Air inlet casing of aero-engine

Abstract

The invention belongs to the technical field of aero-engine air inlet casing design, and particularly relates to an aero-engine air inlet casing, which combines the characteristics of a multi-functional composite material, adopts the functional gradient design idea of the composite material, realizes a multifunctional composite material air inlet casing structure, replaces an air inlet casing of a metal welding structure, and improves the air inlet performance of the aero-engine. A plurality of functions such as radar wave absorbing and force bearing supporting are designed in an integrated mode, the radar detectability of the aero-engine is effectively reduced, meanwhile, the space utilization of an assembled airplane and the universality of different models of aircrafts can be improved, the checkability and maintainability of the aero-engine are guaranteed, the weight of the aero-engine and the pneumatic loss of the aero-engine are reduced, and the aero-engine is suitable for being used in the field of aircrafts. The reliability of thrust work of the aero-engine is guaranteed, and the problems of weld crack, failure and the like caused by vibration, fatigue and internal stress can be avoided.

Description

Technical Field

[0001] The present application belongs to the technical field of aircraft engine air intake casing design, and specifically relates to an aircraft engine air intake casing. Background Art

[0002] The air intake casing is located at the front end of the aircraft engine and is an important load-bearing component of the aircraft engine. The current air intake casing is usually composed of a titanium alloy casing, a support plate, etc., and is welded to form a spoke structure. The radial load of the low-pressure rotor of the aircraft engine is borne by the bearings assembled inside. The support plate of the air intake casing is usually a cavity structure. While transmitting the load of the inner and outer rings, it realizes the arrangement of the anti-icing air duct, the oil inlet and return pipelines, and the lead wires.

[0003] Aircraft engines require air as a working fluid to work and cannot be completely encapsulated inside the aircraft. In addition, their structure is complex and forms a strong radar reflection source in the forward direction. In order to reduce the radar detectability of aircraft engines, the following three technical solutions are usually used to design the air intake casing.

[0004] Option 1: A coating with radar absorbing function is applied to the inner and outer flow channel surfaces of the air intake casing and the outer side of the support plate, so as to absorb the incident and reflected radar waves entering the air intake of the aircraft engine.

[0005] The coating with radar absorbing function is a high-density material. Directly coating it on the inner and outer flow surface of the air intake casing and the outer side of the support plate will greatly increase the weight of the air intake casing and its aircraft engine.

[0006] The coating with radar absorbing function is very hard, and the thickness required to be coated on the inner and outer flow path surfaces of the air intake casing and the outer side of the support plate is about 1mm. The bonding strength with the metal surface is low, and it is easy to fall off during the operation of the aircraft engine, causing the hard coating to fall off and damage the rear fan, compressor, turbine and other components. In severe cases, it will cause damage to the entire aircraft engine and failure.

[0007] Option 2: In the aircraft air inlet, at a certain axial distance from the front end of the aircraft engine, a wave-absorbing guide fluid capable of absorbing radar waves is arranged to absorb incident and reflected radar waves entering the aircraft engine air inlet.

[0008] The absorbing guide fluid is composed of an absorbing outer ring, an absorbing inner ring, and an absorbing support plate. The overall structure is complex, and the weight and size are large. Using the absorbing guide fluid to reduce the radar detectability of an aircraft engine will cause a significant loss in many key indicators of the aircraft engine, such as weight, size, and thrust.

[0009] The waveguide fluid is set at a certain axial distance from the front end of the aircraft engine, which greatly increases the distance from the inspection and maintenance operation position at the front end of the aircraft engine to the first-stage rotor of the fan, greatly increases the difficulty of inspecting and maintaining the fan, and increases the axial space required for the installation of the aircraft engine. It not only affects the space utilization of the installed aircraft, but also seriously limits the versatility of the aircraft engine for different types of aircraft. In addition, it will greatly affect the reduction of the flow field quality at the aircraft engine inlet, increase the aerodynamic loss of the aircraft engine, and affect the thrust of the aircraft engine.

[0010] The absorbing guide fluid is at a certain axial distance from the front end of the aircraft engine. When the aircraft engine is working, the leading edge of the absorbing support plate is prone to ice. For this reason, the leading edge of the absorbing support plate is usually designed as a hollow metal structure with an anti-icing channel and its anti-icing holes. When the aircraft engine is working, the high-temperature and high-pressure bleed air of the aircraft engine is introduced into the anti-icing channel and discharged through the anti-icing holes to achieve an anti-icing effect. However, the leading edge of the absorbing support plate with such a metal structure will greatly affect the absorption effect of the absorbing guide fluid on radar waves, making it difficult to effectively reduce the radar detectability of the aircraft engine.

[0011] Option 3: The inlet cap of the air intake casing is removed, and the waveguide fluid is directly assembled to the front mounting edge of the air intake casing to shorten the axial distance between the waveguide fluid and the air intake casing, thereby reducing the distance from the front inspection and maintenance operation position of the aircraft engine to the first-stage rotor of the fan, reducing the difficulty of inspecting and maintaining the fan, and reducing the axial space required for the installation of the aircraft engine, thereby improving the utilization of the space for installing the aircraft and versatility for different types of aircraft. In addition, the wave-absorbing support plate is designed to correspond one-to-one with the support plate inside the air intake casing to reduce the impact on the inlet flow field quality of the aircraft engine, reduce the aerodynamic loss of the aircraft engine, and improve the thrust of the aircraft engine.

[0012] Although the design of removing the inlet cap of the air intake casing and directly installing the waveguide fluid on the front mounting edge of the air intake casing can reduce the distance from the front inspection and maintenance operation position of the aircraft engine to the first-stage rotor of the fan, the existence of the waveguide fluid itself will still bring considerable difficulties to the inspection and maintenance of the fan, and affect the space utilization of the installed aircraft, limiting the versatility of the aircraft engine for different types of aircraft. In addition, the problem of blade discontinuity between the wave-absorbing support plate and the support plate inside the air intake casing will still produce large aerodynamic losses, affecting the thrust of the aircraft engine. In addition, there will still be large losses in many key indicators of the aircraft engine such as weight, size, thrust, etc., and it is difficult to effectively reduce the radar detectability of the aircraft engine.

[0013] In summary, although the above three technical solutions can reduce the radar detectability of aircraft engines to a certain extent, they still have many problems, such as affecting the space utilization of the aircraft, limiting the versatility of aircraft engines for different types of aircraft, reducing the inspectability and maintainability of aircraft engines, increasing the weight of aircraft engines, increasing the aerodynamic losses of aircraft engines, reducing the thrust of aircraft engines, and affecting the reliability of aircraft engine operations.

[0014] In addition, the current air intake casings largely use metal welding structures. When the welding process or the post-welding heat treatment process is unstable, it is very easy to cause problems such as weld cracks and failure due to vibration, fatigue and internal stress.

[0015] This application is proposed in view of the above-mentioned technical defects. Summary of the invention

[0016] The purpose of the present application is to provide an aircraft engine air intake casing which can simultaneously meet all the functional requirements of current air intake casings, can effectively reduce the radar detectability of the aircraft engine, and has the advantages of light weight, compactness, and reliability.

[0017] The technical solution of this application is: An air intake casing of an aircraft engine comprises an outer casing, a support plate inner ring, and a support plate; The outer casing is a circular ring structure made of carbon fiber reinforced composite materials. From front to back, it is composed of the front wave absorbing function area and the support plate assembly area. A front absorbing ring is arranged in the front absorbing functional area, the front absorbing ring is attached to the inner side of the front absorbing functional area and is made of absorbing composite material; The support plate inner ring is arranged on the inner side of the outer casing, facing the support plate assembly area, and is made of carbon fiber reinforced composite material or lightweight metal material; There are multiple support plates, which are supported between the support plate assembly area and the support plate inner ring along the circumferential direction, and the leading edge extends into the inner side of the front wave absorbing functional area, including an external wave-transmitting skin, a leading edge wave absorbing structure, a front section wave absorbing structure, and a rear section wave absorbing structure; The external wave-transparent skin constitutes the aerodynamic shape of the support plate structure, which is made of lightweight electromagnetic wave-transparent materials, and the interior is filled with the leading edge wave-absorbing structure, the front section wave-absorbing structure, and the rear section wave-absorbing structure from front to back; The leading edge absorbing structure is made of absorbing prepreg, the front section absorbing structure is made of absorbing honeycomb material, and the rear section absorbing structure is made of absorbing prepreg; The rear section absorbing structure has a supporting hole in the middle along the height direction of the support plate, and a bearing structure is arranged in the supporting hole. The bearing structure is made of carbon fiber composite material, and the upper and lower ends are formed with an upper edge plate outer layer and a lower edge plate outer layer, and the upper edge plate inner layer and the lower edge plate inner layer are laid on the inner side to form an upper edge plate and a lower edge plate, and the upper edge plate inner layer and the lower edge plate inner layer are made of absorbing prepreg; Each upper edge plate is connected to the support plate assembly area, and each upper edge plate forms a full ring structure; each lower edge plate is connected to the support plate inner ring, and each lower edge plate forms a full ring structure.

[0018] Optionally, in the above-mentioned aircraft engine air intake casing, the front end and rear end of the outer casing 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 intake duct and the annular mounting edge at the front end of the fan casing; The inner ring of the support plate is connected to the bearing seat, the bearing is installed in the bearing seat, and the bearing is sleeved on the front end of the low-pressure rotating shaft.

[0019] Optionally, in the above-mentioned aircraft engine air intake casing, the rear-section absorbing structure inside some support plates and their bearing structure have assembly holes along the height direction of the support plates for the arrangement of air bleed pipes, oil inlet and return pipes, and leads, and the thickness of this part of the support plates is greater than that of other support plates.

[0020] Optionally, in the above-mentioned aircraft engine air intake casing, an electric anti-icing layer is arranged on the outer side of the leading edge of the external wave-transmitting skin of each support plate, and the electric anti-icing layer is made of an electric heating material with wave-transmitting function.

[0021] Optionally, the above-mentioned aircraft engine air intake casing further includes an adjustable blade inner ring and adjustable blades; The outer casing has an adjustable blade mounting area behind the support plate mounting area; The adjustable blade assembly area has a plurality of upper journal mounting holes distributed along the circumferential direction; A rear absorbing ring is arranged in the adjustable blade assembly area, the rear absorbing ring is close to the inner side of the adjustable blade assembly area, a through hole is opened at a corresponding position of the upper journal mounting hole, and the rear absorbing ring is made of absorbing composite material; The adjustable blade inner ring is arranged on the inner side of the outer casing, facing the adjustable blade assembly area, and has a plurality of lower journal mounting holes distributed along the circumferential direction; There are multiple adjustable blades, which are circumferentially arranged between the adjustable blade assembly area and the adjustable blade inner ring. The upper journal of each adjustable blade is installed in each upper journal installation hole, and the lower journal is installed in each lower journal installation hole.

[0022] Optionally, in the above-mentioned aircraft engine air intake casing, the inner ring of the adjustable blade includes an outer ring wave absorbing structure and an inner ring supporting structure; The outer ring absorbing structure is made of absorbing prepreg; The inner ring supporting structure is connected to the outer periphery of the outer ring absorbing structure, and the front end is connected to the rear end of the inner ring of the support plate.

[0023] Optionally, in the above-mentioned aircraft engine air intake casing, each adjustable blade corresponds to each support plate in a circumferential position, is closely located behind the corresponding support plate, and has a matching thickness with the corresponding support plate.

[0024] Optionally, in the above-mentioned aircraft engine air intake casing, each adjustable blade is made of carbon fiber composite material, and a wave absorbing layer is provided on one side.

[0025] Optionally, the above-mentioned aircraft engine air intake casing further includes an adjustment mechanism; The adjusting mechanism includes a linkage ring, a rocker arm, a pull rod, and a crank; The linkage ring sleeve is arranged on the outer periphery of the outer casing; There are multiple rocker arms, one end of which is connected to each upper journal and the other end is hinged to the linkage ring; One end of the pull rod is hinged on the linkage ring; The bent portion of the crank is hinged on the outside of the outer casing, one end of the crank 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; The actuating mechanism can drive the linkage ring to rotate through the crank and the pull rod, and then drive each adjustable blade to rotate synchronously through each rocker arm, so that the angle of each adjustable blade is closed or opened.

[0026] Optionally, the above-mentioned aircraft engine air intake casing further includes a cap; The cap is arranged at the front end of the outer casing, and the rear end extends into the inner side of the leading edge absorbing structure and the front section absorbing structure, including an outer electric anti-icing cone, an absorbing cone, an absorbing inner ring, a supporting inner ring, and a reflective back plate; The outer electric anti-icing cone forms the aerodynamic shape of the cap and is made of electric heating material with wave-transmitting ability; The wave-absorbing cone is arranged inside the outer electric anti-icing cone, close to the inner side of the front end of the outer electric anti-icing cone, and is made of a honeycomb composite material with wave-absorbing function; The reflective back plate is arranged inside the absorbing cone, close to the inside of the absorbing cone, and is made of a carbon fiber composite material or a metal material with electromagnetic wave reflection function; The absorbing inner ring is arranged on the inner side of the outer electric anti-icing cone, abuts against the inner side of the rear end of the outer electric anti-icing cone, and abuts against the absorbing cone, and is formed by co-curing with the outer electric anti-icing cone, the absorbing cone, and the reflective back plate; The supporting inner ring is arranged inside the absorbing inner ring, close to the inner side of the absorbing inner ring, and is made of carbon fiber reinforced composite material or light metal material, and the rear end is connected to the front end of the support plate inner ring.

[0027] This application has at least the following beneficial technical effects: Provided is an aircraft engine air intake casing, which combines the characteristics of multiple functional composite materials, adopts the composite material functional gradient design concept, realizes a multifunctional composite material air intake casing structure, replaces the metal welded structure air intake casing, integrates multiple functions such as radar absorbing and load-bearing support, and can effectively reduce the radar detectability of the aircraft engine while improving the space utilization of the equipped aircraft, the versatility for different types of aircraft, and the inspectability and maintainability of the aircraft engine, reduce the weight of the aircraft engine and its aerodynamic loss, ensure the reliability of the thrust operation of the aircraft engine, and avoid problems such as weld cracks and failures caused by vibration, fatigue and internal stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a partial cross-sectional schematic diagram of an aircraft engine air intake casing equipped with a relatively thin support plate provided by an embodiment of the present application; Figure 2 It is a partial cross-sectional schematic diagram of an aircraft engine air intake casing provided by an embodiment of the present application equipped with a relatively thick support plate; Figure 3 is a schematic diagram of an outer casing provided in an embodiment of the present application; Figure 4 is a lateral schematic diagram of a support plate provided in an embodiment of the present application; Figure 5 is a schematic diagram of a support plate provided in an embodiment of the present application along the axial direction of an aircraft engine; Figure 6 is a partial cross-sectional schematic diagram of a thinner support plate provided in an embodiment of the present application; Figure 7 is a schematic diagram of an upper edge plate of a support plate provided in an embodiment of the present application; Figure 8 is a schematic diagram of the lower edge plate of the support plate provided in an embodiment of the present application; Fig. 9 is a partial cross-sectional schematic diagram of a thicker support plate provided in an embodiment of the present application; Fig.10 is a partial cross-sectional schematic diagram of an adjustable blade inner ring provided in an embodiment of the present application; Fig.11 is a partial cross-sectional schematic diagram of an adjustable blade provided in an embodiment of the present application; Fig.12 It is a schematic diagram of reflection and absorption of incident radar waves when the adjustable blade inner ring angle provided in an embodiment of the present application is opened; Fig.13 It is a schematic diagram of reflection and absorption of incident radar waves when the adjustable blade inner ring angle provided in an embodiment of the present application is closed; Fig.14 is a schematic diagram of an adjustment mechanism provided in an embodiment of the present application; Fig.15is a schematic diagram of a cap provided in an embodiment of the present application; Fig.16 This is a schematic diagram of the lead-out of the outer electric anti-icing cone provided in an embodiment of the present application; in: 1-outer casing; 2-support plate inner ring; 3-support plate; 4-adjustable blade inner ring; 5-adjustable blade; 6-adjustment mechanism; 7-cap; 8-bearing seat; 9-bearing; 10-low-pressure shaft; 11-front absorbing functional area; 12-support plate assembly area; 13-adjustable blade assembly area; 14-front absorbing ring; 15-rear absorbing ring; 31-external wave-transmitting skin; 32-front edge wave-absorbing structure; 33-front section wave-absorbing structure; 34-rear section wave-absorbing structure; 35-bearing structure; 36-upper edge plate outer layer; 37-lower edge plate outer layer; 38-upper edge plate inner layer; 39-lower edge plate inner layer; 310-electric anti-icing layer; 41-outer ring wave absorbing structure; 42-inner ring supporting structure; 51-wave absorbing layer; 61-linkage ring; 62-rocker arm; 63-pull rod; 64-crank; 71-outer electric anti-icing cone; 72-wave absorbing cone; 73-wave absorbing inner ring; 74-support inner ring; 75-reflective back plate.

[0029] In order to better illustrate the present embodiment, some contents of the drawings may be omitted, enlarged or reduced, which is only used for illustrative purposes and should not be construed as limiting the present application. DETAILED DESCRIPTION

[0030] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0031] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application should be the common meanings understood by those skilled in the art in the field to which this application belongs. The term "include" used in the description of this application means that the concepts appearing before the term include the concepts listed after the term and their equivalents, without excluding other related concepts.

[0032] In addition, the words indicating orientation used in the description of this application are only used to indicate relative directions or positional relationships. When the absolute position of the object being described changes, its relative positional relationship may also change accordingly. It should also be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and other similar words used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0033] Composite materials have the characteristics of multi-function, multi-configuration, high specific stiffness, high specific strength, and good designability. When used to manufacture air intake casings, the fiber reinforcement of resin-based composite materials can be utilized to effectively inhibit the expansion of component cracks. In addition, the high damping characteristics of resin-based composite materials are more suitable for their high-frequency and complex vibration working environment than metal welded air intake casings. On the basis of meeting multi-functional requirements, the reliability of the air intake casing is greatly improved, and problems such as weld cracks and failure of metal welded air intake casings caused by unstable welding process or post-welding heat treatment process are avoided.

[0034] Based on the above embodiments of the present application, an aircraft engine air intake casing is provided, which is a multifunctional all-composite air intake casing, such as Figure 1-Figure 2 As 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.

[0035] 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.

[0036] 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.

[0037] 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 .

[0038] 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.

[0039] The support plate assembly area 12 provides a corresponding spatial structure for the assembly of the support plate 3 .

[0040] 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.

[0041] 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.

[0042] The support plate inner ring 2 is arranged inside the outer casing 1, facing the support plate assembly area 12, and is made of carbon fiber reinforced composite materials, such as T800 grade or T1100 grade carbon fiber reinforced epoxy or bismuth resin-based composite materials, or made of light metal and other high specific stiffness materials, such as TC4 titanium alloy, to support the support plate 3. The support plate inner ring 2 is connected to the bearing seat 8, and the bearing 9 is installed in the bearing seat 8. The bearing 9 is sleeved on the front end of the low-pressure shaft 10.

[0043] There are multiple 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 front edges extend into the inner side of the front wave absorbing functional area 11.

[0044] Support plate 3 Figure 4-Figure 5 As shown, it includes 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 .

[0045] The outer wave-transparent skin 31 constitutes the aerodynamic shape of the support plate 3 structure and is made of a lightweight electromagnetic wave-transparent material, such as a glass fiber reinforced resin-based composite material, which can transmit radar waves so as to facilitate the internal structure to absorb radar waves. 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 sequence from front to back. Figure 6 shown.

[0046] The leading edge absorbing structure 32 is made of absorbing prepreg, such as carbonyl iron powder (CIP) and acetylene black (CB) and other absorbents added with glass fiber to increase the resin matrix composite material.

[0047] The front section wave-absorbing structure 33 is made of wave-absorbing honeycomb material and is located at the position with the maximum thickness inside the external wave-transmitting skin 31 , which can improve the wave-absorbing performance while reducing the mass of the support plate 3 .

[0048] The rear-stage absorbing structure 34 is made of absorbing prepreg, such as carbonyl iron powder (CIP) and acetylene black (CB) absorbents added with glass fiber to increase the resin matrix composite material.

[0049] The rear section wave absorbing structure 34 has a supporting hole in the middle along the height direction of the support plate 3, and a bearing structure 35 is arranged in the supporting 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. The carbon fibers between the upper edge plate outer layer 36, the lower edge plate outer layer 37 and the bearing structure 35 are continuous and have a high bearing capacity, and are the supporting layer. The upper edge plate inner layer 38 and the lower edge plate inner layer 39 are laid on the inner side of the upper edge plate outer layer 36 and the lower edge plate outer layer 37, and are bonded and connected to the upper edge plate outer layer 36 and the lower edge plate outer layer 37 to form an upper edge plate and a lower edge plate, such as Figure 7-Figure 8 As shown, the upper edge plate inner layer 38 and the lower edge plate inner layer 39 are made of absorbing prepreg, such as carbonyl iron powder (CIP) and acetylene black (CB) and other absorbents added with glass fiber to increase the resin matrix composite material.

[0050] Each upper edge plate is connected to the support plate assembly area 12, which can be connected by countersunk screws, and each lower edge plate forms a complete ring structure. The front wave absorbing functional area 11 can be reinforced according to the number and distribution of holes thereon.

[0051] Each lower edge plate is connected to the support plate inner ring 2, which can be connected by countersunk screws, and each upper edge plate forms a complete ring structure. The support plate inner ring 2 can be reinforced according to the number and distribution of holes thereon.

[0052] The rear-end absorbing structure 34 and the bearing structure 35 of some support plates 3 have assembly holes along the height direction of the support plates 3 for arranging the air bleed 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. Fig. 9 shown.

[0053] An electric anti-icing layer 310 is arranged outside the front edge of the wave-transmitting skin 31 outside each support plate 3. The electric anti-icing layer 310 is made of an electric heating material with a wave-transmitting function, such as a graphene film. The electric anti-icing layer 310 can be bonded to the front edge of the wave-transmitting skin 31 outside. The electric anti-icing layer 310 is wired and powered through the inside of the support plate 3 and its assembly hole.

[0054] The adjustable blade inner ring 4 is arranged inside the outer casing 1, facing the adjustable blade assembly area 13, and has a plurality of lower journal mounting holes distributed along the circumferential direction. The opening positions of the lower journal mounting holes can be enhanced as required.

[0055] Adjustable blade inner ring 4 Fig.10 As shown, it includes an outer ring absorbing structure 41 and an inner ring supporting structure 42.

[0056] The outer ring absorbing structure 41 is made of absorbing prepreg, such as acetylene carbon black (CB) and other absorbents added with glass fiber to increase the resin matrix composite material.

[0057] The inner ring support structure 42 is connected to the inner side of the outer ring absorbing structure 41, and is bonded to the outer ring absorbing structure 41. The front end is connected to the rear end of the inner ring 2 of the support plate, and can be connected by bolts through an annular connecting edge. The material selection of the inner ring support structure 42 can be determined by comprehensively considering weight reduction, cost, process and other aspects, such as T1100 grade carbon fiber added resin-based composite material, TC4 titanium alloy, 2A70 aluminum alloy, etc.

[0058] There are multiple adjustable blades 5, which are circumferentially arranged between the adjustable blade assembly area 13 and the adjustable blade inner ring 4. The upper journal of each adjustable blade 5 is installed in each upper journal mounting hole, and the lower journal is installed in each lower journal mounting hole. A journal bushing can be arranged between each upper journal and the upper journal mounting hole, and between each lower journal and the lower journal mounting hole.

[0059] Each adjustable blade 5 corresponds to each support plate 3 in circumferential position, is closely adjacent to the rear of the corresponding support plate 3, and has a thickness matching that of the corresponding support plate 3, so as to ensure the stability of the airflow in the air intake casing and reduce aerodynamic losses.

[0060] Each adjustable blade 5 is made of carbon fiber composite material, and a wave absorbing layer 51 is provided on one side. Fig.11 As shown, the absorbing layer 51 is made of absorbing prepreg, such as acetylene carbon black (CB) and other absorbents, glass fiber and resin-based composite materials, so that the adjustable blade 5 can have a absorbing function, such as Figure 12-13 As shown, the wave absorbing capability of the air intake casing can be compensated, thereby shortening the axial length of the air intake casing while the air intake casing meets the load-bearing and other functions.

[0061] The wave absorbing layer 51 may be arranged on the outward side of the adjustable blade 5 when the adjustable blade 5 is closed, and may be formed with the adjustable blade 5 by co-curing.

[0062] Adjustment mechanism 6 Fig.14 As shown, it includes a linkage ring 61, a rocker arm 62, a pull rod 63, and a crank 64.

[0063] The linkage ring 61 is sleeved on the outer circumference of the outer casing 1 .

[0064] There are multiple rocker arms 62, one end of which is connected to each upper journal, and can be connected to each upper journal by a fastener, and the other end is hinged to the linkage ring 61, and can be hinged to each upper journal by a pin through a joint bearing.

[0065] One end of the pull rod 63 is hinged on the linkage ring 61 , and can be hinged by a pin through a single-double-ear structure.

[0066] The bent part of the crank 64 is hinged to the outside of the outer casing 1, specifically by a pin hinge, one end is hinged to the other end of the pull rod 63, specifically by a single-double ear structure with a pin hinge, and the other end is hinged to the actuating mechanism, specifically by a single-double ear structure with a pin hinge. The actuating mechanism is connected to the outside of the outer casing 1, specifically by an actuating cylinder.

[0067] The pull rod 63, the crank 64 and the actuating mechanism can be provided in two groups, distributed at 180 degrees.

[0068] 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 blade 5 to rotate synchronously through each rocker arm 62, so that the angle of each adjustable blade 5 is closed or opened.

[0069] The cap cover 7 is arranged at the front end of the outer casing 1 , and the rear end thereof extends into the inner side of the leading edge absorbing structure 32 and the front section absorbing structure 33 , and is connected to the front end of the support plate inner ring 2 .

[0070] Hood 7 Fig.15 As shown, it includes an outer electric anti-icing cone 71, a wave-absorbing cone 72, a wave-absorbing inner ring 73, a supporting inner ring 74, and a reflective back plate 75.

[0071] The outer electric anti-icing cone 71 constitutes the aerodynamic shape of the cap 7 and is made of an electric heating material with wave-transmitting ability, such as a graphene film.

[0072] The wave absorbing cone 72 is arranged inside the outer layer electric anti-icing cone 71, 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 outer layer electric anti-icing cone 71 is wired through the inside of the wave absorbing cone 72 and its assembly hole, such as Fig.16 shown.

[0073] The reflective back plate 75 is disposed inside the absorbing cone 72 and is close to the inside of the absorbing cone 72 . It is made of a carbon fiber composite material or a metal material having an electromagnetic wave reflection function, such as a T300 grade carbon fiber reinforced resin-based composite material, TC4 titanium alloy, etc.

[0074] The absorbing inner ring 73 is arranged inside the outer electric anti-icing cone 71 , abutting against the inner side of the rear end of the outer electric anti-icing cone 71 , and against the absorbing cone 72 , and is formed by co-curing with the outer electric anti-icing cone 71 , the absorbing cone 72 , and the reflective back plate 75 .

[0075] The supporting inner ring 74 is arranged inside the wave absorbing inner ring 73 and is close to the inner side of the wave absorbing inner ring 73 . The rear end is connected to the front end of the support plate inner ring 2 by bolts through an annular mounting edge.

[0076] The supporting inner ring 74 is made of carbon fiber reinforced composite materials, such as T1100 grade carbon fiber reinforced resin-based composite materials, or made of lightweight metal materials, such as TC4 titanium alloy, etc., and is adhesively connected to the absorbing inner ring 73, and is connected to the absorbing inner ring 73 and the rear end of the absorbing cone 72 by fasteners.

[0077] The aircraft engine air intake casing disclosed in the above embodiment has the following advantages over the prior art solutions: 1. Use a variety of composite material wave absorbing methods such as wave absorbing prepregs and wave absorbing honeycombs to achieve gradient wave absorption in different areas of the air intake casing, reduce the radar detectability of the aircraft engine, and avoid the risk of coating with radar absorbing function falling off.

[0078] 2. Combining the characteristics of various functional composite materials, the functional gradient design concept of composite materials is adopted to realize a multifunctional composite material air intake casing structure, replacing the metal welded structure air intake casing, integrating multiple functions such as radar absorption and load-bearing support, and canceling the use of radar absorbing coatings and absorbing waveguide fluids. This can greatly reduce the weight of the air intake casing and its aircraft engine, shorten the axial size of the aircraft engine, improve the utilization of the space for installing aircraft, and facilitate the inspection and maintenance of the fan. It also greatly alleviates the contradiction between the radar detectability of the aircraft engine and multiple key indicators such as weight, size, and thrust, and can relax the restrictions on the design of reducing the radar detectability of the aircraft engine.

[0079] 3. A thermoelectric film with wave-transmitting function is used on the cap and support plate to replace the bleed air anti-icing. The incident radar wave can penetrate the thermoelectric film and be absorbed by the corresponding internal absorbing composite material, which can further ensure that the radar detectability of the aircraft engine is reduced.

[0080] 4. The adjustable blades are designed to absorb radar waves, which can further reduce the radar detectability of the aircraft engine. On the basis of ensuring the radar detectability of the aircraft engine, the axial size of the aircraft engine can be further shortened, the space utilization of the aircraft can be improved, the compatibility with different types of aircraft can be improved, and the inspection and maintenance of the fan can be facilitated.

[0081] 5. The multifunctional integrated design concept is adopted to make the inner and outer flow paths and the support plate of the air intake casing an integrated structure. There is no interruption or discontinuity in the flow path and the support plate blade shape. This can greatly improve the quality of the aircraft engine inlet flow field, reduce the loss along the airflow through the support plate, and improve the thrust of the aircraft engine.

[0082] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles 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 fall within the scope of protection 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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