An aeroengine inlet casing

Abstract

This application belongs to the technical field of aero-engine inlet casing design, and specifically relates to an aero-engine inlet casing. By combining the characteristics of various functional composite materials and adopting the design concept of functional gradient of composite materials, a multi-functional composite material inlet casing structure is realized, replacing the metal welded structure inlet casing. The integrated design of multiple functions such as radar wave absorption and load-bearing support can effectively reduce the radar detectability of aero-engines, improve the space utilization of the equipped aircraft, the versatility for different types of aircraft, ensure the inspectability and maintainability of aero-engines, reduce the weight and aerodynamic loss of aero-engines, ensure the reliability of the thrust operation of aero-engines, and avoid problems such as weld cracks and failures caused by vibration, fatigue, and internal stress.

Description

Technical Field

[0001] This application belongs to the technical field of aero-engine inlet casing design, and particularly relates to an aero-engine inlet casing. Background Art

[0002] The inlet casing is located at the very front end of an aero-engine and is an important load-bearing component of the aero-engine. The current inlet casing is usually composed of a titanium alloy casing, struts, etc., and is formed into a spoke structure by welding. The radial load of the low-pressure rotor part of the aero-engine is borne by the bearings assembled inside. The struts of the inlet casing are usually cavity structures, which, while transferring the inner and outer ring loads, realize the layout of the anti-icing bleed air path, the oil inlet and return pipelines, the lead wires, etc.

[0003] An aero-engine requires air as a working medium to participate in the operation, and cannot be completely encapsulated inside the aircraft. Coupled with its complex structure, a strong radar reflection source is formed forward. To reduce the radar detectability of the aero-engine, usually the following three technical solutions are adopted for the relevant design of the inlet casing.

[0004] Solution 1:

[0005] Coatings with radar wave absorbing functions are applied on the inner and outer flow surfaces of the inlet casing and the outer sides of the struts, and the coatings are used to absorb the incident and reflected radar waves entering the aero-engine inlet duct.

[0006] The coatings with radar wave absorbing functions are high-density materials. Directly applying them on the inner and outer flow surfaces of the inlet casing and the outer sides of the struts will significantly increase the weight of the inlet casing and its aero-engine.

[0007] The coatings with radar wave absorbing functions have high hardness. The required coating thickness on the inner and outer flow surfaces of the inlet casing and the outer sides of the struts is about 1 mm, and the bonding strength with the metal surface is relatively low. During the operation of the aero-engine, they are prone to peeling off, generating hard coating blocks, which may damage the rear fan, compressor, turbine and other components. In severe cases, it may lead to the damage and failure of the entire aero-engine.

[0008] Solution 2:

[0009] In the aircraft inlet duct, at a certain axial distance from the front end of the aero-engine, a radar wave absorbing fluid guide is provided to absorb the incident and reflected radar waves entering the aero-engine inlet duct.

[0010] The radar wave absorbing fluid guide is composed of structures such as a radar wave absorbing outer ring, a radar wave absorbing inner ring, and radar wave absorbing struts. The overall structure is complex, and the weight and size are relatively large. Using the radar wave absorbing fluid guide to reduce the radar detectability of the aero-engine will cause significant losses in many key indicators such as the weight, size, and thrust of the aero-engine.

[0011] The absorbing waveguide fluid is arranged at a certain axial distance in front of the aeroengine, which greatly increases the distance from the inspection and maintenance operation position at the front end of the aeroengine to the first-stage rotor of the fan, greatly increasing the difficulty of inspecting and maintaining the fan, and also increasing the axial space required for the installation of the aeroengine. This not only affects the space utilization of the aircraft equipped, but also seriously limits the universality of the aeroengine for different types of aircraft. In addition, it will greatly affect the reduction of the flow field quality at the inlet of the aeroengine, increase the aerodynamic loss of the aeroengine, and affect the thrust of the aeroengine.

[0012] The absorbing waveguide fluid is at a certain axial distance in front of the aeroengine. When the aeroengine is operating, ice is likely to form at the leading edge of the absorbing strut. Therefore, the leading edge of the absorbing strut is usually designed as a hollow metal structure with an anti-icing channel and its anti-icing holes. When the aeroengine is operating, high-temperature and high-pressure bleed air from the aeroengine is introduced into the anti-icing channel and discharged through the anti-icing holes to achieve the anti-icing effect. However, the leading edge of the absorbing strut with such a metal structure will greatly affect the absorption effect of the absorbing waveguide fluid on radar waves and it is difficult to effectively reduce the radar detectability of the aeroengine.

[0013] Solution 3:

[0014] Remove the inlet cowl of the inlet casing and directly assemble the absorbing waveguide fluid onto the front mounting edge of the inlet casing to shorten the axial distance between the absorbing waveguide fluid and the inlet casing, so as to reduce the distance from the inspection and maintenance operation position at the front end of the aeroengine to the first-stage rotor of the fan, reduce the difficulty of inspecting and maintaining the fan, and reduce the axial space required for the installation of the aeroengine, improve the space utilization of the aircraft equipped, and the universality for different types of aircraft. In addition, design the absorbing struts to correspond one by one with the inner struts of the inlet casing to reduce the impact on the flow field quality at the inlet of the aeroengine, reduce the aerodynamic loss of the aeroengine, and improve the thrust of the aeroengine.

[0015] Although the design of removing the inlet cowl of the inlet casing and directly assembling the absorbing waveguide fluid onto the front mounting edge of the inlet casing can reduce the distance from the inspection and maintenance operation position at the front end of the aeroengine to the first-stage rotor of the fan, due to the existence of the absorbing waveguide fluid itself, it will still bring certain difficulties to the inspection and maintenance of the fan, and affect the space utilization of the aircraft equipped, limiting the universality of the aeroengine for different types of aircraft. And there is a problem of discontinuous blade profiles between the absorbing struts and the inner struts of the inlet casing, which will still cause relatively large aerodynamic losses and affect the thrust of the aeroengine. In addition, there will still be problems such as relatively large losses in many key indicators such as the weight, size, and thrust of the aeroengine, and it is difficult to effectively reduce the radar detectability of the aeroengine.

[0016] In summary, although the above three technical solutions can reduce the radar detectability of aero-engines to a certain extent, they have problems in many aspects, such as affecting the space utilization of the aircraft to be equipped, restricting the universality of aero-engines for different types of aircraft, reducing the inspectability and maintainability of aero-engines, increasing the weight of aero-engines, increasing the aerodynamic losses of aero-engines, reducing the thrust of aero-engines, and affecting the working reliability of aero-engines.

[0017] In addition, the current inlet casings mostly adopt metal welded structures. When the welding process or the post-welding heat treatment process is unstable, problems such as weld cracks and failures caused by vibration, fatigue, and internal stress are very likely to occur.

[0018] In view of the existence of the above technical defects, this application is proposed. Summary of the Invention

[0019] The purpose of this application is to provide an aero-engine inlet casing that can simultaneously meet all the functional requirements of the current inlet casing, can effectively reduce the radar detectability of the aero-engine, and has the advantages of being lightweight, compact, and reliable.

[0020] The technical solution of this application is as follows:

[0021] An aero-engine inlet casing includes an outer casing, an inner support ring for struts, and struts;

[0022] The outer casing is a circular ring structure, made of carbon fiber reinforced composite material, and successively includes a front wave-absorbing functional area and a strut assembly area from front to back;

[0023] A front wave-absorbing ring is arranged in the front wave-absorbing functional area, and the front wave-absorbing ring abuts against the inner side of the front wave-absorbing functional area and is made of wave-absorbing composite material;

[0024] The inner support ring for struts is arranged inside the outer casing, facing the strut assembly area, and is made of carbon fiber reinforced composite material or lightweight metal material;

[0025] There are multiple struts, which are circumferentially supported between the strut assembly area and the inner support ring for struts, and the leading edges extend into the inner side of the front wave-absorbing functional area, and include an external wave-transparent skin, a leading-edge wave-absorbing structure, a front-section wave-absorbing structure, and a rear-section wave-absorbing structure;

[0026] The external wave-transparent skin constitutes the aerodynamic shape of the strut structure, is made of lightweight electromagnetic wave-transparent material, and the leading-edge wave-absorbing structure, the front-section wave-absorbing structure, and the rear-section wave-absorbing structure are successively filled inside from front to back;

[0027] The leading-edge wave-absorbing structure is made of wave-absorbing prepreg, the front-section wave-absorbing structure is made of wave-absorbing honeycomb material, and the rear-section wave-absorbing structure is made of wave-absorbing prepreg;

[0028] The middle of the rear-stage wave-absorbing structure has support holes along the height direction of the strut. A bearing structure is arranged in the support holes. The bearing structure is made of carbon fiber composite material. The upper and lower ends are formed with an outer upper flange and an outer lower flange. The inner side is laid with an inner upper flange and an inner lower flange to form the upper flange and the lower flange. The inner upper flange and the inner lower flange are made of wave-absorbing prepreg;

[0029] The assembly areas of each upper flange connecting to the strut form an integral ring structure among each other; the assembly areas of each lower flange connecting to the inner ring of the strut form an integral ring structure among each other.

[0030] Optionally, in the above-mentioned aero-engine inlet casing, the front end and the rear end of the outer casing are formed with annular mounting edges, which are respectively used to connect with the annular mounting edge at the rear end of the aircraft inlet duct and the annular mounting edge at the front end of the fan casing;

[0031] The inner ring of the strut is connected to a bearing seat, a bearing is installed in the bearing seat, and the bearing is sleeved on the front end of the low-pressure rotating shaft.

[0032] Optionally, in the above-mentioned aero-engine inlet casing, there are assembly holes along the height direction of the strut on the rear-stage wave-absorbing structure and its bearing structure inside some struts, for arranging the air intake pipeline, the oil inlet and return pipeline, and the lead wire. The thickness of this part of the strut is greater than that of other struts.

[0033] Optionally, in the above-mentioned aero-engine inlet casing, an electric anti-icing layer is arranged on the outer side of the leading edge of the wave-transparent skin outside each strut. The electric anti-icing layer is made of electro-thermal material with wave-transparent function.

[0034] Optionally, in the above-mentioned aero-engine inlet casing, it further includes an adjustable vane inner ring and adjustable vanes;

[0035] There is an adjustable vane assembly area behind the strut assembly area of the outer casing;

[0036] The adjustable vane assembly area has a plurality of upper journal mounting holes distributed circumferentially;

[0037] A rear wave-absorbing ring is arranged in the adjustable vane assembly area. The rear wave-absorbing ring is abutted against the inner side of the adjustable vane assembly area, and through holes are opened at the corresponding positions of the upper journal mounting holes. It is made of wave-absorbing composite material;

[0038] The adjustable vane inner ring is arranged inside the outer casing, facing the adjustable vane assembly area, and it has a plurality of lower journal mounting holes distributed circumferentially;

[0039] There are a plurality of adjustable vanes, which are arranged circumferentially between the adjustable vane assembly area and the adjustable vane inner ring. The upper journals of each adjustable vane are installed in each upper journal mounting hole, and the lower journals are installed in each lower journal mounting hole.

[0040] Optionally, in the above-mentioned aero-engine inlet casing, the adjustable vane inner ring includes an outer ring wave-absorbing structure and an inner ring support structure;

[0041] The outer ring wave-absorbing structure is made of wave-absorbing prepreg;

[0042] The inner ring support structure is connected to the outer periphery of the outer ring wave-absorbing structure, and the front end is connected to the rear end of the inner ring of the strut.

[0043] Optionally, in the above-mentioned aero-engine inlet casing, each adjustable vane and each strut correspond to each other in the circumferential position, are closely arranged behind the corresponding strut, and have a matching thickness with the corresponding strut.

[0044] Optionally, in the above-mentioned aero-engine inlet casing, each adjustable vane is made of carbon fiber composite material and is provided with a wave-absorbing layer on one side.

[0045] Optionally, in the above-mentioned aero-engine inlet casing, it further includes an adjustment mechanism;

[0046] The adjustment mechanism includes a linkage ring, a rocker arm, a pull rod, and a crank;

[0047] The linkage ring is sleeved on the outer periphery of the outer casing;

[0048] There are multiple rocker arms, one end is connected to each upper journal, and the other end is hinged to the linkage ring;

[0049] One end of the pull rod is hinged to the linkage ring;

[0050] The bent part of the crank is hinged to the outside of the outer casing, one end is hinged to the other end of the pull rod, and the other end is hinged to the actuating mechanism, and the actuating mechanism is connected to the outside of the outer casing;

[0051] The actuating mechanism can drive the linkage ring to rotate through the crank and the pull rod, and then drive each adjustable vane to rotate synchronously through each rocker arm, so that the angles of each adjustable vane are closed or opened.

[0052] Optionally, in the above-mentioned aero-engine inlet casing, it further includes a cap;

[0053] The cap is arranged at the front end of the outer casing, and the rear end extends into the inner sides of the leading edge wave-absorbing structure and the front section wave-absorbing structure, and includes an outer layer electric anti-icing cone, a wave-absorbing cone, a wave-absorbing inner ring, a support inner ring, and a reflection back plate;

[0054] The outer layer electric anti-icing cone forms the aerodynamic shape of the cap and is made of electrothermal material with wave-transmitting ability;

[0055] The wave-absorbing cone is arranged inside the outer layer electric anti-icing cone and abuts against the inner side of the front end of the outer layer electric anti-icing cone, and is made of honeycomb composite material with wave-absorbing function;

[0056] The reflective backplane is arranged inside the wave-absorbing cone and abuts against the inner side of the wave-absorbing cone. It is made of a carbon fiber composite material or a metal material with electromagnetic wave reflection function.

[0057] The wave-absorbing inner ring is arranged inside the outer-layer electric anti-icing cone, abuts against the inner side of the rear end of the outer-layer electric anti-icing cone, and presses against the wave-absorbing cone. It is co-cured and formed with the outer-layer electric anti-icing cone, the wave-absorbing cone, and the reflective backplane.

[0058] The support inner ring is arranged inside the wave-absorbing inner ring and abuts against the inner side of the wave-absorbing inner ring. It is made of a carbon fiber reinforced composite material or a lightweight metal material, and its rear end is connected to the front end of the inner ring of the support plate.

[0059] The present application has at least the following beneficial technical effects:

[0060] An aero-engine inlet casing is provided. Combining the characteristics of various functional composite materials and adopting the idea of functional gradient design of composite materials, a multi-functional composite material inlet casing structure is realized, replacing the metal welded structure inlet casing. The integration design of multiple functions such as radar wave absorption and load-bearing support is carried out. While effectively reducing the radar detectability of the aero-engine, it can improve the space utilization of the equipped aircraft, the universality for different types of aircraft, and ensure the inspectability and maintainability of the aero-engine, reduce the weight and aerodynamic loss of the aero-engine, ensure the reliability of the thrust operation of the aero-engine, and avoid problems such as weld cracks and failures caused by vibration, fatigue, and internal stress. Description of the Drawings

[0061] Figure 1 It is a partial cross-sectional schematic diagram of the aero-engine inlet casing equipped with a thinner support plate provided by an embodiment of the present application;

[0062] Figure 2 It is a partial cross-sectional schematic diagram of the aero-engine inlet casing equipped with a thicker support plate provided by an embodiment of the present application;

[0063] Figure 3 It is a schematic diagram of the outer casing provided by an embodiment of the present application;

[0064] Figure 4 It is a schematic diagram of the side of the support plate provided by an embodiment of the present application;

[0065] Figure 5 It is a schematic diagram of the support plate along the axial direction of the aero-engine provided by an embodiment of the present application;

[0066] Figure 6 It is a partial cross-sectional schematic diagram of the thinner support plate provided by an embodiment of the present application;

[0067] Figure 7 It is a schematic diagram of the upper edge plate of the support plate provided by an embodiment of the present application;

[0068] Figure 8 It is a schematic diagram of the lower edge plate of the strut provided by an embodiment of the present application;

[0069] Figure 9 It is a partial sectional schematic diagram of a relatively thick strut provided by an embodiment of the present application;

[0070] Figure 10 It is a partial sectional schematic diagram of an adjustable vane inner ring provided by an embodiment of the present application;

[0071] Figure 11 It is a partial sectional schematic diagram of an adjustable vane provided by an embodiment of the present application;

[0072] Figure 12 It is a schematic diagram of the reflection and absorption of incident radar waves when the angle of the adjustable vane inner ring is opened provided by an embodiment of the present application;

[0073] Figure 13 It is a schematic diagram of the reflection and absorption of incident radar waves when the angle of the adjustable vane inner ring is closed provided by an embodiment of the present application;

[0074] Figure 14 It is a schematic diagram of the adjusting mechanism provided by an embodiment of the present application;

[0075] Figure 15 It is a schematic diagram of the cap provided by an embodiment of the present application;

[0076] Figure 16 It is a schematic diagram of the lead-out of the outer layer electric anti-icing cone provided by an embodiment of the present application;

[0077] Wherein:

[0078] 1 - Outer casing; 2 - Strut inner ring; 3 - Strut; 4 - Adjustable vane inner ring; 5 - Adjustable vane; 6 - Adjusting mechanism; 7 - Cap; 8 - Bearing seat; 9 - Bearing; 10 - Low-pressure rotating shaft;

[0079] 11 - Front wave-absorbing functional area; 12 - Strut assembly area; 13 - Adjustable vane assembly area; 14 - Front wave-absorbing ring; 15 - Rear wave-absorbing ring;

[0080] 31 - External wave-transparent skin; 32 - Leading-edge wave-absorbing structure; 33 - Front-section wave-absorbing structure; 34 - Rear-section wave-absorbing structure; 35 - Load-bearing structure; 36 - Outer layer of the upper edge plate; 37 - Outer layer of the lower edge plate; 38 - Inner layer of the upper edge plate; 39 - Inner layer of the lower edge plate; 310 - Electric anti-icing layer;

[0081] 41 - Outer ring wave-absorbing structure; 42 - Inner ring support structure;

[0082] 51 - Wave-absorbing layer;

[0083] 61 - Linking ring; 62 - Rocker arm; 63 - Pull rod; 64 - Crank;

[0084] 71 - Outer layer electric anti - ice cone; 72 - Wave - absorbing cone; 73 - Wave - absorbing inner ring; 74 - Support inner ring; 75 - Reflective backplane.

[0085] To better illustrate this embodiment, some contents in the attached drawings will be omitted, enlarged or reduced, which are only for exemplary illustration and should not be construed as a limitation to this application. Specific embodiments

[0086] To make the technical solutions and their advantages of this application clearer, the technical solutions of this application will be further described clearly and completely in combination with the attached drawings. It can be understood that the specific embodiments described here are only partial embodiments of this application, which are only used to explain this application rather than limit this application. It should be noted that for the convenience of description, only the parts related to this application are shown in the attached drawings, and other related parts can refer to the general design.

[0087] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application should be the ordinary meanings understood by those of ordinary skill in the field to which this application belongs. The "including" used in the description of this application means that the concept appearing before this word covers the concepts listed after this word and their equivalents, without excluding other related concepts.

[0088] In addition, the words indicating directions used in the description of this application are only used to indicate relative directions or position relationships. When the absolute position of the object being described changes, its relative position relationship may also change accordingly. It should also be noted that unless otherwise clearly specified and limited, the "installation", "connection" and other similar words used in the description of this application should be understood in a broad sense. For example, connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. Those skilled in the art can understand their specific meanings in this application according to the specific situation.

[0089] Composite materials have characteristics such as multi - function, multi - configuration, high specific stiffness, high specific strength, etc., and have good designability. When manufacturing an inlet casing with them, the fiber reinforcement of resin - based composite materials can be utilized to effectively inhibit the crack propagation of components. Coupled with the high damping characteristics of resin - based composite materials, compared with metal - welded inlet casings, it is more suitable for its working environment of high frequency and complex vibration. On the basis of meeting multi - function requirements, the reliability of the inlet casing is greatly improved, and problems such as weld cracks and failures caused by unstable welding processes or post - welding heat treatment processes of metal - welded inlet casings are avoided.

[0090] Based on the above, this application embodiment provides an aero - engine inlet casing, which is a multi - function all - composite material inlet casing, as Figure 1 - Figure 2As shown, it includes an outer casing 1, a support plate inner ring 2, a support plate 3, an adjustable blade inner ring 4, adjustable blades 5, an adjustment mechanism 6, and a cap 7.

[0091] Outer case 1 Figure 3 As shown, it is a circular ring structure, which is made of carbon fiber reinforced composite materials with high specific stiffness and high specific strength, such as T800 grade or T1100 grade carbon fiber reinforced epoxy or BMI resin-based composite materials, forming the overall frame of the air intake casing, and the fiber laying direction or weaving method is determined according to the load-bearing characteristics of the air intake casing.

[0092] The front and rear ends of the outer casing 1 are formed with an annular mounting edge and an annular mounting edge, which are respectively used to connect with the annular mounting edge at the rear end of the aircraft air inlet and the annular mounting edge at the front end of the fan casing by bolts or the like. The annular mounting edges at the front and rear ends of the outer casing 1 ensure the continuity of the composite material structural fibers with the outer casing 1 body as much as possible.

[0093] The outer casing 1 includes, from front to back, a front wave absorbing functional area 11 , a support plate assembly area 12 , and an adjustable blade assembly area 13 .

[0094] A front absorbing ring 14 is arranged in the front absorbing functional area 11. The front absorbing ring 14 is close to the inner side of the front absorbing functional area 11 and is made of absorbing composite materials. The specific material selection can be determined by comprehensively considering the requirements of absorbing index, weight index and molding process, such as carbonyl iron powder (CIP) and acetylene black (CB) and other absorbents are added with glass fiber to increase the resin-based composite material. The front end of the front absorbing ring 14 can be designed to have an outward folded edge, which is close to the front side of the annular mounting edge at the front end of the outer casing 1 and is connected to the annular mounting edge by bolts.

[0095] The support plate assembly area 12 provides a corresponding spatial structure for the assembly of the support plate 3 .

[0096] The adjustable blade assembly area 13 provides a corresponding spatial structure for assembling the adjustable blade 5, and has a plurality of upper shaft neck mounting holes distributed along the circumferential direction. The opening positions of the upper shaft neck mounting holes can be reinforced and designed as required.

[0097] A rear absorbing ring 15 is arranged in the adjustable blade assembly area 13. The rear absorbing ring 15 is attached to the inner side of the adjustable blade assembly area 13. A through hole is provided at the corresponding position of the upper journal mounting hole. The rear absorbing ring 15 is made of absorbing composite material. The specific material selection can be determined by comprehensively considering the requirements such as absorbing index, weight index and molding process. For example, absorbents such as carbonyl iron powder (CIP) and acetylene black (CB) are added with glass fiber to increase the resin-based composite material. The rear absorbing ring 15 can be attached to the inner side of the adjustable blade assembly area 13, or connected to the adjustable blade assembly area 13 by bolts.

[0098] The inner ring 2 of the strut is arranged inside the outer casing 1, facing the strut assembly area 12, and is made of carbon fiber reinforced composite materials such as T800 or T1100 grade carbon fiber reinforced epoxy or bismaleimide resin matrix composites, or high specific stiffness materials such as light metals, such as TC4 titanium alloy, to support the strut 3. The inner ring 2 of the strut is connected to the bearing seat 8 inside, and the bearing 9 is installed inside the bearing seat 8, and the bearing 9 is sleeved on the front end of the low-pressure rotating shaft 10.

[0099] There are multiple struts 3, which are circumferentially supported between the strut assembly area 12 and the inner ring 2 of the strut, and the leading edge extends into the inner side of the front wave-absorbing functional area 11.

[0100] As shown in Figure 4 - Figure 5 the figure, the strut 3 includes an external wave-transparent skin 31, a leading-edge wave-absorbing structure 32, a front-segment wave-absorbing structure 33, and a rear-segment wave-absorbing structure 34.

[0101] The external wave-transparent skin 31 forms the aerodynamic shape of the strut 3 structure and is made of a light electromagnetic wave-transparent material, such as glass fiber reinforced resin matrix composite material, which can achieve the transmission of radar waves to facilitate the absorption of radar waves by the internal structure. The leading-edge wave-absorbing structure 32, the front-segment wave-absorbing structure 33, and the rear-segment wave-absorbing structure 34 are filled inside in sequence from front to back, as shown in Figure 6 the figure.

[0102] The leading-edge wave-absorbing structure 32 is made of wave-absorbing prepreg, such as absorbents such as carbonyl iron powder (CIP) and acetylene carbon black (CB) added to glass fiber reinforced resin matrix composite material.

[0103] The front-segment wave-absorbing structure 33 is made of wave-absorbing honeycomb material and is located at the position with the largest thickness inside the external wave-transparent skin 31, which can reduce the mass of the strut 3 while improving the wave-absorbing performance.

[0104] The rear-segment wave-absorbing structure 34 is made of wave-absorbing prepreg, such as absorbents such as carbonyl iron powder (CIP) and acetylene carbon black (CB) added to glass fiber reinforced resin matrix composite material.

[0105] There is a support hole along the height direction of the strut 3 in the middle of the rear-segment wave-absorbing structure 34. A bearing structure 35 is arranged inside the support hole. The bearing structure 35 is made of carbon fiber composite material. The upper end and the lower end are formed with an upper flange outer layer 36 and a lower flange outer layer 37. The carbon fiber between the upper flange outer layer 36 and the lower flange outer layer 37 is continuous and has a high bearing capacity, serving as a support layer. An upper flange inner layer 38 and a lower flange inner layer 39 are laid inside the upper flange outer layer 36 and the lower flange outer layer 37, and are adhesively connected to form the upper flange and the lower flange, as shown in Figure 7 - Figure 8As shown, the inner layer of the upper edge plate 38 and the inner layer of the lower edge plate 39 are made of microwave absorbing prepreg. For example, absorbents such as carbonyl iron powder (CIP) and acetylene carbon black (CB) are added to glass fiber to increase the resin matrix composite material.

[0106] Each upper edge plate connecting support plate assembly area 12 can be specifically connected by countersunk head screws, and an integral ring structure is formed between each lower edge plate. The front microwave absorbing functional area 11 can be strengthened according to the number and distribution of holes on it.

[0107] Each lower edge plate connecting support plate inner ring 2 can be specifically connected by countersunk head screws, and an integral ring structure is formed between each upper edge plate. The support plate inner ring 2 can be strengthened according to the number and distribution of holes on it.

[0108] There are assembly holes along the height direction of the support plate 3 on the rear section microwave absorbing structure 34 and its load-bearing structure 35 inside a part of the support plate 3 for arranging the air supply pipeline, the oil inlet and return pipeline, the lead wire, etc. The thickness of this part of the support plate 3 is greater than that of other support plates 3, as Figure 9 shown.

[0109] An electric anti-icing layer 310 is arranged on the outer side of the leading edge of the external wave-transparent skin 31 of each support plate 3. The electric anti-icing layer 310 is made of an electrothermal material with wave-transparent function, such as graphene film. The electric anti-icing layer 310 can be bonded to the leading edge of the external wave-transparent skin 31. The electric anti-icing layer 310 is led and powered through the inside of the support plate 3 and its assembly holes.

[0110] The adjustable vane inner ring 4 is arranged inside the outer casing 1, facing the adjustable vane assembly area 13, and has a plurality of lower journal mounting holes distributed circumferentially. The opening position of the lower journal mounting holes can be strengthened according to needs.

[0111] The adjustable vane inner ring 4 is as Figure 10 shown, including an outer ring microwave absorbing structure 41 and an inner ring support structure 42.

[0112] The outer ring microwave absorbing structure 41 is made of microwave absorbing prepreg. For example, absorbents such as acetylene carbon black (CB) are added to glass fiber to increase the resin matrix composite material.

[0113] The inner ring support structure 42 is connected to the inner side of the outer ring microwave absorbing structure 41 and is adhesively connected to the outer ring microwave absorbing structure 41. The front end is connected to the rear end of the support plate inner ring 2, and can be specifically connected by bolts through a circular connecting edge. The material selection of the inner ring support structure 42 can be determined considering multiple aspects such as weight reduction, cost, and process, such as T1100 grade carbon fiber reinforced resin matrix composite material, TC4 titanium alloy, 2A70 aluminum alloy, etc.

[0114] There are multiple adjustable vanes 5, which are arranged circumferentially between the adjustable vane assembly area 13 and the adjustable vane inner ring 4. The upper journals of each adjustable vane 5 are installed in the respective upper journal mounting holes, and the lower journals are installed in the respective lower journal mounting holes. Journal bushings can be provided between each upper journal and the upper journal mounting hole, and between each lower journal and the lower journal mounting hole.

[0115] Each adjustable vane 5 corresponds to each support plate 3 in the circumferential position, is closely adjacent to the rear of the corresponding support plate 3, and has a matching thickness with the corresponding support plate 3 to ensure the stability of the airflow in the inlet casing and reduce the aerodynamic loss.

[0116] Each adjustable vane 5 is made of carbon fiber composite material, and an absorbing layer 51 is provided on one side, as Figure 11 shown. The absorbing layer 51 is made of absorbing prepreg. For example, absorbents such as acetylene carbon black (CB) are added to glass fiber to increase the resin matrix composite material, so that the adjustable vane 5 can have the absorbing function, as Figure 12 - Figure 13 shown. Thus, the absorbing ability of the inlet casing can be compensated, and furthermore, on the basis that the inlet casing meets the load-bearing and other functions, the axial length of the inlet casing can be shortened.

[0117] The absorbing layer 51 can be provided on the side facing outward when the adjustable vane 5 is closed, and is co-cured with the adjustable vane 5.

[0118] The adjusting mechanism 6 is as Figure 14 shown, and includes a linkage ring 61, a rocker arm 62, a pull rod 63, and a crank 64.

[0119] The linkage ring 61 is sleeved on the outer periphery of the outer casing 1.

[0120] There are multiple rocker arms 62. One end is connected to each upper journal, and can be specifically connected by fasteners. The other end is hinged to the linkage ring 61, and can be specifically hinged by a spherical plain bearing with a pin shaft.

[0121] One end of the pull rod 63 is hinged to the linkage ring 61, and can be specifically hinged by a single / double ear structure with a pin shaft.

[0122] The bent part of the crank 64 is hinged to the outside of the outer casing 1, and can be specifically hinged by a pin shaft. One end is hinged to the other end of the pull rod 63, and can be specifically hinged by a single / double ear structure with a pin shaft. The other end is hinged to the actuating mechanism, and can be specifically hinged by a single / double ear structure with a pin shaft. The actuating mechanism is connected to the outside of the outer casing 1, and can specifically be an actuating cylinder.

[0123] There can be two groups of the pull rod 63, the crank 64, and the actuating mechanism, which are distributed at 180°.

[0124] The actuating mechanism can drive the linkage ring 61 to rotate through the crank 64 and the pull rod 63, and then drive each adjustable vane 5 to rotate synchronously through each rocker arm 62, so that the angles of the adjustable vanes 5 are closed or opened.

[0125] The cap 7 is arranged at the front end of the outer casing 1, and the rear end extends into the inner sides of the leading edge wave-absorbing structure 32 and the front section wave-absorbing structure 33, and is connected to the front end of the inner ring of the support plate 2.

[0126] The cap 7 is as Figure 15 shown, and includes an outer electric anti-icing cone 71, a wave-absorbing cone 72, a wave-absorbing inner ring 73, a support inner ring 74, and a reflection back plate 75.

[0127] The outer electric anti-icing cone 71 forms the aerodynamic shape of the cap 7 and is made of an electrothermal material with wave-transmitting ability, such as graphene film.

[0128] The wave-absorbing cone 72 is arranged inside the outer electric anti-icing cone 71 and abuts against the inner side of the front end of the outer electric anti-icing cone 71, and is made of a honeycomb composite material with wave-absorbing function. The outer electric anti-icing cone 71 leads wires through the inside of the wave-absorbing cone 72 and its assembly holes, as Figure 16 shown.

[0129] The reflection back plate 75 is arranged inside the wave-absorbing cone 72 and abuts against the inner side of the wave-absorbing cone 72, and is made of a carbon fiber composite material or a metal material with electromagnetic wave reflection function, such as T300 grade carbon fiber reinforced resin matrix composite material, TC4 titanium alloy, etc.

[0130] The wave-absorbing inner ring 73 is arranged inside the outer electric anti-icing cone 71 and abuts against the inner side of the rear end of the outer electric anti-icing cone 71, abuts against the wave-absorbing cone 72, and is co-cured and formed with the outer electric anti-icing cone 71, the wave-absorbing cone 72, and the reflection back plate 75.

[0131] The support inner ring 74 is arranged inside the wave-absorbing inner ring 73 and abuts against the inner side of the wave-absorbing inner ring 73, and the rear end is bolted to the front end of the inner ring of the support plate 2 through an annular mounting edge.

[0132] The support inner ring 74 is made of a fiber-reinforced composite material such as carbon, such as T1100 grade carbon fiber reinforced resin matrix composite material, or made of a light metal material such as TC4 titanium alloy, and is adhesively connected to the wave-absorbing inner ring 73, and is connected to the wave-absorbing inner ring 73 and the rear end of the wave-absorbing cone 72 by fasteners.

[0133] The aeroengine inlet casing disclosed in the above embodiments has the following advantages in many aspects compared with the prior art solutions:

[0134] 1. By adopting various composite material wave absorption means such as wave-absorbing prepreg and wave-absorbing honeycomb, gradient wave absorption in different regions of the intake casing is achieved, reducing the radar detectability of the aeroengine and avoiding the risks caused by the falling off of the coating with radar wave absorption function.

[0135] 2. Combining the characteristics of various functional composite materials and adopting the design concept of functional gradient of composite materials, a multi-functional composite material intake casing structure is realized, replacing the metal welded structure intake casing. The integration design of multiple functions such as radar wave absorption and load-bearing support is carried out, canceling the use of the coating with radar wave absorption function and its wave-absorbing fluid guide. This can greatly reduce the weight of the intake casing and the aeroengine, shorten the axial dimension of the aeroengine, improve the utilization of the space of the equipped aircraft, enhance the versatility for different types of aircraft, and facilitate the inspection and maintenance of the fan. Moreover, it greatly alleviates the contradiction between the radar detectability of the aeroengine and multiple key indicators such as weight, size, and thrust, and can relax the restrictive constraints for the improvement of the radar detectability design of the aeroengine.

[0136] 3. Using a wave-transparent thermoelectric film to replace the bleed air anti-icing on the cowl and struts. The radar wave can penetrate the thermoelectric film and be absorbed by the corresponding internal wave-absorbing composite material, thereby further ensuring the reduction of the radar detectability of the aeroengine.

[0137] 4. The adjustable vane is designed for wave absorption. By using the absorption of the adjustable vane for radar waves, the radar detectability of the aeroengine is further reduced. On the basis of ensuring the radar detectability of the aeroengine, the axial dimension of the aeroengine can be further shortened, the utilization of the space of the equipped aircraft can be improved, the versatility for different types of aircraft can be enhanced, and the inspection and maintenance of the fan can be facilitated.

[0138] 5. Adopting the design concept of multi-functional integration, the internal and external flow paths and struts of the intake casing are of an integral structure, without discontinuity or non-continuity of the flow path and the strut airfoil. This can greatly improve the quality of the inlet flow field of the aeroengine, reduce the along-way loss of the air flow passing through the struts, and increase the thrust of the aeroengine.

[0139] So far, the technical solution of the present application has been described in combination with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present application.

Claims

1. An air intake casing of an aircraft engine, characterized in that: It comprises an outer casing (1), a support plate inner ring (2), and a support plate (3); The outer casing (1) is a circular ring structure, made of carbon fiber reinforced composite material, and comprises, from front to back, a front wave absorbing functional area (11) and a support plate assembly area (12); A front wave absorbing ring (14) is arranged in the front wave absorbing functional area (11); the front wave absorbing ring (14) is attached to the inner side of the front wave absorbing functional area (11) and is made of a wave absorbing composite material; The support plate inner ring (2) is arranged on the inner side of the outer casing (1) and directly faces the support plate assembly area (12), and is made of carbon fiber reinforced composite material or lightweight metal material; There are a plurality of support plates (3), which are supported between the support plate assembly area (12) and the support plate inner ring (2) along the circumferential direction, and the leading edge extends into the inner side of the front wave absorbing functional area (11), and include an external wave-transmitting skin (31), a leading edge wave absorbing structure (32), a front section wave absorbing structure (33), and a rear section wave absorbing structure (34); The external wave-transmitting skin (31) forms the aerodynamic shape of the support plate (3) structure and is made of a lightweight electromagnetic wave-transmitting material. The interior is filled with a leading edge wave-absorbing structure (32), a front section wave-absorbing structure (33), and a rear section wave-absorbing structure (34) in order from front to back. The leading edge absorbing structure (32) is made of absorbing prepreg, the front section absorbing structure (33) is made of absorbing honeycomb material, and the rear section absorbing structure (34) is made of absorbing prepreg; The rear section wave absorbing structure (34) has a support hole in the middle along the height direction of the support plate (3), and a bearing structure (35) is arranged in the support hole. The bearing structure (35) is made of carbon fiber composite material, and an upper edge plate outer layer (36) and a lower edge plate outer layer (37) are formed at the upper and lower ends, and an upper edge plate inner layer (38) and a lower edge plate inner layer (39) are laid on the inner side to form an upper edge plate and a lower edge plate, and the upper edge plate inner layer (38) and the lower edge plate inner layer (39) are made of wave absorbing prepreg; Each upper edge plate is connected to the support plate assembly area (12), and each upper edge plate forms a complete ring structure; each lower edge plate is connected to the support plate inner ring (2), and each lower edge plate forms a complete ring structure.

2. The aircraft engine air intake casing according to claim 1, characterized in that: The outer casing (1) has a front end and a rear end formed with an annular mounting edge and an annular mounting edge, respectively used to connect with the annular mounting edge at the rear end of the aircraft air inlet and the annular mounting edge at the front end of the fan casing; The inner ring (2) of the support plate is connected to a bearing seat (8), a bearing (9) is installed in the bearing seat (8), and the bearing (9) is sleeved on the front end of the low-pressure rotating shaft (10).

3. The aircraft engine air intake casing according to claim 2, characterized in that: The rear-end wave absorbing structure (34) and the bearing structure (35) inside a part of the support plates (3) have assembly holes along the height direction of the support plates (3) for arranging air ducts, oil inlet and return ducts, and lead wires. The thickness of the part of the support plates (3) is greater than the thickness of the other support plates (3).

4. The aircraft engine air intake casing according to claim 3, characterized in that: An electric anti-icing layer (310) is arranged on the outer side of the leading edge of the wave-transmitting skin (31) outside each support plate (3), and the electric anti-icing layer (310) is made of an electric heating material with a wave-transmitting function.

5. The aircraft engine air intake casing according to claim 4, characterized in that: It also includes an adjustable blade inner ring (4) and adjustable blades (5); An adjustable blade assembly area (13) is provided behind the support plate assembly area (12) of the outer casing (1); The adjustable blade assembly area (13) has a plurality of upper journal mounting holes distributed along the circumferential direction; A rear absorbing ring (15) is arranged in the adjustable blade assembly area (13); the rear absorbing ring (15) is close to the inner side of the adjustable blade assembly area (13), a through hole is provided at a position corresponding to the upper journal mounting hole, and the rear absorbing ring (15) is made of a composite absorbing material; The adjustable blade inner ring (4) is arranged on the inner side of the outer casing (1) and faces the adjustable blade assembly area (13), and has a plurality of lower journal mounting holes distributed along the circumferential direction. There are a plurality of adjustable blades (5), which are arranged circumferentially between the adjustable blade assembly area (13) and the adjustable blade inner ring (4); the upper shaft neck of each adjustable blade (5) is mounted in each upper shaft neck mounting hole, and the lower shaft neck is mounted in each lower shaft neck mounting hole.

6. The aircraft engine air intake casing according to claim 5, characterized in that: The adjustable blade inner ring (4) comprises an outer ring wave absorbing structure (41) and an inner ring supporting structure (42); The outer ring wave absorbing structure (41) is made of wave absorbing prepreg; The inner ring support structure (42) is connected to the inner side of the outer ring wave absorbing structure (41), and the front end is connected to the rear end of the support plate inner ring (2).

7. The aircraft engine air intake casing according to claim 6, characterized in that: Each adjustable blade (5) corresponds to each support plate (3) in a one-to-one circumferential position, is closely located behind the corresponding support plate (3), and has a matching thickness with the corresponding support plate (3).

8. The aircraft engine air intake casing according to claim 7, characterized in that: Each adjustable blade (5) is made of carbon fiber composite material and is provided with a wave absorbing layer (51) on one side.

9. The aircraft engine air intake casing according to claim 8, characterized in that: Also includes an adjustment mechanism (6); The adjusting mechanism (6) comprises a linkage ring (61), a rocker arm (62), a pull rod (63), and a crank (64); The linkage ring (61) is sleeved on the outer circumference of the outer casing (1); There are a plurality of rocker arms (62), one end of which is connected to each upper journal, and the other end of which is hinged to the linkage ring (61); One end of the pull rod (63) is hinged on the linkage ring (61); The bent portion of the crank (64) is hinged on the outside of the outer casing (1), one end of the crank is hinged to the other end of the pull rod (63), and the other end is hinged to the actuating mechanism, and the actuating mechanism is connected to the outside of the outer casing (1); The actuating mechanism can drive the linkage ring (61) to rotate via the crank (64) and the pull rod (63), and then drive the adjustable blades (5) to rotate synchronously via the rocker arms (62), so that the angles of the adjustable blades (5) are closed or opened.

10. The aircraft engine air intake casing according to claim 9, characterized in that: Also includes a cap (7); The cap (7) is arranged at the front end of the outer casing (1), and the rear end extends into the inner side of the leading edge absorbing structure (32) and the front section absorbing structure (33), and comprises an outer layer electric anti-icing cone (71), an absorbing cone (72), an absorbing inner ring (73), a supporting inner ring (74), and a reflective back plate (75); The outer electric anti-icing cone (71) forms the aerodynamic shape of the cap (7) and is made of an electric heating material with wave-transmitting capability; The wave absorbing cone (72) is arranged on the inner side of the outer layer electric anti-icing cone (71), is close to the inner side of the front end of the outer layer electric anti-icing cone (71), and is made of a honeycomb composite material with wave absorbing function; The reflective back plate (75) is arranged inside the wave absorbing cone (72), is close to the inside of the wave absorbing cone (72), and is made of a carbon fiber composite material or a metal material having an electromagnetic wave reflection function; The wave absorbing inner ring (73) is arranged on the inner side of the outer electric anti-icing cone (71), abuts against the inner side of the rear end of the outer electric anti-icing cone (71), abuts against the wave absorbing cone (72), and is formed by co-curing with the outer electric anti-icing cone (71), the wave absorbing cone (72), and the reflective back plate (75); The supporting inner ring (74) is arranged inside the absorbing inner ring (73), abutting against the inner side of the absorbing inner ring (73), and is made of a carbon fiber reinforced composite material or a lightweight metal material, with a rear end connected to a front end of the supporting plate inner ring (2).

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