Aircraft dry metal tube
The drying metal tubes manufactured using 3D printing technology solve the problems of bulky structure, low drying efficiency, and interlayer delamination under vibration in traditional drying metal tubes used in aircraft fluid transport systems, achieving a balance between efficient drying and mechanical properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HANGZHOU HANGLI ADDITIVE MFG TECH CO LTD
- Filing Date
- 2025-09-29
- Publication Date
- 2026-07-24
AI Technical Summary
Traditional drying metal pipes in aircraft fluid transport systems suffer from bulky structures, low drying efficiency, poor compatibility with pipelines, and are prone to interlayer delamination, moisture leakage, or structural failure under vibration conditions, failing to balance mechanical performance and drying function.
A dry metal tube consisting of a functional inner layer, a supporting middle layer, and a protective outer layer is manufactured using 3D printing technology. The functional inner layer is coated with a hydrophilic coating, the supporting middle layer adopts a biomimetic hexagonal grid structure, and the protective outer layer is coated with an anti-oxidation coating. The entire structure is formed by metallurgical bonding, and the layers are bonded together.
It improves drying efficiency and reliability, increases moisture adsorption rate by more than 30%, keeps internal humidity stable below 5%, reduces weight by 30%, increases compressive strength by 35%, avoids interlayer delamination and structural failure under vibration environment, and meets the mechanical performance requirements of aircraft.
Smart Images
Figure CN224546289U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of aviation fluid transport components technology, and in particular to an aircraft drying metal pipe. Background Technology
[0002] Aviation fluid transport components refer to tubular or channel-like parts used in the fuel system, hydraulic system, environmental control system, lubrication system, etc. of aircraft (including fixed-wing and rotary-wing aircraft) to transport fluid media (such as fuel, hydraulic oil, coolant, air, etc.). They are key structural components that ensure the core functions of aircraft such as power transmission, attitude control, and environmental regulation.
[0003] In aircraft fluid transport systems, residual moisture on the inner wall of metal pipes can easily lead to corrosion, icing, or media contamination, seriously affecting flight safety. Traditional drying metal pipes rely on external drying devices, which suffer from problems such as bulky structure, low drying efficiency, and poor compatibility with pipelines. Moreover, traditional casting and machining processes cannot achieve complex internal functional structures. Due to manufacturing process limitations, functional structures are difficult to integrate, and interlayer delamination is prone to occur under vibration environments, leading to moisture leakage or structural failure. It is impossible to balance mechanical performance and drying function. Utility Model Content
[0004] Due to the limitations of existing manufacturing processes for drying metal tubes, it is difficult to integrate functional structures. Under vibration, interlayer delamination is prone to occur, leading to moisture leakage or structural failure. This makes it impossible to balance mechanical performance and drying function. Therefore, this utility model proposes an aircraft drying metal tube.
[0005] This utility model proposes an aircraft drying metal tube, comprising a functional inner layer, a supporting intermediate layer, and a protective outer layer arranged sequentially from the inside out. The functional inner layer, the supporting intermediate layer, and the protective outer layer are integrally formed by 3D printing technology, and the layers are metallurgically bonded together. The inner wall of the functional inner layer is coated with a hydrophilic coating, and the outer surface of the protective outer layer is coated with an anti-oxidation coating.
[0006] The protective outer layer is fixedly connected to both ends with connecting flanges, and the connecting flanges and the protective outer layer are integrally formed by 3D printing technology.
[0007] Preferably, the functional inner layer is made of titanium alloy-based composite material, the hydrophilic coating is made of hydroxyapatite solution, and the inner wall of the functional inner layer is provided with honeycomb micropores with a diameter of 50-200 μm.
[0008] Preferably, the functional inner layer is provided with a water guide groove along the axial direction that communicates with the honeycomb micropores, the width of the water guide groove is 0.8-1.2mm, and the depth of the water guide groove is 0.5-1.0mm.
[0009] Preferably, the material of the supporting intermediate layer is titanium alloy, the shape of the supporting intermediate layer is a periodic hexagonal grid structure, and the single grid unit of the supporting intermediate layer is a regular hexagonal prism with a side length of 3-8mm and a wall thickness of 0.3-0.8mm.
[0010] Preferably, the outer surface of the supporting intermediate layer is provided with axial reinforcing ribs at intervals along the axial direction. The cross-section of the axial reinforcing ribs is an isosceles trapezoid with an upper base width of 1-2 mm, a lower base width of 2-3 mm, and a thickness of 2-5 mm.
[0011] Preferably, the protective outer layer is made of titanium alloy-based composite material, and the inner wall of the protective outer layer is fixedly connected with connecting serrations. One end of the connecting serrations is fixedly connected to the outer surface of the supporting intermediate layer. The connecting serrations are triangular in shape, with a height of 0.2-0.3 mm and a base length of 0.5-1 mm. Multiple connecting serrations are evenly distributed along the circumferential direction. The anti-oxidation coating is made of chromium trioxide nanoparticles.
[0012] Preferably, the inner wall of the drying metal tube is provided with a collection chamber with micropores, and the outer surface of the micropores of the collection chamber is fixedly connected to one end of the water guiding channel.
[0013] The beneficial effects of this utility model are as follows: 1. By setting up a functional inner layer, both drying efficiency and reliability are improved. The honeycomb micropores (50-200μm) of the functional inner layer and the axial water guide channel form an "adsorption-guidance" closed loop. Combined with the hydrophilic coating of hydroxyapatite, the moisture adsorption rate is increased by more than 30%, and the humidity inside the tube can be stably controlled below 5%. This solves the technical problems of existing drying metal tube manufacturing process limitations, difficulty in integrating functional structure, easy delamination between layers under vibration environment, moisture leakage or structural failure, and inability to balance mechanical performance and drying function.
[0014] 2. By setting a supporting intermediate layer, the performance of the drying tube can be improved. The hexagonal biomimetic grid and axial stiffening rib design of the supporting intermediate layer can reduce weight by 30% while maintaining a compressive strength of ≥30MPa and increasing axial stiffness by 35%, thus preventing buckling of long pipes. The bending section is designed with "inner grid densification + outer wall thickness reinforcement" to ensure uniform stress distribution and solve the problem of performance degradation in irregular sections. This also solves the technical problems of existing drying metal tube manufacturing process limitations, difficulty in integrating functional structures, easy delamination under vibration environment, causing moisture leakage or structural failure, and inability to balance mechanical performance and drying function. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of an aircraft drying metal tube proposed in this utility model; Figure 2 This is a perspective view of the supporting intermediate layer structure of an aircraft drying metal tube proposed in this utility model. Figure 3 This is a perspective view of the water guide channel structure of an aircraft drying metal pipe proposed in this utility model. Figure 4 This is a perspective view of the serrated connection structure of an aircraft drying metal pipe proposed in this utility model.
[0016] In the diagram: 1. Functional inner layer; 11. Honeycomb micropores; 12. Water guide channel; 13. Collection chamber; 14. Hydrophilic coating; 2. Supporting intermediate layer; 21. Axial reinforcing rib; 3. Protective outer layer; 31. Connecting serrations; 32. Antioxidant coating; 33. Connecting flange. Detailed Implementation
[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.
[0018] Reference Figures 1-4 An aircraft drying metal tube includes a functional inner layer 1, a supporting intermediate layer 2, and a protective outer layer 3 arranged sequentially from the inside out. The functional inner layer 1, the supporting intermediate layer 2, and the protective outer layer 3 are integrally formed by 3D printing technology, and a metallurgical bond is formed between each layer. The printing layer thickness of the functional inner layer 1 is 0.02 mm, and the printing layer thickness of the supporting intermediate layer 2 and the protective outer layer 3 is 0.03-0.05 mm. The inner wall of the functional inner layer 1 is coated with a hydrophilic coating 14, and the outer surface of the protective outer layer 3 is coated with an anti-oxidation coating 32.
[0019] Specifically, the inner functional layer 1 is made of titanium alloy-based composite material, the hydrophilic coating 14 is made of hydroxyapatite solution, and the inner wall of the inner functional layer 1 is provided with honeycomb micropores 11 with a diameter of 50-200 μm. In the curved section of the aircraft drying metal tube, the density of the honeycomb micropores 11 on the inner side is 10%-20% higher than that on the outer side.
[0020] Specifically, the functional inner layer 1 is provided with a water guide groove 12 along the axial direction that communicates with the honeycomb micropores 11. The width of the water guide groove 12 is 0.8-1.2mm and the depth of the water guide groove 12 is 0.5-1.0mm.
[0021] The 0.5-1.0mm deep water guide groove 12 can quickly collect the water adsorbed by the micropores, with a water conduction rate ≥0.5mL / h; the increased micropore density on the inner side of the bending section not only enhances the ability to capture condensate that is easily generated in the bending section, but also disperses the bending stress through the "density gradient", so that the overall strength of the bending section decreases by ≤5%, which meets the mechanical requirements of pipeline bending conditions (curvature radius ≥5 times the pipe diameter).
[0022] Printing process for functional inner layer 1: First, lay up titanium alloy-based composite powder for functional inner layer 1. Mix Ti-6Al-4V with 5%-15% hydroxyapatite nanoparticles and mix at 300 r / min for 2 hours under inert gas protection to ensure uniform dispersion of components. Then, vacuum dry at 80℃ for 4 hours and perform airflow sieving to improve flowability. Print using a laser power of 50-80W, scanning speed of 1200-1500 mm / s, and layer thickness of 0.02 mm. Through laser power modulation, the low-power (50W) region partially melts the powder, forming three-dimensional interconnected honeycomb micropores 11 with a diameter of 50-200 μm, while the high-power (80W) region precisely forms micropores 0.8-1 μm wide. A 0.2mm thick, 0.5-1.0mm deep axial water guide groove 12 ensures that the honeycomb micropores 11 are connected to the water guide groove 12. During printing, for the honeycomb micropore 11 area, the laser adopts an island scanning strategy (island size 5×5mm) to partially melt the powder with a low power of 50W, accurately forming three-dimensional connected regular hexagonal prism micropores. When printing the water guide groove 12, the laser power is increased to 80W and the scanning speed is reduced to 1000mm / s to ensure that the groove wall is dense and pore-free. Before printing the curved section, the parameters are automatically adjusted by the slicing software, and the number of low-power (50W) laser scans in the inner honeycomb micropore 11 area is increased by 10%-20%, thereby increasing the density of the honeycomb micropores 11.
[0023] The hydrophilicity of hydroxyapatite and the large specific surface area of the hexagonal honeycomb micropores 11 (50-100 times that of a solid structure in the same volume) work synergistically to increase the water adsorption rate by more than 30%. The hexagonal honeycomb micropores 11, through their "dispersed force" characteristics, can maintain the compressive strength of the functional inner layer 1 at ≥15MPa while achieving a water absorption rate of ≥15%, effectively preventing the collapse of the honeycomb micropores 11 and ensuring the compatibility of drying function and structural strength.
[0024] By setting up a functional inner layer 1, both drying efficiency and reliability are improved. The honeycomb micropores 11 (50-200μm) of the functional inner layer 1 and the axial water guide channel 12 form an "adsorption-guidance" closed loop. Combined with the hydrophilic coating 14 of hydroxyapatite, the moisture adsorption rate is increased by more than 30%, and the humidity inside the tube can be stably controlled below 5%. This solves the technical problems of existing drying metal tube manufacturing process limitations, difficulty in integrating functional structures, easy interlayer peeling under vibration environment, moisture leakage or structural failure, and inability to balance mechanical performance and drying function.
[0025] Specifically, the material of the supporting intermediate layer 2 is titanium alloy, and the shape of the supporting intermediate layer 2 is a periodic hexagonal grid structure. The single grid unit of the hexagonal grid is a regular hexagonal prism with a side length of 3-8mm and a wall thickness of 0.3-0.8mm.
[0026] Specifically, the outer surface of the supporting intermediate layer 2 is provided with axial reinforcing ribs 21 spaced along the axial direction. The cross-section of the axial reinforcing ribs 21 is an isosceles trapezoid with an upper base width of 1-2 mm, a lower base width of 2-3 mm, and a thickness of 2-5 mm. In the bending section of the aircraft drying metal tube, the side length of the hexagonal grid unit on the inner side is reduced by 10%-20% compared to the outer side, and the wall thickness of the hexagonal grid on the outer side is increased by 0.1-0.2 mm compared to the inner side. The reduced grid side length on the inner side (compression zone) of the bending section enhances the local compressive strength; the increased wall thickness on the outer side (tension zone) improves the tensile strength. Through the parameter matching of "inner strengthening + outer reinforcement", the maximum stress of the bending section is ≤ 60% of the material yield strength (taking Ti-6Al-4V as an example, the yield strength is 830 MPa), avoiding "inner collapse and outer cracking" at the bending point, and ensuring the mechanical reliability of the complex tube shape.
[0027] The axial stiffener 21 works in conjunction with the hexagonal grid to increase the axial compressive stiffness of the supporting intermediate layer 2 by 35%, effectively preventing buckling deformation of long pipelines (>1m) under vibration or bending conditions; the isosceles trapezoidal section further disperses the axial load through "gradual force distribution", so that the structure can meet the fluid pressure requirements of 10-30MPa in the pipe while being lightweight (weight reduction ≥30%).
[0028] Printing process for the intermediate support layer 2: Replace the support layer powder with Ti-6Al-4V or Inconel 718, store it under inert gas protection to prevent oxidation, adjust the laser power to 100-120W, the scanning speed to 1000mm / s, and the layer thickness to 0.05mm. Use a parallel line scanning strategy (the scanning direction of adjacent layers is 60°) to print a periodic hexagonal grid (each grid is a regular hexagonal prism with a side length of 3-8mm and a wall thickness of 0.3-0.8mm); Simultaneously print axial reinforcing ribs 21 (4-8 evenly distributed along the circumference, with an isosceles trapezoidal cross-section, an upper base of 1-2mm, a lower base of 2-3mm, and a spacing of 30-50mm between adjacent ribs).
[0029] By setting up a supporting intermediate layer 2, the performance of the drying tube can be improved. The design of the hexagonal biomimetic mesh and axial stiffener 21 of the supporting intermediate layer 2 reduces the weight by 30% while maintaining a compressive strength of ≥30MPa and increasing the axial stiffness by 35%, thus preventing buckling of long pipes. The bending section is designed with "inner mesh densification + outer wall thickness reinforcement" to ensure uniform stress distribution and solve the problem of performance degradation in irregular sections. This also solves the technical problems of existing drying metal tube manufacturing process limitations, difficulty in integrating functional structures, easy delamination under vibration environment, leading to moisture leakage or structural failure, and inability to balance mechanical performance and drying function.
[0030] Specifically, the outer protective layer 3 is made of titanium alloy-based composite material. The inner wall of the outer protective layer 3 is fixedly connected with connecting serrations 31. One end of the connecting serrations 31 is fixedly connected to the outer surface of the supporting intermediate layer 2. The connecting serrations 31 are triangular in shape, with a height of 0.2-0.3 mm and a base length of 0.5-1 mm, and are evenly distributed along the circumference. The anti-oxidation coating 32 is made of chromium trioxide nanoparticles with a surface roughness Ra≤1.6μm. After heat treatment, the Cr2O3 nanoparticles form a stable anti-oxidation layer, so that the oxidation rate of the outer protective layer 3 is ≤0.01 mm / year in an environment below 300℃, effectively isolating the internal structure from external moisture and corrosive media. The smooth surface with Ra≤1.6μm can reduce the aerodynamic drag outside the tube by more than 15% compared with conventional rough surfaces, which is suitable for aircraft aerodynamic optimization requirements.
[0031] Specifically, the inner wall of the drying metal tube is provided with a collection chamber 13 with micropores. The outer surface of the micropores of the collection chamber 13 is fixedly connected to one end of the water guide channel 12. The water collection chamber 13 is an annular cavity, located at one or both ends of the drying metal tube, and is completely aligned with the end of the water guide channel 12 of the functional inner layer 1, ensuring that the water (gas) in the water guide channel 12 flows into the collection chamber 13 without residue. The water collection chamber 13 is usually integrally formed with the end interface of the drying metal tube and manufactured simultaneously by 3D printing. A drain valve is provided on the outer surface of the drying metal tube. The drain valve (diameter 2-3mm) is located on the non-flow channel side of the collection chamber 13 (the side wall facing the outside of the tube), rather than the inner wall of the flow channel, to avoid communication with the mainstream medium when the valve is opened. The vent hole (diameter 0.5-1mm) is covered with a waterproof and breathable membrane (only allowing gaseous water to drain out, preventing liquid medium from seeping in), and the vent hole faces the outside of the tube and does not directly contact the flow channel. It is used in conjunction with an external drying device, which is not limited to a heater.
[0032] The protective outer layer 3 is fixedly connected to both ends with connecting flanges 33. The connecting flanges 33 and the protective outer layer 3 are integrally formed using 3D printing technology. The flanges are integrally formed with the pipe body, avoiding stress concentration and leakage risks associated with traditional welding and threaded connections, thus improving airtightness (leakage rate ≤1×10⁻). 6(Pa・m³ / s); The sealing groove is adapted to O-rings and other seals, further ensuring the airtightness of the pipeline system, and simplifying the assembly process and improving installation efficiency.
[0033] Printing process of protective outer layer 3: Replace the protective layer powder (Ti-6Al-4V mixed with 5%-10%Cr2O3 nanoparticles, mechanically mixed at 300r / min for 2h to ensure uniform composition), adjust the laser power to 150W, scanning speed to 800mm / s, layer thickness to 0.05mm, and use a spiral scanning strategy to print a dense, non-porous structure; the connection surface with the supporting intermediate layer 2 is formed into a sawtooth transition structure by controlling the laser parameters; the end flange is printed synchronously, and a sealing groove with a width of 1-2mm and a depth of 0.5-1mm is reserved. After printing, the part is subjected to hot isostatic pressing (HIP, 1100℃ / 100MPa / 2h) to eliminate internal pores and stress, and then subjected to heat treatment at 400℃ / 1h to allow the Cr2O3 particles to diffuse and bond with the titanium alloy matrix, and cure the anti-oxidation coating 32.
[0034] The three-layer integrated molding completely avoids the risk of interlayer delamination associated with traditional segmented assembly, with an interlayer bonding strength ≥20MPa, capable of stably withstanding aerospace vibration environments (5-2000Hz). The honeycomb micropores of the functional inner layer 1 and the water guiding channel 12 form an "adsorption-guidance" network, increasing the water adsorption rate by more than 30% compared to non-porous structures. The hexagonal grid and reinforcing rib design of the supporting middle layer 2 achieves a weight reduction of ≥30% while maintaining a compressive strength of ≥30MPa. The dense structure of the protective outer layer 3, combined with Cr2O3 antioxidant components, provides a temperature resistance range of -55℃ to 300℃, an oxidation rate ≤0.01mm / year, and a surface roughness Ra≤1.6μm, effectively optimizing the aerodynamic resistance outside the tube.
[0035] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.
Claims
1. An aircraft drying metal tube, characterized in that: It includes a functional inner layer (1), a supporting intermediate layer (2) and a protective outer layer (3) arranged sequentially from the inside to the outside. The functional inner layer (1), the supporting intermediate layer (2) and the protective outer layer (3) are integrally formed by 3D printing technology, and metallurgical bonding is formed between each layer. The inner wall of the functional inner layer (1) is coated with a hydrophilic coating (14), and the outer surface of the protective outer layer (3) is coated with an anti-oxidation coating (32). The protective outer layer (3) is fixedly connected to both ends by connecting flanges (33), and the connecting flanges (33) and the protective outer layer (3) are integrally formed by 3D printing technology.
2. The aircraft drying metal tube according to claim 1, characterized in that: The functional inner layer (1) is made of titanium alloy-based composite material, the hydrophilic coating (14) is made of hydroxyapatite solution, and the inner wall of the functional inner layer (1) is provided with honeycomb micropores (11) with a diameter of 50-200 μm.
3. The aircraft drying metal tube according to claim 2, characterized in that: The functional inner layer (1) is provided with a water guide groove (12) communicating with the honeycomb micropores (11) along the axial direction. The width of the water guide groove (12) is 0.8-1.2mm and the depth of the water guide groove (12) is 0.5-1.0mm.
4. The aircraft drying metal tube according to claim 1, characterized in that: The material of the supporting intermediate layer (2) is titanium alloy. The shape of the supporting intermediate layer (2) is a periodic hexagonal grid structure. The single grid unit of the supporting intermediate layer (2) is a regular hexagonal prism with a side length of 3-8mm and a wall thickness of 0.3-0.8mm.
5. The aircraft drying metal tube according to claim 1, characterized in that: The outer surface of the supporting intermediate layer (2) is fixedly connected with axial reinforcing ribs (21) at intervals along the axial direction. The cross section of the axial reinforcing ribs (21) is an isosceles trapezoid with an upper base width of 1-2 mm, a lower base width of 2-3 mm, and a thickness of 2-5 mm.
6. The aircraft drying metal tube according to claim 1, characterized in that: The protective outer layer (3) is made of titanium alloy-based composite material. The inner wall of the protective outer layer (3) is fixedly connected with connecting saw teeth (31). One end of the connecting saw teeth (31) is fixedly connected to the outer surface of the supporting intermediate layer (2). The connecting saw teeth (31) are triangular in shape. The height of the connecting saw teeth (31) is 0.2-0.3 mm. The length of the bottom edge of the connecting saw teeth (31) is 0.5-1 mm. Multiple connecting saw teeth (31) are evenly distributed along the circumferential direction. The anti-oxidation coating (32) is made of chromium trioxide nanoparticles.
7. The aircraft drying metal tube according to claim 3, characterized in that: The inner wall of the drying metal tube is provided with a collection chamber (13) with micropores, and the outer surface of the micropores of the collection chamber (13) is fixedly connected to one end of the water guide trough (12).