Wind power blade structure prefabricated part, wind power blade and design method of the prefabricated part

Abstract

This application relates to the field of wind turbine blades, and discloses a structural preform for wind turbine blades, a wind turbine blade, and a design method for the structural preform. Among them, a structural preform for wind turbine blades is characterized by including a structural surface with a flow guiding structure. The structural surface includes alternately arranged first flow guiding regions and second flow guiding regions. The flow guiding directions of the flow guiding structures in the first flow guiding regions and the second flow guiding regions are cross - arranged, and the flow guiding structure in the first flow guiding region is distributed in a mesh shape. It is used to solve the problem that the quality of wind turbine blades increases due to the improvement of the penetration effect by continuous felt. By setting a flow guiding structure on the structural surface of the structural preform of the wind turbine blade, and the first flow guiding region and the second flow guiding region with different flow guiding directions in the flow guiding structure, and the first flow guiding region has a mesh - shaped first flow guiding structure, thereby improving the penetration effect of the resin during the molding process of the wind turbine blade, reducing the use of continuous felt, and thus reducing the overall weight of the wind turbine blade.

Description

Technical Field

[0001] This application belongs to the field of wind turbine blades, and particularly relates to a prefabricated component for the structure of a wind turbine blade, a wind turbine blade, and a design method for the prefabricated component. Background Art

[0002] During the manufacturing process of the skin of a wind turbine blade, the main forming process is as follows: lay successively continuous fiber reinforced materials such as glass fiber, continuous felt, prefabricated components for the structure of a wind turbine blade, and structural core materials such as balsa wood core and foam core on a one-sided airtight blade shell mold; lay various forming auxiliary materials on the reinforced material, and the basic sequence is release cloth or separator film → flow net → vacuum bag film; use a vacuum pump to extract air from the fiber reinforced body in the cavity of the blade mold to keep the fiber reinforced body in a vacuum state; under the action of negative pressure, inject resin into the mold cavity to make the resin flow and penetrate in the fiber reinforced body, and after the resin infiltrates the fiber reinforced body, cure it at room temperature or in a heated state; perform post-treatment to obtain a wind turbine blade with a qualified ratio of resin and reinforcing fiber.

[0003] Among them, the prefabricated component for the structure of a wind turbine blade refers to a component prefabricated outside the wind turbine blade mold, such as a root prefabricated component, a pultruded plate, a prefabricated web, a prefabricated trailing edge main beam, etc. These prefabricated components can be manufactured by different process methods, such as manual layup, vacuum assisted resin transfer molding (VARTM), prepreg, mold molding, etc.

[0004] In order to improve the penetration effect of resin, in the prior art, continuous felt is laid between the prefabricated component for the structure of a wind turbine blade and the fiber layer. However, with the continuous increase in the size of wind turbine blades, the weight of wind turbine blades is also continuously increasing. The extensive use of continuous felt is one of the important reasons for increasing the weight of wind turbine blades, which has an adverse impact on the overall weight control of wind turbine blades. Summary of the Invention

[0005] The embodiments of this application provide a prefabricated component for the structure of a wind turbine blade, a wind turbine blade, and a design method for the prefabricated component, which can ensure the penetration effect of resin and reduce the weight of the wind turbine blade.

[0006] On the one hand, the embodiments of this application provide a prefabricated component for the structure of a wind turbine blade, including a structural surface with a flow guiding structure. The structural surface includes alternately arranged first flow guiding regions and second flow guiding regions, and the flow guiding directions of the flow guiding structures in the first flow guiding regions and the second flow guiding regions are cross-arranged, and the flow guiding structure in the first flow guiding region is distributed in a net shape.

[0007] According to the prefabricated component for the structure of a wind turbine blade provided by the embodiments of this application, the flow guiding structures in the first flow guiding region and the second flow guiding region are opposite to the forming direction of the structure of the structural surface.

[0008] The prefabricated structure of a wind turbine blade provided by an embodiment of the present application, the flow guiding structure in the second flow guiding region extends along the span direction of the wind turbine blade.

[0009] The prefabricated structure of a wind turbine blade provided by an embodiment of the present application, the included angle range of the flow guiding structure in the first flow guiding region along the span direction of the wind turbine blade is ±30° to ±45°.

[0010] The prefabricated structure of a wind turbine blade provided by an embodiment of the present application, the flow guiding structure in the first flow guiding region includes successively connected flow guiding parts, and the flow guiding part includes a pair of grooves that cross-connect;

[0011] The flow guiding structure in the second flow guiding region includes protrusions, the flow guiding parts are arranged along the length direction of the protrusions, and the protrusions in each second flow guiding region are arranged in parallel.

[0012] The prefabricated structure of a wind turbine blade provided by an embodiment of the present application, the flow guiding structure in the first flow guiding region includes grooves, the depth range of the grooves is 2 ± 0.5 mm, and the width range of the grooves is 2 mm to 3 mm; the flow guiding structure in the second flow guiding region includes protrusions, the height range of the protrusions protruding from the structural surface is 2 mm to 3 mm, and the width range of the protrusions is 2 mm to 3 mm.

[0013] On the other hand, an embodiment of the present application provides a wind turbine blade, including:

[0014] An outer skin; an inner skin; a structural layer, the structural layer is disposed between the outer skin and the inner skin, the structural layer includes the above-mentioned prefabricated structure of the wind turbine blade, and the structural surface of the prefabricated structure of the wind turbine blade faces away from the inner skin.

[0015] The wind turbine blade provided by an embodiment of the present application, the outer skin includes a fiber layer, and the flow guiding structure in the first flow guiding region of the prefabricated structure of the wind turbine blade extends along the fiber direction of the fiber layer.

[0016] On yet another aspect, an embodiment of the present application further provides a design method for a prefabricated structure, including:

[0017] Based on the structural strength parameters at a specified position of the wind turbine blade and the corresponding relationship table between the structural strength parameters and the grooving rate of the prefabricated structure of the wind turbine blade, determine the grooving rate of the prefabricated structure; based on the grooving rate and the corresponding relationship formula between the grooving rate and the cross-sectional area of the flow guiding structure of the prefabricated structure, determine the cross-sectional area of the flow guiding structure of the prefabricated structure, wherein the grooving rate is proportional to the mass of the local outer skin perfusion liquid corresponding to the prefabricated structure per unit time, and is inversely proportional to the surface area of the side of the prefabricated structure with the flow guiding structure, the cross-sectional area of the flow guiding structure, and the perfusion liquid density; based on the cross-sectional area of the flow guiding structure of the prefabricated structure and the structural layout of the flow guiding structure, determine the design parameters of the flow guiding structure of the prefabricated structure.

[0018] According to the design method of the structural prefabrication provided by the embodiments of the present application, the steps for obtaining the correspondence table between the structural strength parameters and the grooving rate of the structural prefabrication of the wind turbine blade include: based on the preset parameters and the preset structural layout of the wind turbine blade, simulating to obtain the structural strength parameters at the specified position through simulation. The preset parameters of the wind turbine blade include the mass of the local outer skin perfusion liquid corresponding to the structural prefabrication per unit time, the cross-sectional area of the diversion structure of the structural prefabrication, the surface area of the side of the structural prefabrication with the diversion structure, and the perfusion liquid density; based on the following relationship formula of the grooving rate, determining the grooving rate of the structural prefabrication at the specified position;

[0019]

[0020] Wherein, W is the grooving rate, G is the mass of the local outer skin perfusion liquid corresponding to the structural prefabrication per unit time; S1 is the surface area of the side of the structural prefabrication with the diversion structure; S2 is the cross-sectional area of the diversion structure; ρ is the perfusion liquid density; based on the structural strength parameters at the specified position and the grooving rate of the structural prefabrication, establishing a correspondence table between the structural strength parameters and the grooving rate of the structural prefabrication of the wind turbine blade under different cross-sectional areas of the diversion structure of the structural prefabrication.

[0021] According to the design method of the structural prefabrication provided by the embodiments of the present application, the calculation formula for the mass of the local outer skin perfusion liquid corresponding to the structural prefabrication per unit time includes:

[0022]

[0023] G is the mass of the local outer skin perfusion liquid corresponding to the structural prefabrication per unit time; S3 is the surface area of the side of the outer skin corresponding to the structural prefabrication; N is the number of fiber layers of the outer skin; ρ 2 is the fiber areal density; G 总 is the total content of the perfusion liquid; G 纤 is the fiber content; T is the total perfusion duration.

[0024] In the wind turbine blade structural prefabrication, wind turbine blade and design method of the structural prefabrication according to the embodiments of the present application, by arranging a diversion structure on the structural surface of the wind turbine blade structural prefabrication, and the first diversion area and the second diversion area with different diversion directions of the diversion structure, and the first diversion area has a mesh-shaped first diversion structure, thereby improving the penetration effect of the perfusion liquid during the forming process of the wind turbine blade, reducing the use of continuous felt, and thus reducing the overall weight of the wind turbine blade. Description of the Drawings

[0025] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 One of the schematic structural diagrams of the flow guiding structure of the structural surface of the wind turbine blade structural prefabrication for some embodiments of the present application;

[0027] Figure 2 Another schematic structural diagram of the flow guiding structure of the structural surface of the wind turbine blade structural prefabrication for some embodiments of the present application;

[0028] Figure 3 Schematic diagram of the prefabrication mold of the wind turbine blade structural prefabrication for some embodiments of the present application;

[0029] Figure 4 Schematic cross-sectional view of the wind turbine blade for some embodiments of the present application;

[0030] Figure 5 Schematic diagram of the internal structural prefabrication of the wind turbine blade for some embodiments of the present application;

[0031] Figure 6 One of the flowcharts of the design method of the wind turbine blade structural prefabrication for some embodiments of the present application;

[0032] Figure 7 For Figure 1 Cross-sectional view of the wind turbine blade structural prefabrication at B-B in

[0033] Figure 8 One of the flowcharts of the design method of the wind turbine blade structural prefabrication for some embodiments of the present application.

[0034] Reference numerals:

[0035] 100: Structural surface; 101: First flow guiding region; 102: Second flow guiding region; 103: Flow guiding part; 110: Flow guiding structure; 201: Structural prefabrication; 202: Outer skin; 203: Inner skin; 210: Trailing edge beam prefabrication; 211: Auxiliary beam prefabrication; 212: Main beam prefabrication; 300: Mold body; 301: Baffle; 302: Reverse flow guiding structure. Detailed implementation manners

[0036] The features and exemplary embodiments of various aspects of the present application will be described in detail below. To make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application and not to limit the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0037] It should be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "comprising..." do not exclude the presence of additional identical elements in the process, method, article or device comprising the said elements.

[0038] Wind turbine blade: An important component with an aerodynamic shape that can receive and capture wind energy to obtain energy. Its forming processes include processes such as mold closing and bonding forming, integral infusion forming, etc. It has components such as main beams, webs, and skins inside, and main materials include glass / carbon fiber, structural adhesive, matrix resin, sandwich core materials, and antioxidant coatings, etc.

[0039] Infusion molding process: The vacuum infusion molding process is a new type of low-cost forming technology for large composite materials. Its basic principle is to lay the designed fiber materials on the mold, lay other auxiliary materials on the layup according to the process design, and finally cover the entire product with a vacuum bag film. By evacuating to generate negative pressure, the resin enters and infiltrates the fibers while discharging the gas, and finally cures to form a composite material product.

[0040] Continuous mat - CFM: It is a glass fiber non-woven reinforcing substrate for composite materials. It is formed by randomly distributing continuous fibers of a certain count in a loop shape and is combined by the mechanical action between the original yarn strands and a small amount of binder. In large wind turbine blades, the glass fiber continuous mat is mainly laid between the fiberglass prefabricated parts and the fiber cloth layers to increase the penetration speed of the infused resin, improve production efficiency and the infusion quality of the blades.

[0041] As a member of new energy sources, wind energy has the advantages of large capacity and mature technology. In recent years, it has developed rapidly with the strong support of governments of various countries. In order to improve the energy capture efficiency, the single-unit capacity of wind turbines is getting larger and larger, developing from 500 kW 20 years ago to today's 12 MW commercial wind turbines. The large wind turbine blades have reached more than 100 meters in length, and their component sizes are also increasing continuously. During the manufacturing process of wind turbine blades, the vacuum infusion molding process mainly includes: ① laying continuous fiber reinforced materials such as glass fiber, structural prefabricated parts, and continuous felt, as well as structural core materials such as balsa wood core and foam core on the single-sided airtight blade shell mold; ② laying various molding auxiliary materials on the reinforced materials, and the basic sequence is release cloth or isolation film → flow guide net → vacuum bag film; ③ using a vacuum pump to extract air from the fiber reinforced body in the blade mold cavity to keep the fiber reinforced body in a vacuum state; ④ under the action of negative pressure, injecting resin into the mold cavity to make the resin flow and penetrate in the fiber reinforced body, and after the resin infiltrates the fiber reinforced body, curing at room temperature or under heating; ⑤ performing post-treatment to obtain a wind turbine blade with a qualified ratio of resin and reinforcing fibers.

[0042] Currently, in order to ensure the perfusion and penetration effect of large-size structural prefabricated parts, the following methods are used in the existing technology:

[0043] 1) Perfusing the wind turbine blade multiple times, with a certain number of structural layers perfused each time, so as to ensure the perfusion quality. However, this method increases the perfusion time and reduces the perfusion efficiency.

[0044] 2) Placing a continuous felt of a certain size under the structural prefabricated part to ensure the infiltration and penetration effect through the auxiliary diversion of the continuous felt. However, this method increases the overall mass of the wind turbine blade.

[0045] 3) At the structural position of the structural prefabricated part, designing special perfusion injection ports to divert and infiltrate the structural fiber layer. However, this method complicates the perfusion structure and the penetration effect is not ideal.

[0046] To solve the problems of the existing technology, the embodiments of the present application provide a structural prefabricated part for a wind turbine blade, a wind turbine blade, and a design method for the structural prefabricated part. First, the structural prefabricated part for a wind turbine blade provided by the embodiments of the present application will be introduced below.

[0047] As Figure 1 and Figure 2 shown, a structural prefabricated part 201 for a wind turbine blade in the embodiments of the present application includes a structural surface 100 having a diversion structure 110. The structural surface 100 includes alternately arranged first diversion regions 101 and second diversion regions 102. The diversion directions of the diversion structures 110 in the first diversion regions 101 and the second diversion regions 102 are arranged crosswise, and the diversion structures 110 in the first diversion regions 101 are distributed in a mesh shape.

[0048] The prefabricated component 201 of the wind turbine blade structure is sheet-shaped and can be a straight structure or an arc structure based on different prefabricated structures. The prefabricated component 201 of the wind turbine blade structure includes two opposite surfaces, one of which is the structural surface 100 provided with a diversion structure 110 for contacting the outer skin 202 of the wind turbine blade, and the other is the fitting surface for contacting the inner skin 203 of the wind turbine blade. The diversion structure 110 is used to divert the perfusion liquid during the molding process of the wind turbine blade, thereby improving the penetration effect of the perfusion liquid. Among them, the perfusion liquid can be resin or other materials.

[0049] To improve the diversion effect of the diversion structure 110, the structural surface 100 includes a first diversion area 101 and a second diversion area 102. The diversion directions of the diversion structures 110 in the first diversion area 101 and the second diversion area 102 cross, and different diversion directions are alternately arranged, so that the diversion structure 110 has a diversion effect along the length and width directions of the prefabricated component 201 of the wind turbine blade structure. To improve the penetration effect of the perfusion liquid, a reticularly distributed diversion structure 110 is provided in the first diversion area 101. The reticular distribution increases the cross-sectional area of the diversion structure 110, thereby improving the penetration effect of the perfusion liquid.

[0050] Specifically, for the reticularly distributed diversion structure 110, the first diversion area 101 includes multiple diversion structures 110, and the multiple diversion structures 110 are staggered to form a net. Multiple diversion directions are formed in the first diversion area 101, and the densely distributed diversion structures 110 increase the cross-sectional area of the diversion structure 110, thereby improving the penetration effect up and down.

[0051] In addition, for the diversion structures 110 in the first diversion area 101 and the second diversion area 102, in some embodiments of the present application, the diversion structures 110 in the first diversion area 101 and the second diversion area 102 are formed in opposite directions with respect to the formation direction of the structural surface 100. Among them, the formation direction includes convex or concave outward based on the structural surface 100. For example, the diversion structure 110 in the first diversion area 101 includes a groove, and the diversion structure 110 in the second diversion area 102 includes a protrusion; or, the diversion structure 110 in the first diversion area 101 includes a protrusion, and the diversion structure 110 in the second diversion area 102 includes a groove.

[0052] A flow guiding structure 110 with opposite structure forming directions is provided on the structural plane 100. When the structural strength of a part of the flow guiding structure 110 is reduced, the structural strength of another part of the flow guiding structure 110 can be increased, so as to achieve the uniformity and stability of the structural strength of the entire wind turbine blade structural preform 201, and avoid excessive flow guiding structures 110 from affecting other properties of the wind turbine blade structural preform 201, such as structural strength. Moreover, the groove has a drainage effect, and the protrusion has a flow disturbance effect. The combined setting can avoid rotation or vortex and enhance the mixing effect.

[0053] Of course, in other embodiments of the present application, the flow guiding structures 110 in the first flow guiding region 101 and the second flow guiding region 102 may have the same structure forming direction relative to the structural plane 100. For example, the flow guiding structures 110 in the first flow guiding region 101 and the second flow guiding region 102 are both grooves or both protrusions.

[0054] For the wind turbine blade structural preform 201 at a special position, in some embodiments of the present application, the flow guiding structure 110 in the second flow guiding region 102 extends along the span direction of the wind turbine blade. For example, for a spar preform, the spar preform is integrally arranged along the span direction of the wind turbine blade. During the pouring process, the pouring ports are mostly arranged along the span direction of the wind turbine blade. Therefore, in order to improve the fluidity of the pouring liquid along the span direction of the wind turbine blade, the flow guiding structure 110 in the second flow guiding region 102 extends along the span direction of the wind turbine blade, which can better guide the pouring liquid along the span direction of the wind turbine blade and improve the penetration effect of the pouring liquid along the span direction of the wind turbine blade.

[0055] Based on the above introduction, the flow guiding structures 110 in the second flow guiding region 102 extend and are staggered along the chord direction of the wind turbine blade, so as to improve the flow guiding and penetration effects of the pouring liquid along the chord direction of the wind turbine blade.

[0056] Of course, in other embodiments of the present application, for the wind turbine blade structural preform 201 at other positions, such as the root preform and the auxiliary spar preform 211, the flow guiding structure 110 in the second flow guiding region 102 may extend along the span direction of the wind turbine blade, or may extend along the chord direction of the wind turbine blade, or may be arranged in other directions such as the circumferential direction.

[0057] Furthermore, in an alternative embodiment of the present application, the range of the angle A between the flow guiding structure 110 in the first flow guiding region 101 and the span direction of the wind turbine blade is ±30° to ±45°. The flow guiding direction of the flow guiding structure 110 is made consistent with the fiber direction of the biaxial fiber cloth of the inner and outer skins 202, so as to improve the penetration effect and reduce the influence of the flow guiding structure 110 on the fiber layer structure of the outer skin 202.

[0058] Continuing with reference to 1, in a specific embodiment of the present application, the guide structure 110 of the first guide area 101 includes guide portions 103 arranged in sequence, and the guide portion 103 includes a pair of cross-connected grooves; the guide structure 110 of the second guide area 102 includes a protrusion, and the guide portion 103 is arranged along the length direction of the protrusion, and the protrusions of each second guide area 102 are arranged in parallel.

[0059] Of course, a plurality of parallel protrusions may also be provided in the second flow guiding area 102 , and the flow guiding parts 103 may be arranged in a plurality of rows and columns in the first flow guiding area 101 .

[0060] In some optional embodiments of the present application, with respect to the size setting of the flow guiding structure 110, the flow guiding structure 110 of the first flow guiding area 101 includes a groove, the depth of the groove is in the range of 2±0.5 mm, and the width of the groove is in the range of 2 mm to 3 mm.

[0061] In an optional embodiment of the present application, the guide structure 110 of the second guide area 102 includes a protrusion, the height of the protrusion protruding from the structural surface 100 ranges from 2 mm to 3 mm, and the width of the protrusion ranges from 2 mm to 3 mm.

[0062] As for the preparation method of the wind turbine blade structure prefabricated part 201, the wind turbine blade structure prefabricated part 201 can be formed by a mold. Taking the main beam prefabricated part 212 as an example, the structural layer is laid on the prefabricated part mold with the oppositely set guide structure 110, and the wind turbine blade structure prefabricated part 201 with the guide structure 110 is placed on the back of the wind turbine blade mold with the corresponding structural layer of the blade. The vacuum exhaust system is laid around the prefabricated part mold and fixed with double-sided tape. The starting and ending points of the exhaust system are the same as the starting and ending points of the main beam layer. The exhaust system is connected to the vacuum exhaust hole. The exhaust hole can use the exhaust hole provided by the mold, or it can be connected in a dispersed manner using a vacuum pump source. The minimum exhaust spacing is 300mm and the maximum spacing is 2000mm, which can be appropriately adjusted according to the structural design of different thicknesses. According to the structural layer design, the unidirectional cloth layer / sheet on the main beam is laid in sequence, and the starting and ending points are checked. If deviations are found in the starting and ending points, the corresponding cloth layer / sheet should be adjusted immediately to ensure that the layer position meets the design requirements. Lay out the forming auxiliary materials on the top of the cloth layer, lay out the demoulding cloth according to the starting and ending points, adjust the axial position, fix it with glue spray, adjust the chord width on both sides so that it can cover the cloth layer on the beam as a whole, and ensure that the corners in the cavity are tight, without wrinkles or overhangs. Lay out the porous membrane and the guide net in the same way. The connecting pipe on the glue injection port is connected to the glue outlet hose of the glue machine, and the outside is sealed with vacuum tape and locked with a pipe clamp. Inject and solidify.

[0063] Among them, Figure 3As shown in the figure, for the precast mold, the precast mold includes a mold body 300, edge guards 301 disposed on both sides of the mold body 300, and a reverse flow guiding structure 302 formed on the upper surface of the mold body 300. The structural precast 201 is formed between the edge guards 301. At the position on the precast mold where there is a groove, a carving pen is used or groove carving is performed on the surface of the precast mold on a gantry milling device. The groove depth is 2 ± 0.5 mm, the width of the groove on the surface of the precast mold is 2 - 3 mm, and the groove can be segmented. For example, the groove is segmented in a length range of 10 ± 5 mm for each segment. For example, the angle range of the intersecting grooves is ±30° to ±45°. After carving, a gel coat protection is applied to the surface of the precast mold and polished smoothly with P120 sandpaper.

[0064] At the position on the precast mold where there is a protrusion, a pre-impregnated fiber yarn bundle or a resin strip of a specified size is placed. The diameter of the fiber yarn bundle or the resin strip is 2 - 3 mm, and it is placed on the mold according to the specified size and spacing. Among them, the protrusion can be placed separately on the precast mold or during the precast forming stage.

[0065] As Figure 4 shown, an embodiment of the present application provides a wind turbine blade having the structural precast 201 of the above embodiment, including: an outer skin 202, an inner skin 203, and a structural layer. The structural layer is disposed between the outer skin 202 and the inner skin 203. The structural layer includes the wind turbine blade structural precast 201 of the above embodiment, and the structural surface 100 of the wind turbine blade structural precast 201 faces away from the inner skin 203. As Figure 5 shown, the structural precast 201 includes a main beam precast 212, a trailing edge beam precast 210, a secondary beam precast 211, etc.; the main beam precast 212, the trailing edge beam precast 210, and the secondary beam precast 211 are disposed along the span direction of the wind turbine blade.

[0066] Among them, the inner skin 203 and the outer skin 202 are usually made of composite materials, and these composite materials have excellent properties such as high strength, high modulus, light weight, and corrosion resistance. For example, common skin materials include thermoplastic composite materials, fiberglass, and carbon fiber reinforced materials, etc. Since the inner skin 203 mainly bears the internal stress and deformation of the blade, more attention may be paid to aspects such as the fatigue resistance, corrosion resistance, and thermal stability of the material in material selection and design.

[0067] Specifically, in the embodiments of the present application, the outer skin 202 includes a fiber layer. For example, a fiberglass cloth. The flow guiding structure 110 in the first flow guiding area 101 of the prefabricated structure 201 of the wind turbine blade is arranged along the fiber direction of the fiber layer. In the case of a biaxial fiberglass cloth, the fiber angle is ±30° to ±45°. Based on the laying direction of the fiberglass cloth, the range of the angle A of the flow guiding structure 110 in the first flow guiding area 101 along the span direction of the wind turbine blade is ±30° to ±45°. The flow guiding direction of the flow guiding structure 110 is made consistent with the fiber direction of the biaxial fiber cloth of the inner and outer skins 202, improving the penetration effect and reducing the influence of the flow guiding structure 110 on the fiber layer structure of the outer skin 202.

[0068] The preparation process of the wind turbine blade is introduced below, mainly including preliminary preparation - laying and assembly - vacuum infusion and curing. Specifically as follows:

[0069] Preliminary preparation: Uniformly coat a layer of mold release agent on the surface of the mold to form a dense layer for subsequent demolding operations. The choice of the mold release agent should consider its compatibility with the resin to ensure that it will not contaminate the blade material. Material preparation: Prepare sufficient glass fiber, carbon fiber or other feasible reinforcing fibers such as basalt fiber that meet the requirements of structural mechanical properties, and ensure that its quality meets the design requirements. Prepare sandwich materials such as PVC foam board, balsa wood or honeycomb core, and ensure accurate dimensions and smooth surfaces. Prepare resin materials such as epoxy resin according to the process requirements, and pay attention to the shelf life and storage conditions of the resin. Prepare auxiliary materials such as release cloth, porous film, flow guiding net, infusion channel, air extraction system, etc., and ensure sufficient quantity and reliable quality.

[0070] Laying and assembly:

[0071] Glass fiber laying on the outer surface of the shell: Lay the fiberglass cloth on the mold according to the design drawing, pay attention to the direction and angle of the fiberglass cloth, and ensure close fitting with the mold contour. The fiberglass cloths need to be overlapped, and the overlap size is usually 10 - 20 cm to ensure the firmness of the overlap part. Accurately position the preformed structural prefabrication 201 on the mold and fix it with tooling to ensure the accurate position of the structural prefabrication 201 without deviation. Lay the PVC foam board between the upper and lower layers of fiberglass cloth to form a sandwich structure. Pay attention to the tight connection between the plates during laying to avoid generating air bubbles or voids.

[0072] Glass fiber laying on the inner surface of the shell: Lay the fiberglass cloth on the inner surface, pay attention to the cooperation relationship with the embedded parts, and avoid dislocation or wrinkles during laying. Lay the non - grinding cloth at the parts that need to avoid grinding treatment to reduce the workload of subsequent processes. Arrange the infusion channel and air extraction system according to the design requirements to ensure that the resin can be smoothly introduced and evenly penetrate the fiberglass cloth.

[0073] Vacuum infusion and curing:

[0074] After sealing one or two layers of vacuum, check that the vacuum value within a certain period of time reaches 80% - 95% of the local atmospheric pressure and its decrease value meets the requirements, then the thermoplastic resin stirred and mixed in proportion can be introduced into the preform body where the laying has been completed. During the perfusion process, it is necessary to control the temperature, humidity and proportion of the resin to ensure that the resin can fully infiltrate the fiber and core materials. At the same time, attention should be paid to the control of the perfusion speed and pressure difference to avoid defects such as bubbles or dry spots. After the resin infiltration is completed, raise the temperature to a certain range (such as 50 - 70 °C) for pre-curing treatment. The pre-curing time is determined according to the resin type and process requirements. After pre-curing is completed, raise the temperature further to the curing temperature (such as 75 °C) for post-curing treatment. The post-curing time usually ranges from several hours to dozens of hours, and is specifically determined according to the curing characteristics of the resin and process requirements. During the curing process, it is necessary to keep the mold temperature stable and monitor the curing degree of the resin. After curing for a certain time according to the curing system, use a hardness tester to select the hardness at the positions of 5%, 35%, 50%, 85%, 95% of the axial length and the points of 5%, 50%, 95% in width. Only when the hardness meets the design value can it be judged that the curing is completed. After curing, remove the surface auxiliary materials and appropriately shape the flange edge to ensure that the thickness of its bonding area meets the requirements.

[0075] In the skin bonding area, place structural adhesive or adhesive film, close the mold for bonding, apply a certain pressure to make its interface in close contact, and heat and cure to connect the whole blank blade to obtain the blank blade.

[0076] As Figure 6 shown, the embodiment of the present application provides a design method for a prefabricated structure of a wind turbine blade, including: steps S1 to S3.

[0077] S1: Based on the structural strength parameters at the specified positions of the wind turbine blade and the corresponding relationship table between the structural strength parameters and the slotting rate of the prefabricated structure of the wind turbine blade, determine the slotting rate of the prefabricated structure.

[0078] S2: Based on the slotting rate and the corresponding relationship formula between the slotting rate and the cross-sectional area of the diversion structure of the prefabricated structure, determine the cross-sectional area of the diversion structure of the prefabricated structure, where the slotting rate is directly proportional to the mass of the local outer skin perfusion liquid corresponding to the prefabricated structure per unit time and inversely proportional to the surface area of the side of the prefabricated structure with a diversion structure, the cross-sectional area of the diversion structure, and the perfusion liquid density.

[0079] S3: Based on the cross-sectional area of the diversion structure of the prefabricated structure and the structural layout of the diversion structure, determine the design parameters of the diversion structure of the prefabricated structure.

[0080] Among them, step S1 is introduced.

[0081] The designated positions of the wind turbine blade include at least one of the maximum chord length region and the variable diameter region. Since the maximum chord length region and the variable diameter region are weak regions in the wind turbine blade, in order to save design time, tests can be conducted on the weak regions. When the structural strength parameters are met in the weak regions, the other positions of the wind turbine blade also meet the requirements of the structural strength parameters. Among them, the maximum chord length region is the length region from 8% to 15% of the length of the wind turbine blade along the span direction from the blade root, and the variable diameter region is generally the length region from 2m to 8m at the trailing edge.

[0082] The structural strength parameters can include one or several of the maximum stress, allowable stress, maximum generalized elastic deformation, allowable generalized elastic deformation, safety factor, bending strength, tensile strength, etc. For example, the maximum stress represents the maximum stress value that the blade withstands under specific working conditions, usually in MPa. This value should not exceed the allowable stress of the material to ensure that the blade does not fail. The maximum generalized elastic deformation represents the maximum deformation amount generated by the blade when it is stressed, usually in mm. This value should not exceed the allowable generalized elastic deformation to ensure that the blade can still maintain its normal working state after deformation. The bending strength represents the ability of the blade to resist failure under bending loads. The tensile strength reflects the maximum load-bearing capacity of the blade under tensile loads.

[0083] Regarding the correspondence table between the structural strength parameters and the slotting rate of the structural prefabrication of the wind turbine blade, one or a group of structural strength parameters correspond to one slotting rate. Therefore, in special application scenarios or specified power generation amounts of the wind turbine blade, the structural strength parameters of the wind turbine blade are determined to meet the actual use requirements. Due to the one-to-one correspondence between the structural strength parameters and the slotting rate, the slotting rate of the structural prefabrication is determined.

[0084] It should be noted that the slotting rate of the structural prefabrication in this application is a characterization of the diversion and penetration effects of the perfusion liquid by the diversion structure when there is a diversion structure in the structural prefabrication. The larger the slotting rate, the better the diversion and penetration effects. Similarly, the smaller the slotting rate, the worse the diversion and penetration effects.

[0085] Step S2 is introduced.

[0086] Specifically, the corresponding relationship formula between the slotting rate W and the cross-sectional area S2 of the diversion structure of the structural prefabrication is:

[0087]

[0088] Among them, W is the slotting rate, G is the mass of the perfusion liquid corresponding to the local outer skin of the structural prefabrication per unit time; S1 is the surface area of the side of the structural prefabrication with the diversion structure; S2 is the cross-sectional area of the diversion structure; ρ is the density of the perfusion liquid.

[0089] Under the condition that the grooving rate, the mass of the local outer skin perfusion liquid corresponding to the structural prefabricated part per unit time, the surface area of the side of the structural prefabricated part with a diversion structure, and the density of the perfusion liquid are known data, the cross-sectional area of the diversion structure can be calculated.

[0090] Among them, the mass of the local outer skin perfusion liquid corresponding to the structural prefabricated part per unit time = the total mass of the local outer skin perfusion liquid corresponding to the structural prefabricated part / the total perfusion duration. The total mass of the local outer skin perfusion liquid corresponding to the structural prefabricated part and the total perfusion duration can be obtained by three-dimensional simulation of the perfusion process, and then the mass of the local outer skin perfusion liquid corresponding to the structural prefabricated part per unit time can be obtained.

[0091] Step S3 is introduced.

[0092] Combined with Figure 1 and Figure 2 the structural layout of the diversion structure of the wind turbine blade structural prefabricated part shown, and the cross-sectional area S2 of the diversion structure calculated in step S2, parameters such as the length, width, depth, and height of the diversion structure are obtained.

[0093] For example, as Figure 7 shown, in the embodiment of the present application, the diversion structure 110 is a groove, and the sizes of all the grooves on the structural surface 100 of the structural prefabricated part 201 are the same. The cross-section of the groove can be rectangular. Therefore, the cross-sectional area of the groove = the length L of the groove * the width M of the groove. Among them, the length and width of the groove are design parameters, and the requirements for the cross-sectional area of the diversion structure 110 are met by adjusting the length and width of the groove. Of course, the cross-section of the groove can be semi-circular, and the calculation formula for the cross-sectional area S 槽 of the groove is: where R is the radius of the groove; the radius of the groove is a design parameter, and the requirements for the cross-sectional area of the diversion structure 110 are met by adjusting the radius of the groove.

[0094] Of course, in other embodiments of the present application, the diversion structure can be a protrusion or a combination of a groove and a protrusion, and the calculation method is the same, which will not be elaborated here.

[0095] As Figure 8 shown, in some other alternative embodiments of the present application, for the obtaining step of the correspondence table between the structural strength parameters and the grooving rate of the wind turbine blade structural prefabricated part in step S1, it includes:

[0096] S11: Based on the preset parameters and the preset structural layout of the wind turbine blade, the structural strength parameters at the specified position are obtained by simulation. The preset parameters of the wind turbine blade include the mass of the local outer skin perfusion liquid corresponding to the structural prefabricated part per unit time, the cross-sectional area of the diversion structure of the structural prefabricated part, the surface area of the side of the structural prefabricated part with a diversion structure, and the density of the perfusion liquid.

[0097] S12: Based on the above-mentioned slotting rate calculation formula (1), determine the slotting rate of the structural precast at the specified position;

[0098]

[0099] Wherein, W is the slotting rate, G is the mass of the local outer skin perfusion liquid corresponding to the structural precast per unit time; S1 is the surface area of one side of the structural precast with a diversion structure; S2 is the cross-sectional area of the diversion structure; ρ 1 is the density of the perfusion liquid.

[0100] S13: Based on the structural strength parameters at the specified position and the slotting rate of the structural precast, establish a correspondence table between the structural strength parameters and the slotting rate of the structural precast of the wind turbine blade under different cross-sectional areas of the diversion structure of the structural precast.

[0101] Specifically, when designing the structural precast of a wind turbine blade with a specific size or specific model, while keeping other parameters unchanged and only changing the cross-sectional area of the structural precast, different slotting rates and structural strength parameters are obtained, and a correspondence table between the structural strength parameters and the slotting rate of the structural precast of the wind turbine blade under different cross-sectional areas of the diversion structure of the structural precast is established. It is realized that when designing the structural precast, a suitable slotting rate is selected.

[0102] Regarding step S11. The preset parameters of the wind turbine blade may include blade length, width, shape, bending angle, twist angle, etc. The preset structural layout includes the laying materials and stacking layers of the outer skin and the inner skin, etc. Specifically, the preset parameters of the wind turbine blade include the mass of the local outer skin perfusion liquid corresponding to the structural precast per unit time, the cross-sectional area of the diversion structure of the structural precast, the surface area of one side of the structural precast with a diversion structure, and the density of the perfusion liquid.

[0103] By adjusting the size of the cross-sectional area of the diversion structure of the structural precast, the corresponding structural strength parameters and slotting rates are obtained, thereby establishing a correspondence table between the structural strength parameters and the slotting rate of the structural precast of the wind turbine blade.

[0104] In addition, in an alternative embodiment of the present application, for the calculation formula of the mass of the local outer skin perfusion liquid corresponding to the structural precast per unit time in step S2, it includes:

[0105]

[0106] G is the mass of the local outer skin perfusion liquid corresponding to the structural precast per unit time; S3 is the surface area of one side of the outer skin corresponding to the structural precast; N is the number of fiber layers of the outer skin; ρ 2 is the fiber surface density; G总 is the total content of the perfusion fluid; G 纤 is the fiber content; T is the total perfusion duration.

[0107] Analyze the above formula (2).

[0108] Among them, the total fiber mass G_out of the outer skin: G 外 = S3 × N × ρ 2 . The total area of all fibers on the outer skin is obtained by multiplying the surface area by the number of fiber layers, and then multiplying by the fiber areal density (the mass of fibers per unit area) gives the total mass of all fibers on the outer skin.

[0109] The mass of fibers in the perfusion fluid:

[0110] This part is calculated by "total content of perfusion fluid / fiber content", that is, G 总 / G 纤 . The total content of the perfusion fluid is the total mass of the perfusion fluid, and the fiber content is the proportion (or mass fraction) of fibers in the perfusion fluid. Dividing the two gives the total mass of fibers in the perfusion fluid.

[0111] The mass of the liquid perfused per unit time:

[0112] Finally, dividing the total fiber mass of the outer skin by the mass of fibers in the perfusion fluid gives the mass of the perfusion fluid required to cover all the fibers on the outer skin (without considering losses and wastes during the perfusion process). However, the mass of the perfusion fluid accumulates throughout the perfusion process, so we also need to divide by the total perfusion duration T to obtain the actual mass of the liquid perfused per unit time.

[0113] As described above, this is only the specific implementation manner of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the above-described systems, modules, and units can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated herein. It should be understood that the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present application.

Claims

1. A prefabricated wind turbine blade structure, characterized in that: It comprises a structural surface with a flow guiding structure, wherein the structural surface comprises a first flow guiding area and a second flow guiding area which are arranged alternately, the flow guiding directions of the flow guiding structures of the first flow guiding area and the second flow guiding area are arranged crosswise, and the flow guiding structures of the first flow guiding area are distributed in a mesh shape; The flow guiding structures of the first flow guiding area and the second flow guiding area are formed in opposite directions relative to the structure of the structure surface; The guide structure of the first guide area includes guide parts arranged in sequence, and the guide parts include a pair of cross-connected grooves; the guide structure of the second guide area includes a protrusion, and the guide part is arranged along the length direction of the protrusion, and the protrusions of each second guide area are arranged in parallel.

2. The wind turbine blade structure prefabricated component according to claim 1, characterized in that: The flow guiding structure of the second flow guiding area is extended along the span direction of the wind turbine blade.

3. The wind turbine blade structure prefabricated component according to any one of claims 1 to 2, characterized in that: The included angle range of the guide structure of the first guide area along the span direction of the wind turbine blade is ±30° to ±45°.

4. The wind turbine blade structure prefabricated component according to claim 1, characterized in that: The guide structure of the first guide area includes a groove, the depth of the groove is in the range of 2±0.5 mm, and the width of the groove is in the range of 2 mm to 3 mm; The guide structure of the second guide area includes a protrusion, the height of the protrusion protruding from the structural surface is in the range of 2mm to 3mm, and the width of the protrusion is in the range of 2mm to 3mm.

5. A wind turbine blade, characterized in that: include: Outer skin; Inner skin; A structural layer is disposed between the outer skin and the inner skin, and the structural layer comprises the wind turbine blade structural preform according to any one of claims 1 to 4, wherein the structural surface of the wind turbine blade structural preform faces away from the inner skin.

6. The wind turbine blade according to claim 5, characterized in that: The outer skin comprises a fiber layer, and the flow-guiding structure of the first flow-guiding region of the wind turbine blade structure preform is extended along the fiber direction of the fiber layer.

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