Nano smooth surface treatment method and system suitable for aircraft drag reduction

Abstract

The invention provides a nano smooth surface treatment method and system suitable for aircraft drag reduction. The nano smooth surface treatment method comprises the steps that sand blasting treatment is conducted on an operation part of the surface; the operation part is divided into strips; determining a scanning path according to the strip; determining the laser power, the scanning rate and the defocusing amount according to the strip and the target roughness, and formulating a laser strategy; polishing according to a laser strategy; and cleaning the polished surface. According to the method, a nano finish treatment method is adopted, the aerodynamic resistance of the high-speed flying aircraft is reduced under the condition that the structure is not changed, the technological operation is simple and feasible, the surface friction resistance of the high-speed aircraft is reduced by 40% or above under the condition that no attack angle exists, and the effects of increasing the voyage and reducing aerodynamic heat are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft surface drag reduction design, and specifically relates to a nano-smooth surface treatment method and system suitable for aircraft drag reduction, and in particular to a nano-smooth surface treatment method suitable for high-speed aircraft. Background Art

[0002] When flying, an aircraft will generate huge resistance, which seriously affects its flight performance. The resistance during flight can be divided into shock wave resistance and friction resistance, of which friction resistance accounts for about 50% of the total resistance. The greater the resistance, the more fuel it consumes, the less effective load, and the shorter the range. Therefore, reducing the resistance of an aircraft is an important consideration during its development.

[0003] In terms of reducing the frictional resistance of aircraft, the current domestic and foreign aircraft drag reduction structure designs usually change the surface structure of the aircraft, such as adding slits, setting porous materials, etc.

[0004] Patent document "Hypersonic aircraft drag reduction method based on porous media" (CN104149970A) discloses the use of porous materials to reduce the friction resistance of the surface of high-speed aircraft; Patent document "A slit parallel blowing method for hypersonic aircraft drag reduction" (CN112758309A) discloses the purpose of drag reduction by machining slits on the surface of the aircraft. Patent document "New high-speed surface drag reduction structure" (CN102777450A) uses axles and rotating bodies to reduce drag; Patent document "Aircraft drag reduction device" (CN103183126A) discloses the use of a perforated shell to form an air interface on the surface of the aircraft to reduce friction with atmospheric gases.

[0005] On the one hand, the above-mentioned existing technologies are difficult to process and manufacture, and are difficult to construct on the surface of an already formed aircraft; on the other hand, by introducing some drag-reducing structures, the thermal protection of the aircraft surface may be seriously affected. For example, eddy currents caused by slits and porous materials may cause thermal sealing problems for the aircraft.

[0006] Therefore, in view of the defects of the prior art, a method for reducing the drag of a high-speed aircraft without changing the surface structure of the aircraft is needed. Summary of the invention

[0007] In view of the defects in the prior art, the object of the present invention is to provide a nano-smooth surface treatment method and system suitable for aircraft drag reduction.

[0008] A nano-smooth surface treatment method suitable for aircraft drag reduction provided by the present invention comprises:

[0009] Step S1: sandblasting the operating part of the surface;

[0010] Step S2: dividing the operation area into strips;

[0011] Step S3: determining a scanning path according to the strip;

[0012] Step S4: Determine the laser power, scanning rate and defocus amount according to the strip and target roughness, and formulate a laser strategy;

[0013] Step S5: polishing according to the laser strategy;

[0014] Step S6: Cleaning the polished surface.

[0015] Preferably, in step S2, polishing is performed in an intermittent strip manner.

[0016] The spaced strips are nano-smooth strips.

[0017] The nano-smooth strips are small strips at set intervals and are arranged on the surface of the aircraft.

[0018] The division is to divide the operating part into equal parts and arrange them in intervals in the manner of nano-smooth strips / non-nano-smooth strips / nano-smooth strips.

[0019] Preferably, the equal parts are divided into ten equal parts.

[0020] The width of the nano-smooth strip is 5 cm.

[0021] The surfaces of the aircraft are the nose cone, wings, control surfaces and fuselage surfaces of the aircraft.

[0022] Preferably, the scanning path in step S3 is a scanning path of laser polishing, and the scanning direction is a direction with the smallest inclination gradient.

[0023] In the laser strategy of step S4, two lasers are used for laser scanning.

[0024] The two lasers are a high-power pulse laser and a low-power continuous laser.

[0025] The operating parts are the entire area of ​​the wing and the control surface, and the partial area of ​​the nose cone and the fuselage surface.

[0026] Preferably, the target roughness is 1 μm or less.

[0027] The laser power is 60w.

[0028] The scanning rate is 4.5 mm / min.

[0029] The defocus amount is 0.

[0030] The scanning interval in the laser strategy is 75 μm, and polishing is performed on the entire area of ​​the wing and control surface surface, and polishing is performed in an interval strip manner on the nose cone and fuselage surface.

[0031] A nano-smooth surface treatment system suitable for reducing drag of aircraft provided by the present invention comprises:

[0032] Module M1: sandblasting the operating parts of the surface;

[0033] Module M2: Divide the operation area into strips;

[0034] Module M3: determine the scanning path according to the strip;

[0035] Module M4: Determine the laser power, scanning rate and defocus amount according to the strip and target roughness, and formulate the laser strategy;

[0036] Module M5: Polishing according to laser strategy;

[0037] Module M6: Cleaning of polished surfaces.

[0038] Preferably, the module M2 is polished in an intermittent strip manner.

[0039] The spaced strips are nano-smooth strips.

[0040] The nano-smooth strips are small strips at set intervals and are arranged on the surface of the aircraft.

[0041] The division is to divide the operating part into equal parts and arrange them in intervals in the manner of nano-smooth strips / non-nano-smooth strips / nano-smooth strips.

[0042] Preferably, the equal parts are divided into ten equal parts.

[0043] The width of the nano-smooth strip is 5 cm.

[0044] The surfaces of the aircraft are the nose cone, wings, control surfaces and fuselage surfaces of the aircraft.

[0045] Preferably, the scanning path in the module M3 is a scanning path for laser polishing, and the scanning direction is a direction with the smallest inclination gradient.

[0046] The laser strategy of the module M4 uses two lasers for laser scanning.

[0047] The two lasers are a high-power pulse laser and a low-power continuous laser.

[0048] The operating parts are the entire area of ​​the wing and the control surface, and the partial area of ​​the nose cone and the fuselage surface.

[0049] Preferably, the target roughness in the module M4 is 1 μm or less.

[0050] The laser power is 60w.

[0051] The scanning rate is 4.5 mm / min.

[0052] The defocus amount is 0.

[0053] The scanning interval in the laser strategy is 75 μm, and polishing is performed on the entire area of ​​the wing and control surface surface, and polishing is performed in an interval strip manner on the nose cone and fuselage surface.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] 1. The present invention solves the problem of reducing aerodynamic drag of a high-speed flying aircraft without changing its structure, and the process operation is simple and feasible.

[0056] 2. The present invention adopts a nano-finish treatment method, which has the effect of increasing the range and reducing aerodynamic heat.

[0057] 3. The surface treatment method of the present invention can reduce the surface friction of a high-speed aircraft by more than 40% without any attack angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0059] Figure 1 Schematic diagram of the aircraft's spaced nano-smooth surface drag reduction structure.

[0060] Figure 2 Schematic diagram of the distribution of friction coefficient on the aircraft surface.

[0061] Figure 3 Schematic diagram of the comparison of laser polishing surface roughness.

[0062] Figure 4 Schematic diagram of ultrasonic-assisted laser processing.

[0063] The figure shows:

[0064] (a) Unpolished surface roughness (b) Surface roughness after polishing DETAILED DESCRIPTION

[0065] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0066] When high-altitude, high-speed aircraft flow through the nano-smooth surface of the aircraft, the viscosity of the aircraft surface is very small, reducing the viscous resistance near the boundary layer near the wall, thereby reducing the friction resistance. According to the present invention, a nano-smooth surface treatment method suitable for aircraft drag reduction is provided, comprising:

[0067] by Figure 1 For example, the laser polishing method is used to nano-finish the surface of the nose cone and fuselage of the high-speed aircraft. Laser polishing is carried out, and intermittent nano-finishing treatment is used to make the surface roughness reach the nanometer level.

[0068] Step S1: sandblasting the operating parts that need polishing to remove surface oil and other residues;

[0069] Step S2: dividing the polishing area into strips to determine the part to be subjected to nano-smoothing treatment;

[0070] Theoretically, when the surface is completely smooth, the friction is minimal. However, due to the limitation of laser polishing spot size, it is difficult to achieve a completely smooth surface and the processing efficiency is very low. Figure 2 For example, considering that the friction resistance gradually increases from the end, and there is a recovery process from small to large of friction resistance and heat flow in the transition area between strip and non-strip, the intermittent strip method is adopted for processing and preparation.

[0071] The spaced strips, i.e., nano-smooth strips, require a surface roughness of nanometer level. Different nano-smooth strip arrangement methods are selected according to the flow rate of different airflows on the aircraft surface to achieve the effect of reducing friction resistance. Multiple small strips with certain intervals should be arranged as much as possible to distribute on the entire aircraft surface.

[0072] When the nano-smooth strips meet certain arrangements, they can achieve the effect of reducing the drag on the surface of high-speed aircraft. The smaller the nano-smooth strips are and the denser the distribution is, the better the drag reduction effect is and the more obvious the heat reduction effect is. In the case of no angle of attack, this arrangement achieves the best drag reduction effect and can reduce the surface friction of high-speed aircraft by more than 40%.

[0073] In more preferred examples, the area of ​​the aircraft to be surface treated, that is, the operating part, is divided into ten equal parts, and the nano-polished strips are arranged in the form of nano-polished strips / non-nano-polished strips / nano-polished strips, and the strip width is 5 cm. Such an intermittent strip distribution not only takes into account the processing efficiency, but also ensures the drag reduction effect, and can better guide the actual aircraft surface treatment construction process.

[0074] Step S3: Formulate a laser strategy according to the divided strips and determine the scanning path;

[0075] The commonly used polishing methods mainly include mechanical polishing, chemical polishing, electrolytic polishing, etc., but these methods are prone to damage the aircraft surface, difficult processing, and precision that does not reach the nanometer level. The advantages of laser polishing are non-contact, high precision, good flexibility, wide application range, low pollution, and processable curved surfaces. Therefore, the preparation of nano-smooth strips is carried out by surface treatment through laser polishing.

[0076] In more preferred embodiments, the nose cone, wing, rudder leading edge, fuselage and flat areas of the high-speed aircraft are treated with nano-smooth surface treatment, which can reduce the impact of drag and aerodynamic heat.

[0077] The nose cone and the flat area of ​​the fuselage are locally and intermittently nano-finished. When the curved surface of the aircraft is processed, the scanning direction is set to the direction with the smallest tilt gradient.

[0078] Step S4: Determine the laser power, scanning rate and defocus amount according to the strip size and target roughness;

[0079] In more preferred embodiments, the surface is polished at an optimal scanning rate (100-400 μm / s or 4.5 mm / min), and two lasers are used to control the spot size in real time to achieve constant energy density, wherein a high-power pulsed laser is used for polishing and a low-power continuous laser is used for detection.

[0080] In more preferred examples, in order to achieve the maximum drag reduction of high-speed aircraft, the complex curved areas such as the nose cone, wings, rudders, and fuselage of high-speed aircraft must be nano-finished. The wing and rudder areas are fully polished because the wing and rudder areas have the greatest impact on drag and the smallest area, so there is no need for strip division. The flat area on the aircraft surface is divided into nano-smooth strips / non-nano-smooth strips at intervals, with a target roughness of 1μm and below. The final laser power is determined to be 60w, the scanning rate is 4.5mm / min, the defocus is 0, and the scanning spacing is 75μm.

[0081] Step S5: performing continuous laser polishing;

[0082] Step S6: After polishing, the surface is cleaned.

[0083] The surface treatment method of the present invention is suitable for reducing the drag of high-speed aircraft at zero angle of attack, and is processed with nano finish and distributed in intervals on the surface of the aircraft. Wind tunnel tests have proved that the friction resistance of the aircraft is reduced by 40% by using the surface treatment method.

[0084] The present invention also provides a nano-smooth surface treatment system suitable for aircraft drag reduction. The nano-smooth surface treatment system suitable for aircraft drag reduction can be realized by executing the process steps of the nano-smooth surface treatment method suitable for aircraft drag reduction, that is, those skilled in the art can understand the nano-smooth surface treatment method suitable for aircraft drag reduction as a preferred implementation of the nano-smooth surface treatment system suitable for aircraft drag reduction.

[0085] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0086] A nano-smooth surface treatment system suitable for reducing drag of aircraft provided by the present invention comprises:

[0087] Module M1: sandblasting the operating parts of the surface;

[0088] Module M2: Divide the operation area into strips;

[0089] Module M3: determine the scanning path according to the strip;

[0090] Module M4: Determine the laser power, scanning rate and defocus amount according to the strip and target roughness, and formulate the laser strategy;

[0091] Module M5: Polishing according to laser strategy;

[0092] Module M6: Cleaning of polished surfaces.

[0093] In more preferred embodiments, the module M2 is polished in an intermittent strip manner.

[0094] The spaced strips are nano-smooth strips.

[0095] The nano-smooth strips are small strips at set intervals and are arranged on the surface of the aircraft.

[0096] The division is to divide the operating part into equal parts and arrange them in intervals in the manner of nano-smooth strips / non-nano-smooth strips / nano-smooth strips.

[0097] In more preferred embodiments, the equal parts are divided into ten equal parts.

[0098] The width of the nano-smooth strip is 5 cm.

[0099] The surfaces of the aircraft are the nose cone, wings, control surfaces and fuselage surfaces of the aircraft.

[0100] In more preferred examples, the scanning path in the module M3 is a scanning path for laser polishing, and the scanning direction is a direction with the smallest inclination gradient.

[0101] The laser strategy of the module M4 uses two lasers for laser scanning.

[0102] The two lasers are a high-power pulse laser and a low-power continuous laser.

[0103] The operating parts are the entire area of ​​the wing and the control surface, and the partial area of ​​the nose cone and the fuselage surface.

[0104] In more preferred embodiments, the target roughness is 1 μm or less.

[0105] The laser power is 60w.

[0106] The scanning rate is 4.5 mm / min.

[0107] The defocus amount is 0.

[0108] The scanning interval in the laser strategy is 75 μm, and polishing is performed on the entire area of ​​the wing and control surface surface, and polishing is performed in an interval strip manner on the nose cone and fuselage surface.

[0109] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A nano-smooth surface treatment method suitable for aircraft drag reduction, characterized in that: include: Step S1: sandblasting the operating part of the surface; Step S2: dividing the operation area into strips; Step S3: determining a scanning path according to the strip; Step S4: Determine the laser power, scanning rate and defocus amount according to the strip and target roughness, and formulate a laser strategy; Step S5: polishing according to the laser strategy; Step S6: Cleaning the polished surface.

2. The nano-smooth surface treatment method for aircraft drag reduction according to claim 1, characterized in that: In step S2, polishing is performed by using a spaced strip method; The spaced strips are nano-smooth strips; The nano-smooth strips are small strips with set intervals, arranged on the surface of the aircraft; The division is to divide the operating part into equal parts and arrange them in intervals in the manner of nano-smooth strips / non-nano-smooth strips / nano-smooth strips.

3. The nano-smooth surface treatment method for aircraft drag reduction according to claim 2, characterized in that: The said equal division is divided into ten equal parts; The width of the nano-smooth strip is 5 cm; The surfaces of the aircraft are the nose cone, wings, control surfaces and fuselage surfaces of the aircraft.

4. The nano-smooth surface treatment method for aircraft drag reduction according to claim 1, characterized in that: The scanning path in step S3 is a scanning path of laser polishing, and the scanning direction is a direction with the smallest inclination gradient; In the laser strategy of step S4, two lasers are used for laser scanning; The two lasers are a high-power pulse laser and a low-power continuous laser; The operating parts are the entire area of ​​the wing and the control surface, and the partial area of ​​the nose cone and the fuselage surface.

5. The nano-smooth surface treatment method for aircraft drag reduction according to claim 1, characterized in that: The target roughness in step S4 is 1 μm or less; The laser power is 60w; The scanning rate is 4.5 mm / min; The defocus amount is 0; The scanning interval in the laser strategy is 75 μm, and polishing is performed on the entire area of ​​the wing and control surface surface, and polishing is performed in an interval strip manner on the nose cone and fuselage surface.

6. A nano-smooth surface treatment system suitable for aircraft drag reduction, characterized in that: include: Module M1: sandblasting the operating parts of the surface; Module M2: Divide the operation area into strips; Module M3: determine the scanning path according to the strip; Module M4: Determine the laser power, scanning rate and defocus amount according to the strip and target roughness, and formulate the laser strategy; Module M5: Polishing according to laser strategy; Module M6: Cleaning of polished surfaces.

7. The nano-smooth surface treatment system for aircraft drag reduction according to claim 6, characterized in that: The module M2 is polished by using a spaced strip method; The spaced strips are nano-smooth strips; The nano-smooth strips are small strips with set intervals, arranged on the surface of the aircraft; The division is to divide the operating part into equal parts and arrange them in intervals in the manner of nano-smooth strips / non-nano-smooth strips / nano-smooth strips.

8. The nano-smooth surface treatment system for aircraft drag reduction according to claim 7, characterized in that: The said equal division is divided into ten equal parts; The width of the nano-smooth strip is 5 cm; The surfaces of the aircraft are the nose cone, wings, control surfaces and fuselage surfaces of the aircraft.

9. The nano-smooth surface treatment system for aircraft drag reduction according to claim 6, characterized in that: The scanning path in the module M3 is a scanning path for laser polishing, and the scanning direction is a direction with the smallest inclination gradient; The laser strategy of the module M4 uses two lasers for laser scanning; The two lasers are a high-power pulse laser and a low-power continuous laser; The operating parts are the entire area of ​​the wing and the control surface, and the partial area of ​​the nose cone and the fuselage surface.

10. The nano-smooth surface treatment system for aircraft drag reduction according to claim 6, characterized in that: The target roughness in the module M4 is 1 μm or less; The laser power is 60w; The scanning rate is 4.5 mm / min; The defocus amount is 0; The scanning interval in the laser strategy is 75 μm, and polishing is performed on the entire area of ​​the wing and control surface surface, and polishing is performed in an interval strip manner on the nose cone and fuselage surface.

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