Electric heating assembly for ice prevention and removal of engine blade and preparation method and application of electric heating assembly

Abstract

The invention relates to the technical field of engine blades, and discloses an electric heating assembly for ice prevention and removal of an engine blade and a preparation method and application of the electric heating assembly. The electric heating assembly and the engine blade are conformal, the long edge of the short axis direction of the engine blade is parallel to the first direction, and the second direction is perpendicular to the first direction; the electric heating assembly comprises a plurality of electric heating pieces which are sequentially arranged in the second direction and connected through a parallel circuit, each electric heating piece is provided with two second edges oppositely arranged in the second direction, and the second edges are parallel to the first direction; the electric heating piece comprises a conductive fabric, and the conductive fabric comprises a fiber fabric and a graphene electric heating layer conformally wrapping the fiber fabric. The electric heating assembly has good heat distribution uniformity, and the anti-icing and de-icing effects of the engine blade can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric heating devices, in particular to an electric heating assembly for preventing and removing ice on an engine blade and a preparation method and application thereof. BACKGROUND

[0002] The strong suction generated by the high-speed operation of the engine blade can cause the outside air to be sucked, and low-temperature water droplets and / or ice and snow in cold weather conditions can be sucked into the engine, causing the engine blade to ice, thereby affecting the performance of the engine and the safety of the aircraft. Metal-based electric heating technology is an effective means to prevent and remove ice on the engine blade, but the density of the metal-based electric heating material is relatively high, which does not meet the development requirements of the lightweight aircraft. The graphene fiber fabric has a relatively low density and a relatively high flexibility, which is conducive to the lightweight of the aircraft. The graphene fiber fabric is usually conformal to the engine blade, and the two edges of the graphene fiber fabric are provided with a positive electrode and a negative electrode. By applying a voltage to the positive electrode and the negative electrode, the graphene fiber fabric is heated under the action of the Peltier effect to play a role in preventing and removing ice on the engine blade.

[0003] However, the profiled engine blade is not rectangular, and when the profiled graphene fiber fabric is used to heat the profiled engine blade as a whole, the thermal distribution uniformity of the profiled graphene fiber fabric is poor, which limits the effect of preventing and removing ice on the engine blade, and is not conducive to the effect of preventing and removing ice on the profiled engine blade. SUMMARY

[0004] Therefore, the present application provides an electric heating assembly for preventing and removing ice on an engine blade and a preparation method and application thereof to improve the effect of preventing and removing ice on the engine blade.

[0005] In a first aspect, the present application provides an electric heating assembly for preventing and removing ice on an engine blade, the electric heating assembly is conformal to the engine blade, the long side of the engine blade in the short axis direction is parallel to a first direction, and a second direction is perpendicular to the first direction; the electric heating assembly comprises a plurality of electric heating elements arranged in sequence along the second direction and connected in parallel circuit, each electric heating element has two second edges arranged oppositely in the second direction, and the second edges are parallel to the first direction; the electric heating element comprises a conductive fabric, and the conductive fabric comprises a fiber fabric and a graphene heating layer conformally coated on the fiber fabric.

[0006] In the above electric heating assembly conformal to the engine blade, the plurality of electric heating elements are connected in parallel circuit, so that each electric heating element can independently generate heat. Each electric heating element has its corresponding current preferential transmission path, thereby increasing the number of current preferential transmission paths in the electric heating assembly, and further improving the thermal distribution uniformity of the electric heating assembly. The temperature difference between the plurality of electric heating elements can be very small or substantially no temperature difference, which is conducive to improving the effect of preventing and removing ice on the engine blade.

[0007] In some optional embodiments, the difference between the lengths of the two second edges of the electric heating element is 5mm-15mm. Thus, on the basis of controlling the design, preparation and assembly difficulty of the electric heating assembly, the shape of the electric heating element is close to a rectangle, which is conducive to improving the heating uniformity of different areas in the same electric heating element, thereby improving the anti-icing effect of the engine blade.

[0008] In some optional embodiments, the spacing between adjacent electric heating elements is 0.05mm-0.1mm. Thus, not only can the adjacent electric heating elements be prevented from being mistakenly contacted, but also the parallel state of the plurality of electric heating elements can be maintained, and the heating uniformity of different areas of the electric heating assembly can be improved, thereby improving the deicing effect of different areas of the engine blade surface.

[0009] In some optional embodiments, the electric heating element has two first edge regions oppositely arranged in a first direction; the electric heating element further comprises a first electrode and a second electrode located on the surface of the conductive fabric, the first electrode and the second electrode are respectively located at the two first edge regions, the first electrodes of adjacent electric heating elements are electrically connected, and the second electrodes of adjacent electric heating elements are electrically connected. By dividing a plurality of electric heating elements and arranging the first electrodes and the second electrodes of each electric heating element at the first edge regions, the first electrodes and the second electrodes in each electric heating element are approximately parallel distributed, thereby maximizing the consistency of the in-plane electric field strength of each electric heating element and improving the heating uniformity of each electric heating element.

[0010] In some optional embodiments, the electric heating assembly further comprises a first bus bar and a second bus bar, the first bus bar covers and is connected with the first electrodes of a plurality of the electric heating elements, and the second bus bar covers and is connected with the second electrodes of a plurality of the electric heating elements. By the first bus bar and the second bus bar, not only the plurality of electric heating elements are connected into a whole, but also the plurality of electric heating elements are connected in parallel.

[0011] In some optional embodiments, the fiber fabric comprises one or more of glass fiber fabric, quartz fiber fabric, aluminum oxide fiber fabric, silicon carbide fiber fabric, and boron fiber fabric.

[0012] In some optional embodiments, the thickness of the graphene electric heating layer is 10nm-100nm.

[0013] In some optional embodiments, the electric heating element further comprises an encapsulation layer covering the conductive fabric, and the encapsulation layers in the plurality of electric heating elements are in an integral structure.

[0014] In a second aspect, the present application provides a preparation method of an electric heating assembly for preventing and removing ice on an engine blade, comprising: The long side of the short axis direction of the engine blade is parallel to the first direction, the second direction is perpendicular to the first direction, the preset area of the plurality of electrothermal elements is divided according to the shape and size of the engine blade, and the division line is parallel to the first direction; The sheet resistance of each electrothermal element is calculated according to the area of the preset area of each electrothermal element, the height in the second direction and the median line width in the first direction, and the test voltage and the preset power density of the electrothermal assembly, and the preset power densities of the plurality of electrothermal elements are the same; The corresponding electrothermal element is prepared based on the size, shape and sheet resistance of the preset area of each electrothermal element, and the electrothermal element comprises a conductive fabric, and the conductive fabric comprises a fiber fabric and a graphene electrothermal layer conformally covering the fiber fabric; The plurality of electrothermal elements are arranged in sequence along the second direction and connected in parallel to obtain an electrothermal assembly, and the electrothermal assembly is conformal to the engine blade.

[0015] In some optional embodiments, the preset area of the plurality of electrothermal elements comprises a preset area of a first electrothermal element to a preset area of an Nth electrothermal element, N is an integer greater than 1, n is an integer greater than or equal to 1 and less than or equal to N; the sheet resistance of the nth electrothermal element is calculated by the following formula:

[0016] In the formula, R n方 is the sheet resistance of the nth electrothermal element, the unit is Ω / □; U is the test voltage of the electrothermal assembly, the unit is V; S n is the area of the preset area of the nth electrothermal element, the unit is m 2 ; P m is the preset power density of the electrothermal assembly, the unit is W / m 2 ; L n is the height of the preset area of the nth electrothermal element in the second direction, the unit is m; W n is the median line width of the preset area of the nth electrothermal element in the first direction, the unit is m.

[0017] In some optional embodiments, the preset area of the electrothermal element comprises a main heating zone and two electrode zones adjacent to the main heating zone, the preset area of the electrothermal element has two first edges oppositely arranged in the first direction, and the two electrode zones are respectively located at the two first edges; S n is the area of the main heating zone in the preset area of the nth electrothermal element, W n is the median line width of the main heating zone in the preset area of the nth electrothermal element in the first direction.

[0018] In some alternative embodiments, the preparing of the corresponding electrothermal element based on the size, shape and sheet resistance of the preset region of each electrothermal element comprises: forming a corresponding graphene electrothermal layer on the surface of the fiber fabric based on the sheet resistance of each electrothermal element to obtain a corresponding initial conductive fabric; cutting the initial conductive fabric based on the size and shape of the preset region of each electrothermal element to obtain the conductive fabric; and forming a first electrode and a second electrode on the surface of the conductive fabric to obtain the electrothermal element; the preset region of the electrothermal element has two first edge regions oppositely arranged in a first direction, and the first electrode and the second electrode correspond to the two first edge regions, respectively.

[0019] In some alternative embodiments, the connecting of the plurality of electrothermal elements in parallel circuit comprises: the first electrode is a metal electrode, a first bus bar is sequentially covered with the first electrodes of the plurality of electrothermal elements, and the first bus bar and the first electrodes are welded together; and the second electrode is a metal electrode, a second bus bar is sequentially covered with the second electrodes of the plurality of electrothermal elements, and the second bus bar and the second electrodes are welded together.

[0020] In a third aspect, the application provides an application of the electrothermal assembly in the first aspect to de-icing of an engine blade. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments or the related art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0022] Figure 1 is a structural schematic diagram of an electrothermal assembly in an engine blade according to an embodiment of the present application.

[0023] Figure 2 is Figure 1 is a schematic diagram of an analog circuit of the electrothermal assembly in

[0024] Figure 3 is Figure 1 is a sectional view of the electrothermal element in

[0025] Figure 4 is a planar structural schematic diagram of an engine blade according to an embodiment of the present application.

[0026] Figure 5 is a schematic diagram of partitioning an engine blade according to an embodiment of the present application.

[0027] Figure 6Infrared image of an engine blade provided with the electrothermal assembly according to Example 1.

[0028] Figure 7 Infrared image of an engine blade provided with the electrothermal assembly according to Example 1.

[0029] Figure 8 Infrared image of an engine blade provided with the electrothermal assembly according to Comparative Example 1.

[0030] Legend of reference signs: 100 - electrothermal element; 110 - conductive fabric; 120 - first electrode; 130 - second electrode; 200 - first busbar; 300 - second busbar; 400 - insulating adhesive layer; 500 - encapsulating layer; 600 - engine blade; 700 - planar model; 710 - preset region. DETAILED DESCRIPTION

[0031] The application will be further described below in conjunction with the drawings and embodiments. It can be understood that the embodiments described herein are only used to explain the application, but not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings, but not all the structures.

[0032] As described in the background, when the profiled graphene fiber fabric is used to conduct overall electrical heating on the profiled engine blade, the thermal distribution uniformity of the profiled graphene fiber fabric is poor. This is because the distance between the positive electrode and the negative electrode on the profiled graphene fiber fabric is not constant, and the current preferentially transmits from the positive electrode to the negative electrode along the shortest path, resulting in different current transmission conditions in different regions of the graphene fiber fabric, thereby causing poor thermal distribution uniformity of the profiled graphene fiber fabric.

[0033] Based on this, in a first aspect, the application provides an electrothermal assembly for deicing an engine blade, the electrothermal assembly being conformal to the engine blade, Figure 1 shows a structural schematic view of the electrothermal assembly in the engine blade, Figure 2 shows a schematic view of the simulation circuit of the electrothermal assembly. The long side of the engine blade 600 in the short axis direction is parallel to the first direction, and the second direction is perpendicular to the first direction; the electrothermal assembly includes a plurality of electrothermal elements 100 arranged in sequence along the second direction and connected in parallel circuit, the electrothermal element 100 has two second edges oppositely arranged in the second direction, and the second edges are parallel to the first direction. Figure 3 shows a cross-sectional view at A-A' in Figure 1 , referring to Figure 3 , the electrothermal element 100 includes a conductive fabric 110, and the conductive fabric 110 includes a fiber fabric (not shown) and a graphene electrothermal layer (not shown) conformally coated on the fiber fabric.

[0034] In the above electric heating assembly conforming to the engine blade 600, the plurality of electric heating elements 100 are connected in parallel circuit, so that each electric heating element 100 can independently generate heat, and each electric heating element 100 has its corresponding current preferential transmission path, thereby increasing the number of current preferential transmission paths in the electric heating assembly, and further improving the heat distribution uniformity of the electric heating assembly. The temperature difference between the plurality of electric heating elements 100 can be very small or substantially no temperature difference, which is beneficial to improve the anti-icing effect of the engine blade.

[0035] The engine blade has a long axis and a short axis. The long axis refers to the axis of the blade in the main extension direction, which is usually consistent with the length direction of the blade. The long axis is substantially the extension direction from the blade root to the blade tip, and is the direction in which the blade bears the main load such as centrifugal force and air flow impact force. The short axis is the axis perpendicular to the long axis direction. The engine blade has a first side and a second side in the short axis direction, and the length of the first side is greater than the length of the second side. The first side is the long side of the engine blade in the short axis direction.

[0036] In the present application, the electric heating assembly conforms to the engine blade means that the shapes and sizes of the two are consistent or substantially consistent. As shown in Figure 1 For the engine blade with the long side and the short side in the short axis direction being non-parallel, the electric heating assembly cannot cover the entire area of the engine blade, but since the area without the electric heating assembly at the short side is usually small, the heat emitted by the electric heating assembly can diffuse to this area to meet the anti-icing requirements of this area.

[0037] The electric heating element 100 can be trapezoidal or quasi-trapezoidal, or rectangular. In the present application, quasi-trapezoidal refers to a quadrilateral containing a set of parallel opposite sides and a set of non-parallel opposite sides, and at least one of the non-parallel opposite sides contains a curved segment.

[0038] The difference between the lengths of the two second edges of the electric heating element 100 can be 5mm-15mm, such as 5mm, 7mm, 9mm, 11mm, 13mm, 15mm, etc., or a range consisting of any of the above values. It should be understood that the smaller the difference between the lengths of the two second edges of the electric heating element 100, the closer the shape of the electric heating element 100 to a rectangle, and the higher the heat generation uniformity of different areas of the same electric heating element 100. However, this results in a larger number of electric heating elements 100 in the electric heating assembly, increasing the difficulty of design, preparation and assembly of the electric heating assembly. By limiting the difference between the lengths of the two second edges of the electric heating element 100 to the above range, it is not only beneficial to control the difficulty of design, preparation and assembly of the electric heating assembly, but also makes the shape of the electric heating element 100 close to a rectangle, which is beneficial to improve the heat generation uniformity of different areas of the same electric heating element 100, thereby improving the anti-icing effect of the engine blade.

[0039] The interval between adjacent electric heating elements 100 can be 0.05mm-0.1mm, such as 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, or a range formed by any of the above values. Adjacent electric heating elements 100 need to be spaced apart to avoid accidental contact between adjacent electric heating elements 100, but the spacing area between adjacent electric heating elements 100 cannot generate heat by itself and relies on the heat diffusion of adjacent electric heating elements 100. By limiting the interval between adjacent electric heating elements 100 to the above range, not only can accidental contact between adjacent electric heating elements 100 be avoided, but the parallel state of multiple electric heating elements 100 can also be maintained, and the heating uniformity of different areas of the electric heating assembly can be improved, thereby improving the deicing effect of different areas of the engine blade surface.

[0040] The number of electric heating elements in the electric heating assembly is determined by the length of the major axis of the engine blade, the difference between the lengths of the two second edges of the electric heating element, and the interval between adjacent electric heating elements.

[0041] The fiber fabric includes but is not limited to one or more of glass fiber fabric, quartz fiber fabric, alumina fiber fabric, silicon carbide fiber fabric, and boron fiber fabric, preferably glass fiber fabric. The infrared heating rate of graphene glass fiber fabric is as high as 0.92, close to the radiation level of a black body, and the emissivity remains stable in a wide wavelength range, thereby providing stable high heat output.

[0042] In some optional embodiments, the thickness of the graphene electric heating layer can be 10nm-100nm, such as 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, or a range formed by any of the above values.

[0043] Reference Figure 3 The electric heating element 100 further includes a first electrode 120 and a second electrode 130 on the surface of the conductive fabric 110. The electric heating element 100 has two first edge regions oppositely arranged in the first direction, and the first electrode 120 and the second electrode 130 are respectively located at the two first edge regions. The first electrodes 120 of adjacent electric heating elements are electrically connected, and the second electrodes 130 of adjacent electric heating elements are electrically connected. By dividing multiple electric heating elements and arranging the first electrodes and the second electrodes of each electric heating element at the first edge regions, the first electrodes and the second electrodes in each electric heating element are approximately parallel, thereby maximizing the uniformity of the in-plane electric field strength of each electric heating element and improving the heating uniformity of each electric heating element.

[0044] The first electrode 120 and the second electrode 130 are positive and negative electrodes respectively. The material of the first electrode 120 is metal, for example, one or more of copper, silver; the material of the second electrode 130 is metal, for example, one or more of copper, silver.

[0045] In some optional embodiments, the electric heating assembly can further include a first bus bar 200 and a second bus bar 300, the first bus bar 200 covering and connected with the first electrodes 120 of the plurality of electric heating elements 100, and the second bus bar 300 covering and connected with the second electrodes 130 of the plurality of electric heating elements 100. By the first bus bar 200 and the second bus bar 300, the plurality of electric heating elements 100 are not only connected into a whole, but also connected in parallel.

[0046] In some optional embodiments, the electric heating assembly can further include a first lead electrode and a second lead electrode for external connection of a power supply to apply voltage to the electric heating assembly.

[0047] Specifically, the first electrode 120 can be welded with the first bus bar 200, or bonded with the first bus bar 200 through conductive glue, so as to realize mechanical connection and electrical connection of the first electrode 120 and the first bus bar 200. The first bus bar 200 can be a metal mesh or a metal foil, and the material of the first bus bar 200 includes but is not limited to one or more of copper, silver.

[0048] The second electrode 130 can be welded with the second bus bar 300, or bonded with the second bus bar 300 through conductive glue, so as to realize mechanical connection and electrical connection of the second electrode 130 and the second bus bar 300. The second bus bar 300 can be a metal mesh or a metal foil, and the material of the second bus bar 300 includes but is not limited to one or more of copper, silver.

[0049] The length of the first bus bar 200 covering and connected with the first electrodes 120 of the plurality of electric heating elements 100 constitutes a first electrical connection, and the length exceeding the plurality of electric heating elements 100 constitutes a first lead electrode; the length of the second bus bar 300 covering and connected with the second electrodes 130 of the plurality of electric heating elements 100 constitutes a second electrical connection, and the length exceeding the plurality of electric heating elements 100 constitutes a second lead electrode; the first electrical connection and the second electrical connection are used to realize parallel connection of the plurality of electric heating elements 100, and the first lead electrode and the second lead electrode are used to external connection of a power supply. The first lead electrode and the second lead electrode can be led out from the same side of the electric heating assembly, or led out from the two opposite sides of the electric heating assembly.

[0050] The width of the first electrical connecting member can be the same or substantially the same as the width of the first electrode 120. The thickness of the first electrode 120 can be 50-80 pm, such as 50 pm, 55 pm, 60 pm, 65 pm, 70 pm, 75 pm, 80 pm, or a range defined by any of the above values. The width of the first electrode 120 can be 2-10 mm, such as 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or a range defined by any of the above values. By limiting the width and thickness of the first electrode 120 to the above ranges, the connection between the first electrode 120 and the first electrical connecting member is facilitated, and the connection strength between the first electrode 120 and the first electrical connecting member is improved, thereby improving the structural stability of the electric heating assembly.

[0051] The width of the second electrical connecting member can be the same or substantially the same as the width of the second electrode 130. The thickness of the second electrode 130 can be 50-80 pm, such as 50 pm, 55 pm, 60 pm, 65 pm, 70 pm, 75 pm, 80 pm, or a range defined by any of the above values. The width of the second electrode 130 can be 2-10 mm, such as 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or a range defined by any of the above values. By limiting the width and thickness of the second electrode 130 to the above ranges, the connection between the second electrode 130 and the second electrical connecting member is facilitated, and the connection strength between the second electrode 130 and the second electrical connecting member is improved, thereby improving the structural stability of the electric heating assembly.

[0052] The electric heating assembly can further include an insulating layer (not shown) covering the first and second lead-out electrodes, to prevent the first and second lead-out electrodes from being mistakenly contacted, thereby causing the electric heating assembly to short circuit. The material of the insulating layer includes, but is not limited to, one or more of polyimide (PI), polytetrafluoroethylene (PTFE), and polyester resin (PTE).

[0053] Reference Figure 3 The electric heating assembly can further include an insulating adhesive layer 400 covering the first and second electrical connecting members, to improve the connection strength between the first and second electrical connecting members and the electric heating element 100, and facilitate the stable transmission of the current from the external power source to the electric heating element 100 during the operation of the electric heating assembly. Specifically, the insulating adhesive layer 400 can be located on the side surface of the first electrical connecting member away from the first electrode 120, and on the side surface of the second electrical connecting member away from the second electrode 130.

[0054] In some alternative embodiments, the first electrical connection and the first lead electrode can be independently provided, and the second electrical connection and the second lead electrode can be independently provided. The first lead electrode and the second lead electrode can be wires.

[0055] With reference to Figure 3 The electric heating element 100 can further include an encapsulation layer 500 covering the conductive fabric 110. The encapsulation layer 500 can extend to the side surface of the insulating adhesive layer 400 away from the first electrode 120 and the second electrode 130. The encapsulation layer 500 can provide mechanical and chemical protection for the electric heating element 100, so as to avoid chemical reactions between the electric heating element 100 and oxygen and water vapor in the air, and improve the service life of the electric heating element 100.

[0056] The encapsulation layer 500 can include one or more of an epoxy resin adhesive film, a bismaleimide resin adhesive film, and a phenolic resin adhesive film.

[0057] The thickness of the encapsulation layer 500 can be 0.08mm-0.1mm, such as 0.08mm, 0.09mm, 0.1mm, or a range defined by any of the above values. By limiting the thickness of the encapsulation layer 500 to the above range, the encapsulation layer 500 has effective encapsulation capability and good flexibility, which is beneficial to improve the adhesion effect of the electric heating assembly in the engine blade.

[0058] Optionally, the encapsulation layers 500 of the plurality of electric heating elements 100 are of an integrated structure, which can improve the connection strength between the plurality of electric heating elements 100, thereby improving the structural stability of the electric heating assembly.

[0059] In a second aspect, the present application provides a preparation method of an electric heating assembly for deicing an engine blade, comprising: In step S1, the long side of the engine blade in the short axis direction is parallel to a first direction, a second direction is perpendicular to the first direction, a plurality of preset areas of electric heating elements are divided according to the shape and size of the engine blade, and the division line is parallel to the first direction. In step S2, the square resistance of each electric heating element is calculated according to the area of the preset area of each electric heating element, the height L in the second direction and the midline width W in the first direction, and the test voltage and the preset power density of the electric heating assembly. The preset power density of the plurality of electric heating elements is the same. In step S3, the corresponding electric heating element is prepared based on the size, shape and square resistance of the preset area of each electric heating element. The electric heating element includes a conductive fabric, and the conductive fabric includes a fiber fabric and a graphene electric heating layer conformally covering the fiber fabric. In step S4, the plurality of electric heating elements are arranged in sequence along the second direction and connected in parallel to obtain an electric heating assembly, and the electric heating assembly is conformal to the engine blade.

[0060] The preparation method of the electrothermal assembly can be used to prepare the electrothermal assembly provided in the first aspect, and thus the features (such as materials and sizes) and effects described for the electrothermal assembly also apply to the preparation method of the electrothermal assembly, which will not be repeated here.

[0061] In step S1, the preset regions of the plurality of electrothermal elements are divided according to the shape and size of the engine blade, including: In step S11, referring to Figure 4 , a plane model 700 of the engine blade is established according to the shape and size of the engine blade, the plane model 700 corresponding to the long side of the short axis direction of the engine blade being parallel to the first direction, the plane model being a model that converts a three-dimensional curved surface structure into a two-dimensional plane representation, which unfolds the curved surface of the curved surface object to form a plane.

[0062] In step S12, referring to Figure 5 , the plane model 700 is parallelly segmented, and the segmentation line is parallel to the first direction, obtaining a plurality of preset regions 710 of the electrothermal elements in the form of trapezoids or quasi-trapezoids, and in the segmentation process, the length difference between the parallel opposite sides in each preset region 710 of the electrothermal element needs to be ensured to be 5mm-15mm, so that the obtained preset region 710 of the electrothermal element is close to a rectangle. The preset regions of the plurality of electrothermal elements include a preset region of a first electrothermal element to a preset region of an Nth electrothermal element, N being an integer greater than 1, and n being an integer greater than or equal to 1 and less than or equal to N.

[0063] In step S2, the sheet resistance of the nth electrothermal element is calculated using the following formula:

[0064] In the formula, R n方 is the sheet resistance of the nth electrothermal element, with units of Ω / □; U is the test voltage of the electrothermal assembly, with units of V; S n is the area of the preset region of the nth electrothermal element, with units of m 2 ; P m is the preset power density of the electrothermal assembly, with units of W / m 2 ; L n is the height of the preset region of the nth electrothermal element in the second direction, which can be understood as the height of the trapezoid or quasi-trapezoid, with units of m; and W n is the midline width of the preset region of the nth electrothermal element in the first direction, which can be understood as the midline width of the trapezoid or quasi-trapezoid, with units of m.

[0065] The power density represents the power per unit area, which is used to reflect the concentration degree of energy. By limiting the preset power densities of the plurality of electric heating elements to be the same in step S2, it is beneficial to make the actual heat generation per unit area of different electric heating elements in the working process of the electric heating assembly the same or similar, thereby improving the overall heat generation uniformity of the electric heating assembly.

[0066] As a preferred embodiment, the preset region of the electric heating element includes a main heating area and two electrode areas adjacent to the main heating area, and the preset region of the electric heating element has two first edges oppositely arranged in the first direction, and the two electrode areas are respectively located at the two first edges; S n Wn is the area of the main heating area in the preset region of the nth electric heating element, n Wn is the area of the main heating area in the preset region of the nth electric heating element,

[0067] In step S3, the corresponding electric heating element is prepared based on the size, shape and sheet resistance of the preset region 710 of each electric heating element, including: In step S31, a corresponding graphene electric heating layer is formed on the surface of the fiber fabric based on the sheet resistance of each electric heating element 100, to obtain a corresponding initial conductive fabric; the process of forming the graphene electric heating layer includes but is not limited to chemical vapor deposition. The sheet resistance of the electric heating element 100 can be adjusted by controlling the thickness of the graphene electric heating layer. The areas of the preset regions 710 of the plurality of electric heating elements can be the same or different, so the sheet resistances of the plurality of electric heating elements 100 can be the same or different, and correspondingly, the thicknesses of the graphene electric heating layers in the plurality of electric heating elements 100 can be the same or different.

[0068] In step S32, the initial conductive fabric is cut based on the size and shape of the preset region 710 of each electric heating element, to obtain the conductive fabric 110; laser cutting technology can be used for cutting.

[0069] In step S33, a first electrode 120 and a second electrode 130 are formed on the surface of the conductive fabric 110, to obtain the electric heating element 100; the preset region 710 of the electric heating element has two first edge regions oppositely arranged in the first direction, and the first electrode 120 and the second electrode 130 correspond to the two first edge regions respectively, that is, the first electrode 120 and the second electrode 130 are formed in the two electrode areas respectively. The process of forming the first electrode and the second electrode includes but is not limited to spraying process. The first electrode and the second electrode are formed in the edge regions of the non-parallel opposite sides of the graphene electric heating layer.

[0070] In step S4, the plurality of electric heating elements 100 are connected in parallel circuit, including: the first electrode is a metal electrode, the first bus bar 200 covers the first electrodes 120 of the plurality of electric heating elements 100 in turn, and the first bus bar 200 and the first electrodes 120 are welded together; the second electrode is a metal electrode, the second bus bar 300 covers the second electrodes 130 of the plurality of electric heating elements 100 in turn, and the second bus bar 300 and the second electrodes 130 are welded together.

[0071] The first bus bar 200 beyond the length of the plurality of electric heating elements 100 constitutes a first lead electrode, after welding the first bus bar 200 and the first electrode 120, a polymer film can be attached to the surface of the first lead electrode and an electrical connection end for connecting to an external power source is reserved. After welding the first bus bar 200 and the first electrode 120, an insulating adhesive layer 400 can also be formed on the surface of the side of the first bus bar 200 away from the first electrode 120.

[0072] The second bus bar 300 beyond the length of the plurality of electric heating elements 100 constitutes a second lead electrode, after welding the second bus bar 300 and the second electrode 130, a polymer film can be attached to the surface of the second lead electrode and an electrical connection end for connecting to an external power source is reserved. After welding the second bus bar 300 and the second electrode 130, an insulating adhesive layer 400 can also be formed on the surface of the side of the second bus bar 300 away from the second electrode 130.

[0073] The preparation method of the electric heating assembly can further include: Step S5, after connecting the plurality of electric heating elements 100 in parallel circuit, a packaging layer 500 covering the conductive fabric 110 is formed, and the packaging layer 500 in the plurality of electric heating elements 100 is an integral structure. The packaging layer 500 can extend to the surface of the side of the insulating adhesive layer 400 away from the first electrode 120 and the second electrode 130.

[0074] The electric heating assembly is prepared into a structural and functional integrated electric heating composite engine blade through a composite material forming process with outer skin material, insulating layer material, inner skin material, etc.

[0075] In a third aspect, the application provides the use of the electric heating assembly of the first aspect in the deicing of an engine blade.

[0076] Specifically, the electric heating assembly is arranged in the engine blade, and the structure of the engine blade is as follows: the engine blade includes oppositely arranged first and second skins and an electric heating assembly located between the first and second skins and conformal to the first and second skins. The first and second skins can be unidirectional carbon fiber composite laminates.

[0077] The engine blade can further comprise a first insulating layer between the first skin and the electrothermal assembly, and a second insulating layer between the second skin and the electrothermal assembly, and the materials of the first and second insulating layers can be glass fiber composite materials.

[0078] The engine blade has an electrode lead-out portion, and the first lead-out electrode and the second lead-out electrode are electrically connected to an external power source through the electrode lead-out portion.

[0079] The engine blade can be applied to an aircraft.

[0080] The following embodiment provides a specific electrothermal assembly for understanding the technical effects of the present application. This embodiment is only an example and cannot limit the protection scope of the present application.

[0081] Embodiment The present embodiment provides an electrothermal assembly for deicing of an engine blade, and the preparation method is as follows: According to the shape and size of the engine blade, a planar model of the engine blade is established, and the long side of the planar model corresponding to the short axis direction of the engine blade is parallel to the first direction; Referring to Figure 5 The planar model is parallelly divided, and the division line is parallel to the first direction, to obtain a plurality of preset regions of the electrothermal members in trapezoidal or quasi-trapezoidal shape. In the division process, it is necessary to ensure that the length difference of the parallel opposite sides in each preset region of the electrothermal member is 5mm-15mm, and the preset regions of the six electrothermal members are cut to obtain the preset regions of the six electrothermal members. The numbering of the preset regions is 1#, 2#, 3#, 4#, 5# and 6# along the long axis direction of the engine blade; The area S of each preset region, the height L of the trapezoidal or quasi-trapezoidal shape, and the width W of the median line of the trapezoidal or quasi-trapezoidal shape are measured, wherein the area S and the width W of the median line are measured excluding the positive and negative electrode setting regions, and the positive and negative electrode setting regions are respectively located at the edge positions of the non-parallel opposite sides of the preset region, and the width of the positive and negative electrode setting regions is 3mm; in combination with the test voltage U and the preset power density P of the electrothermal assembly m The square resistance R of each electrothermal member is calculated n方 The test voltage U is 100V, and the preset power density of the six electrothermal members is 1000W / m 2 The parameters of each electrothermal member are shown in Table 1; Table 1: Parameters of electrothermal members

[0082] Based on the square resistance of each electrothermal member, a corresponding thickness of the graphene electrothermal layer is formed on the surface of the glass fiber fabric, to obtain a corresponding graphene glass fiber fabric. Based on the size and shape of the preset region of each electrothermal element, the graphene glass fiber fabric is cut by using a laser cutting technology; An anode and a cathode are formed on the surface of the cut graphene glass fiber fabric by using a spraying process, the anode and the cathode correspond to the setting region of the anode and the setting region of the cathode in the preset region respectively, the materials of the anode and the cathode are copper, and the thicknesses of the anode and the cathode are both 60 μm, thereby 6 electrothermal elements are prepared, and the electrothermal elements have numbers corresponding to the preset regions; Referring to Figure 1 The 6 electrothermal elements are arranged in sequence, and the parallel opposite sides in the adjacent electrothermal elements are parallel to each other; The first bus bar covers the anodes of the 6 electrothermal elements in sequence, the first bus bar and the anodes are welded together, and the part of the first bus bar that exceeds the 6 electrothermal elements constitutes a first lead electrode; the second bus bar covers the cathodes of the 6 electrothermal elements in sequence, the second bus bar and the cathodes are welded together, and the part of the second bus bar that exceeds the 6 electrothermal elements constitutes a second lead electrode; the first bus bar and the second bus bar are both copper meshes; Polyimide (PI) is attached to the surfaces of the first lead electrode and the second lead electrode, and the electrical connection ends connected with an external power supply are reserved; silica gel is coated on the surface of the side of the first bus bar away from the anodes and the surface of the side of the second bus bar away from the cathodes to form insulating glue layers; the two test pens of a universal meter are connected with the electrical connection ends of the first lead electrode and the second lead electrode respectively, and the inter-electrode resistance of the electrothermal assembly is measured to be 343.2 Ω.

[0083] A resin glue layer covering the electrothermal elements is formed by using a hot press tank process, and the resin glue layers in the 6 electrothermal elements are connected together, the thickness of the resin glue layer is 0.08 mm to 0.1 mm, and the material of the resin glue layer is epoxy resin, thereby an electrothermal assembly conforming to the engine blade is prepared. The two test pens of a universal meter are connected with the electrical connection ends of the first lead electrode and the second lead electrode respectively, and the inter-electrode resistance of the electrothermal assembly is measured to be 354.3 Ω, which indicates that the conductive network of the electrothermal assembly remains complete after hot pressing. Compared with before hot pressing, the inter-electrode resistance increases by 3.2% after hot pressing, because the epoxy resin is impregnated between the graphene glass fiber fabrics during the curing process, which reduces the connection points between the fabric networks, thereby causing a small increase in the resistance.

[0084] Comparative Example The comparative example provides an electrothermal assembly for deicing of an engine blade, which is different from the example only in that the electrothermal assembly has only one electrothermal element conforming to the engine blade, and the electrothermal element is prepared by using a graphene glass fiber fabric, and the sheet resistance of the graphene glass fiber fabric is 1396 Ω / □.

[0085] Performance Test Before and after assembling the electric heating assembly into the engine blade, connect the electrical connection ends of the first and second lead electrodes of the electric heating assembly to a power source. Apply 100V AC to the electric heating assembly. After the electric heating assembly stabilizes, use a PT100 infrared thermal imager to capture an infrared image of the electric heating assembly or engine blade and the maximum temperature difference. The PT100 infrared thermal imager captures infrared radiation energy from non-contact detection objects and converts it into an electrical signal, generating a pseudo-color thermal image and temperature values. This allows for intuitive observation of infrared images of the detected object and automatically tracks the temperature at each point in the image.

[0086] The temperature uniformity of Example 1 was obtained by using the above temperature uniformity test method: Before the electric heating component was assembled in the engine blade, the infrared image of the electric heating component in Example 1 was as follows: Figure 6 As shown, the overall color of the infrared image is relatively uniform, indicating that the temperature difference between the heating elements is small and the heating element as a whole is uniform. After the heating element is assembled in the engine blade, the infrared image of the engine blade is as follows: Figure 7 As shown, the overall color of the infrared image is relatively uniform, indicating that the overall heating of the engine blades is uniform.

[0087] The temperature uniformity of comparative example 1 was obtained by using the above temperature uniformity test method: before the electric heating component was assembled in the engine blade, the heating uniformity of the electric heating component was poor; after the electric heating component was assembled in the engine blade, the infrared image of the engine blade was as follows: Figure 8 As shown, the upper part of the infrared image is purple and the lower part is bright orange. The color difference is large, indicating that there is a large temperature difference in the engine blades and the heating uniformity of the engine blades is poor.

[0088] Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0089] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0090] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0091] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0092] The above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described above, and that various obvious changes, readjustments, combinations, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of protection of the present invention is determined by the scope of the appended claims.

Claims

1. An electric heating component for engine blade deicing, characterized in that: The electric heating component is conformal to the engine blade, the long side of the engine blade in the short axis direction is parallel to the first direction, and the second direction is perpendicular to the first direction; the electric heating component includes a plurality of electric heating elements arranged in sequence along the second direction and connected in parallel circuits, the electric heating element having two second edges arranged opposite to each other in the second direction, and the second edges are parallel to the first direction; the electric heating element includes a conductive fabric, and the conductive fabric includes a fiber fabric and a graphene electric heating layer conformally covering the fiber fabric.

2. The electric heating component according to claim 1, characterized in that The difference in length between the two second edges of the heating element is 5 mm to 15 mm; And / or, the spacing between adjacent electric heating elements is 0.05 mm to 0.1 mm.

3. The electric heating component according to claim 1, characterized in that The electric heating element has two first edge areas arranged opposite to each other in a first direction; the electric heating element also includes a first electrode and a second electrode located on the surface of the conductive fabric, the first electrode and the second electrode are respectively located in the two first edge areas, the first electrodes of adjacent electric heating elements are electrically connected, and the second electrodes of adjacent electric heating elements are electrically connected.

4. The electric heating component according to claim 3, characterized in that Also includes: a first bus bar, the first bus bar covering the first electrodes of the plurality of the electric heating elements and being connected to the first electrodes; A second bus bar covers the second electrodes of the plurality of electric heating elements and is connected to the second electrodes.

5. The electric heating component according to any one of claims 1 to 4, characterized in that: The fiber fabric includes one or more of glass fiber fabric, quartz fiber fabric, alumina fiber fabric, silicon carbide fiber fabric, and boron fiber fabric; And / or, the thickness of the graphene electric heating layer is 10nm~100nm; And / or, the electric heating element further includes a packaging layer covering the conductive fabric, and the packaging layers in the plurality of electric heating elements are an integrated structure.

6. A method for preparing an electric heating component for engine blade deicing, characterized in that: include: The long side of the short axis direction of the engine blade is parallel to the first direction, the second direction is perpendicular to the first direction, and the preset areas of the multiple electric heating elements are divided according to the shape and size of the engine blade, and the dividing line is parallel to the first direction; Calculating the square resistance of each electric heating element according to the area of ​​the preset region of each electric heating element, the height in the second direction and the median width in the first direction, as well as the test voltage and preset power density of the electric heating assembly, wherein the preset power density of the plurality of electric heating elements is the same; A corresponding electric heating element is prepared based on the size, shape and square resistance of a preset area of ​​each electric heating element, wherein the electric heating element includes a conductive fabric, and the conductive fabric includes a fiber fabric and a graphene electric heating layer conformally covering the fiber fabric; A plurality of the electric heating elements are arranged in sequence along the second direction and connected in parallel circuit to obtain an electric heating assembly, and the electric heating assembly is conformal to the engine blade.

7. The preparation method according to claim 6, characterized in that The preset areas of the plurality of electric heating elements include the preset area of ​​the first electric heating element to the preset area of ​​the Nth electric heating element, N is an integer greater than 1, and n is an integer greater than or equal to 1 and less than or equal to N; Use the following formula to calculate the square resistance of the nth electric heating element: Where R n方 is the square resistance of the nth electric heating element, in Ω / □; U is the test voltage of the electric heating component, in V; S n The area of ​​the preset area of ​​the nth electric heating element, in m 2 ; P m The preset power density of the electric heating component, in W / m 2 ; L n is the height of the preset area of ​​the nth electric heating element in the second direction, in meters; W n is the median width of the preset area of ​​the nth electric heating element in the first direction, in m.

8. The preparation method according to claim 7, characterized in that The preset area of ​​the electric heating element includes a main heating area and two electrode areas adjacent to the main heating area. The preset area of ​​the electric heating element has two first edges arranged opposite to each other in a first direction, and the two electrode areas are respectively located at the two first edges; n is the area of ​​the main heating zone in the preset area of ​​the nth electric heating element, W n is the median width of the main heating zone in the preset area of ​​the nth electric heating element in the first direction.

9. The preparation method according to claim 6, characterized in that The method of preparing a corresponding electric heating element based on the size, shape and square resistance of a preset area of ​​each electric heating element includes: Based on the square resistance of each electric heating element, a corresponding graphene electric heating layer is formed on the surface of the fiber fabric to obtain a corresponding initial conductive fabric; Cutting the initial conductive fabric based on the size and shape of a preset area of ​​each electric heating element to obtain the conductive fabric; The electric heating element is obtained by forming a first electrode and a second electrode on the surface of the conductive fabric; a preset area of ​​the electric heating element has two first edge areas arranged opposite to each other in a first direction, and the first electrode and the second electrode correspond to the two first edge areas respectively.

10. The preparation method according to claim 9, characterized in that Connecting a plurality of the electric heating elements in parallel circuits comprises: The first electrode is a metal electrode, the first bus bar is sequentially covered with the first electrodes of the plurality of electric heating elements, and the first bus bar and the first electrode are welded together; The second electrode is a metal electrode. The second bus bar is sequentially covered with the second electrodes of the plurality of electric heating elements, and the second bus bar and the second electrode are welded together.

11. Use of the electric heating component according to any one of claims 1 to 5 in engine blade deicing.

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