Aircraft airway and preparation method thereof

Abstract

The invention provides an aircraft airway and a preparation method thereof. The aircraft airway comprises an airway main body and a cooling structure, the air channel main body is provided with an airflow channel for airflow to pass through; the cooling structure is arranged on the inner wall of the air flow channel and provided with a liquid flow channel allowing liquid fuel to flow, one end of the liquid flow channel is used for being connected with a liquid fuel tank of the aircraft, and the other end of the liquid flow channel is used for being connected with a combustion chamber of the aircraft. On the premise that the dead weight of the aircraft is not increased, heat dissipation of the air channel and preheating of liquid fuel are achieved; and the cooling structure can reduce the dependence of the aircraft airway on a high-cost and high-temperature-resistant material with unstable engineering performance, so that the research and development cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and more specifically, to an aircraft air duct and a preparation method thereof. Background Art

[0002] For abdominal inlet hypersonic aircraft, in order to reduce the coupling and interference of the aircraft forebody on the inlet flow field, an integrated design of the inlet and the forebody is mostly adopted, and the inlet often uses a rectangular inlet that is easier for integrated design and modular installation; in addition, in order to match and connect to a circular combustion chamber, the inlet end of the inlet uses a square flange while the exhaust end is a circular flange, that is, a square-to-round inlet duct structure; while the inlet end of the exhaust duct uses a circular flange structure and the exhaust end uses a square flange, that is, a round-to-square exhaust duct structure.

[0003] During the high-speed flight of the aircraft, the square-to-round inlet duct reaches an extreme high-temperature working condition of 2000°C - 3000°C due to air friction; while the round-to-square exhaust duct reaches an extreme high-temperature working condition of 3000°C due to the high-temperature gas ejected from the combustion chamber. Conventionally, a ceramic layer / high-temperature alloy matrix composite structure is generally used to manufacture round-to-square components of hypersonic aircraft engines, which is difficult to meet the requirements of extreme working conditions with increasing temperatures. New materials that can withstand 3000°C high temperatures not only have high costs, but also their performance stability cannot yet meet the requirements of engineering applications, and their development cycle is long and the cost is high. Summary of the Invention

[0004] (I) Technical Problems to be Solved

[0005] The technical problem to be solved by the present invention is that the aircraft air ducts prepared from existing materials are difficult to meet the requirements of extreme working conditions with increasing temperatures.

[0006] (II) Technical Solutions

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides an aircraft air duct, including an air duct main body and a cooling structure; the air duct main body has an air flow passage for air flow to pass through; the cooling structure is arranged on the inner wall of the air flow passage, and the cooling structure has a liquid flow passage for liquid fuel to flow through. One end of the liquid flow passage is used to connect to the liquid fuel tank of the aircraft, and the other end of the liquid flow passage is used to connect to the combustion chamber of the aircraft.

[0009] Preferably, it further includes a heat insulation screen, and the heat insulation screen is arranged on the side of the cooling structure facing away from the air duct main body.

[0010] Preferably, it further includes a lattice structure, one end of the lattice structure is connected to the heat insulation screen, and the other end of the lattice structure is connected to the cooling structure.

[0011] Preferably, a ceramic heat insulation layer is provided on the side of the heat insulation screen facing away from the cooling structure.

[0012] Preferably, the cooling structure has a plurality of fuel inlets communicating with the liquid flow channels and fuel outlets communicating with the liquid flow channels. The plurality of fuel inlets are arranged at intervals along the circumferential direction of the cooling structure. The fuel inlets are used to connect to the liquid fuel tank of the aircraft, and the fuel outlets are used to connect to the combustion chamber of the aircraft.

[0013] Preferably, the cooling structure further includes a plurality of partition plates, and the plurality of partition plates divide the liquid flow channels into a plurality of rectangular flow channels.

[0014] Preferably, the airway main body is a square-to-round inlet or a round-to-square exhaust duct.

[0015] In a second aspect, the present invention further provides a preparation method for any one of the aircraft airways in the above technical solutions, including the following steps:

[0016] Design a process model of the aircraft airway;

[0017] Using the selective laser melting additive manufacturing technology, print the raw material along a preset printing path into a blank of the aircraft airway;

[0018] Perform heat treatment and machining on the blank of the aircraft airway to obtain the aircraft airway.

[0019] Preferably, the raw material is nickel-based superalloy powder or titanium alloy powder, and the single-layer thickness of the powder layer is 20μm - 50μm.

[0020] In a third aspect, the present invention further provides an aircraft power system, including an aircraft main body, a liquid fuel tank, a combustion chamber, and any one of the aircraft airways in the above technical solutions. The liquid fuel tank and the combustion chamber are provided in the aircraft main body. The airway main body is connected to the combustion chamber. One end of the liquid flow channel is connected to the liquid fuel tank, and the other end of the liquid flow channel is connected to the combustion chamber.

[0021] (III) Beneficial effects

[0022] The above technical solutions of the present invention have at least the following advantages:

[0023] In the present invention, based on the existing components of the current aircraft, the air duct of the aircraft is modified. A cooling structure is designed in the air duct of the aircraft and the moving path of the liquid fuel is changed, so that the liquid fuel first passes through the cooling structure and then enters the combustion chamber for combustion. By introducing the liquid fuel as a high-temperature heat dissipation and cooling medium, and utilizing the thermophysical behaviors such as the flow and combustion of the liquid fuel, on the one hand, when the liquid fuel flows through the cooling structure, the liquid fuel can take away the heat on the air duct of the aircraft, realizing the heat dissipation of the air duct of the aircraft. At the same time, the heat will preheat the liquid fuel, and after preheating, the liquid fuel is sprayed into the combustion chamber for combustion, improving the combustion efficiency, and realizing the heat dissipation of the air duct and the preheating of the liquid fuel without increasing the self-weight of the aircraft; on the other hand, the cooling structure can reduce the dependence of the air duct of the aircraft on high-temperature resistant materials with unstable engineering performance and high cost, and greatly reduce the R & D cost.

[0024] In the present invention, the selective laser melting additive manufacturing technology is adopted to realize the preparation of the air duct of the aircraft, and the functional-structure-manufacturing integrated collaborative technology is used to solve the design and manufacturing technical problems of extreme high-temperature components such as the intake duct and exhaust duct of hypersonic aircraft.

[0025] In the present invention, the working temperature of engine components of hypersonic aircraft such as the intake duct and exhaust duct can be effectively increased, the development cycle can be shortened, the R & D cost can be reduced, the fuel efficiency can be improved, and the carbon emission can be reduced. Brief Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is a schematic structural diagram of the air duct of the aircraft provided by the embodiment of the present invention.

[0028] Figure 2 It is a cross-sectional view of the air duct of the aircraft provided by the embodiment of the present invention.

[0029] Figure 3 It is a schematic structural diagram of the power system of the aircraft provided by the embodiment of the present invention.

[0030] The reference numerals in the drawings are as follows:

[0031] 1. Air duct main body; 2. Cooling structure; 3. Heat insulation screen; 4. Lattice structure; 11. Air flow channel; 12. Fuel inlet; 13. Fuel outlet; 21. Liquid flow channel; 22. Partition board; 20. Liquid fuel tank; 30. Combustion chamber. Detailed Embodiments

[0032] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected or indirectly connected to the other element.

[0034] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0035] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating relative importance or indicating the number of technical features. In the description of the present invention, "a plurality of" means two or more, unless otherwise specifically defined. The following describes the specific implementation of the present invention in more detail with reference to specific embodiments:

[0036] Such as Figure 1 、 Figure 2 and Figure 3As shown in the figure, an embodiment of the present invention provides an aircraft air duct, which includes an air duct main body 1 and a cooling structure 2; the air duct main body 1 has an air flow passage 11 for air flow to pass through; the cooling structure 2 is arranged on the inner wall of the air flow passage 11, and the cooling structure 2 has a liquid flow passage 21 for liquid fuel to flow through. One end of the liquid flow passage 21 is used to connect to the liquid fuel tank 20 of the aircraft, and the other end of the liquid flow passage is used to connect to the combustion chamber 30 of the aircraft. Specifically, when this embodiment works, the liquid fuel in the liquid fuel tank 20 is pumped into the cooling structure 2. When the normal-temperature liquid fuel flows through the cooling structure 2, it can exchange heat with the air duct main body 1. The heat on the air duct main body 1 in the high-temperature state is absorbed by the liquid fuel, causing the temperature of the liquid fuel to rise, thereby achieving the effect of preheating the liquid fuel. The preheated liquid fuel then enters the combustion chamber for combustion, making the liquid fuel burn more fully. At the same time, after the heat exchange, the temperature of the air duct main body 1 drops, reducing the operating temperature of the air duct main body 1 and achieving the purpose of heat dissipation. Further, this embodiment does not introduce a new cooling medium to cool the air duct main body 1, but improves it based on the existing structural conditions of the current aircraft. Therefore, it will not increase the weight of the aircraft, and on the premise of ensuring the light weight of the aircraft, it realizes the cooling of the air duct and the preheating of the liquid fuel.

[0037] In one embodiment, it further includes a heat insulation screen 3, and the heat insulation screen 3 is arranged on the side of the cooling structure 2 facing away from the air duct main body 1.

[0038] In one embodiment, it further includes a lattice structure 4. One end of the lattice structure 4 is connected to the heat insulation screen 3, and the other end of the lattice structure 4 is connected to the cooling structure 2. In the prior art, the heat insulation screen is generally fixed on the inner wall surface of the air duct main body 1 by riveting. The riveting process is relatively complex, which will increase the production and manufacturing cycle of the structure, and the heat dissipation effect is not good. In this embodiment, the lattice structure is used to connect the heat insulation screen and the cooling structure. The lattice structure can transfer the heat on the heat insulation screen to the cooling structure to achieve heat dissipation of the heat insulation screen; in addition, the lattice structure can improve the stiffness of the heat insulation screen, relieve the thermal mismatch thermal stress of the heat insulation screen, and enhance the stability of the structure. Moreover, the lattice structure can also play a shock-absorbing role and buffer the thermal shock received by the heat insulation screen.

[0039] In one embodiment, a ceramic heat insulation layer is provided on the side of the heat insulation screen 3 facing away from the cooling structure 2. Specifically, the ceramic heat insulation layer includes but is not limited to a zirconia ceramic layer, and the ceramic heat insulation layer can improve the high-temperature resistance performance of the heat insulation screen.

[0040] In one embodiment, the cooling structure 1 has a plurality of fuel inlets 12 communicating with the liquid flow channels 21 and fuel outlets 13 communicating with the liquid flow channels 21. The plurality of fuel inlets 12 are arranged at intervals along the circumferential direction of the cooling structure 2. The fuel inlets 12 are used to connect with the liquid fuel tank 20 of the aircraft, and the fuel outlets 13 are used to connect with the combustion chamber 30 of the aircraft. Liquid fuel enters the cooling structure from the plurality of fuel inlets 12, which can improve the uniformity of heat absorption of the liquid fuel, ensure that the temperatures of the liquid fuel at various positions along the circumference of the cooling structure are similar, and further improve the preheating effect of the liquid fuel.

[0041] In one embodiment, the cooling structure 2 further includes a plurality of partition plates 22, and the plurality of partition plates 22 divide the liquid flow channels 21 into a plurality of rectangular flow channels 211. Specifically, the rectangular flow channels 211 are conformally embedded in the inner wall surface of the air flow channels 11, that is, the shape in the length direction of the rectangular flow channels 211 changes following the shape change in the length direction of the air flow channels 11, and the minimum wall thickness of the rectangular flow channels 211 is generally 0.8 mm or more.

[0042] In one embodiment, the airway main body 1 is a square-to-round intake airway or a round-to-square exhaust airway. The square-to-round intake airway is an intake airway whose opening cross-section gradually changes from square to round, and the round-to-square exhaust airway is an exhaust airway whose opening cross-section gradually changes from round to square.

[0043] The embodiment of the present invention also provides a preparation method for any one of the above-mentioned aircraft airways, including the following steps:

[0044] Design the process model of the aircraft airway;

[0045] Adopt the selective laser melting additive manufacturing technology to print the raw material along the preset printing path into a blank of the aircraft airway; specifically, the selective laser melting additive manufacturing technology is a powder bed-based metal 3D printing technology. By using a high-energy laser beam (power 100 - 1000 W, spot diameter 50 - 100 μm) to melt the metal powder layer by layer (such as titanium alloy, stainless steel, nickel-based superalloy, etc.), the precision forming of complex metal parts is realized. Its core principle is discrete-layering-accumulation. By slicing the three-dimensional model into two-dimensional layer data (layer thickness 20 - 50 μm), powder is laid layer by layer and melted, and finally a metal part with a density of more than 99% is formed.

[0046] Perform heat treatment and machining on the blank of the aircraft airway to obtain the aircraft airway.

[0047] In one embodiment, the raw material is nickel-based superalloy powder or titanium alloy powder, and the single-layer thickness of the powder layer is 20 μm - 50 μm.

[0048] An embodiment of the present invention further provides an aircraft power system, including an aircraft body, a liquid fuel tank 20, a combustion chamber 30, and any one of the aircraft airways in the above embodiments. The liquid fuel tank 20 and the combustion chamber 30 are provided in the aircraft body. The airway main body 1 is connected to the combustion chamber 30. One end of the liquid flow channel 21 is connected to the liquid fuel tank 20, and the other end of the liquid flow channel 21 is connected to the combustion chamber 30.

[0049] In this example, the GH3536 superalloy circular-to-square exhaust duct is taken as an example, and the specific implementation steps are as follows:

[0050] Structural design: The GH3536 superalloy circular-to-square exhaust duct in the prior art is a single-wall solid structure with an open cross-section gradually changing from circular to square; this application improves it by designing a cooling structure 2 on the airway main body 1 to form a double-wall structure. And a fuel inlet 12 and a fuel outlet 13 communicating with the liquid flow channel 21 are designed. The fuel inlet 12 is connected to the liquid fuel tank 20 through a pipeline, and the fuel outlet 13 is connected to the combustion chamber 30 through a pipeline and a liquid pump. Multiple partition plates 22 divide the liquid flow channel 21 to form a plurality of rectangular flow channels 211, and the rectangular flow channels 211 are conformally embedded in the inner wall surface of the air flow channel 11, with a minimum wall thickness generally above 0.8 mm, and the flow channel size specification is 2 mm×3 mm; aiming at the problems of long connection period and poor heat dissipation effect of the heat insulation screen of the existing GH3536 superalloy circular-to-square exhaust duct realized by riveting, this embodiment uses a lattice structure to connect the heat insulation screen and the cooling structure. On the one hand, the lattice structure can transfer the heat of the heat insulation screen to the cooling structure through heat conduction, and the flowing liquid fuel takes away the heat of the cooling structure; on the other hand, the lattice structure can improve the stiffness of the heat insulation screen and relieve the thermal mismatch thermal stress of the heat insulation screen. Based on the above design, for the aircraft airway, a simulation analysis of the bearing capacity under multi-constraint simulated thermal conditions such as thermal-mechanical coupling, efficient heat dissipation, and additive manufacturing is carried out to optimize the active cooling structure and manufacturing process.

[0051] Preparation method: Design the forming direction and support structure of the optimized aircraft airway to form a process model; use GH3536 superalloy powder, the powder layer thickness is generally 20 μm - 50 μm, and the laser power is generally 300 - 600 W, and layer-by-layer melting is carried out according to each layer filling path until the entire aircraft airway is formed; after taking out the part from the forming cylinder, use high-pressure gas to clean the powder in the aircraft airway; for the post-treatment of the aircraft airway, first perform stress relief heat treatment on the part at 650 °C, then take out the substrate and support; then perform solution heat treatment on the aircraft airway and perform machining on the assembly surface to ensure dimensional accuracy; finally, perform non-destructive testing such as X-ray and fluorescence on the aircraft airway. The heat insulation screen can be prepared with a layer of high-temperature resistant ceramic heat insulation layer by thermal spraying method, such as zirconia ceramic layer, etc., to improve the high-temperature resistant performance of the heat insulation screen.

[0052] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An aircraft air duct, characterized in that, Comprising: An airway body having an air flow passage for air flow to pass through; A cooling structure provided on the inner wall of the air flow passage, the cooling structure having a liquid flow passage for liquid fuel to flow through, one end of the liquid flow passage being used to connect to the liquid fuel tank of the aircraft, and the other end of the liquid flow passage being used to connect to the combustion chamber of the aircraft.

2. The aircraft air duct according to claim 1, characterized in that It further includes a heat insulation screen provided on the side of the cooling structure facing away from the airway body.

3. The aircraft air duct according to claim 2, wherein, It further includes a lattice structure, one end of the lattice structure being connected to the heat insulation screen, and the other end of the lattice structure being connected to the cooling structure.

4. The aircraft air duct according to claim 2, wherein, A ceramic heat insulation layer is provided on the side of the heat insulation screen facing away from the cooling structure.

5. The aircraft air duct according to claim 1, characterized in that, The cooling structure has a plurality of fuel inlets communicating with the liquid flow passage and fuel outlets communicating with the liquid flow passage. The plurality of fuel inlets are arranged at intervals along the circumferential direction of the cooling structure. The fuel inlets are used to connect to the liquid fuel tank of the aircraft, and the fuel outlets are used to connect to the combustion chamber of the aircraft.

6. The aircraft air duct according to claim 1, characterized in that, The cooling structure further includes a plurality of partition plates that divide the liquid flow passage into a plurality of rectangular flow passages.

7. The aircraft air duct according to claim 1, wherein The airway body is a square-to-round intake airway or a round-to-square exhaust airway.

8. A method for preparing an aircraft air duct as described in any one of claims 1-7, characterized in that, Including the following steps: Designing a process model of the aircraft airway; Using the selective laser melting additive manufacturing technology to print the raw material along a preset printing path into an aircraft airway blank; Performing heat treatment and machining on the aircraft airway blank to obtain the aircraft airway.

9. The method for preparing an aircraft air duct according to claim 8, characterized in that, The raw material is nickel-based superalloy powder or titanium alloy powder, and the single-layer thickness of the powder layer is 20μm - 50μm.

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