and stiffness of the structural model by the finite element analysis method, lattice units are filled inside the accommodating chamber 6. The lattice units in the lattice design are mainly divided into trusses and three-period minimal surfaces. Since the three-period minimal surfaces are not suitable for drawing with traditional three-dimensional software, and the surfaces of the lattice units and the powder in the manufacturing process are difficult to remove, truss-type lattice units based on pillars are adopted. The three-dimensional lattice unit in the lattice design is a porous structure composed of trusses. The rod diameter and inclination angle of the lattice unit are highly designable, and have outstanding specific strength and specific stiffness.

[0043] The acute angle between the support rod 7 of the lattice unit and the first straight line is less than 45° and greater than 20°.

[0044] During the process of lattice unit filling, the connection part between the lattice unit and the accommodating chamber 6 often plays a key role in load transfer. When filling irregular structures, the lattice units are prone to cut-off and incomplete phenomena at the boundaries, which makes the lattice units have interface peeling at the boundary of the component when loaded, resulting in the external load cannot be effectively transferred to the internal lattice units, and the lattice units cannot effectively bear the load. If larger lattice units are used to uniformly fill the structural area inside the casing, the lattice units will have incomplete units such as cut-off at the filling boundary, which makes the lattice units and the components have interface peeling at the boundary when loaded, causing the lattice units to be unable to effectively bear the load; if smaller lattice units are used for filling, a large number of lattice units will be generated, which will greatly affect the modeling efficiency and increase the amount of manufacturing powder in the additive manufacturing process.

[0045] In the accommodating chamber 6 described in the present application, the length of the strut 7 and / or the rod diameter of the strut 7 of the lattice unit from the inside to the outside is gradually reduced. In the boundary area, the size of the lattice unit is changed to reduce the length of the strut 7 and / or the rod diameter of the strut 7 of the lattice unit, and dense filling is performed at the boundary. The relative size of the lattice unit is changed at different spatial positions according to the accommodating chamber 6, and variable density filling is performed from the boundary to the inside. At the same time, the strength and rigidity of the casing are analyzed. If the preset requirements are not met, the rod diameter and density distribution of the filled lattice unit are further modified, and finally the lattice unit arrangement is made close to the shape of the filling domain. This can effectively reduce the phenomenon of incomplete lattice units at the irregular structural boundaries, so that the lattice units and the structure will not be separated and damaged at the boundary when bearing.

[0046] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A combustion chamber casing of a small aircraft engine, comprising a combustion chamber outer shell (1), a combustion chamber inner ring (2) and a front support plate (3), wherein the air inlet end of the combustion chamber outer shell (1) and the proximal end of the combustion chamber inner ring (2) are connected to the front support plate (3), and the combustion chamber outer shell (1) surrounds the outer periphery of the combustion chamber inner ring (2), characterized in that: The combustion chamber inner ring (2) and the combustion chamber outer ring are provided with an annular support plate at the end close to the front support plate (3); the inner ring of the annular support plate is connected to the combustion chamber inner ring (2); the outer ring of the annular support plate is connected to the front support plate (3); the outer ring of the annular support plate is closer to the front support plate (3) than the inner ring; the annular support plate, the combustion chamber inner ring (2) and the front support plate (3) form a receiving chamber (6); the receiving chamber (6) is filled with a support structure (63); The combustion chamber inner ring (2), the combustion chamber outer shell (1), the front support plate (3), the annular support plate and the support structure (63) are manufactured by additive printing, and the annular support plate and the support structure (63) are used to provide support for the front support plate (3) when printing the front support plate (3).

2. The small aircraft engine combustion chamber casing according to claim 1, characterized in that: The combustion chamber inner ring (2), the combustion chamber outer shell (1), the annular support plate and the support structure (63) are made of the same material.

3. The small aircraft engine combustion chamber casing according to claim 1, characterized in that: The annular support plate comprises an annular inclined plate (61), the inner ring of the annular inclined plate (61) is connected to the inner ring (2) of the combustion chamber, the outer ring of the annular inclined plate (61) is connected to the front support plate (3), and the outer ring of the annular inclined plate (61) is closer to the front support plate (3) than the inner ring.

4. The small aircraft engine combustion chamber casing according to claim 1, characterized in that: The annular support plate comprises an annular inclined plate (61) and an annular connecting plate (62), wherein the annular connecting plate (62) is perpendicular to the axial direction of the combustion chamber inner ring (2), the inner ring of the annular connecting plate (62) is connected to the combustion chamber inner ring (2), the outer ring of the annular connecting plate (62) is connected to the inner ring of the annular inclined plate (61), the outer ring of the annular inclined plate (61) is connected to the front support plate (3), and the outer ring of the annular inclined plate (61) is closer to the front support plate (3) than the inner ring.

5. The small aircraft engine combustion chamber casing according to claim 3 or 4, characterized in that: The angle between the annular inclined plate (61) and the central axis of the combustion inner ring is greater than 20 degrees.

6. The small aircraft engine combustion chamber casing according to claim 1, characterized in that: The support structure (63) is a porous structure.

7. The small aircraft engine combustion chamber casing according to claim 6, characterized in that: The support structure (63) is formed by stacking a plurality of lattice units, wherein the lattice units include a plurality of support rods (7), one end of each support rod (7) of a lattice unit is interconnected as the center of the lattice unit, all the support rods (7) of the lattice unit are in a body-centered cubic structure, the support rods (7) of adjacent lattice units of the support structure (63) are interconnected, and the support rods (7) on the outer side of the lattice units of the outermost layer of the support structure (63) in the accommodating chamber (6) are connected to the inner wall of the accommodating chamber (6).

8. The small aircraft engine combustion chamber casing according to claim 7, characterized in that: The ends of the support rods (7) in the lattice unit that are aligned with each other along the axis direction of the combustion inner ring are connected via a column (71).

9. The small aircraft engine combustion chamber casing according to claim 7, characterized in that: The length and / or the rod diameter of the support rod (7) of the lattice unit in the accommodating chamber (6) gradually decreases from the inside to the outside.

10. The small aircraft engine combustion chamber casing according to claim 7, characterized in that: A straight line passing through the center of the lattice unit and parallel to the axial direction of the combustion chamber inner ring (2) is a first straight line, and the acute angle between the support rod (7) of the lattice unit and the first straight line is less than 45° and greater than 20°.

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