A wind power blade wave-absorbing core material structure and a wind power blade

Abstract

The present application relates to a kind of wind power blade wave-absorbing core structure and wind power blade, wave-absorbing core structure includes core material base, core material base is equipped with slot, slot depth is less than core material thickness, slot is provided with reinforcing fiber woven cloth or wave-absorbing structure, the reinforcing fiber woven cloth also has wave-absorbing agent in combination, the wave-absorbing structure includes two layers of glass fiber woven cloth and the wave-absorbing material between the two layers of glass fiber woven cloth is set.This application will be combined with the wave-absorbing agent reinforcing fiber woven cloth or wave-absorbing structure into core material slot on the basis of existing core material slot, reinforcing fiber woven cloth will extend to the surface of core material, then the core material and upper and lower skin and other auxiliary layer material are laid on blade mold, then integrally cast, improve the wave-absorbing performance and mechanical properties of wind power blade sandwich structure, while reducing the problem that core material and upper and lower skin appear peeling during long time operation of wind power blade, leading to blade failure.

Description

Technical Field

[0001] This invention relates to the field of wind turbine blade technology, and in particular to the core material structure of wind turbine blades, specifically a wind turbine blade wave-absorbing core material structure and a wind turbine blade. Background Technology

[0002] With the increasing size of wind turbine blades and the gradual deployment of wind farms along coastlines and near-shore areas, the massive volume of wind turbine towers and blades results in a large electromagnetic wave reflection area. This can adversely affect the operational performance of military radar and communication equipment. Strong reflections can cause signal saturation or even signal burnout in radar and communication receivers, hindering the normal operation of military equipment. Currently, coating with absorbing materials is commonly used. However, offshore wind turbine blades present complex challenges. As usage time increases, the absorbing materials, such as patches and coatings, age and are prone to damage and detachment. Maintenance of offshore wind turbine blades is affected by various objective factors, including weather and transportation, resulting in high maintenance costs.

[0003] Besides radar-absorbing products such as coated radar-absorbing materials, a radar-absorbing composite sandwich structure can be used based on the material properties of wind turbine blades. Patent application number 20230700568.9 discloses a radar-stealth radar-absorbing foam sandwich composite structure. This structure uses chopped strand mat (CSM) to wrap the sandwich structure, preventing damage from strong impacts that could lead to a decrease in radar absorption and mechanical properties. While wrapping the sandwich structure with CSM does improve overall structural stability, it reduces the conformability of the core material, and this method is difficult to widely apply.

[0004] To achieve better bandwidth and absorption effect, existing absorbing composite materials use a triple structure of matching layer-absorbing layer-conductor stacking for wave absorption. To increase the wave absorption effect, the thickness of the matching layer and absorbing layer is reduced and the stacking is repeated several times. The resulting sandwich structure of absorbing composite material has poor mechanical properties. At the same time, the increase in the number of layers will significantly increase the weight of the blade, making it difficult to apply directly to the existing wind turbine blade profile. In addition, the processing method is complicated and prone to undetectable processing problems, resulting in a lot of waste. Summary of the Invention

[0005] The purpose of this invention is to provide a wind turbine blade absorbing core material structure and a wind turbine blade. Based on existing grooved core material structures, reinforcing fiber woven fabric is first combined with a wave-absorbing agent and then placed into the horizontal and / or vertical grooves of the core material, or the wave-absorbing structure is placed into the grooves of the core material. Subsequently, the core material, along with the upper and lower skins and other auxiliary materials, is laid onto a blade mold and then integrally cast. This solution improves the wave-absorbing performance and mechanical properties of the wind turbine blade sandwich structure, while reducing the problem of blade failure caused by the core material peeling off from the upper and lower skins during long-term operation.

[0006] The present invention is specifically achieved through the following technical solution: a wind turbine blade wave-absorbing core material structure proposed according to the present invention includes a core material matrix, a groove provided on the core material matrix, the groove depth being less than the core material thickness, a reinforcing fiber woven fabric or a wave-absorbing structure being disposed in the groove, the reinforcing fiber woven fabric also being bonded with a wave-absorbing agent, and the wave-absorbing structure comprising two layers of glass fiber woven fabric and a wave-absorbing material disposed between the two layers of glass fiber woven fabric.

[0007] Preferably, the reinforcing fiber woven fabric is selected from one or more of glass fiber, carbon fiber, carbon / glass hybrid fiber, quartz fiber, Kevlar fiber, ultra-high molecular weight polyethylene fiber, and PBO fiber, and the microwave absorbing agent is selected from graphene aqueous dispersion, carbon nanotube aqueous dispersion, or nano nickel aqueous dispersion.

[0008] Furthermore, the microwave absorbing agent is combined with the reinforcing fiber woven fabric through impregnation or spraying. After being impregnated with the microwave absorbing agent, the reinforcing fiber woven fabric is first air-dried and then dried at 80°C for 4 hours. Similarly, after the microwave absorbing agent dispersion is sprayed onto the reinforcing fiber woven fabric, the fabric is also first air-dried and then dried at 80°C for 4 hours. Both methods require the reinforcing fiber woven fabric to be heated and dried at 80°C before use, until the blades are laid up.

[0009] Preferably, the absorbing material is selected from at least one of carbon fiber, carbon nanotubes, graphene, alumina, and silicon nitride, and the absorbing material accounts for 10-20% of the mass of the absorbing structure.

[0010] Preferably, the wave-absorbing material is laid in a trapezoidal shape between two layers of fiberglass woven fabric, and the two inclined sides of the trapezoidal wave-absorbing material are inclined straight sides or stepped.

[0011] Preferably, the two oblique straight edges of the trapezoidal absorbing material can change their shape and tilt angle depending on the location of the blade.

[0012] Furthermore, the core material has multiple horizontal grooves and multiple vertical grooves, with the horizontal grooves intersecting with the vertical grooves. The horizontal grooves and / or vertical grooves are provided with reinforcing fiber woven fabric or wave-absorbing structures, and the reinforcing fiber woven fabric is bonded with a wave-absorbing agent.

[0013] Furthermore, the core material is provided with corrugated grooves, the depth of which is less than the thickness of the core material. The corrugated grooves are oblique grooves opened along the diagonal of the rectangle formed by the intersecting horizontal and vertical grooves, and each corrugated groove is provided with the wave-absorbing structure.

[0014] Furthermore, the core material has multiple sloping grooves, which may or may not intersect each other. The absorbing structure is provided in the sloping groove. After the absorbing structure is inserted into the sloping groove, the two layers of glass fiber woven fabric contact the core material on the two sides of the sloping groove respectively.

[0015] Furthermore, depending on the grooving pattern, the absorbing material is placed between two layers of fiberglass woven fabric and then pre-cured before the entire absorbing structure is placed into the corresponding core material groove.

[0016] The present invention also provides a wind turbine blade, which includes the wave-absorbing core material structure as described above.

[0017] Compared with existing technologies, this invention has significant advantages and beneficial effects. Through the above technical solution, this invention achieves considerable technological advancement and practicality, and has broad application value, possessing at least the following advantages:

[0018] (1) Existing wind turbine blade core materials are grooved and perforated before use to allow resin to fill the grooves and improve core material performance. This invention, based on the existing grooving, first combines reinforcing fiber woven fabric with a wave-absorbing agent and then places it into the groove of the core material. Subsequently, the core material, along with the upper and lower skins and other auxiliary materials, is laid onto the blade mold and then integrally cast, improving the wave-absorbing performance and mechanical properties of the wind turbine blade. After the reinforcing fiber woven fabric is placed into the groove of the core material, and the core material is cast together with the upper and lower skins and other auxiliary materials to form the wind turbine blade, the upper and lower skins still contact the reinforcing fiber woven fabric in the core material groove. This transforms the peeling performance between the upper and lower skins and the core material into interlayer performance between the fabrics, effectively solving the peeling problem between the core material and the skin, and significantly reducing the blade failure caused by the peeling of the core material from the upper and lower skins during long-term blade operation.

[0019] (2) The present invention can also place a wave-absorbing structure in the slots of the core material. The wave-absorbing structure consists of two layers of fiberglass woven fabric and wave-absorbing material disposed between the two layers of fiberglass woven fabric, and is cured by injecting epoxy resin. After the wave-absorbing structure is inserted into each slot, the core material, upper and lower skins and other auxiliary materials are laid on the blade mold, and then integrally injected and molded, which improves the wave-absorbing performance and mechanical properties of the wind turbine blade, and can ensure that the wave-absorbing structure has good stability during use.

[0020] (3) The present invention can also place a reinforcing fiber woven fabric with a wave-absorbing agent in the horizontal and / or vertical grooves of the core material, and at the same time open a wave groove on the core material and place a wave-absorbing structure in the wave groove. This method combines the reinforcing fiber woven fabric with a wave-absorbing agent with the wave-absorbing structure, further enhancing the wave-absorbing performance and mechanical properties of the core material. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the core material with horizontal and vertical grooves in Example 1.

[0022] Figure 2 This is a schematic diagram of the structure of the integrated reinforced fiber woven fabric in Example 1.

[0023] Figure 3 This is a schematic diagram of the core material with inclined grooves in Example 2.

[0024] Figure 4 yes Figure 3 A magnified view of a local area of ​​K.

[0025] Figure 5 This is a schematic diagram of a unidirectional inclined groove.

[0026] Figure 6 This is a schematic diagram of the three-layer structure of the wave-absorbing structure.

[0027] Figure 7 yes Figure 6 The cross-sectional view along the AA direction shows that the microwave absorbing material is trapezoidal.

[0028] Figure 8 yes Figure 7 A schematic diagram of the trapezoidal microwave absorbing material with its two inclined sides designed in a stepped shape.

[0029] Figure 9 Is Figure 1 The diagram shows the addition of wave grooves to the existing structure.

[0030] 1-Core material matrix, 2-Horizontal groove, 3-Vertical groove, 4-Slanted groove, 5-Wave groove, 6-Reinforcing fiber woven fabric, 7-First layer of glass fiber woven fabric, 8-Wave absorbing material, 9-Second layer of glass fiber woven fabric. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0032] A wind turbine blade core material structure includes a core material substrate 1 with grooves on it. The groove depth is less than the core material thickness. Reinforcing fiber woven fabric 6 and / or a wave-absorbing structure are disposed within the grooves. The reinforcing fiber woven fabric is also bonded with a wave-absorbing agent, which is bonded to the reinforcing fiber woven fabric by impregnation or spraying.

[0033] The reinforcing fiber woven fabric can be selected from one or more of the following: glass fiber, carbon fiber, carbon / glass hybrid fiber, quartz fiber, Kevlar fiber, ultra-high molecular weight polyethylene fiber, and PBO fiber.

[0034] Preferably, the microwave absorbing agent is selected from graphene aqueous dispersion, carbon nanotube aqueous dispersion, or nano nickel aqueous dispersion.

[0035] After the reinforcing fiber woven fabric is impregnated in the wave-absorbing agent, it is first air-dried naturally, then dried at about 80°C for 4 hours, and finally placed into the groove of the core material. Before the blades are laid up, the core material is dried again at 80°C.

[0036] Alternatively, after the wave-absorbing agent dispersion is sprayed onto the reinforcing fiber woven fabric, the reinforcing fiber woven fabric is first naturally dried, then dried at about 80℃ for 4 hours, and finally placed into the groove of the core material. Before the blades are laid up, the core material is dried again at 80℃.

[0037] Preferably, the absorbing material is selected from at least one of carbon fiber, carbon nanotubes, graphene, alumina, and silicon nitride, and the absorbing material accounts for 10-20% of the mass of the absorbing structure.

[0038] The present invention will now be described in detail with reference to specific embodiments.

[0039] Example 1

[0040] like Figure 1 As shown, the grooving includes multiple horizontal grooves 2 and multiple vertical grooves 3. The horizontal grooves are parallel to side A of the core material, and the vertical grooves are parallel to side B of the core material. Sides A and B are two intersecting sides of the core material, and side A is perpendicular to side B. The multiple horizontal grooves intersect with the multiple vertical grooves.

[0041] In this embodiment, the reinforcing fiber woven fabric is impregnated with the wave-absorbing agent beforehand and combined with the wave-absorbing agent. After being naturally air-dried, it is dried at 80°C for 4 hours. Then, the reinforcing fiber woven fabric combined with the wave-absorbing agent is placed into the horizontal or vertical groove of the core material. Subsequently, the core material, the upper and lower skins and other auxiliary materials are laid on the blade mold and then integrally cast.

[0042] In other embodiments, an integral reinforcing fiber woven fabric adapted to the grooves in the core material can also be prepared according to the structure of the horizontal and vertical grooves. In this embodiment, the integral reinforcing fiber woven fabric includes multiple horizontally arranged reinforcing fiber woven fabrics and multiple vertically arranged reinforcing fiber woven fabrics, and the multiple horizontally arranged reinforcing fiber woven fabrics and the multiple vertically arranged reinforcing fiber woven fabrics are interwoven, consistent with the groove structure on the core material, such as... Figure 2 As shown, after combining it with the wave-absorbing agent by impregnation or spraying, it is naturally air-dried and dried at 80℃ for 4 hours. Then it is integrally placed into the groove of the core material. At this time, reinforcing fiber woven fabric combined with wave-absorbing agent is placed in the horizontal and vertical grooves of the core material. Then the core material, along with the upper and lower skins and other auxiliary materials, is laid on the blade mold and then integrally cast.

[0043] It should be noted that in the above embodiments, after the reinforcing fiber woven fabric is placed into the groove of the core material, and after the core material is poured together with the upper and lower skins and other auxiliary materials to make the wind turbine blade, the upper and lower skins are still in contact with the reinforcing fiber woven fabric in the groove of the core material. This transforms the peeling performance between the upper and lower skins and the core material into the interlayer performance between the fabrics, effectively solving the peeling problem between the core material and the skin, and significantly reducing the blade failure caused by the peeling of the core material from the upper and lower skins during long-term blade operation.

[0044] Example 2

[0045] like Figure 3 As shown, the core material has a crisscrossing groove structure, with the groove depth less than the core material thickness. A wave-absorbing structure is then placed within these grooves to enhance the blade's wave-absorbing performance.

[0046] The aforementioned microwave absorbing structure comprises two layers of fiberglass woven fabric stacked on top of each other, and a microwave absorbing material disposed between the two layers of fiberglass woven fabric. The microwave absorbing material is cut into a trapezoidal structure and laid between the two layers of fiberglass woven fabric. The inclined straight sides of the trapezoid provide the microwave absorption angle, thereby enhancing the microwave absorption capability. Figure 7 As shown, the two straight, sloping sides of the trapezoidal absorbing material can change their shape and tilt angle depending on their placement on the blade.

[0047] The absorbing material can also be cut into a pyramid structure, such as... Figure 8 As shown, the two oblique straight edges of the trapezoidal absorbing material are designed as steps and then laid between two layers of fiberglass woven fabric.

[0048] The aforementioned microwave absorbing structure is formed by injecting epoxy resin and then curing it. Specifically, a first layer of fiberglass woven fabric 7 can be laid in the mold first, followed by the cut microwave absorbing material 8, and then a second layer of fiberglass woven fabric 9 can be laid on the microwave absorbing material. The mold is then closed, and epoxy resin is injected. After the epoxy resin cures, the upper and lower layers of fiberglass woven fabric and the middle microwave absorbing material are combined together.

[0049] The absorbing material in the absorbing structure can be at least one of carbon fiber, carbon nanotubes, graphene, alumina, silicon nitride, etc.

[0050] In this embodiment, the wave-absorbing structure is inserted into the inclined groove of the core material, such as... Figure 4 As shown, multiple crisscrossing grooves divide the core material into small square or triangular prism units. An absorbing structure is inserted into the groove of each prism unit. For example: Figure 4 In the middle, multiple inclined troughs crisscross, Figure 4The local area shown is divided into small square prism units or small triangular prism units. When inserting absorbing structures, absorbing structures are inserted in slots AB, AD, DC, CB, DE, DF, FG, GC, GH, HI, IC, and HJ. Following this method... Figure 3 An absorbing structure is inserted into each of the inclined slots shown.

[0051] When inserting the absorbing structure, the long side of the structure is inserted along the thickness direction of the core material, that is, the long side of the absorbing structure is inserted into the inclined groove along the depth direction of the groove. After the absorbing structure is inserted into the inclined groove, the long bottom edge of the trapezoidal absorbing material is located at the bottom of the inclined groove, and the short bottom edge is located at the top of the inclined groove. The two layers of glass fiber woven fabric of the absorbing structure are in contact with the core material on the two sides of the inclined groove, respectively. The long side of the absorbing structure refers to the side parallel to the upper or lower bottom of the trapezoidal absorbing material, i.e. Figures 6 to 8 The MN segment shown is the long side of the microwave absorbing structure. When the microwave absorbing structure is inserted into the inclined groove of the core material, a machine is used for insertion to improve efficiency.

[0052] After the aforementioned absorbing structure is inserted into the inclined groove of the core material, the core material, along with the upper and lower skins and other auxiliary materials, is laid onto the blade mold, and then integrally cast to complete the blade manufacturing process.

[0053] In other embodiments, the core material may also have unidirectional oblique grooves, such as... Figure 5 As shown.

[0054] Example 3

[0055] Based on Example 1, a corrugated groove 5 can also be opened on the core material, such as... Figure 9 As shown, the depth of the corrugated groove is also less than the thickness of the core material. The corrugated groove is an oblique groove opened along the diagonal of the rectangle formed by the intersecting horizontal and vertical grooves. The wave-absorbing structure described in Example 2 can be inserted into each corrugated groove. This example combines the reinforcing fiber woven fabric with wave-absorbing agent with the wave-absorbing structure, further enhancing the wave-absorbing performance and mechanical properties of the core material. After the reinforcing fiber woven fabric with wave-absorbing agent is inserted into the horizontal and / or vertical grooves of the core material, the wave-absorbing structure is inserted into the corrugated groove. Then, the core material, upper and lower skins, and other auxiliary materials are laid onto the blade mold, and then integrally cast to complete the blade manufacturing.

[0056] Example 4

[0057] like Figure 1 As shown, the slotting includes multiple horizontal slots 2 and multiple vertical slots 3. The horizontal slots are parallel to side A of the core material, and the vertical slots are parallel to side B of the core material. Sides A and B are two intersecting sides of the core material, and sides A and B are perpendicular to each other. The multiple horizontal slots intersect with the multiple vertical slots. The wave-absorbing structure described in Embodiment 2 is provided in the horizontal and vertical slots of the core material.

[0058] The above description is merely an embodiment of the present invention and is not intended to limit the present invention in any way. The present invention can also have other embodiments based on the above structure and function, which will not be listed hereafter. Therefore, any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A wind power blade wave-absorbing core structure, comprising a core body, wherein a slot is arranged on the core body, and the depth of the slot is less than the thickness of the core body, characterized in that The wave-absorbing structure is inserted into the corresponding groove of the core material, and the long side of the wave-absorbing structure is inserted into the groove along the thickness direction of the core material, that is, the long side of the wave-absorbing structure is inserted into the groove along the depth direction of the groove; after the wave-absorbing structure is inserted into the groove, the long bottom side of the trapezoidal wave-absorbing material is located at the bottom of the groove, and the short bottom side is located at the top of the groove; the two glass fiber woven cloths of the wave-absorbing structure are in contact with the core material on the two sides of the groove, respectively; the long side of the wave-absorbing structure refers to the side parallel to the upper bottom or the lower bottom of the trapezoidal wave-absorbing material.

2. The wave- absorbing core material structure for wind power blades according to claim 1, characterized in that The wave-absorbing material is selected from at least one of carbon fiber, carbon nanotube, graphene, aluminum oxide and silicon nitride.

3. The wind turbine blade wave absorbing core structure of claim 1 or 2, wherein The groove of the core material includes a plurality of horizontal grooves and a plurality of vertical grooves, the plurality of horizontal grooves intersect with the plurality of vertical grooves, and the wave-absorbing structure is arranged in the horizontal grooves and / or the vertical grooves.

4. The wave- absorbing core material structure for wind power blades according to claim 3, characterized in that The wave-absorbing structure is arranged in the horizontal grooves and / or the vertical grooves.

5. The wave- absorbing core material structure for wind power blades according to claim 1 or 2, characterized in that The groove of the core material includes a plurality of inclined grooves, the inclined grooves are staggered with each other or not staggered with each other, and the wave-absorbing structure is arranged in the inclined grooves.

6. A wind turbine blade, characterised in that The wave-absorbing core material structure includes the wave-absorbing core material structure according to claim 1.

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