GRAPHENE NANOPLATE-REINFORCED EPOXY HEATING LAYER AND INTERLOCKING LOW VOLTAGE ANTI-ICING SYSTEM WITH INTERLOCKING ELECTRODES. SYSTEM

Abstract

The invention aims to prevent icing on unmanned aerial vehicles and wind turbine blades, and It involves an electrothermal system for its removal. Known graphene-reinforced epoxy heaters have low Due to their conductivity, they require high voltage. In the invention, on the substrate (11) to the heating layer (20) containing 15-30% by weight of graphene nanoplatelets (22) in the epoxy matrix (21), Current through an interlocking electrode arrangement (30) with finger spacing (g) 2?15 mm By applying this voltage, the resistance is reduced and Joule heating is achieved with a voltage not exceeding 48 V. The system, which includes an insulating protective layer (40) and a power and control unit (50), wing attack It provides ice prevention and ice removal without requiring chemical liquids or mechanical parts on its edges.

Description

TARIFF GRAPHENE NANOPLATE-REINFORCED EPOXY HEATING LAYER AND INTERLOCKING LOW VOLTAGE ANTI-ICING SYSTEM WITH INTERLOCKING ELECTRODES. SYSTEM Technical Area The invention relates to the wings, tail surfaces, and propellers of unmanned aerial vehicles, as well as wind protection. Preventing ice formation on aerodynamic surfaces such as turbine blades and removing existing ice It relates to electrothermal systems used for the purpose of eliminating [the disease]. Specifically, the invention involves highly dispersed graphene in an epoxy-based polymer matrix. an electrically conductive heating layer composed of nanoplatelets and connected to this layer Joule heating by applying a low direct current voltage through interlocking (comb-type) electrodes. It relates to an anti-icing system provided. State of the Art Icing on aircraft occurs when supercooled water droplets in the atmosphere cool to below 0°C. It forms when ice freezes upon impact with the surfaces below. Ice accumulates on the leading edge of the wing. By changing the geometry and surface roughness of the airfoil profile, the lift force can be reduced. This leads to an increase in drag force and flow separation (loss of hold). This situation, Especially in unmanned aerial vehicles with limited weight and energy capacity, altitude loss occurs and This can lead to accidents. Similarly, ice forming on wind turbine blades can damage energy. This leads to significant losses in production and uneven loads on the wings. Known methods for combating ice include the application of glycol-based chemical liquids. circulating hot air from the engine through the inside of the wing, inflatable rubber covers and metal wire or electrothermal heating with foil heaters. Chemical liquids are heated before flight. It requires constant renewal and places a chemical burden on the environment. Hot weather and Because inflatable systems require heavy piping, valve and pump assemblies, small unmanned aerial vehicles (UAVs) are preferred. Not suitable for vehicles. Metal wire and foil heaters, however, have a composite fin structure. integration challenges, local hotspots, added weight, and fatigue-related rupture risks. It carries. In recent years, carbon nanomaterials such as carbon nanotubes, graphene, and graphene nanoribbons have been used. De-icing of conductive polymer composites through Joule heating Its use has been reported in scientific publications. For example, Raji et al. (ACS Applied Materials & Interfaces, 2016, 8(5), 3551–3556) Ice with graphene nanostrip-reinforced epoxy composites Redondo has achieved a solution; however, the production of graphene nanostrips is complex and costly. and colleagues (Composites Science and Technology, 2018, 164, 65–73) found 8–12% graphene by weight. 1 They achieved ice prevention and ice removal with epoxy coatings containing nanoplatelets; however because the electrical conductivity of the coatings remained low and the electrodes were placed at both ends of the heated area Because of its placement, a high voltage of 750–800 V had to be applied. Farcas and colleagues (Nanomaterials, 2021, 11(9), 2427) in hybrid epoxies containing carbon nanotube and graphite Heating was achieved with a voltage of 50–100 V. The main problems encountered in known solutions are: (i) graphene nanoplatelet / epoxy High voltage is required in these systems due to limited conductivity; these voltages are 12– This is not possible in small unmanned aerial vehicles operating with 24V battery systems, and the user (ii) posing a risk in terms of safety; (ii) the viscosity of epoxy rapidly decreasing at high filler ratios Due to the increase in volume and the clumping of the filler, a homogeneous and workable mixture is obtained. (iii) the inability to monitor the heater temperature using separate temperature sensors and their The need for cabling. In current technology, cost-effective graphene nanoplatelets a prepared epoxy heater with sufficient power density at low and safe voltage levels a system that is configured to provide and uses its own resistance as a temperature sensor A solution is needed. Purpose of the Invention The purpose of the invention is to provide low direct current voltages not exceeding 48 V, preferably 24 V. A functional, graphene nanoplatelet-reinforced epoxy-based anti-icing system has been developed. to place. Another objective of the invention is to create a heating layer containing a high percentage of graphene nanoplatelets. By applying current through interlocking electrodes, the electrical resistance of the heating layer is reduced. one order of magnitude higher than parallel strip electrodes of the same material and thickness placed at the ends The goal is to reduce the voltage too much and thus achieve sufficient power density at low voltage. Another purpose of the invention is to integrate additional mechanical parts, pipes, or components into the wing surface. The goal is to provide a heating structure that does not require chemical liquids, is lightweight, and does not compromise the aerodynamic profile. Another aim of the invention is to analyze the temperature-dependent resistance change of the heating layer. By utilizing this, the heater temperature can be determined without the need for a separate temperature sensor, and The goal is to reduce energy consumption by only turning on the heater when necessary. Explanation of the Figures The diagrams prepared to help better understand the invention are explained below: Figure 1 shows the leading edge region of a wing to which the system described in the invention is applied. This is a cross-sectional view. Figure 2 shows the top view of the interlocking electrode arrangement on the heating layer. It is the appearance. 2 Figure 3 shows the substrate, electrode, conductive interlayer, heating layer, and shielding layer. This is a cross-sectional detail view of the resulting layered structure. Figure 4 shows the block diagram of the power and control unit. Explanation of References in Figures 10th Wing 11. Substrate 12. Attacking winger 20. Heating layer 21. Polymer matrix 22. Graphene nanoplatelet 30. Electrode assembly 31. First electrode 32. Second electrode 33. First finger 34. Second finger 35. Conductive interlayer 40. Protective layer 50. Power and control unit 51. Power supply 52. Switching element 53. Current-voltage measurement unit 54. Control unit 55. Ambient temperature sensor 60. Connecting conductor g. Finger spacing Description of the Invention The invention provides protection against icing of a wing (10) or similar aerodynamic surface. for protection; a structural substrate (11), electrically located on the substrate (11) a conductive heating layer (20), interlocking electrode that conducts current to the heating layer (20) electrically insulating covering the assembly (30), heating layer (20) and electrode assembly (30) a protective layer (40) and a low direct current voltage applied to the electrode assembly (30) It is an electrothermal anti-icing system containing a power and control unit (50). The substrate (11) is glass fiber reinforced epoxy, carbon which forms the outer surface of the wing (10). It is a composite structure laminated onto a fiber-reinforced epoxy or polymer foam core. 3 In carbon fiber applications where the substrate (11) is electrically conductive, the substrate (11) A thin insulating epoxy or glass fiber interlayer is placed between the heating layer (20) and the heating layer. The heating layer (20) consists of an epoxy-based polymer matrix (21) and within this matrix (21) by weight. graphene nanoplatelets distributed between 15% and 30%, preferably between 20% and 25% (22) It consists of a polymer matrix (21), based on bisphenol-A diglycidyl ether, with an equivalent weight of 170–190 g / eq. It is obtained by curing an epoxy resin with an amine-based hardener. Graphene nanoplatelets (22), preferably 5–10 nm thick, 5–25 µm lateral dimension, 100–150 m² / g surface area It has a surface area and a carbon content of over 99% by weight. Graphene at these ratios. nanoplatelets (22) significantly above the electrical percolation threshold, matrix (21) It forms continuous conductive networks that are in contact with each other along the length. The thickness of the heating layer (20) is 100– 500 µm, preferably in the 150–300 µm range. The electrode arrangement (30) consists of a first electrode (31) and a second electrode, as shown in Figure 2. It consists of electrodes (32). The first electrode (31) is a bar and from this bar, parallel to each other. The first electrode (33) includes the fingers. The second electrode (32) connects to a bar on the opposite side and from this bar to the first It includes the second fingers (34) that extend between the fingers (33). Adjacent first (33) The distance (g) between the second fingers (34) is 2–15 mm, preferably 5–10 mm. The electrodes (31, 32), 35–50 µm thick copper foil, silver-based conductive ink or fine metal mesh To reduce the contact resistance between the electrodes (31, 32) and the heating layer (20), A silver-based conductive interlayer (35) is applied. The technical effect provided by the interlocking electrode arrangement (30) is as follows: It is explained. The layer resistance of the heating layer (20) is Rs, the electrical conductivity of the material is σ and the layer The thickness is expressed by the relation Rs = 1 / (σ·t), where t is the thickness of the heated area. In parallel strip electrodes with distance L and length W, the resistance is R = R s·L / W. In the interlocking electrode arrangement (30) in the invention, the current is applied in N parallel intervals, finger It passes through short paths of length Lp and finger spacing g, and the resistance is approximately R = Rs·g / (Lp·N) becomes. The power density released in the heater is given by q = V² / (R·A), where V The applied voltage is A, and the heated area is A. In one application example, a sheet for a heating area measuring 54 mm × 50 mm. When considering a heating layer (20) with a resistance of 2000 Ω / □, placed at the two ends of the area With parallel strip electrodes, the resistance is approximately 2160 Ω and the power density at 24 V is approximately It remains at a level of 0.01 W / cm². On the same heating layer, finger length 40 mm, finger spacing (g) When an interlocking electrode arrangement (30) with a number of parallel intervals of mm and 5 mm is applied The resistance drops to approximately 100 Ω, and a power density of approximately 0.2 W / cm² is obtained at 24 V. Thus, with a graphene nanoplatelet / epoxy material that has limited conductivity and is cost-effective, high Sufficient heat flux is provided for ice prevention and ice removal without the need for voltage. Finger gap 4 35 (g) is determined according to the measured layer resistance of the heating layer (20) and the voltage to be used above They are determined using relationships. In the wing (10) application, the heating layer (20) is the leading edge as shown in Figure 1. (12) and extending along the (12) edge and towards the top and bottom surfaces of the attacking edge, preferably It is applied to an area covering 10–30% of the wing beam. The electrodes (31, 32) are used for heating. It extends along the edges of the region and within the region in the direction of the wingspan. Protective layer (40), 30–100 µm thick plain epoxy or covering the heating layer (20) and electrodes (31, 32). It is a polyurethane-based coating; it provides electrical insulation and protection against abrasion and rain erosion. It protects and maintains the aerodynamic smoothness of the surface. Electrodes (31, 32), connecting conductors It is connected to the power and control unit (50) via (60). The power and control unit (50) is powered by the aircraft’s battery or separate unit, as shown in Figure 4. a power source that can be a battery and provides a direct current voltage not exceeding 48 V, preferably 24 V. The source (51) switches the current between the power supply (51) and the heating layer (20) on and off or pulse A switching element (52) that adjusts with width modulation is applied to the heating layer (20). a current-voltage measuring unit (53) that measures voltage and current, a control unit (54) and preferably includes an ambient temperature sensor (55). The electrical resistance of the graphene nanoplatelet / epoxy heating layer (20) with temperature It changes in a repeatable manner. The control unit (54) receives from the current-voltage measuring unit (53) Calculate the instantaneous resistance of the heating layer (20) from the relation R = V / I with the values ​​and in advance Using the determined resistance-temperature calibration relationship, the temperature of the heating layer (20) Thus, the heating layer (20) acts as both a heater and a temperature sensor and determines. There is no need for separate temperature sensors and their wiring. The control unit (54) monitors the environment. The temperature taken from the temperature sensor (55) is below a predetermined lower threshold value, e.g. +3 When the temperature drops below °C, it activates the switching element (52); heating layer (20) It maintains its temperature within a predetermined target range, for example between +5 °C and +20 °C. The system cuts off power when the temperature reaches a predetermined upper limit, for example, +60 °C. Ice Prevention mode provides continuous heating at low power, while defrosting mode provides high power at specific intervals. Pulsed heating is applied with force; in pulsed heating, the ice-surface interface is melted, breaking down the ice layer. It is separated from the surface by aerodynamic forces. The heating layer (20) is used in one application to heat graphene nanoplatelets (22) in a solvent such as acetone. dispersed within by ultrasonic process, by adding hardener-free epoxy resin to the suspension. mixing, removal of solvent under heating and vacuum, addition of hardener and the bottom of the mixture on which the electrodes (31, 32) and the conductive interlayer (35) are pre-placed It is obtained by applying the film to the layer (11) with an applicator, brush or spray and curing it. Then the heating layer (20) and the electrodes (31, 32) are covered with a protective layer (40). 35 The system in question consists of tail surfaces, propeller blades, rotor except for the wings (10). other parts exposed to icing such as blades, wind turbine blades, antenna and sensor covers It can also be applied to surfaces with the same layered structure. The examples given in this description illustrate the invention. This does not limit the scope of protection; a person skilled in the field can determine the scope defined in the claims. They can carry out similar practices without separating. How the invention can be applied to industry. The invention concerns an anti-icing system, unmanned aerial vehicles, and aircraft manufacturers. an additional process applied by [company name] in composite wing production lines, after wing lamination. It can be produced through coating and electrode placement steps. The graphene nanoplatelet used is epoxy. Resin, hardener, copper foil, and silver-based conductive materials are commercially available. These are the materials; the equipment used in preparing the heating layer is composite and coating. It is widely used in the industry. The invention is also used in the wind energy sector for turbines. It can be used in industry by applying it to the leading edges of wings. 6

Claims

REQUESTS 1. An electrothermal anti-icing system for an aerodynamic surface such as a wing (10). its feature is a structural substrate (11) that forms the aerodynamic surface, substrate (11) a polymer matrix (21) based on epoxy and positioned on it and within this matrix (21) electrical containing graphene nanoplatelets distributed between 15% and 30% by weight (22) as a conductive heating layer (20), in electrical contact with the heating layer (20) and first electrode (31) with first fingers (33) that run parallel to each other a second finger (34) that extends to fit between the fingers (33) consisting of electrodes (32) and the distance (g) between adjacent fingers (33, 34) is between 2 mm and 15 mm an interlocking electrode assembly (30), heating layer (20) and electrode an electrically insulating protective layer (40) covering the apparatus (30) and electrode a power and control device that applies a direct current voltage not exceeding 48 V to the device (30) It contains unit (50).

2. It is a system according to claim 1 and its feature is; graphene nanoplatelet (22) in the heating layer (20) The percentage should be between 20% and 25% by weight.

3. A system according to claim 1 or 2, whose characteristic is that graphene nanoplatelets (22) are between 5 nm and 10 nm thickness between 5 µm and 25 µm, lateral dimension between 100 m² / g and 150 m² / g It has a surface area.

4. It is a system according to any of the previous requirements and its feature is; the heating layer (20) Its thickness should be between 100 µm and 500 µm.

5. A system according to any of the previous requests, and its feature is; adjacent fingers (33, 34) The range between them (g) is between 5 mm and 10 mm.

6. A system according to any of the previous requirements, and its feature is; electrodes (31, 32) The heating layer (20) is the presence of a silver-based conductive interlayer (35).

7. A system that, according to any of the previous requirements, has the following characteristic: a power and control unit. (50) It is a direct current voltage application between 12 V and 24 V.

8. It is a system according to any of the previous requirements and its feature is; the heating layer (20), along the leading edge (12) of the wing (10) and on the upper and lower surfaces of the leading edge (12) It is positioned so that it lies flat.

9. A system that, according to any of the previous requirements, has the following characteristic: a power and control unit. (50) measures the voltage applied to the heating layer (20) and the current passing through the heating layer (20). The voltage and current of the heating layer (20) are measured with the current-voltage measurement unit (53). 1 calculating the electrical resistance of the heating layer and determining its temperature dependence on the variation of this resistance. (20) A switch that turns the current going to the heating layer (20) on and off by determining its temperature. It includes a control unit (54) that controls element (52).

10. It is a system according to claim 9 and its characteristic is that the power and control unit (50) is at an ambient temperature. it includes the sensor (55) and the control unit (54) has a predetermined ambient temperature sub- When the value falls below the threshold, it activates the switching element (52) and the heater when the specified temperature of the layer (20) reaches a predetermined upper limit value This is to disable the switching element (52).

11. It is a system according to any of the previous requirements and its feature is; the protection layer (40) 30 A pure epoxy or polyurethane-based layer with a thickness between µm and 100 µm. It is the fact that.

12. A system according to any of the previous requirements; its characteristic is that the electrodes (31, 32) are copper. It is made of foil.

13. An unmanned aerial vehicle wing containing a system according to any of claims 1 to 12 (10).

14. A wind turbine blade containing a system according to any of claims 1 to 12. 2

Images