Low-resistance large civil aircraft fuselage based on bionic microstructure technology

Abstract

The application discloses a low-resistance large civil aircraft fuselage based on a bionic microstructure technology, and is characterized in that, aiming at the flow field attribute characteristics of different positions of the fuselage of the large civil aircraft in a cruising flight state, three kinds of drag-reducing microstructures with different shapes are respectively arranged in five sections at different positions of the fuselage to form a drag-reducing surface of the whole fuselage, the drag-reducing characteristics of the microstructures with different shapes can be effectively utilized in combination, the fuselage resistance of the whole aircraft in the cruising flight state is obviously reduced, and the flight efficiency of the aircraft is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aircraft, and particularly relates to a low-resistance large civil aircraft fuselage based on bionic microstructure technology. BACKGROUND

[0002] With the continuous progress of science and technology, people have put forward more stringent requirements on the speed and fuel efficiency of aircraft. The traditional aircraft design technology is gradually approaching its performance bottleneck, while nature has endowed various organisms with exquisite structures and functions through a long evolution process. These biological structures often have excellent performance, such as the microstructure on the surface of shark skin which helps to reduce resistance and achieve efficient and fast progress. Numerous studies at home and abroad have shown that the application of bionic microstructure in aircraft design and manufacturing can break through the limitations of traditional technology and further improve the performance of aircraft.

[0003] At present, the application of bionic microstructure technology in aircraft design is mostly, such as the sand ridge simulation hierarchical drag reduction double-layer micro-rib structure disclosed by Chinese patent CN116142443A, the sand ridge simulation aerodynamic drag reduction tongue-shaped microstructure authorized by Chinese patent CN108327894B, and the hypersonic flow drag reduction structure applied for by Chinese patent CN118665701A. The above designs all involve changing the traditional microstructure shape, and using new complex three-dimensional microstructure design to further improve the drag reduction ability of the microstructure. However, there is no specific form and design scheme of applying microstructure technology to the surface of each component of the aircraft.

[0004] For example, the aerodynamic article and method thereof applied for by Chinese patent CN109311532A, the thin film drag reduction mechanism suitable for aircraft fuselage applied for by Chinese patent CN112027051A, the manufacturing method of microstructure drag reduction film on the surface of unmanned aerial vehicle rotor surface authorized by Chinese patent CN109795673B, and the amorphous metal tension strip authorized by Chinese patent CN102348599B. Although the above designs all involve the application of microstructure technology on aircraft and its components, they are mostly developed and innovated from the angles of specific materials, structures and preparation process methods of related microstructure products, trying to obtain greater use benefits. However, they do not propose new specific forms and design schemes of aerodynamic drag reduction microstructure for fuselage which take into account the flow characteristics of aircraft wall surface. SUMMARY

[0005] In order to overcome the prior art, the present application provides a low-resistance large civil aircraft fuselage based on bionic microstructure technology, which is characterized by three kinds of drag reduction microstructures with different shapes arranged in five segments at different positions of the fuselage, forming a drag reduction surface of the entire fuselage, which can effectively utilize the drag reduction characteristics of different microstructures to reduce the fuselage resistance during cruising flight, thereby improving the flight efficiency of the aircraft.

[0006] The technical scheme adopted by the present application to solve its technical problems is as follows:

[0007] A low-resistance large civil aircraft fuselage based on bionic microstructure technology, comprising a nose drag reduction section, a front straight drag reduction section, a middle straight drag reduction section, a rear straight drag reduction section and a tail contraction drag reduction section.

[0008] The nose drag reduction section is a fuselage surface with triangular cross-section flow direction drag reduction microstructure, the triangular top angle of the nose drag reduction section microstructure is alpha1, the microstructure height is h1, and the microstructure width Wherein The optimal drag reduction dimensionless width of the nose drag reduction section microstructure, mu is the dynamic viscosity coefficient of the fluid, rho is the density of the fluid, tau w1 The local friction stress of the nose drag reduction section surface;

[0009] The front straight drag reduction section is a fuselage surface with triangular cross-section flow direction drag reduction microstructure, the triangular top angle of the nose drag reduction section microstructure is alpha2, the microstructure height is h2, and the microstructure width Wherein The optimal drag reduction dimensionless width of the front straight drag reduction microstructure, tau w2 The local friction stress of the front straight drag reduction section surface;

[0010] The middle straight drag reduction section is a fuselage surface with triangular cross-section flow direction drag reduction microstructure, the triangular top angle of the nose drag reduction section microstructure is alpha3, the microstructure height is h3, and the microstructure width Wherein The optimal drag reduction dimensionless width of the middle straight drag reduction microstructure, tau w3 The local friction stress of the middle straight drag reduction section surface;

[0011] The rear straight drag reduction section is a fuselage surface with triangular cross-section flow direction drag reduction microstructure, the triangular top angle of the nose drag reduction section microstructure is alpha4, the microstructure height is h4, and the microstructure width Wherein The optimal drag reduction dimensionless width of the rear straight drag reduction section microstructure, tau w4 The local friction stress of the rear straight drag reduction section surface;

[0012] The tail contraction drag-reducing section is a fuselage surface with triangular cross-sectional flow-direction drag-reducing microstructures, the microstructure size of the tail contraction drag-reducing section is the smallest, the microstructure triangular apex angle is a5, the microstructure height is h5, and the microstructure width is s5. wherein is the optimal drag-reducing dimensionless width of the microstructure of the tail contraction drag-reducing section, and τ w5 is the local friction stress of the surface of the tail contraction drag-reducing section;

[0013] The microstructure heights of the nose drag-reducing section, the front straight drag-reducing section, the middle straight drag-reducing section, the rear straight drag-reducing section, and the tail contraction drag-reducing section are all equal, that is, the microstructure height at any place on the fuselage surface is constant, that is, h1=h2=h3=h4=h5; the microstructure widths of the sections on the fuselage are discontinuously changed, the microstructure widths on the fuselage surface from the nose to the tail first decrease, then increase, and finally gradually decrease, that is, s1=s3>s2=s4>s5.

[0014] Preferably, the microstructure triangular apex angle of the nose drag-reducing section is a1=100°, the microstructure height is h1=0.643s1,

[0015]

[0016] Preferably, the microstructure triangular apex angle of the front straight drag-reducing section is a2=60°, the microstructure height is h2=0.866s2,

[0017] Preferably, the microstructure triangular apex angle of the middle straight drag-reducing section is a3=100°, the microstructure height is h3=0.643s3,

[0018] Preferably, the microstructure triangular apex angle of the rear straight drag-reducing section is a4=60°, the microstructure height is h4=0.866s4,

[0019] Preferably, the microstructure triangular apex angle of the tail contraction drag-reducing section is a5=20°, the microstructure height is h5=0.984s5,

[0020] Preferably, the microstructure coverage range of the nose drag reduction section is L1-L2, wherein L1=0.020-0.030L, L2=0.155-0.165L, L is the total length of the fuselage, the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-30°; the microstructure coverage range of the front straight drag reduction section is L2-L3, L3=0.360-0.370L, the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-5°; the microstructure coverage range of the middle straight drag reduction section is L3-L4, wherein L4=0.505-0.515L, the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-15°; the microstructure coverage range of the rear straight drag reduction section is L4-L5, wherein L5=0.745-0.755L, the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-5°; the microstructure coverage range of the tail contraction drag reduction section is L5-L6, wherein L6=0.975-0.985L, the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-20°.

[0021] Preferably, the microstructure is formed on the surface of the fuselage by laser etching processing, or is covered on the surface of the fuselage by pasting a flexible film with the structure.

[0022] The beneficial effects of the present application are as follows:

[0023] The present application adopts three kinds of drag reduction microstructures with different shapes according to the flow field attribute characteristics of different positions of the fuselage of a large civil aircraft in a cruising flight state, which are arranged in five sections at different positions of the fuselage to form a drag reduction surface of the entire fuselage, so that the drag reduction characteristics of different microstructures can be effectively utilized to achieve a significant reduction of the fuselage drag of the aircraft in cruising flight. Therefore, the present application can improve the flight efficiency of the aircraft and reduce the drag suffered by the aircraft in operation, which has important significance for green and sustainable development of energy saving and emission reduction. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a schematic diagram of the fuselage of the aircraft of the present application;

[0025] Figure 2 It is a comparison diagram of the calculation results of the aerodynamic characteristics of the drag coefficient with the angle of attack of the embodiment of the present application;

[0026] Figure 3 It is a comparison diagram of the calculation results of the aerodynamic characteristics of the polar curve of the lift coefficient with the drag coefficient of the embodiment of the present application.

[0027] The symbols: a-triangle top angle 100° microstructure, b-triangle top angle 60° microstructure, c-triangle top angle 20° microstructure, 1-nose drag reduction section, 2-front straight drag reduction section, 3-middle straight drag reduction section, 4-rear straight drag reduction section, 5-tail contraction drag reduction section. DETAILED DESCRIPTION

[0028] The application will be further described below in connection with the drawings and examples.

[0029] The application aims to provide a low-resistance large civil aircraft fuselage based on bionic microstructure technology, which adopts three kinds of drag-reducing microstructures with different shapes according to the flow field attribute characteristics of different positions of the large civil aircraft fuselage in the cruising flight state, and arranges the microstructures in five segments at different positions of the fuselage to form a drag-reducing surface of the entire fuselage, so that the drag-reducing characteristics of the microstructures with different shapes can be effectively utilized to significantly reduce the fuselage resistance in the cruising flight of the aircraft as a whole, thereby improving the flight efficiency of the aircraft.

[0030] The technical scheme adopted by the application is as follows:

[0031] As shown in Figure 1 , a low-resistance large civil aircraft fuselage based on bionic microstructure technology, the fuselage includes a nose drag-reducing segment, a front straight drag-reducing segment, a middle straight drag-reducing segment, a rear straight drag-reducing segment, and a tail contraction drag-reducing segment.

[0032] The nose drag-reducing segment is a fuselage surface with triangular cross-section flow direction drag-reducing microstructures, the microstructure size is large, the microstructure triangular top angle is α1=100°, the microstructure height h1=0.643s1, and the microstructure width wherein is the optimal drag-reducing dimensionless width of the microstructure of the nose drag-reducing segment, μ is the dynamic viscosity coefficient of the fluid, ρ is the density of the fluid, τ w1 is the local friction stress of the surface of the nose drag-reducing segment;

[0033] The front straight drag-reducing segment is a fuselage surface with triangular cross-section flow direction drag-reducing microstructures, the microstructure size is medium, the microstructure triangular top angle α2=60°, the microstructure height h2=0.866s2, and the microstructure width wherein is the optimal drag-reducing dimensionless width of the microstructure of the front straight drag-reducing segment, τ w2 is the local friction stress of the surface of the front straight drag-reducing segment;

[0034] The middle straight drag-reducing segment is a fuselage surface with triangular cross-section flow direction drag-reducing microstructures, the microstructure size is large, the microstructure triangular top angle is α3=100°, the microstructure height h3=0.643s3, and the microstructure width wherein is the optimal drag-reducing dimensionless width of the microstructure of the middle straight drag-reducing segment, τ w3 is the local friction stress of the surface of the middle straight drag-reducing segment;

[0035] The rear straight-drag-reduction section is a fuselage surface with triangular cross-section flow-direction drag-reduction microstructures, the microstructure size is medium, the microstructure triangular apex angle is a4=60°, the microstructure height h4=0.866s4, and the microstructure width s4=0.866s4. wherein is the optimal drag-reduction dimensionless width of the rear straight-drag-reduction section microstructure, τ w4 is the local friction stress of the rear straight-drag-reduction section surface;

[0036] The tail contraction-drag-reduction section is a fuselage surface with triangular cross-section flow-direction drag-reduction microstructures, the microstructure size is minimum, the microstructure triangular apex angle is a5=20°, the microstructure height h5=0.984s5, and the microstructure width s5=0.984s5. wherein is the optimal drag-reduction dimensionless width of the tail contraction-drag-reduction section microstructure, τ w5 is the local friction stress of the tail contraction-drag-reduction section surface;

[0037] The microstructure height of each section on the fuselage is equal, that is, the microstructure height at any place on the fuselage surface is constant, that is, h1=h2=h3=h4=h5. The microstructure width of each section on the fuselage is discontinuously changed, the microstructure width on the fuselage surface from the nose to the tail first decreases, then increases, and finally gradually decreases, that is, s1=s3>s2=s4>s5.

[0038] The microstructure coverage interval of the nose drag-reduction section is L1~L2, wherein L1=0.020~0.030L, L2=0.155~0.165L, L is the total length of the fuselage, and the angle between the extension direction of the microstructure and the fuselage axis is within the range of 0~30°.

[0039] The microstructure coverage interval of the front straight-drag-reduction section is L2~L3, wherein L2=0.155~0.165L, L3=0.360~0.370L, and the angle between the extension direction of the microstructure and the fuselage axis is within the range of 0~5°.

[0040] The microstructure coverage interval of the medium straight-drag-reduction section is L3~L4, wherein L3=0.360~0.370L, L4=0.505~0.515L, and the angle between the extension direction of the microstructure and the fuselage axis is within the range of 0~15°.

[0041] The microstructure coverage interval of the rear straight-drag-reduction section is L4~L5, wherein L4=0.505~0.515L, L5=0.745~0.755L, and the angle between the extension direction of the microstructure and the fuselage axis is within the range of 0~5°.

[0042] The microstructure coverage interval of the tail contraction drag reduction section is L5-L6, wherein L5=0.745-0.755L, L6=0.975-0.985L, and the extension direction of the microstructure and the fuselage axis form an angle in the range of 0-20°.

[0043] The microstructure is formed on the fuselage surface by laser etching or is covered on the fuselage surface by pasting a flexible film with the structure.

[0044] Embodiment:

[0045] A common large civil aircraft has the following design parameters: the total length of the fuselage L=38.9m, the wing span 35.8m, the height 11.95m, the cruising flight height 10km, and the cruising flight speed 0.785Ma, i.e. 235.1m / s.

[0046] The nose drag reduction section is the fuselage surface with triangular cross-section flow-directional drag reduction microstructure, and the microstructure has a large size.

[0047] According to the calculation, the local friction stress τ of the surface of the nose drag reduction section is w1 =40Pa, the fluid medium is the atmosphere at the height of 10km, the fluid density is ρ=0.41351kg / m 3 , and the dynamic viscosity coefficient of the fluid is μ=1.46×10 -5 Ns / m 2 . The optimal drag reduction dimensionless width of the microstructure of the nose drag reduction section is The width of the microstructure is The height of the microstructure h1=0.643s1=3.9×10 -5 m, and the triangular top angle of the microstructure is α1=100°. The microstructure coverage interval of the nose drag reduction section is L1-L2, wherein L1=0.020-0.030L=0.778-1.167m, L2=0.155-0.165L=6.030-6.419m, and the extension direction of the microstructure and the fuselage axis form an angle in the range of 0-30°.

[0048] The front straight drag reduction section is the fuselage surface with triangular cross-section flow-directional drag reduction microstructure, and the microstructure has a medium size.

[0049] According to the calculation, the local friction stress τ of the surface of the front straight drag reduction section is w2 =20Pa, and the optimal drag reduction dimensionless width of the microstructure of the front straight drag reduction section is The width of the microstructure is The height of the microstructure h2=0.866s2=3.9×10 -5m, the microstructure triangle top angle is a1=60°. The microstructure coverage interval of the front straight drag reduction section is L2~L3, wherein L2=0.155~0.165L=6.030~6.419m, L3=0.360~0.370L=14.004~14.393m, and the angle between the extension direction of the microstructure and the fuselage axis is within the range of 0~5°.

[0050] The medium straight drag reduction section is the fuselage surface with the triangular cross-section flow-direction drag reduction microstructure, and the microstructure size is relatively large.

[0051] According to calculation, the local friction stress τ of the surface of the medium straight drag reduction section w3 =40Pa, the optimal drag reduction dimensionless width of the microstructure of the medium straight drag reduction section Microstructure width Microstructure height h3=0.643s3=3.9x10 -5 m, the microstructure triangle top angle is a1=100°. The microstructure coverage interval of the medium straight drag reduction section is L3~L4, wherein L3=0.360~0.370L=14.004~14.393m, L4=0.505~0.515L=19.645~20.034m, and the angle between the extension direction of the microstructure and the fuselage axis is within the range of 0~15°.

[0052] The rear straight drag reduction section is the fuselage surface with the triangular cross-section flow-direction drag reduction microstructure, and the microstructure size is medium.

[0053] According to calculation, the local friction stress τ of the surface of the rear straight drag reduction section w4 =20Pa, the optimal drag reduction dimensionless width of the microstructure of the rear straight drag reduction section Microstructure width Microstructure height h4=0.866s4=3.9x10 -5 m, the microstructure triangle top angle is a1=60°. The microstructure coverage interval of the rear straight drag reduction section is L4~L5, wherein L4=0.505~0.515L=19.645~20.034m, L5=0.745~0.755L=28.981~29.370m, and the angle between the extension direction of the microstructure and the fuselage axis is within the range of 0~5°.

[0054] The contraction drag reduction section is the fuselage surface with the triangular cross-section flow-direction drag reduction microstructure, and the microstructure size is the smallest.

[0055] According to calculation, the local friction stress τ of the surface of the contraction drag reduction section w5 =5Pa, the optimal drag reduction dimensionless width of the microstructure of the contraction drag reduction section Microstructure width Microstructure height h5=0.984s5=3.9x10-5 m, the microstructure triangle top angle is a1=20°. The microstructure coverage interval of the contraction drag reduction section is L5-L6, wherein L5=0.745-0.755L=28.981-29.370m, L6=0.975-0.985L=37.928-38.317m, and the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-20°.

[0056] In order to verify the performance of the low-drag aircraft fuselage based on the bionic microstructure technology, the CFD numerical calculation based on the modeling method is respectively carried out on the ordinary smooth fuselage without microstructure and the aircraft with the low-drag fuselage of the application, and the calculation results of the aerodynamic characteristics are as shown in Figure 2 and Figure 3 It can be seen from the figures that the drag coefficients of the aircraft designed by the application are lower than those of the ordinary smooth fuselage without microstructure.

Claims

1. A low-drag large civil transport fuselage based on biomimicry microstructure technology, characterized in that, The drag reduction section comprises a nose drag reduction section, a front straight drag reduction section, a middle straight drag reduction section, a rear straight drag reduction section and a tail contraction drag reduction section. The head drag reduction section is a fuselage surface with triangular cross-section flow direction drag reduction microstructure, the triangular top angle of the head drag reduction section microstructure is α1, the microstructure height is h1, and the microstructure width is w1 wherein is the optimal drag reduction dimensionless width of the head drag reduction section microstructure, μ is the dynamic viscosity coefficient of the fluid, ρ is the density of the fluid, τ w1 is the local friction stress of the head drag reduction section surface; The front equi-rectangular drag-reducing section is a fuselage surface with triangular cross-section flow-direction drag-reducing microstructures, the triangular top angle of the front equi-rectangular drag-reducing section microstructure is α2, the microstructure height is h2, and the microstructure width is w2 wherein is the optimal drag-reducing dimensionless width of the front equi-rectangular drag-reducing microstructure, τ w2 is the local friction stress of the front equi-rectangular drag-reducing section surface; The medium straight drag-reducing section is a fuselage surface with triangular cross-section flow-direction drag-reducing microstructures, the triangular top angle of the medium straight drag-reducing section microstructure is α3, the microstructure height is h3, and the microstructure width is w3 wherein is the optimal drag-reducing dimensionless width of the medium straight drag-reducing microstructure, τ w3 is the local friction stress of the medium straight drag-reducing section surface; The rear equidistance drag-reducing section is a fuselage surface with triangular cross-section flow-direction drag-reducing microstructures, a top angle of the microstructure triangular section is α4, a microstructure height is h4, and a microstructure width is w4 wherein is the optimal drag-reducing dimensionless width of the rear equidistance drag-reducing section microstructure, τ w4 is a local friction stress of the rear equidistance drag-reducing section surface; The tail contraction drag-reducing section is a fuselage surface with triangular cross-section flow-direction drag-reducing microstructures, the microstructure size of the tail contraction drag-reducing section is minimum, the microstructure triangular top angle is α5, the microstructure height is h5, and the microstructure width s5= wherein is the optimal drag-reducing dimensionless width of the tail contraction drag-reducing section microstructure, τ w5 is the local friction stress of the tail contraction drag-reducing section surface; The microstructure heights of the nose drag reduction section, the front straight drag reduction section, the middle straight drag reduction section, the rear straight drag reduction section and the tail contraction drag reduction section are equal, i.e. the microstructure height at any position on the fuselage surface is constant, i.e. h1=h2=h3=h4=h5; the microstructure widths of the sections of the fuselage are discontinuously changed, the microstructure width on the fuselage surface decreases first and then increases from the nose to the tail, and finally gradually decreases, i.e. s1=s3>s2=s4>s5.

2. A low-drag large civil transport fuselage based on biomimicry microstructure technology according to claim 1, characterized in that, The microstructure triangle top angle of the nose drag-reducing section is a1=100°, and the microstructure height h1=0.643s1, 3. A low-drag large civil transport fuselage based on biomimicry microstructure technology according to claim 1, characterized in that, The front equi-rectangular drag-reducing section microstructure triangle top angle a2=60°, microstructure height h2=0.866s2, 4. A low-drag large civil transport fuselage based on biomimicry microstructure technology according to claim 1, characterized in that, The medium-drag-reducing segment microstructure has a triangular top angle of a3= 100° and a microstructure height of h3= 0.643s3, 5. A low-drag large civil transport fuselage based on biomimicry microstructure technology according to claim 1, characterized in that, The rear equilateral drag-reducing section microstructure triangle top angle is α4=60°, microstructure height h4=0.866s4, 6. A low-drag large civil transport fuselage based on biomimicry microstructure technology according to claim 1, characterized in that, The microstructure triangle top angle of the tail contraction drag-reducing section is α5=20°, and the microstructure height h5=0.984s5, 7. A low-drag large civil transport fuselage based on biomimicry microstructure technology according to claim 1, characterized in that, The microstructure coverage interval of the nose drag reduction section is L1-L2, wherein L1=0.020-0.030L, L2=0.155-0.165L, L is the total length of the fuselage, the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-30°; the microstructure coverage interval of the front straight drag reduction section is L2-L3, L3=0.360-0.370L, the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-5°; the microstructure coverage interval of the middle straight drag reduction section is L3-L4, L4=0.505-0.515L, the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-15°; the microstructure coverage interval of the rear straight drag reduction section is L4-L5, L5=0.745-0.755L, the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-5°; the microstructure coverage interval of the tail contraction drag reduction section is L5-L6, L6=0.975-0.985L, the angle between the extension direction of the microstructure and the fuselage axis is in the range of 0-20°.

8. A low-drag large civil transport fuselage based on biomimicry microstructure technology according to claim 1, characterized in that, The microstructure is formed on the fuselage surface by laser etching processing, or is covered on the fuselage surface by pasting a flexible film with the structure.

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