Antidrag deicing stealth patch, method of making and aircraft

Abstract

The application provides an anti-icing and drag-reducing stealth patch, a preparation method thereof and an aircraft, and relates to the field of stealth technology.The anti-icing and drag-reducing stealth patch comprises, from bottom to top, a substrate layer, a heating layer and a super-smooth drag-reducing layer, wherein the heating layer is composed of a glass fiber cloth layer connected to the substrate layer and a graphene layer distributed in an island-like network on the glass fiber cloth layer, the super-smooth drag-reducing layer is composed of a polydimethylsiloxane coating layer and silicon oil injected into the polydimethylsiloxane coating layer, and a plurality of drag-reducing micro-grooves are arranged on the super-smooth drag-reducing layer in an interval manner.The application can realize the functions of radar wave penetration, anti-icing and drag reduction, can be used in harsh environments, and can meet the use requirements of civil and military aircrafts.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surface engineering, and more particularly to an anti-icing stealth patch capable of reducing drag and a preparation method thereof, and an aircraft with the anti-icing stealth patch. BACKGROUND

[0002] Airplane icing usually occurs at the leading edge of the wing, the horizontal tail, the engine inlet, etc., which can cause great damage to the performance of flight. For example, wing icing will damage the aerodynamic performance of the airplane, increase the drag and gravity of the airplane, and tail icing will also affect the maneuverability of the airplane. These problems will make the airplane lose balance, take off with difficulty, and even cause air disasters. Existing wind tunnel tests and flight tests show that wing icing of only a thickness of sandpaper can reduce the lift by 30% and increase the drag by 40%, and in severe cases, it can reach 80%. At present, the main methods for preventing and removing ice from the wings of airplanes include hot gas anti-icing and electric heating anti-icing. Hot gas anti-icing is to introduce hot gas generated by an engine into the leading edge of the airplane wing after a series of adjustments such as pressure, and make the hot gas flow along the leading edge channel of the airplane wing, so as to transfer heat to the inside of the inner skin of the airplane wing during the flow process, so that the temperature of the inner skin of the airplane wing is higher than the freezing point, thereby preventing icing. However, the hot gas anti-icing has high energy consumption, low anti-icing efficiency, and it is difficult to implement such an anti-icing system. The electric heating anti-icing system is a widely used anti-icing method. The electric heating system that has been applied is to embed resistance wires into the wing, and prevent the leading edge of the airplane wing from icing by heating. However, this electric heating anti-icing method has problems such as high difficulty in manufacturing heating elements, difficult arrangement, high power consumption, etc. The new type of electric heating anti-icing has simple construction and low power consumption, and has received widespread attention from scientific researchers in recent years.

[0003] The new type of electric heating anti-icing mainly adopts surface spraying of electric heating coating or pasting of electric heating film. The advantage of this method is that it can reduce the heat loss of traditional embedded resistance wires, and the construction is relatively simple. However, the surface of the electric heating coating or film needs to be protected by coating, which will reduce the heating and deicing efficiency. Therefore, some researchers have proposed a method of spraying a super-hydrophobic coating on the electric heating coating or film. By coating a low-surface-energy super-hydrophobic coating on the electric heating coating / film, the two can work together to achieve high-efficiency and energy-saving anti-icing, and the preparation method is simple and easy to operate.

[0004] The above scheme can achieve low-power anti-icing, but when used in military airplanes and harsh environments, the following problems still exist:

[0005] 1. The electric heating coating or electric heating film has certain electric conductivity and reflects electromagnetic waves, so it faces certain problems in military airplanes which need to be stealthy.

[0006] 2. Current super-hydrophobic coating has poor resistance to erosion in the aviation "dynamic" environment and poor reusability after icing, so it cannot be applied on the aircraft;

[0007] 3. The surface prepared by the method of combining the electric heating coating or the electric heating film with the super-hydrophobic coating only has the anti-icing function, the function is relatively single, and therefore the actual application on the civil aircraft and military aircraft is not conducive. SUMMARY

[0008] (I) Technical problems to be solved

[0009] The technical problem to be solved by the present application is that the existing deicing system has the problems of inability to be stealth, single function and poor reusability when applied to the aircraft.

[0010] (II) Technical solutions

[0011] To achieve the above-mentioned purpose, the technical solutions adopted by the present application are as follows:

[0012] In a first aspect, the present application provides a stealth patch capable of reducing drag and deicing, comprising a substrate layer, a heating layer and a super-smooth drag-reducing layer which are sequentially stacked from bottom to top; wherein the heating layer is composed of a glass fiber cloth layer connected to the substrate layer and a graphene layer which is distributed in an island network on the glass fiber cloth layer, the super-smooth drag-reducing layer is composed of a polydimethylsiloxane coating and silicone oil injected into the polydimethylsiloxane coating, and a plurality of drag-reducing micro-grooves are arranged on the super-smooth drag-reducing layer at intervals.

[0013] Preferably, it further comprises a film bottom glue, which is arranged on the side of the substrate layer away from the heating layer.

[0014] Preferably, it further comprises an insulating adhesive layer, which bonds the substrate layer and the heating layer.

[0015] Preferably, it further comprises a metal electrode, which is electrically connected to the heating layer.

[0016] Preferably, the drag-reducing micro-grooves are micro-scale and have a triangular cross-section.

[0017] Preferably, the substrate layer is a polyimide film.

[0018] In a second aspect, the present application further provides a preparation method of the stealth patch capable of reducing drag and deicing according to any one of the above technical solutions, which comprises the following steps:

[0019] bonding the heating layer on the substrate layer;

[0020] spraying polydimethylsiloxane on the heating layer and solidifying it into a dimethylsiloxane coating;

[0021] A plurality of drag reduction micro-grooves are processed on the surface of the dimethyl silicone coating, and silicone oil is injected into the dimethyl silicone coating to form a super-smooth drag reduction layer.

[0022] Preferably, the step of bonding the heating layer on the base layer specifically comprises the following steps:

[0023] Spraying an insulating adhesive material with a thickness of 10-30 microns on the base layer;

[0024] After the insulating adhesive material is semi-solidified, the heating layer is flatly attached on the insulating adhesive material, and the thickness of the heating layer is not greater than 25 microns.

[0025] Preferably, the step of spraying polydimethylsiloxane on the heating layer and solidifying it into a dimethyl silicone coating specifically comprises the following steps:

[0026] A spraying coating is prepared, which comprises the following components by mass fraction: 70-90% polydimethylsiloxane and 10-30% silane coupling agent;

[0027] After the spraying coating is sprayed on the surface of the heating layer and is heated and solidified, the polydimethylsiloxane coating is formed, and the thickness of the polydimethylsiloxane coating is not less than 40 microns.

[0028] In a third aspect, the present application further provides an aircraft comprising a body and the ice-removing and drag-reducing stealth patch according to any one of the above technical solutions, wherein the ice-removing and drag-reducing stealth patch is connected to the body.

[0029] (III) Beneficial Effects

[0030] The above technical solution of the present application has at least the following advantages:

[0031] In the application, by growing a graphene layer on the glass fiber cloth layer, the graphene is distributed in a network-like micro-island form on the surface of the glass fiber cloth layer, the radar wave is diffracted and transmitted through the gap between the islands, so that a heating layer with a large macroscopic resistivity and a radar electromagnetic wave transmission effect is obtained, which can be heated by power supply and further achieve the functions of deicing and ice prevention, and can transmit radar waves, so that when the application is applied to an aircraft, the stealth function of the aircraft can be realized. In the application, the super-smooth drag reduction layer is composed of a polydimethylsiloxane coating and silicon oil injected into the polydimethylsiloxane coating, a polydimethylsiloxane coating material with excellent wear resistance and erosion resistance is sprayed on the heating layer to protect the heating layer, so that the surface of the application has good wear resistance and erosion resistance, and then the silicon oil is sprayed to achieve a super-smooth state and good hydrophobicity, thereby solving the problem of repeated use of the aircraft in the flight environment and ice. A plurality of drag reduction micro-grooves are arranged on the super-smooth drag reduction layer, which can solve the problem of frictional resistance caused by flow separation and turbulence and realize the function of drag reduction. Through the above structure, the patch can realize the functions of wave transmission, deicing and drag reduction, which does not affect the stealth function of the aircraft and can meet the use requirements of military aircraft, has excellent wear resistance and erosion resistance, and can meet the repeated use requirements of the aircraft. At the same time, the application not only can realize the functions of radar wave transmission, deicing and ice prevention, but also can realize the function of drag reduction, which is beneficial to reducing the flight resistance of the aircraft and further improving the comprehensive performance of the aircraft. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] Figure 1 is a structural schematic diagram of the stealth patch capable of reducing drag and deicing provided by the embodiments of the application.

[0034] Figure 2 is a microstructure photograph of the drag reduction micro-groove provided by the embodiments of the application.

[0035] Figure 3 is a wave transmission test curve of the stealth patch capable of reducing drag and deicing provided by the embodiments of the application.

[0036] Figure 4 is a test result of the ice wind tunnel test of the embodiments of the application together with the prior art.

[0037] In the drawings, the reference signs are as follows:

[0038] 1, diaphragm bottom glue; 2, base layer; 3, insulating adhesive layer; 4, heating layer; 5, metal electrode; 6, dimethyl silicone coating; 7, drag reduction micro groove; 8, silicone oil; 9, glass fiber. DETAILED DESCRIPTION

[0039] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0040] It should be noted that when an element is referred to as being "fixed" 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 being "connected to" another element, it can be directly connected or indirectly connected to the other element.

[0041] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application, and do not indicate that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0042] In addition, the terms "first", "second", "third", etc. 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 application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited. The specific implementation of the present application will be described in more detail below in combination with specific examples:

[0043] As Figure 1As shown, the embodiment of the present application provides an anti-icing and drag-reducing stealth patch, which comprises a substrate layer 2, a heating layer 4 and a super-smooth drag-reducing layer arranged in sequence from bottom to top; wherein the heating layer 4 is composed of a glass fiber cloth layer connected to the substrate layer 2 and a graphene layer distributed in the form of network islands on the glass fiber cloth layer; the super-smooth drag-reducing layer is composed of a polydimethylsiloxane coating layer 6 and a silicone oil 8 injected into the polydimethylsiloxane coating layer 6; and a plurality of drag-reducing micro grooves 7 are arranged on the super-smooth drag-reducing layer in intervals. Specifically, graphene is a kind of conductive material with low resistivity; the dense graphene material has small resistance and also has a reflection effect on electromagnetic waves; in order to obtain graphene material with larger resistivity, graphene is grown on the glass fiber cloth, so that it is distributed in the form of network, the macroscopic resistivity is increased, and the network-shaped microscopic island gaps are formed, so that the radar waves can be diffracted and transmitted, thereby realizing the transmission of radar waves under the premise of meeting the heating function, and when it is applied to an aircraft, the stealth function of the aircraft can be realized. The super-smooth drag-reducing layer has better anti-washing performance than the super-hydrophobic surface in the prior art, can resist repeated washing of high-speed wind in harsh environments, is not easy to be damaged, and can realize the function of repeated use; at the same time, the super-smooth drag-reducing layer will not affect the transmission of radar waves, and the surface is not easy to attach ice layer, thereby realizing the function of ice removal. A plurality of drag-reducing micro grooves 7 are processed on the super-smooth drag-reducing layer; when high-speed airflow flows through the drag-reducing micro grooves 7, the speed and pressure pulsation of the gas in the drag-reducing micro grooves 7 on the surface of the aircraft will be reduced, thereby helping to reduce the viscous resistance near the near-wall boundary layer, and thereby helping to reduce the frictional resistance of high-speed gas to the aircraft; the drag-reducing micro grooves 7 can solve the problem of frictional resistance caused by flow separation and turbulence, thereby realizing the purpose of reducing the drag of the aircraft. More specifically, the polydimethylsiloxane coating layer 6 has good hydrophobic performance, thereby repelling water in the air and avoiding the water in the air from adhering to its surface to form an ice layer, thereby realizing the function of ice prevention. The silicone oil 8 includes but is not limited to methyl silicone oil and modified silicone oil; the silicone oil 8 has excellent heat resistance, electrical insulation, weather resistance, hydrophobicity, physiological inertia and small surface tension; in addition, it also has low viscosity-temperature coefficient and high compression resistance, which can further improve the hydrophobicity, heat resistance and electrical insulation of the super-smooth drag-reducing layer, thereby improving the adaptability of the aircraft to harsh environments. The glass fiber cloth layer has glass fibers 9, which can increase the resistance of the heating layer, thereby enabling the heating function to be realized by generating heat through large resistance after being electrified.

[0044] Preferably, it also comprises a film bottom adhesive 1, which is arranged on the side of the substrate layer 2 away from the heating layer 4. The anti-icing and drag-reducing stealth patch can be pasted on the corresponding part of the body of the aircraft through the film bottom adhesive 1, and the film bottom adhesive 1 is solidified and connected to the body by heating.

[0045] Preferably, an insulating adhesive layer 3 is further included, which bonds the substrate layer 2 and the heating layer 4. The insulating adhesive layer 3 can not only realize the adhesive connection of the substrate layer 2 and the heating layer 4, but also realize the insulating function, thereby avoiding the electrical conduction between the heating layer 4 and the substrate layer 2.

[0046] Preferably, a metal electrode 5 is further included, which is electrically connected to the heating layer 4. The metal electrode 5 is preferably a copper electrode, and the material thereof can also be a metal material with good electrical conductivity, such as gold or silver. The metal electrode 5 is used to connect with the power supply system of the aircraft, thereby supplying power to the heating layer 4, so that the heating layer 4 can realize the function of electrical heating.

[0047] Preferably, the drag-reducing micro groove 7 is a micron-scale groove with a triangular cross section.

[0048] Preferably, the substrate layer 2 is a polyimide film.

[0049] The embodiment of the present application also provides a preparation method of the drag-reducing and deicing stealth patch of any one of the above-mentioned embodiments, and the preparation method comprises the following steps:

[0050] The heating layer 4 is bonded to the substrate layer 2;

[0051] The polydimethylsiloxane is sprayed on the heating layer 4 and solidified to form a dimethylsiloxane coating layer 6;

[0052] A plurality of drag-reducing micro grooves 7 are processed on the surface of the dimethylsiloxane coating layer 6, and silicone oil 8 is injected into the dimethylsiloxane coating layer to form an ultra-smooth drag-reducing layer.

[0053] Preferably, the bonding of the heating layer to the substrate layer comprises the following steps:

[0054] The insulating adhesive material with a thickness of 10-30 μm is sprayed on the substrate layer;

[0055] After the insulating adhesive material is semi-solidified, the heating layer is flatly attached to the insulating adhesive material, and the thickness of the heating layer is not greater than 25 μm.

[0056] Preferably, the spraying of the polydimethylsiloxane on the heating layer and the solidification to form a dimethylsiloxane coating layer comprise the following steps:

[0057] The spraying coating is prepared, and the spraying coating comprises the following components in terms of mass fraction: 70-90% of polydimethylsiloxane and 10-30% of silane coupling agent;

[0058] After the spraying coating is sprayed on the surface of the heating layer and is heated and solidified, a polydimethylsiloxane coating layer is formed, and the thickness of the polydimethylsiloxane coating layer is not less than 40 μm.

[0059] The following is a specific embodiment provided in the present application:

[0060] 1) The base layer 2 is preferably a polyimide film, a film bottom glue 1 is arranged at the bottom of the polyimide film, an insulating adhesive layer 3 is formed by uniformly spraying an insulating adhesive material on the base layer 2 by means of paint spraying, the distance between the spraying gun and the base layer 2 is kept at 200 mm and the incident angle is 70°, the insulating adhesive material can be selected from polyurethane, epoxy resin and the like, and the thickness is controlled at about 15 μm;

[0061] 2) After the insulating adhesive layer 3 is semi-solidified, a 20 μm thick graphene glass fiber cloth (heating layer 4) is evenly attached to the surface of the insulating adhesive layer 3, and a copper foil wire with a line width of 2 mm is arranged at both ends as a metal electrode 5;

[0062] 3) After the insulating adhesive layer 3 is cured, 20% silane coupling agent (KH571) is filled in polydimethylsiloxane (PDMS), and after being dispersed sufficiently, a spraying paint is formed, which is uniformly sprayed on the surface of the heating layer 4 by means of paint spraying to form a dimethylsiloxane coating layer; wherein the distance between the spraying gun and the base layer 2 is kept at 200 mm and the incident angle is 70°, the film layer thickness is 50 μm, and it is simultaneously placed in a drying oven and heated to 120°C for 180 seconds;

[0063] 4) As shown in Figure 2 , after the dimethylsiloxane coating layer is cured, a drag-reducing micro groove 7 is etched on the super-smooth drag-reducing layer by means of a femtosecond laser device; wherein the working parameters of the femtosecond laser are set as follows: the defocusing amount is 3 mm, the pulse number is 200, the energy density is 0.3 J / cm 2 , and the scanning number is 8. Specifically, the drag-reducing micro groove 7 has a width of 30 μm, a depth of 30 μm and a triangular cross section, and the distance between adjacent two drag-reducing micro grooves 7 is 5 μm;

[0064] 5) After the drag-reducing micro groove 7 is formed, finally, silicon oil 8 is uniformly sprayed by means of paint spraying, the distance between the spraying gun and the base layer 2 is kept at 200 mm, and then it is injected into the dimethylsiloxane coating layer by means of swelling method to form a super-smooth drag-reducing layer, thereby obtaining an ice-melting and drag-reducing stealth patch.

[0065] The ice-melting and drag-reducing stealth patch obtained in the embodiment is subjected to functional test, and the results are as follows: as shown in Figure 3 , through radar electromagnetic wave vertical reflectivity loss test, the radar wave transmittance in the frequency band of 2-18 GHz is about 95%, it can be seen that the ice-melting and drag-reducing stealth patch provided in the embodiment can realize the transmission of radar wave, thereby improving the stealth performance of the aircraft equipped with the patch; as shown in Figure 4The wing profile wind tunnel test (the power density is 10 kw / m 2 ), the drag reduction rate of the ice-melting and drag-reducing stealth patch provided in the embodiment is 3%-7% under the wind speed of 0.2-0.6 Mach, the ice-melting and drag-reducing stealth patch can quickly melt ice through the wing profile wind tunnel test, and the complete ice-melting speed is faster than that of the single heating coating (or film) and the super-hydrophobic surface composite electric heating patch, and the complete ice-melting time can reach 10 s. It can be seen that, compared with the prior art, the ice-melting and drag-reducing stealth patch provided in the embodiment has great improvement in the functions of drag reduction and ice melting.

[0066] The embodiment of the present application further provides a flying machine, which comprises a machine body and any one of the ice-melting and drag-reducing stealth patches provided in the above embodiments, and the ice-melting and drag-reducing stealth patch is connected to the machine body (the specific position can be the leading edge of the wing of the flying machine, the horizontal tail, the engine air inlet, etc.). The ice-melting and drag-reducing stealth patch provided in the embodiment is connected to the machine body of the flying machine, and the ice-melting and drag-reducing functions of the flying machine are realized without affecting the stealth function of the flying machine, so as to meet the use requirements of the military aircraft and the use requirements in severe environments.

[0067] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A drag-reducing de-icing stealth patch, characterized in that, The super-smooth and drag-reducing layer is composed of a polydimethylsiloxane coating and silicon oil injected into the polydimethylsiloxane coating, and a plurality of drag-reducing micro-grooves are arranged on the super-smooth and drag-reducing layer in a spaced manner, the drag-reducing micro-grooves are microscale and triangular in cross section.

2. The anti-icing, drag-reducing stealth patch of claim 1, wherein, The diaphragm bottom adhesive is arranged on the side of the base layer away from the heating layer.

3. The anti-icing, drag-reducing stealth patch of claim 2, wherein, The insulating adhesive layer is arranged between the base layer and the heating layer.

4. The anti-icing, drag-reducing stealth patch of claim 1, wherein, The metal electrode is electrically connected to the heating layer.

5. The anti-icing, drag-reducing stealth patch of claim 1, wherein, The base layer is a polyimide diaphragm.

6. A method of making a drag-reducing de-icing stealth patch according to any one of claims 1-5, characterized in that, The preparation method comprises the following steps: attaching the heating layer to the base layer; spraying polydimethylsiloxane on the heating layer and solidifying the polydimethylsiloxane into a dimethylsiloxane coating; processing a plurality of drag-reducing micro-grooves on the surface of the dimethylsiloxane coating and injecting silicon oil into the dimethylsiloxane coating to form a super-smooth and drag-reducing layer.

7. The production method according to claim 6, wherein The step of attaching the heating layer to the base layer specifically comprises the following steps: spraying an insulating adhesive material with a thickness of 10-30 μm on the base layer; after the insulating adhesive material is semi-solidified, the heating layer is attached to the insulating adhesive material, and the thickness of the heating layer is not greater than 25 μm.

8. The production method according to claim 6, wherein The step of spraying polydimethylsiloxane on the heating layer and solidifying the polydimethylsiloxane into a dimethylsiloxane coating specifically comprises the following steps: preparing a spraying coating, which comprises the following components by mass fraction: 70-90% polydimethylsiloxane and 10-30% silane coupling agent; after the spraying coating is sprayed on the surface of the heating layer, the spraying coating is heated and solidified to form the polydimethylsiloxane coating, and the thickness of the polydimethylsiloxane coating is not less than 40 μm.

9. An aircraft, characterized in that The aircraft body is connected to the drag-reducing and de-icing stealth patch.

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