An electric heating film compatible with invisible anti-icing

Abstract

This invention discloses an electro-heating film compatible with stealth anti-icing technology, relating to the field of de-icing technology. It includes a heating layer, a dielectric substrate layer, and two electrodes. Both the heating layer and the electrodes are located on the dielectric substrate layer, with the two electrodes located at opposite ends of the substrate layer. The electrodes are used to connect to an external power source. The heating layer comprises several basic units, each including a resistive structure and an inductive structure. The inductive structure is located outside the resistive structure and is connected to it. The inductive structures of adjacent basic units are connected. In the same row of basic units, the inductive structure of the outermost basic unit is connected to the electrode. This invention's electro-heating film compatible with stealth anti-icing solves the de-icing problem of stealth fighters, effectively improving the safety, stability, and all-weather combat capability of the aircraft.

Description

Technical Field

[0001] This invention relates to the field of anti-icing technology, and in particular to an electric heating film compatible with stealth anti-icing. Background Technology

[0002] Existing electrothermal films compatible with stealth anti-icing transmit electromagnetic waves by altering the material's conductivity and thickness, with or without patterning to further enhance wave transmission. Even so, there's still a limitation: as wave transmission increases, the heating power for de-icing cannot keep up, resulting in incomplete de-icing.

[0003] Furthermore, traditional anti-icing methods require frequent maintenance when spraying antifreeze, and the antifreeze on the surface can affect the radar absorption effect of the aircraft's stealth honeycomb structure. Hot air anti-icing methods reach temperatures as high as 200-300°C, and the radar-absorbing coatings and structures are mostly made of composite materials, making them unable to withstand such high temperatures. Electric heating methods, which use metal wire heating films, suffer from strong electromagnetic wave reflection, significantly impacting stealth performance. Superhydrophobic passive anti-icing methods are unsuitable for high-speed flight conditions and often lack hydrophobicity. Therefore, current anti-icing methods are unsuitable for the surfaces of stealth aircraft. Summary of the Invention

[0004] The purpose of this invention is to provide an electrically heated film compatible with stealth anti-icing, which solves the anti-icing problem of stealth fighters and effectively improves the safety, stability and all-weather combat capability of the fighter.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides an electro-heating film compatible with stealth and anti-icing, comprising a heating layer, a dielectric substrate layer, and two electrodes. The heating layer and the electrodes are both located on the dielectric substrate layer, and the two electrodes are respectively located at both ends of the dielectric substrate layer. The electrodes are used to connect to an external power source. The heating layer comprises several basic units, each of which includes a resistive structure and an inductor structure. The inductor structure is located outside the resistive structure and is connected to the resistive structure. The inductor structures of adjacent basic units are connected. Among the basic units in the same row, the inductor structure of the outermost basic unit is connected to the electrode.

[0007] Preferably, the resistor structure includes four resistor sections arranged in a cross shape, and one end of each resistor section is connected sequentially. The inductor structure includes several inductors, and the other end of each resistor section is provided with an inductor.

[0008] Preferably, the resistor structure has a hollow structure, the resistor structure includes a first resistor part and a plurality of second resistor parts, the plurality of second resistor parts are respectively disposed on the outside of the first resistor part, and the inductor structure includes a plurality of inductor components, each of the second resistor parts being connected to one of the inductor components.

[0009] Preferably, the inductor assembly includes at least one inductor.

[0010] Preferably, the inductor assembly includes at least two inductors, which are arranged in parallel.

[0011] Preferably, the dielectric substrate layer is made of a dielectric material.

[0012] Preferably, the resistor structure and the inductor structure are connected by a connection structure.

[0013] Preferably, the connection structure is a copper foil.

[0014] The present invention achieves the following technical effects compared to the prior art:

[0015] The electro-heating film compatible with stealth and anti-icing technology of this invention incorporates inductive components in its surface structure design. This design allows for direct current flow while blocking alternating current, ensuring the film is continuously heated during direct current operation. During stealth operation, electromagnetic waves can be treated as alternating current, and the film remains disconnected, achieving high wave transmission without affecting its heating power. This invention solves the problem that stealth fighters, lacking suitable anti-icing methods, can only fly at high altitudes without clouds or in clear weather, preventing 24-hour all-weather flight. It enables anti-icing for stealth fighters, effectively improving their safety, stability, and all-weather combat capability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a front view of the electro-heating film compatible with stealth and anti-icing according to the present invention (Embodiment 1);

[0018] Figure 2 This is a front view of the basic unit of the present invention (Embodiment 1);

[0019] Figure 3 This is a bottom view of the electro-heating film compatible with stealth and anti-icing according to the present invention;

[0020] Figure 4 Temperature distribution diagram of the heating surface of the electric heating film compatible with stealth and anti-icing according to the present invention (Example 1);

[0021] Figure 5 Transmittance diagram of the electrothermal film compatible with stealth and anti-icing of the present invention under normal incidence of electromagnetic waves in the range of 2-18 GHz (Example 1);

[0022] Figure 6 This is a front view of the electro-heating film compatible with stealth and anti-icing according to the present invention (Embodiment 2);

[0023] Figure 7 This is a front view of the basic unit of the present invention (Embodiment 2);

[0024] Figure 8 Temperature distribution diagram of the heating surface of the electric heating film compatible with stealth and anti-icing according to the present invention (Example 2);

[0025] Figure 9 Transmittance diagram of the electrothermal film compatible with stealth and anti-icing of the present invention under normal incidence of electromagnetic waves in the range of 2-18 GHz (Example 2);

[0026] Wherein: 1-resistor section, 2-inductor, 3-dielectric substrate layer, 4-electrode, 5-first resistor section, 6-second resistor section, 7-hollow structure. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The purpose of this invention is to provide an electrically heated film compatible with stealth anti-icing, which solves the anti-icing problem of stealth fighters and effectively improves the safety, stability and all-weather combat capability of the fighter.

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Example 1

[0031] like Figures 1 to 5As shown: This embodiment provides an electro-heating film compatible with stealth and anti-icing, including a heating layer, a dielectric substrate layer 3, and two electrodes 4. The heating layer and electrodes 4 are both located on the dielectric substrate layer 3, and the two electrodes 4 are located at opposite ends of the dielectric substrate layer 3. The electrodes 4 are used to connect to an external power source. The heating layer includes several basic units, each of which includes a resistive structure and an inductor structure. The inductor structure is located outside the resistive structure and is connected to the resistive structure. The inductor structures of adjacent basic units are connected. In the basic units in the same row, the outer inductor 2 of the inductor structure of the outermost basic unit is connected to the electrode 4.

[0032] In this embodiment, the resistor structure includes four resistor sections 1 arranged in a cross shape, with one end of each section connected sequentially. The inductor structure includes several inductors 2, with an inductor 2 disposed at the other end of each resistor section 1. The edges of the resistor sections 1 and inductors 2 are tightly connected, and their specific positions are not limited, as long as current can be transmitted from the resistor sections 1 to the inductors 2. The contact area between the resistor sections 1 and inductors 2 is maximized. In this embodiment, the centerline of the inductor 2 coincides with the centerline of the resistor section 1.

[0033] In this embodiment, the thickness of the resistor structure is h1, the conductivity is σ, the long side of each basic unit is a1, the short side is b1, the unit is square, the side length is L1, and the resistor structure plays a heating role; the inductive reactance of the inductor structure is L, the diameter of the inductor structure is r, and it plays the role of passing DC for heating and blocking AC for wave transmission.

[0034] In this embodiment, the dielectric substrate layer 3 mainly serves to support the overall heating film, while also insulating the bottom and enhancing the overall strength and flexibility of the film. The dielectric substrate layer 3 is made of a dielectric material, which refers to a substance that can transmit electromagnetic waves, such as epoxy resin, glass, wood, fiberglass cloth, silicone rubber, polyurethane, indium tin oxide, polyimide, or polymethyl methacrylate, one or more of these materials. In this embodiment, polyimide (PI) is preferred. This type of material has a low dielectric constant and low dielectric loss, and also provides wave transmission and dielectric matching effects, which can improve signal transmission efficiency and quality, and avoid energy loss and interference. The thickness of the dielectric substrate layer 3 is h2, and the dielectric substrate layer 3 is square with a side length of S. The center of the dielectric substrate layer 3 coincides with the center of the heating layer.

[0035] In this embodiment, the heating layer is directly connected to electrode 4. Electrode 4 has a thickness of h3, a length of S, and a width of d2. It can be composed of common electrode materials, such as nickel, copper, or silver. Electrode 4 can be installed by directly attaching electrode strips, printing it using 3D printing technology, or screen printing, etc. Electrode 4 serves to connect the power supply and the heating layer, facilitating current transmission. Electrode 4 can be metal nanowires, metal materials Cu or Ag, conductive silver paste, carbon fiber, conductive polymers, etc.

[0036] In this embodiment, the heating layer is a carbon-based conductive nanomaterial thin film or a metal thin film. The matrix types of the carbon-based conductive nanofilm include silicone rubber, epoxy resin, styrene-butadiene-styrene block copolymer, and polyurethane; the filler types of the carbon-based conductive nanofilm include graphene, conductive carbon black, carbon nanotubes, nano-graphite powder, nano-metal powder, and nano-metal wire; the solvent of the carbon-based conductive nanofilm includes water, ethanol, toluene, xylene, and acetone.

[0037] In this embodiment, the inductor structure can be manufactured by 3D printing, 4D printing, magnetron sputtering, laser engraving, masking, welding, printing circuits, or purchasing commercial inductors.

[0038] The fabrication process of the stealth-compatible anti-icing electric heating film in this embodiment is as follows: The resistor used in the heating layer is a polymer-added carbon nanotube synthetic heating resistor 1. The polymer is synthesized as follows: First, prepare an isopropanol solution of coupling agent KH550, adjust the pH value to about 9-10, heat the modified liquid to 50°C at 140 r / min on a shaker, and hydrolyze it for one hour. Then, add carbon nanotubes to the coupling agent and continue to hydrolyze the carbon nanotube coupling agent on a shaker for one hour (140 r / min, 50°C). Wash the modified carbon nanotubes with acetone and filter them. Finally, dry them in an oven at 50°C and then heat them at 120°C for two hours to obtain modified carbon nanotube powder. The modified carbon nanotubes are easier to disperse in the solution.

[0039] Carbon nanotube powder was uniformly dispersed in a viscous liquid of silicone rubber. Xylene solvent was added to dissolve the silicone rubber and carbon nanotubes, resulting in a polymer solution containing dissolved carbon nanotubes. A magnet was added to the polymer solution, and the polymer solution with the magnet was stirred for 1 hour using an electromagnetic stirrer. Then, the nano- and micro-scale particles inside the polymer were uniformly dispersed using an ultrasonic cleaner for about 1 hour.

[0040] Cut the width d2 of the Cu electrode to 10 mm, and attach two Cu electrodes to the surface of the PI film. The thickness of electrode 4 is h3 = 0.1 mm and the length is S = 50 mm.

[0041] Next, a polymer solution of carbon nanotubes is uniformly sprayed onto the PI film. After the spraying thickness reaches the specified requirement, it is left to cure for 24 hours. Then, an infrared laser engraving machine is used to engrave away the unwanted parts of the layer structure formed by the polymer solution of carbon nanotubes sprayed onto the PI film, leaving the designed shape, thus obtaining the resistor structure.

[0042] In this embodiment, a1 = 10 mm, b1 = 1.34 mm, L1 = 10 mm, h1 = 0.1 mm, σ = 200 S / m, r = 1 mm, L = 0.1 mH, and h2 = 0.04 mm.

[0043] Using 3D printing, the designed inductor structure pattern is input into the system. Flexible rubber substrate and conductive copper are printed onto a PI film, with the conductive copper on the PI film and the flexible rubber substrate on the conductive copper, thus obtaining the inductor structure. In this embodiment, four inductors (2) are used in each basic unit, without interference. The inductance value L can be 1uH to 1000H, preferably 1uH to 1mH, and more preferably 1uH to 10uH. The entire structure can be uniformly heated to approximately 100°C, while the electromagnetic S21 parameter (transmission coefficient) is above -2dB, i.e., the transmittance is above 65%.

[0044] The working principle of the stealth-compatible anti-icing electric heating film in this embodiment is as follows: the resistive structure of the original continuous integral heating film with high reflectivity is cut by using an inductive structure, which introduces capacitance and inductance effects into the entire system, so that the entire heating layer exhibits a resonance effect. The waveband used is a non-resonant waveband, that is, the principle of frequency selective surface is reversed. For details, please refer to "Frequency Selective Surface Design Principle".

[0045] This embodiment employs an inductive structure to achieve the effect of passing DC while blocking AC, perfectly solving the requirement of needing to be connected during heating and disconnected during electromagnetic wave irradiation to enhance wave transmission, further addressing the issue of anti-icing for stealth compatibility. This embodiment uses a patterned design, ensuring that the heating area is not too small due to the inductor's small diameter during current transmission. Simultaneously, the patterning reduces the cross-sectional area of ​​the resistive structures, enhancing wave transmission while allowing the current passing through the inductor to fully pass through all resistive structures, ensuring that all surfaces are heated.

[0046] The electric heating film compatible with stealth and anti-icing in this embodiment can reasonably solve the problem of incompatibility between heating and anti-icing and stealth in the prior art. Compared with the solution of the prior art, the wave transmission effect of this embodiment is better and does not affect the overall heating power. The overall thickness and density of this embodiment are small, the bandwidth is wide, and the strength is high. The preparation method of this embodiment is simple and has the advantages of easy operation and low cost.

[0047] Example 2

[0048] like Figures 6 to 9 As shown: The difference between this embodiment and embodiment one is that: In this embodiment, the resistor structure is provided with a hollow structure 7, the resistor structure includes a first resistor part 5 and a plurality of second resistor parts 6, the plurality of second resistor parts 6 are respectively disposed on the outside of the first resistor part 5, the inductor structure includes a plurality of inductor components, and each second resistor part 6 is respectively connected to an inductor component.

[0049] In this embodiment, the inductor assembly includes at least one inductor 2; when the inductor assembly includes at least two inductors 2, the inductors 2 are arranged in parallel.

[0050] In this embodiment, the resistor structure and the inductor structure are connected by a connection structure, preferably a copper foil.

[0051] The fabrication process of the electrothermal film compatible with stealth and anti-icing in this embodiment is as follows: A carbon target with a diameter of 49 mm and a purity of 99% is sputtered onto a thin copper surface using magnetron sputtering at an ionization voltage of 120 V, a current of 25 A, and a sputtering time of 1 h to obtain a few layers of graphite surface. Then, copper is etched using a ferric chloride solution (concentration of 1 mol / L), and the reaction is rapidly carried out at 95 °C. The film is then washed several times with deionized water to form a layer structure. The graphite-containing layer structure is then transferred to the surface of a whole PI film.

[0052] Cut the width d2 of the Cu electrode to 5 mm, and attach two Cu electrodes to the surface of the PI film. The thickness of electrode 4 is h3 = 0.15 mm and the length is S = 70 mm.

[0053] The layer structure on the PI film is then ablated using a CO2 laser engraving machine to remove unwanted parts, leaving the designed shape to obtain the resistor structure. The shape of the inductor 2 is then ablated, and other parts are masked. Copper is sputtered onto the ablated areas using magnetron sputtering. A flexible dielectric layer is then prepared on top of the copper using chemical vapor deposition to obtain the inductor structure. The inductance value L can be 1uH to 1000H, preferably 1uH to 1mH, and more preferably 1uH to 10uH. The entire structure can be uniformly heated to approximately 100°C, while the electromagnetic S21 parameter (transmission coefficient) is above -2dB, i.e., the transmittance is above 65%.

[0054] In this embodiment, L2 = 14mm, P = 10mm, a2 = 5.83mm, b2 = 1.33mm, w = 1.08mm, h1 = 0.1mm, σ = 50S / m, r = 1.33mm, L = 1mH, and h2 = 0.04mm.

[0055] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An electrically heated film compatible with stealth and anti-icing properties, characterized in that: The device includes a heating layer, a dielectric substrate layer, and two electrodes. The heating layer and the electrodes are both located on the dielectric substrate layer, and the two electrodes are located at opposite ends of the dielectric substrate layer. The electrodes are used to connect to an external power source. The heating layer includes several basic units, each of which includes a resistive structure and an inductor structure. The inductor structure is located outside the resistive structure and is connected to the resistive structure. The inductor structures of adjacent basic units are connected. Among the basic units in the same row, the inductor structure of the outermost basic unit is connected to the electrode.

2. The electrothermal film compatible with stealth and anti-icing as described in claim 1, characterized in that: The resistor structure includes four resistor sections arranged in a cross shape, and one end of each resistor section is connected sequentially. The inductor structure includes several inductors, and one inductor is provided at the other end of each resistor section.

3. The electro-heating film compatible with stealth and anti-icing as described in claim 1, characterized in that: The resistor structure has a hollow structure. The resistor structure includes a first resistor part and a plurality of second resistor parts. The plurality of second resistor parts are respectively disposed on the outside of the first resistor part. The inductor structure includes a plurality of inductor components. Each second resistor part is respectively connected to one of the inductor components.

4. The electro-heating film compatible with stealth and anti-icing as described in claim 3, characterized in that: The inductor assembly includes at least one inductor.

5. The electro-heating film compatible with stealth and anti-icing as described in claim 4, characterized in that: The inductor assembly includes at least two inductors, which are arranged in parallel.

6. The electro-heating film compatible with stealth and anti-icing as described in claim 1, characterized in that: The dielectric substrate layer is made of a dielectric material.

7. The electro-heating film compatible with stealth and anti-icing as described in claim 1, characterized in that: The resistive structure and the inductor structure are connected by a connection structure.

8. The electro-heating film compatible with stealth and anti-icing as described in claim 7, characterized in that: The connection structure is made of copper foil.

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