Invisible patch capable of reducing resistance and removing ice, preparation method of invisible patch and aircraft

Abstract

The invention provides a stealth patch capable of reducing resistance and removing ice, a preparation method of the stealth patch and an aircraft. The stealth patch capable of reducing resistance and removing ice comprises a base body layer, a heating layer and a super-smooth resistance reducing layer which are sequentially arranged in a stacked mode from bottom to top. Wherein the heating layer is composed of a glass fiber cloth layer connected to the base body layer and a graphene layer distributed on the glass fiber cloth layer in a network-shaped island mode, the super-slippery resistance reduction layer is composed of a polydimethylsiloxane coating and silicone oil injected into the polydimethylsiloxane coating, and a plurality of resistance reduction micro grooves are formed in the super-slippery resistance reduction layer at intervals. According to the invention, the functions of radar wave penetration, ice prevention / removal and resistance reduction can be realized, the device can be used in a severe environment, and the use requirements of civil and military aircrafts are met.

Description

Technical Field

[0001] The present invention relates to the field of surface engineering technology, and more specifically, to a stealth patch capable of reducing drag and removing ice, a preparation method thereof, and an aircraft having the stealth patch capable of reducing drag and removing ice. Background Art

[0002] Aircraft icing usually occurs on the leading edge of the wing, the horizontal tail, the engine air intake, etc., which will cause great damage to the flight performance. For example, icing on the wing will destroy the aerodynamic performance of the aircraft, increase the aircraft's drag and gravity, and icing on the tail will also affect the aircraft's maneuverability. These problems will cause the aircraft to lose balance, make takeoff difficult, and even cause air crashes. Existing wind tunnel tests and flight tests have shown that when the ice on the leading edge of the wing is only as thick as sandpaper, it can reduce lift by 30% and increase drag by 40%, and even reach 80% in severe cases. At present, the methods for anti-icing of aircraft wings mainly include hot air anti-icing and electric heating anti-icing. Hot air deicing is to use the hot air generated by the engine, and after a series of adjustments such as pressure, enter the leading edge of the aircraft wing, and flow along the leading edge channel of the aircraft wing, transferring heat to the inner skin of the aircraft wing during the flow process, so that the temperature of the inner skin of the wing is higher than the freezing point to prevent ice formation. However, the energy consumption of hot air deicing is high, the deicing efficiency is low, and this type of deicing system is difficult to implement; the electric heating deicing system is a widely used deicing method. The applied electric heating system is to bury the resistance wire inside the wing to prevent the leading edge of the aircraft wing from icing by heating. However, this type of electric heating deicing has problems such as high difficulty in manufacturing the heating element, difficulty in layout, and high power consumption. The new electric heating deicing system is simple to construct and has low power consumption. It has received widespread attention from scientific researchers in recent years.

[0003] The new type of electric heating anti-icing and deicing mainly adopts surface spraying of electric heating coating or pasting of electric heating membrane. The advantage of this method is that it can reduce the loss of heat energy of traditional buried resistance wire and the construction is relatively simple. However, the surface of the electric heating coating or film needs protective coating during use, which will reduce its heating and deicing efficiency. Therefore, some researchers have proposed a method of spraying a super-hydrophobic coating on the electric heating coating or the electric heating membrane. By applying a low surface energy super-hydrophobic coating on the electric heating coating / membrane, the synergistic effect of the two is achieved, which can achieve the purpose of efficient and energy-saving anti-icing / deicing. The preparation method involved is simple and easy to operate.

[0004] The above solution can achieve low-power anti-icing, but it still has the following problems when used in military aircraft and harsh environments:

[0005] 1. Electric heating coating or electric heating membrane, due to its certain conductive properties, has a reflective effect on electromagnetic waves, and military aircraft need to be stealth, so its application on military aircraft faces certain problems;

[0006] 2. Currently, super-hydrophobic coatings have poor erosion resistance and reusability after icing in the "dynamic" environment of aviation, so they cannot be used on aircraft;

[0007] 3. The surface prepared by the composite method of electric heating coating or electric heating membrane and super-hydrophobic coating has only anti-icing function and relatively simple function, so it is not conducive to practical application in civil and military aircraft. Summary of the invention

[0008] 1. Technical issues to be resolved

[0009] The technical problem to be solved by the present invention is that the existing de-icing system, when applied to an aircraft, has the problems of being unable to be stealthy, having a single function and having poor reusability.

[0010] (II) Technical solution

[0011] To achieve the above object, the technical solution adopted by the present invention is:

[0012] In the first aspect, the present invention provides a stealth patch capable of reducing drag and removing ice, comprising a base layer, a heating layer and an ultra-slip drag reduction layer stacked in sequence from bottom to top; wherein the heating layer is composed of a glass fiber cloth layer connected to the base layer and a graphene layer distributed in the glass fiber cloth layer in the form of network-like islands, the ultra-slip drag reduction layer is composed of a polydimethylsiloxane coating and silicone oil injected into the polydimethylsiloxane coating, and a plurality of drag reduction micro grooves are arranged at intervals on the ultra-slip drag reduction layer.

[0013] Preferably, it also includes a diaphragm primer, and the diaphragm primer is arranged on a side of the base layer away from the heating layer.

[0014] Preferably, it also includes an insulating adhesive layer, and the insulating adhesive layer bonds the base layer and the heating layer.

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

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

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

[0018] In a second aspect, the present invention further provides a method for preparing a stealth patch capable of reducing drag and removing ice as described in any one of the above technical solutions, the preparation method comprising the following steps:

[0019] bonding the heating layer onto the base layer;

[0020] Spraying polydimethylsiloxane on the heating layer and solidifying it to form a dimethylsiloxane coating;

[0021] A plurality of drag-reducing micro grooves are processed on the surface of the dimethylsiloxane coating, and silicone oil is injected into the dimethylsiloxane coating to form an ultra-slip drag-reducing layer.

[0022] Preferably, bonding the heating layer to the base layer specifically comprises the following steps:

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

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

[0025] Preferably, the step of spraying polydimethylsiloxane on the heating layer and solidifying it to form a dimethylsiloxane coating specifically comprises the following steps:

[0026] Prepare a spray coating, which comprises the following components by mass fraction: 70-90% polydimethylsiloxane and 10-30% silane coupling agent;

[0027] The spray coating is sprayed on the surface of the heating layer and then heated and cured to form the polydimethylsiloxane coating, wherein the thickness of the polydimethylsiloxane coating is not less than 40 μm.

[0028] In a third aspect, the present invention further provides an aircraft, comprising an airframe and a stealth patch capable of reducing drag and removing ice as described in any one of the above technical solutions, wherein the stealth patch capable of reducing drag and removing ice is connected to the airframe.

[0029] (III) Beneficial effects

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

[0031] In the present invention, a graphene layer is grown on a glass fiber cloth layer, so that the graphene is distributed in a network-like microscopic island on the surface of the glass fiber cloth layer, and the gap between the islands is used to diffract radar waves, thereby obtaining a heating layer with a large macroscopic resistivity and a permeability to radar electromagnetic waves. The heating layer can be heated by powering on, thereby achieving the function of anti-icing / de-icing, and can also penetrate radar waves. When it is applied to an aircraft, the stealth function of the aircraft can be achieved. In the present invention, the ultra-slip drag reduction layer is composed of a polydimethylsiloxane coating and silicone oil injected into the polydimethylsiloxane coating. The polydimethylsiloxane coating material with excellent wear resistance and scouring resistance is sprayed on the heating layer to protect the heating layer, so that the surface of the present invention has good wear resistance and scouring resistance, and then the silicone oil is sprayed and injected to make it reach an ultra-slip state and have good hydrophobic properties, thereby solving the problem of scouring and ice-covering reuse in the flight environment. A plurality of drag reduction micro grooves are arranged at intervals on the ultra-slip drag reduction layer, which can solve the friction resistance problem caused by flow separation and turbulence, and achieve the function of drag reduction. Through the combination of the above structures, the patch can realize the wave transmission, anti-icing and drag reduction functions. It does not affect the stealth function of the aircraft, can meet the use requirements of military aircraft, has excellent wear resistance and anti-scouring performance, and can meet the needs of aircraft reuse; at the same time, it can not only realize the transmission of radar waves and anti-icing / de-icing functions, but also realize the drag reduction function, which is beneficial to reduce the flight resistance of the aircraft and further improve the comprehensive performance of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a schematic diagram of the structure of a stealth patch capable of reducing drag and removing ice provided by an embodiment of the present invention.

[0034] Figure 2 It is a microscopic metallographic photograph of the drag reduction micro groove provided in the embodiment of the present invention.

[0035] Figure 3 This is a wave transmission test curve of the stealth patch capable of reducing drag and removing ice provided by an embodiment of the present invention.

[0036] Figure 4 These are the test results of ice wind tunnel tests conducted on the embodiments of the present invention and the prior art.

[0037] The reference numerals in the figures are:

[0038] 1. Diaphragm base glue; 2. Base layer; 3. Insulating adhesive layer; 4. Heating layer; 5. Metal electrode; 6. Dimethylsiloxane coating; 7. Drag reduction micro groove; 8. Silicone oil; 9. Glass fiber. DETAILED DESCRIPTION

[0039] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

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

[0041] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention, and do not indicate that a device or element must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating relative importance or indicating the number of technical features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The specific implementation of the present invention is described in more detail below in conjunction with specific embodiments:

[0043] like Figure 1As shown, the embodiment of the present invention provides a stealth patch capable of reducing drag and removing ice, comprising a base layer 2, a heating layer 4 and a super-slip drag-reducing layer stacked in sequence from bottom to top; wherein the heating layer 4 is composed of a glass fiber cloth layer connected to the base layer 2 and a graphene layer distributed in the glass fiber cloth layer in a network-like island shape, the super-slip drag-reducing layer is composed of a polydimethylsiloxane coating 6 and silicone oil 8 injected into the polydimethylsiloxane coating 6, and a plurality of drag-reducing micro-grooves 7 are arranged at intervals on the super-slip drag-reducing layer. Specifically, graphene is a conductive material with low resistivity. The dense graphene material has low resistance and also has a reflective effect on electromagnetic waves. In order to obtain a graphene material with a large resistivity, graphene is grown on glass fiber cloth, so that it is distributed in a network-like manner, and the macroscopic resistivity is increased. At the same time, the network-like micro-island gaps formed enable the radar wave to diffract and penetrate, thereby achieving the penetration of radar waves while satisfying the heating function, and then when it is applied to an aircraft, the stealth function of the aircraft can be achieved. Compared with the super-hydrophobic surface in the prior art, the super-slip drag-reducing layer has better anti-scouring performance, can resist the repeated scouring of high-speed wind in harsh environments, is not easily damaged, and can realize its reusable function; at the same time, the super-slip drag-reducing layer will not affect the transmission of radar waves, and the surface is not easy to adhere to ice layers, thereby realizing its deicing function. A plurality of drag-reducing micro-grooves 7 are processed on the super-slip drag-reducing layer. When the high-speed airflow flows through the drag-reducing micro-grooves 7, the velocity 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, thereby helping to reduce the friction resistance of high-speed gas to the aircraft. The drag-reducing micro-grooves 7 can solve the friction resistance problem caused by flow separation and turbulence, thereby achieving the purpose of aircraft drag reduction. More specifically, the polydimethylsiloxane coating 6 has good hydrophobic properties, thereby isolating moisture in the air, preventing moisture in the air from adhering to its surface to form an ice layer, and realizing the anti-icing function. Silicone oil 8 includes but is not limited to methyl silicone oil and modified silicone oil. Silicone oil 8 has excellent heat resistance, electrical insulation, weather resistance, hydrophobicity, physiological inertness and low surface tension. In addition, it has a low viscosity-temperature coefficient and high compression resistance, which can further improve the hydrophobicity, heat resistance and electrical insulation of the super-slip drag reduction layer, thereby improving the aircraft's adaptability to harsh environments. The glass fiber cloth layer has glass fibers 9, which can increase the resistance of the heating layer, thereby achieving heat generation through a larger resistance after power is turned on, thereby achieving the heating function.

[0044] Preferably, it also includes a membrane adhesive 1, which is arranged on the side of the base layer 2 away from the heating layer 4. The stealth patch capable of reducing drag and deicing can be pasted on the corresponding part of the aircraft body through the membrane adhesive 1, and then the membrane adhesive 1 is heated to be cured and connected to the body.

[0045] Preferably, an insulating adhesive layer 3 is further included, and the insulating adhesive layer 3 bonds the base layer 2 and the heating layer 4. The insulating adhesive layer 3 can not only realize the bonding connection between the base layer 2 and the heating layer 4, but also realize the insulation function, thereby preventing the heating layer 4 and the base layer 2 from being electrically conductive.

[0046] Preferably, a metal electrode 5 is also included, and the metal electrode 5 is electrically connected to the heating layer 4. The metal electrode 5 is preferably an electrode made of copper, and its material can also be a metal material with good electrical conductivity such as gold and silver. It is used to connect to the power system of the aircraft, and then supply power to the heating layer 4, so that it can realize the function of electric heating.

[0047] Preferably, the drag-reducing micro grooves 7 are micrometer-scale grooves with a triangular cross section.

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

[0049] The embodiment of the present invention further provides a method for preparing any one of the stealth patches capable of reducing drag and removing ice in the above embodiments, the preparation method comprising the following steps:

[0050] Bonding the heating layer 4 on the base layer 2;

[0051] Spraying polydimethylsiloxane on the heating layer 4 and solidifying it to form a dimethylsiloxane coating 6;

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

[0053] Preferably, bonding the heating layer to the base layer specifically comprises the following steps:

[0054] Spraying an insulating adhesive material with a thickness of 10-30 μm on the substrate layer;

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

[0056] Preferably, spraying polydimethylsiloxane on the heating layer and solidifying it to form a dimethylsiloxane coating specifically comprises the following steps:

[0057] Prepare a spray coating, which comprises the following components by mass fraction: 70-90% polydimethylsiloxane and 10-30% silane coupling agent;

[0058] The spray coating is sprayed on the surface of the heating layer and then heated and cured to form a polydimethylsiloxane coating, wherein the thickness of the polydimethylsiloxane coating is not less than 40 μm.

[0059] The following is a specific embodiment provided by this application:

[0060] 1) The base layer 2 is preferably a polyimide film, and a film primer 1 is provided at the bottom of the polyimide film. The insulating adhesive material is evenly sprayed on the base layer 2 by spraying to form an insulating adhesive layer 3. The spray gun is kept at a distance of 200 mm and an incident angle of 70° from the base layer 2. The sprayed insulating adhesive material can be selected from polyurethane, epoxy resin and other materials, and the thickness is controlled to be 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 copper foil wires with a line width of 2 mm are arranged at both ends thereof as metal electrodes 5;

[0062] 3) After the insulating adhesive layer 3 is cured, 20% silane coupling agent (KH571) is filled into polydimethylsiloxane (PDMS), and after being fully dispersed, a spray coating is formed, and the spray coating is evenly sprayed on the surface of the heating layer 4 by a coating spraying method to form a dimethylsiloxane coating; wherein, the spray gun is kept at a distance of 200 mm and an incident angle of 70° from the base layer 2, and the film thickness is 50 μm, and the film is placed in a drying furnace and heated to 120° C. for 180 seconds;

[0063] 4) If Figure 2 As shown in FIG. 1 , after the dimethylsiloxane coating is cured, a femtosecond laser device is used to etch drag-reducing microgrooves 7 on the surface of the ultra-slip drag-reducing layer; wherein the working parameters of the femtosecond laser are set as follows: the defocus is 3 mm, the number of pulses is 200, and the energy density is 0.3 J / cm 2 , the number of scans is 8 times. Specifically, the drag reduction micro groove 7 has a width of 30 μm, a depth of 30 μm, and a triangular cross section, and the spacing between two adjacent drag reduction micro grooves 7 is 5 μm;

[0064] 5) After the drag-reducing micro-grooves 7 are formed, silicone oil 8 is evenly sprayed by spraying, and the distance between the spray gun and the substrate layer 2 is maintained at 200 mm. Then, the silicone oil is injected into the dimethylsiloxane coating by a swelling method to form an ultra-slip drag-reducing layer, thereby obtaining a stealth patch capable of reducing drag and removing ice.

[0065] The stealth patch capable of reducing drag and removing ice obtained in this embodiment was tested for its functionality, and the results are as follows: Figure 3 As shown in the figure, through the radar electromagnetic wave vertical reflectivity loss test, the radar wave transmittance in the 2-18 GHz frequency band is about 95%. It can be seen that the stealth patch capable of reducing drag and deicing provided in this embodiment can achieve the transmission of radar waves, thereby improving the stealth performance of the aircraft equipped with it; Figure 4As shown in the figure, the stealth patch capable of reducing drag and deicing provided in this embodiment is subjected to wind tunnel tests on airfoil parts together with the electric heating coating and the super-hydrophobic composite electric heating patch in the prior art (the power density is 10kw / m 2 ), the stealth patch capable of reducing drag and deicing provided by this embodiment has a drag reduction rate of 3%-7% at a wind speed of 0.2-0.6 Mach. Through the wind tunnel test of the airfoil, it can quickly de-ice, and the complete de-icing speed is faster than that of a single heating coating (or film) and a super-hydrophobic surface composite electric heating patch, and the complete de-icing time can reach 10s. It can be seen that the stealth patch capable of reducing drag and deicing provided by this embodiment has a significant improvement in the functions of drag reduction and de-icing compared with the prior art.

[0066] An embodiment of the present invention further provides an aircraft, comprising an aircraft body and any one of the stealth patches capable of reducing drag and removing ice in the above embodiments, wherein the stealth patch capable of reducing drag and removing ice is connected to the aircraft body (specifically, the leading edge of the wing, the horizontal tail, the engine air intake, etc. of the aircraft). The stealth patch capable of reducing drag and removing ice provided in this embodiment is connected to the aircraft body, and the functions of removing / anti-icing and reducing drag of the aircraft parts are realized without affecting the stealth function of the aircraft, so as to meet the use requirements of military aircraft and the use requirements in harsh environments.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A stealth patch that can reduce drag and remove ice, It is characterized in that It includes a base layer, a heating layer and an ultra-slip drag reduction layer which are stacked in sequence from bottom to top; wherein the heating layer is composed of a glass fiber cloth layer connected to the base layer and a graphene layer distributed in the glass fiber cloth layer in the form of network-like islands; the ultra-slip drag reduction layer is composed of a polydimethylsiloxane coating and silicone oil injected into the polydimethylsiloxane coating; and a plurality of drag reduction micro grooves are arranged at intervals on the ultra-slip drag reduction layer.

2. The stealth patch capable of reducing drag and removing ice as claimed in claim 1, It is characterized in that It also includes a diaphragm bottom glue, and the diaphragm bottom glue is arranged on a side of the base layer away from the heating layer.

3. The stealth patch capable of reducing drag and removing ice as claimed in claim 2, It is characterized in that It also includes an insulating adhesive layer, which bonds the base layer and the heating layer.

4. The stealth patch capable of reducing drag and removing ice as claimed in claim 1, It is characterized in that It also includes a metal electrode, which is electrically connected to the heating layer.

5. The stealth patch capable of reducing drag and removing ice as claimed in claim 1, It is characterized in that The drag-reducing micro grooves are micrometer-scale grooves with triangular cross-sections.

6. The stealth patch capable of reducing drag and removing ice as claimed in claim 1, It is characterized in that The base layer is a polyimide film.

7. A method for preparing a stealth patch capable of reducing drag and removing ice as claimed in any one of claims 1 to 6, It is characterized in that The preparation method comprises the following steps: bonding the heating layer onto the base layer; Spraying polydimethylsiloxane on the heating layer and solidifying it to form a dimethylsiloxane coating; A plurality of drag-reducing micro grooves are processed on the surface of the dimethylsiloxane coating, and silicone oil is injected into the dimethylsiloxane coating to form an ultra-slip drag-reducing layer.

8. The preparation method according to claim 7, It is characterized in that The bonding of the heating layer onto 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 evenly attached to the insulating adhesive material, and the thickness of the heating layer is not greater than 25 μm.

9. The preparation method according to claim 7, It is characterized in that The step of spraying polydimethylsiloxane on the heating layer and solidifying it to form a dimethylsiloxane coating specifically comprises the following steps: Prepare a spray coating, which comprises the following components by mass fraction: 70-90% polydimethylsiloxane and 10-30% silane coupling agent; The spray coating is sprayed on the surface of the heating layer and then heated and cured to form the polydimethylsiloxane coating, wherein the thickness of the polydimethylsiloxane coating is not less than 40 μm.

10. An aircraft, It is characterized in that The invention comprises a body and a stealth patch capable of reducing drag and removing ice as claimed in any one of claims 1 to 6, wherein the stealth patch capable of reducing drag and removing ice is connected to the body.

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