Wind turbine blade structural preform, wind turbine blade, and design method for structural preform

Abstract

A wind turbine blade structural preform, a wind turbine blade, and a design method for a structural preform. The wind turbine blade structural preform (201) comprises a structural surface (100) having flow guide structures (110), wherein the structural surface (100) comprises first flow guide regions (101) and second flow guide regions (102), which are alternately arranged; the flow guide directions of the flow guide structures (110) of the first flow guide regions (101) and the second flow guide regions (102) intersect; and the flow guide structures (110) of the first flow guide regions (101) are distributed in a mesh pattern. The wind turbine blade comprises an outer skin (202), an inner skin (203), and a structural layer, wherein the structural layer comprises the wind turbine blade structural preform (201). The design method for the wind turbine blade structural preform (201) comprises: determining the slotting ratio of the structural preform (201), determining the cross-sectional area of each flow guide structure (110), and determining design parameters of each flow guide structure (110). The wind turbine blade structural preform can solve the problem of increased weight of the wind turbine blade caused by improving the permeation effect by means of continuous mats.

Description

Wind turbine blade structural preform, wind turbine blade and design method of structural preform

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202411140031.7, filed on August 19, 2024, entitled “Wind turbine blade structural preform, wind turbine blade and design method of structural preform”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application belongs to the field of wind turbine blades, and in particular relates to a wind turbine blade structural preform, a wind turbine blade and a design method of a structural preform. BACKGROUND

[0004] In the manufacturing process of the wind turbine blade skin, the main forming process is as follows: sequentially laying continuous fiber reinforced materials such as glass fiber, continuous felt, wind turbine blade structural preform, and structural core materials such as balsa wood core material and foam core material on a single-sided air-tight blade shell mold; laying various types of forming auxiliary materials on the reinforced materials, the basic order being release cloth or release film → flow guide net → vacuum bag film; using a vacuum pump to extract air from the fiber reinforced body in the blade mold cavity, keeping the fiber reinforced body in a vacuum state; under the action of negative pressure, resin is injected into the mold cavity, so that the resin flows and penetrates in the fiber reinforced body, and after the resin infiltrates the fiber reinforced body, it is cured at room temperature or in a heated state; post-processing is performed to obtain a wind turbine blade with a proportion of resin and reinforced fiber meeting the standard.

[0005] Among them, the wind turbine blade structural preform refers to a component that is made in advance outside the wind turbine blade mold, such as a root preform, a pultruded plate, a preformed web, a preformed trailing edge main beam, etc. These preforms can be made by different process methods, such as manual layup, vacuum assisted resin transfer molding (VARTM), prepreg, mold forming, etc.

[0006] In order to improve the penetration effect of the resin, the prior art lays continuous felt between the wind turbine blade structural preform and the fiber layer, however, as the size of the wind turbine blade continues to increase, the weight of the wind turbine blade also continues to increase, and the large use of continuous felt is one of the important reasons for increasing the weight of the wind turbine blade, which adversely affects the overall weight control of the wind turbine blade. SUMMARY

[0007] The embodiments of the present application provide a wind turbine blade structural preform, a wind turbine blade and a design method of a structural preform, which can ensure the penetration effect of the resin and reduce the weight of the wind turbine blade.

[0008] In one aspect, the embodiments of the present application provide a wind turbine blade structural preform, comprising a structural surface with a flow guiding structure, the structural surface comprising first flow guiding regions and second flow guiding regions arranged alternately, the flow guiding directions of the flow guiding structures of the first flow guiding regions and the second flow guiding regions being arranged crossly, the flow guiding structure of the first flow guiding regions being distributed in a mesh shape.

[0009] According to the wind turbine blade structural preform provided by the embodiments of the present application, the flow guiding structures of the first flow guiding regions and the second flow guiding regions are opposite relative to the structural forming direction of the structural surface.

[0010] According to the wind turbine blade structural preform provided by the embodiments of the present application, the flow guiding structure of the second flow guiding regions is arranged along the spanwise direction of the wind turbine blade.

[0011] According to the wind turbine blade structural preform provided by the embodiments of the present application, the included angle range of the flow guiding structure of the first flow guiding regions along the spanwise direction of the wind turbine blade is ±30° to ±45°.

[0012] According to the wind turbine blade structural preform provided by the embodiments of the present application, the flow guiding structure of the first flow guiding regions comprises flow guiding portions arranged successively, and the flow guiding portions comprise a pair of grooves crossly communicated.

[0013] The flow guiding structure of the second flow guiding regions comprises protrusions, the flow guiding portions are arranged along the length direction of the protrusions, and the protrusions of each second flow guiding region are arranged in parallel.

[0014] According to the wind turbine blade structural preform provided by the embodiments of the present application, the flow guiding structure of the first flow guiding regions comprises grooves, the depth range of the grooves is 2±0.5mm, and the width range of the grooves is 2mm to 3mm; the flow guiding structure of the second flow guiding regions comprises protrusions, the height range of the protrusions protruding from the structural surface is 2mm to 3mm, and the width range of the protrusions is 2mm to 3mm.

[0015] In another aspect, the embodiments of the present application provide a wind turbine blade, comprising:

[0016] an outer skin, an inner skin, and a structural layer arranged between the outer skin and the inner skin, the structural layer comprising the wind turbine blade structural preform, and the structural surface of the wind turbine blade structural preform facing away from the inner skin.

[0017] According to the wind turbine blade provided by the embodiments of the present application, the outer skin comprises a fiber layer, and the flow guiding structure of the first flow guiding regions of the wind turbine blade structural preform is arranged along the fiber direction of the fiber layer.

[0018] In still another aspect, the embodiments of the present application further provide a design method of a structural preform, comprising:

[0019] The structure strength parameter of the specified position of the wind turbine blade and the corresponding relationship table of the structure strength parameter and the slotting rate of the structure preform of the wind turbine blade are used to determine the slotting rate of the structure preform. The slotting rate and the corresponding relationship formula of the slotting rate and the cross-sectional area of the flow guide structure of the structure preform are used to determine the cross-sectional area of the flow guide structure of the structure preform, wherein the slotting rate is proportional to the local outer skin infusion liquid mass corresponding to the structure preform per unit time, and inversely proportional to the surface area of the one side of the structure preform with the flow guide structure, the cross-sectional area of the flow guide structure, and the infusion liquid density. The cross-sectional area of the flow guide structure of the structure preform and the structure layout of the flow guide structure are used to determine the design parameter of the flow guide structure of the structure preform.

[0020] According to the design method of the structure preform provided in the embodiments of the present application, the obtaining step of the corresponding relationship table of the structure strength parameter and the slotting rate of the structure preform of the wind turbine blade comprises: obtaining the structure strength parameter of the specified position through simulation based on the preset parameters and the preset structure layout of the wind turbine blade, wherein the preset parameters of the wind turbine blade include the local outer skin infusion liquid mass corresponding to the structure preform per unit time, the cross-sectional area of the flow guide structure of the structure preform, the surface area of the one side of the structure preform with the flow guide structure, and the infusion liquid density; and determining the slotting rate of the structure preform at the specified position based on the following relationship formula of the slotting rate:

[0021] wherein W is the slotting rate, G is the local outer skin infusion liquid mass corresponding to the structure preform per unit time, S1 is the surface area of the one side of the structure preform with the flow guide structure, S2 is the cross-sectional area of the flow guide structure, and p is the infusion liquid density. The corresponding relationship table of the structure strength parameter and the slotting rate of the structure preform of the wind turbine blade under the cross-sectional area of the flow guide structure of different structure preforms is established based on the structure strength parameter of the specified position and the slotting rate of the structure preform.

[0022] According to the design method of the structure preform provided in the embodiments of the present application, the calculation formula of the local outer skin infusion liquid mass corresponding to the structure preform per unit time comprises:

[0023] G is the local outer skin infusion liquid mass corresponding to the structure preform per unit time, S3 is the surface area of the one side of the outer skin corresponding to the structure preform, N is the number of fiber layers of the outer skin, p2 is the fiber area density, G 总 is the total content of the infusion liquid, G 纤 is the fiber content, and T is the total infusion time.

[0024] The wind power blade structure prefabricated part, the wind power blade and the design method of the structure prefabricated part provided by the embodiments of the present application have the following beneficial effects: the flow guide structure is arranged on the structure surface of the wind power blade structure prefabricated part, the flow guide structure has the first flow guide region and the second flow guide region with different flow guide directions, the first flow guide region has the first flow guide structure in a mesh shape, the permeation effect of the infusion resin in the forming process of the wind power blade is improved, the use of the continuous felt is reduced, and thus the overall weight of the wind power blade is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows, and other drawings can also be obtained by those of ordinary skill in the art without any creative labor on the premise that the drawings are not creative labor.

[0026] Fig. 1 is a structural schematic diagram of the flow guide structure of the structure surface of the wind power blade structure prefabricated part according to some embodiments of the present application;

[0027] Fig. 2 is a structural schematic diagram of the flow guide structure of the structure surface of the wind power blade structure prefabricated part according to some embodiments of the present application;

[0028] Fig. 3 is a schematic diagram of the prefabricated part mold of the wind power blade structure prefabricated part according to some embodiments of the present application;

[0029] Fig. 4 is a schematic diagram of the cross section of the wind power blade according to some embodiments of the present application;

[0030] Fig. 5 is a schematic diagram of the internal structure prefabricated part of the wind power blade according to some embodiments of the present application;

[0031] Fig. 6 is a flowchart of the design method of the wind power blade structure prefabricated part according to some embodiments of the present application;

[0032] Fig. 7 is a cross-sectional view of the wind power blade structure prefabricated part of Fig. 1 along B-B;

[0033] Fig. 8 is a flowchart of the design method of the wind power blade structure prefabricated part according to some embodiments of the present application.

[0034] Reference signs: 100: structure surface; 101: first flow guide region; 102: second flow guide region; 103: flow guide part; 110: flow guide structure; 201: structure prefabricated part; 202: outer skin; 203: inner skin; 210: trailing edge beam prefabricated part; 211: auxiliary beam prefabricated part; 212: main beam prefabricated part; 300: mold body; 301: blocking edge; 302: reverse flow guide structure. DETAILED DESCRIPTION

[0035] The features and exemplary embodiments of the various aspects of the present application will be described in detail below with reference to the drawings. To make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, but not to limit the present application. The present application can be implemented without some of these specific details for those skilled in the art. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0036] It should be noted that, in this paper, 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 that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the elements defined by the statement "include" do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

[0037] Wind turbine blade: an important component with aerodynamic shape, which can receive, capture wind energy and obtain energy. Its forming process includes mold bonding forming and one-piece pouring forming. The internal components include main beam, web, skin and other components. The main materials include glass / carbon fiber, structural adhesive, matrix resin, sandwich core material and antioxidant coating.

[0038] Pouring forming process: vacuum pouring forming process is a new type of large composite material low-cost forming technology. Its basic principle is to lay the designed fiber material on the mold, lay other auxiliary materials on the layer according to the process design, and finally cover the whole product with a vacuum bag film. By creating negative pressure through vacuum extraction, resin enters and infiltrates fiber while expelling gas, and finally solidifies to form a composite material product.

[0039] Continuous felt-CFM: is a glass non-woven reinforcing substrate for composite materials, which is distributed in a certain number of continuous fiber non-directional loop shape, combined by mechanical action between original wire and a small amount of adhesive. In large wind turbine blades, glass fiber continuous felt is mainly laid between glass steel prefabricated parts and fiber cloth layer to increase the permeation speed of pouring resin, improve production efficiency and blade pouring quality.

[0040] As a member of new energy, wind energy has the advantages of large capacity and mature technology, and has developed rapidly in recent years with the support of governments around the world. In order to improve the energy capture efficiency, the single machine capacity of wind turbine is getting larger and larger, from 500kW in 20 years ago to 12MW commercial wind turbine today, and the size of its components is also increasing. In the manufacturing process of wind turbine blade, the vacuum infusion molding process mainly includes: ①laying continuous fiber reinforced materials such as glass fiber, structural preform, continuous felt, and structural core materials such as light wood core and foam core on the single-sided air-tight blade shell mold; ②laying various types of molding auxiliary materials on the reinforced materials, the basic order is release cloth or isolation film → flow guide net → vacuum bag film; ③using a vacuum pump to extract air from the fiber reinforced body in the mold cavity of the blade mold, so that the fiber reinforced body is in a vacuum state; ④under the action of negative pressure, resin is injected into the mold cavity, so that the resin flows and penetrates in the fiber reinforced body, and after the resin infiltrates the fiber reinforced body, it is cured at room temperature or in a heated state; ⑤post-processing to obtain a wind turbine blade with a proportion of resin and reinforced fiber that meets the standard.

[0041] At present, in order to ensure the infusion and penetration effect of large-size structural preform, the existing technology uses the following methods:

[0042] 1) Multiple infusion is performed on the wind turbine blade, and a certain amount of structural layer is infused each time, so as to ensure the infusion quality. However, this method increases the infusion time and reduces the infusion efficiency.

[0043] 2) A certain size of continuous felt is placed below the structural preform to ensure the infiltration and penetration effect by the auxiliary flow guide of the continuous felt. However, this method increases the overall weight of the wind turbine blade.

[0044] 3) A special infusion glue injection port is designed at the structural position of the structural preform to guide and infiltrate the structural fiber layer. However, this method complicates the infusion structure, and the penetration effect is not ideal.

[0045] In order to solve the problems of the prior art, the embodiments of the present application provide a wind turbine blade structural preform, a wind turbine blade and a design method of the structural preform. First, the wind turbine blade structural preform provided by the embodiments of the present application is introduced.

[0046] As shown in FIG. 1 and FIG. 2, a wind turbine blade structural preform 201 according to an embodiment of the present application includes a structural surface 100 with a flow guide structure 110, the structural surface 100 includes first flow guide regions 101 and second flow guide regions 102 arranged alternately, the flow guide directions of the flow guide structures 110 of the first flow guide regions 101 and the second flow guide regions 102 are arranged crossly, and the flow guide structures 110 of the first flow guide regions 101 are distributed in a mesh shape.

[0047] The wind power blade structure preform 201 is in a sheet shape, and can be a flat structure or an arc structure based on different preform structures. The wind power blade structure preform 201 includes two opposite surfaces, one of which is a structure surface 100 provided with a flow guide structure 110 for contacting an outer skin 202 of a wind power blade, and the other is a fitting surface for contacting an inner skin 203 of the wind power blade. The flow guide structure 110 is used to guide the flow of a pouring liquid during the forming process of the wind power blade, thereby improving the penetration effect of the pouring liquid, wherein the pouring liquid can be resin or other materials.

[0048] In order to improve the flow guiding effect of the flow guide structure 110, the structure surface 100 includes a first flow guiding area 101 and a second flow guiding area 102, the flow guiding directions of the flow guide structures 110 of the first flow guiding area 101 and the second flow guiding area 102 are crossed, and different flow guiding directions are arranged alternately, so that the flow guide structure 110 has flow guiding effects in the length and width directions of the wind power blade structure preform 201. In order to improve the penetration effect of the pouring liquid, the first flow guiding area 101 is provided with a mesh-distributed flow guide structure 110, and the mesh distribution improves the cross-sectional area of the flow guide structure 110, thereby improving the penetration effect of the pouring liquid.

[0049] Specifically, for the mesh-distributed flow guide structure 110, the first flow guiding area 101 includes a plurality of flow guide structures 110, and the plurality of flow guide structures 110 are arranged in a mesh shape, a plurality of flow guiding directions are formed in the first flow guiding area 101, and the densely distributed flow guide structures 110 improve the cross-sectional area of the flow guide structure 110, thereby improving the penetration effect of the pouring liquid.

[0050] In addition, for the flow guide structures 110 of the first flow guiding area 101 and the second flow guiding area 102, in some embodiments of the present application, the flow guide structures 110 of the first flow guiding area 101 and the second flow guiding area 102 are opposite to the structure forming direction of the structure surface 100. Wherein, the structure forming direction includes that the structure surface 100 is outward convex or inward concave, for example, the flow guide structure 110 of the first flow guiding area 101 includes a groove, and the flow guide structure 110 of the second flow guiding area 102 includes a protrusion; or the flow guide structure 110 of the first flow guiding area 101 includes a protrusion, and the flow guide structure 110 of the second flow guiding area 102 includes a groove.

[0051] The flow guide structure 110 is arranged on the structural surface 100 in opposite directions, so that when one part of the flow guide structure 110 reduces the structural strength, the other part of the flow guide structure 110 increases the structural strength, thereby achieving uniformity and stability of the structural strength of the entire wind turbine blade structural preform 201, avoiding excessive flow guide structure 110 affecting other performance of the wind turbine blade structural preform 201, such as structural strength. Moreover, the groove has a flow guiding effect, and the protrusion has a flow disturbing effect, and the combination of the arrangement can avoid rotation or vortex and enhance the mixing effect.

[0052] Of course, in other embodiments of the present application, the flow guide structure 110 of the first flow guide area 101 and the second flow guide area 102 can be the same with respect to the structural forming direction of the structural surface 100, for example, the flow guide structure 110 of the first flow guide area 101 and the second flow guide area 102 are all grooves or all protrusions.

[0053] For the wind turbine blade structural preform 201 in a special position, in some embodiments of the present application, the flow guide structure 110 of the second flow guide area 102 is arranged along the spanwise direction of the wind turbine blade. For example, the girder preform is arranged along the spanwise direction of the wind turbine blade as a whole, and during the pouring process, the pouring port is mostly arranged in the spanwise direction of the wind turbine blade. Therefore, in order to improve the flowability of the pouring liquid in the spanwise direction of the wind turbine blade, the flow guide structure 110 of the second flow guide area 102 is arranged along the spanwise direction of the wind turbine blade, which can better guide and pour the pouring liquid in the spanwise direction of the wind turbine blade and improve the penetration effect of the pouring liquid in the spanwise direction of the wind turbine blade.

[0054] Based on the above introduction, the flow guide structure 110 of the second flow guide area 102 is arranged along the chordwise direction of the wind turbine blade, thereby improving the pouring liquid flow guide and penetration effect in the chordwise direction of the wind turbine blade.

[0055] Of course, in other embodiments of the present application, for the wind turbine blade structural preform 201 in other positions, such as the root preform and the auxiliary beam preform 211, the flow guide structure 110 of the second flow guide area 102 can be arranged along the spanwise direction of the wind turbine blade, or along the chordwise direction of the wind turbine blade, or along other directions such as the circumferential direction.

[0056] Further, in the optional embodiments of the present application, the included angle A of the flow guide structure 110 of the first flow guide area 101 along the spanwise direction of the wind turbine blade is in the range of ±30° to ±45°. The flow guide direction of the flow guide structure 110 is consistent with the fiber direction of the biaxial fiber cloth of the inner and outer skins 202, thereby improving the penetration effect and reducing the influence of the flow guide structure 110 on the fiber layer structure of the outer skin 202.

[0057] With reference to 1, in one embodiment of the present application, the flow guide structure 110 of the first flow guide area 101 comprises flow guide portions 103 arranged in sequence, the flow guide portions 103 comprising a pair of grooves in cross communication; the flow guide structure 110 of the second flow guide area 102 comprises a protrusion, the flow guide portions 103 being arranged along the length direction of the protrusion, and the protrusions of each second flow guide area 102 being arranged in parallel.

[0058] Of course, a plurality of parallel protrusions can also be arranged in the second flow guide area 102, and the flow guide portions 103 can be arranged in multiple rows and columns in the first flow guide area 101.

[0059] In some optional embodiments of the present application, the flow guide structure 110 is arranged in terms of size. The flow guide structure 110 of the first flow guide area 101 comprises grooves, the depth of the grooves ranges from 2±0.5 mm, and the width of the grooves ranges from 2 mm to 3 mm.

[0060] In optional embodiments of the present application, the flow guide structure 110 of the second flow guide area 102 comprises protrusions, the height of the protrusions from the structure surface 100 ranges from 2 mm to 3 mm, and the width of the protrusions ranges from 2 mm to 3 mm.

[0061] In terms of the preparation method of the wind turbine blade structure preform 201, the wind turbine blade structure preform 201 can be formed by using a mold. Taking the main beam preform 212 as an example, the structure layer is laid on the preform mold with oppositely arranged flow guide structures 110, the wind turbine blade structure preform 201 with the flow guide structure 110 is placed on the back of the wind turbine blade mold corresponding to the structure layer, the vacuum pumping system is laid around the preform mold, and the double-sided tape is used for fixation. The starting point of the pumping system is the same as the starting point of the main beam layer. The pumping system is connected with the vacuum pumping hole, which can be connected with the vacuum pump source or can be connected with the vacuum pumping hole provided in the mold. The minimum distance of pumping is 300 mm, and the maximum distance is 2000 mm, which can be adjusted according to the thickness of the structure design. According to the structure layer design, the unidirectional layer / sheet on the main beam is laid in sequence, and the starting and ending points are checked. If the deviation of the starting and ending points is found, the corresponding layer / sheet should be adjusted immediately to ensure that the position of the layer meets the design requirements. The upper forming auxiliary material is laid, the release cloth is laid according to the starting and ending points, the axial position is adjusted, the glue is sprayed and fixed by using the glue spraying point, the width of the two sides is adjusted, so that the cloth layer on the beam can be completely covered, and the corners in the cavity can be ensured to be flat without wrinkles or suspension. The porous membrane and the flow guide net are laid by the same method. The connecting pipe on the glue injection port is connected with the glue outlet pipe of the glue machine, the outside is sealed by using the vacuum adhesive tape, and the pipe clamp is locked. The pouring is carried out, and the solidification is carried out.

[0062] As shown in FIG. 3, for the preform mold, the preform mold includes a mold body 300, a baffle 301 arranged on both sides of the mold body 300, and a reverse flow guide structure 302 formed on the upper surface of the mold body 300, and the structural preform 201 is formed between the baffles 301. At the position of the preform mold with the groove, the groove is engraved on the surface of the preform mold using a carving pen or on a gantry milling device, the groove depth is 2±0.5 mm, the groove width on the surface of the preform 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 example, the angle range of the cross arrangement of the grooves is ±30°-±45°. After the engraving is completed, the surface of the preform mold is coated with a gel coat protection, and is polished smooth by P120 sandpaper.

[0063] At the position of the preform mold with the protrusion, a pre-impregnated fiber bundle or a resin adhesive strip of a specified size is placed, and the fiber bundle or the resin adhesive strip has a diameter of 2-3 mm and is placed on the mold according to the specified size and spacing. The protrusion can be placed alone on the preform mold or placed during the preform forming stage.

[0064] As shown in FIG. 4, the wind power blade provided by the embodiment of the present application has the structural preform 201 of the above-mentioned embodiment, and includes an outer skin 202, an inner skin 203, and a structural layer arranged between the outer skin 202 and the inner skin 203. The structural layer includes the wind power blade structural preform 201 of the above-mentioned embodiment, and the structural surface 100 of the wind power blade structural preform 201 faces away from the inner skin 203. As shown in FIG. 5, the structural preform 201 includes a main beam preform 212, a trailing edge beam preform 210, and an auxiliary beam preform 211, and the main beam preform 212, the trailing edge beam preform 210, and the auxiliary beam preform 211 are arranged along the span direction of the wind power blade.

[0065] 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, corrosion resistance, etc. For example, common skin materials include thermoplastic composite materials, glass steel, and carbon fiber reinforced materials, etc. Since the inner skin 203 mainly bears the stress and deformation inside the blade, the material selection and design may pay more attention to the fatigue resistance, corrosion resistance, and thermal stability of the material, etc.

[0066] Specifically, in the embodiments of the present application, the outer skin 202 comprises a fiber layer, for example, a glass fiber cloth, and the flow guiding structure 110 of the first flow guiding area 101 of the wind turbine blade structure preform 201 is arranged along the fiber direction of the fiber layer. In the case of a biaxial glass fiber cloth, the fiber angle is ±30° to ±45°, and based on the laying direction of the glass fiber cloth, the angle A of the flow guiding structure 110 of the first flow guiding area 101 along the spanwise direction of the wind turbine blade ranges from ±30° to ±45°. The flow guiding direction of the flow guiding structure 110 is consistent with the fiber direction of the biaxial fiber cloth of the inner and outer skins 202, thereby improving the penetration effect and reducing the influence of the flow guiding structure 110 on the fiber layer structure of the outer skin 202.

[0067] The preparation process of the wind turbine blade is introduced as follows, mainly including preliminary preparation, laying and assembly, vacuum infusion and curing. Specifically as follows:

[0068] Preliminary preparation: uniformly coat a layer of release agent on the surface of the mold to form a dense layer, which facilitates the subsequent demolding operation. The selection of the release agent should consider its compatibility with the resin to ensure that it does not contaminate the blade materials. Material preparation: prepare sufficient glass fiber, carbon fiber or other basalt fiber that meets the structural mechanical performance requirements of the available reinforcing fiber to ensure that its quality meets the design requirements. Prepare PVC foam board, balsa wood or honeycomb sandwich and other sandwich materials to ensure accurate size and smooth surface. Prepare resin materials such as epoxy resin according to process requirements, pay attention to the shelf life and storage conditions of the resin. Prepare auxiliary materials such as release cloth, porous membrane, flow guiding net, infusion channel, air extraction system, etc. to ensure sufficient quantity and reliable quality.

[0069] Laying and assembly:

[0070] Glass fiber laying on the outer surface of the shell, lay the glass fiber cloth on the mold according to the design drawing, pay attention to the direction and angle of the fiber cloth to ensure close fit with the mold contour. The fiber cloths need to be overlapped, the overlap size is usually 10-20 cm, to ensure that the overlap part is firm and reliable. Precisely position the preformed structure preform 201 on the mold, use the tooling to fix it, ensure that the structure preform 201 is accurately positioned without deviation. Lay the PVC foam board between the upper and lower two layers of fiber cloth to form a sandwich structure. Pay attention to the connection tightness between the boards during laying to avoid air bubbles or voids.

[0071] Glass fiber laying on the inner surface of the shell, lay the glass fiber cloth on the inner surface, pay attention to the cooperation relationship with the embedded parts to avoid misplacement or wrinkles during laying. Lay the no-sanding cloth at the positions that need to be avoided for sanding 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 uniformly infiltrated into the fiber cloth.

[0072] Vacuum infusion and curing:

[0073] After sealing one or two layers of vacuum, check the vacuum value within a certain time to reach 80% to 95% of the local atmospheric pressure, and its drop value meets the requirements, then the hot plastic resin mixed according to the proportion is introduced into the preform which has finished laying. The temperature, humidity and proportion of the resin need to be controlled during the pouring process to ensure that the resin can fully infiltrate the fiber and the core material. At the same time, attention should be paid to the control of pouring speed and pressure difference to avoid defects such as air bubbles or dry spots. After the resin is infiltrated, the temperature is increased to a certain range (such as 50-70℃) for pre-curing treatment. The pre-curing time is determined according to the type of resin and process requirements. After pre-curing, the temperature is further increased to the curing temperature (such as 75℃) for post-curing treatment. The post-curing time usually varies from several hours to several tens of hours, which is determined according to the curing characteristics of the resin and process requirements. The mold temperature needs to be kept stable and the degree of resin curing needs to be monitored during the curing process. After curing for a certain time according to the curing system, the hardness of the points selected at 5%, 35%, 50%, 85%, 95% of the axial length position and 5%, 50%, 95% of the width position is measured by using a hardness tester. When the hardness meets the design value, it can be judged that the curing is completed. After curing, the surface auxiliary material is removed, and the flange edge is appropriately shaped to ensure that the thickness of the bonding area meets the requirements.

[0074] In the skin bonding area, structural glue or adhesive film is placed, the mold is bonded, a certain pressure is applied to make the interface in close contact, heating and curing are performed to connect the whole blank blade, and the blank blade is obtained.

[0075] As shown in FIG. 6, the embodiment of the application provides a design method of a wind power blade structure preform, including steps S1 to S3.

[0076] S1: determining the slotting rate of the structure preform based on the structural strength parameters of the specified position of the wind power blade and the corresponding relationship table of the structural strength parameters and the slotting rate of the structure preform.

[0077] S2: determining the cross-sectional area of the flow guide structure of the structure preform based on the slotting rate and the corresponding relationship formula of the slotting rate and the cross-sectional area of the flow guide structure of the structure preform, wherein the slotting rate is proportional to the local outer skin pouring liquid mass corresponding to the structure preform per unit time, and inversely proportional to the surface area of the one side of the structure preform with the flow guide structure, the cross-sectional area of the flow guide structure and the pouring liquid density.

[0078] S3: determining the design parameters of the flow guide structure of the structure preform based on the cross-sectional area of the flow guide structure of the structure preform and the structural layout of the flow guide structure.

[0079] Among them, step S1 is introduced.

[0080] The specified position of the wind turbine blade includes at least one of a maximum chord length region and a variable diameter region. The maximum chord length region and the variable diameter region are weak regions of the wind turbine blade. In order to save design time, the weak regions can be tested. When the structural strength parameters of the weak regions meet the requirements, the structural strength parameters of other positions of the wind turbine blade also meet the requirements. The maximum chord length region is a length region of 8% to 15% of the wind turbine blade along the span from the blade root. The variable diameter region is generally a length region of 2m to 8m of the trailing edge.

[0081] The structural strength parameters can include one or more of a maximum stress, an allowable stress, a maximum generalized elastic deformation, an allowable generalized elastic deformation, a safety factor, a bending strength, a tensile strength, etc. For example, the maximum stress represents the maximum stress value that the blade bears under a specific working condition, which is usually in units of MPa. The 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 of the blade when it is under stress, which is usually in units of mm. The value should not exceed the allowable generalized elastic deformation to ensure that the blade can maintain its normal working state after deformation. The bending strength represents the ability of the blade to resist damage under bending load. The tensile strength reflects the maximum carrying capacity of the blade under tensile load.

[0082] For the corresponding relationship table of the structural strength parameters and the slotting rate of the structural preform of the wind turbine blade, one or a group of structural strength parameters corresponds to one slotting rate. Therefore, in the special application scenarios or specified power generation of the wind turbine blade, the structural strength parameters of the wind turbine blade are determined to meet the actual use requirements. Since the structural strength parameters and the slotting rate are in one-to-one correspondence, the slotting rate of the structural preform is determined.

[0083] It should be noted that the slotting rate of the structural preform of the present application is used to evaluate the representation of the flow guiding and permeation effect of the flow guiding structure on the pouring liquid when the flow guiding structure is arranged in the structural preform. The greater the slotting rate, the better the flow guiding and permeation effect. Similarly, the smaller the slotting rate, the worse the flow guiding and permeation effect.

[0084] Step S2 is introduced.

[0085] Specifically, the corresponding relationship formula of the slotting rate W and the cross-sectional area S2 of the flow guiding structure of the structural preform is:

[0086] Wherein, W is the slotting rate, G is the mass of the local outer skin pouring liquid corresponding to the structural preform per unit time; S1 is the surface area of one side of the structural preform with the flow guiding structure; S2 is the cross-sectional area of the flow guiding structure; and p is the density of the pouring liquid.

[0087] Under the condition that the slotting rate, the local outer skin infusion liquid mass corresponding to the structural prefabricated part per unit time, the surface area of the one side of the structural prefabricated part with the flow guide structure, and the infusion liquid density are known data, the cross-sectional area of the flow guide structure can be calculated.

[0088] The local outer skin infusion liquid mass corresponding to the structural prefabricated part per unit time = the total local outer skin infusion liquid mass corresponding to the structural prefabricated part / the total infusion time. The total local outer skin infusion liquid mass corresponding to the structural prefabricated part and the total infusion time can be obtained by simulating the infusion process in three dimensions, and then the local outer skin infusion liquid mass corresponding to the structural prefabricated part per unit time can be obtained.

[0089] Step S3 is introduced.

[0090] In combination with the structural layout of the flow guide structure of the structural prefabricated part of the wind turbine blade shown in FIGS. 1 and 2 and the cross-sectional area S2 of the flow guide structure calculated in step S2, the length, width, depth, height and other parameters of the flow guide structure are obtained.

[0091] For example, as shown in FIG. 7, in the embodiment of the present application, the flow guide structure 110 is a groove, the sizes of all the grooves on the structural surface 100 of the structural prefabricated part 201 are the same, and the cross section of the groove can be rectangular, so the cross-sectional area of the groove = the length L of the groove * the width M of the groove, wherein the length and the width of the groove are design parameters, and the length and the width of the groove are adjusted to meet the requirement of the cross-sectional area of the flow guide structure 110. Of course, the cross section of the groove can be semicircular, and the cross-sectional area S of the groove 槽 The calculation formula is: Wherein R is the radius of the groove; the radius of the groove is a design parameter, and the radius of the groove is adjusted to meet the requirement of the cross-sectional area of the flow guide structure 110.

[0092] Of course, in other embodiments of the present application, the flow guide structure can be a protrusion or a combination of grooves and protrusions, and the calculation method is the same, which will not be repeated here.

[0093] As shown in FIG. 8, in some other optional embodiments of the present application, for the obtaining step of the corresponding relationship table of the structural strength parameters and the slotting rate of the structural prefabricated part of the wind turbine blade in step S1, the method comprises:

[0094] S11: based on the preset parameters of the wind turbine blade and the preset structural layout, simulating to obtain the structural strength parameters at the specified position, the preset parameters of the wind turbine blade including the local outer skin infusion liquid mass corresponding to the structural prefabricated part per unit time, the cross-sectional area of the flow guide structure of the structural prefabricated part, the surface area of the one side of the structural prefabricated part with the flow guide structure, and the infusion liquid density.

[0095] S12: Determine the slotting rate of the structural preform at the specified position based on the above slotting rate calculation formula (1);

[0096] Wherein, W is the slotting rate, G is the local outer skin infusion liquid mass corresponding to the structural preform per unit time; S1 is the surface area of the side of the structural preform with the flow guide structure; S2 is the cross-sectional area of the flow guide structure; ρ1 is the infusion liquid density.

[0097] S13: Based on the structural strength parameters of the specified position and the slotting rate of the structural preform, a corresponding relationship table of the structural strength parameters under the cross-sectional area of the flow guide structure of different structural preforms and the slotting rate of the structural preform of the wind turbine blade is established.

[0098] Specifically, when designing the structural preform of a wind turbine blade of a specific size or specific model, while keeping other parameters unchanged, only the cross-sectional area of the structural preform is changed, thereby obtaining different slotting rates and structural strength parameters, and a corresponding relationship table of the structural strength parameters under the cross-sectional area of the flow guide structure of different structural preforms and the slotting rate of the structural preform of the wind turbine blade is established. The appropriate slotting rate is selected when the structural preform is designed.

[0099] Regarding step S11. The preset parameters of the wind turbine blade can include blade length, width, shape, bending angle, twisting angle, etc. The preset structure layout includes the laying material and the number of laminations of the outer skin and the inner skin, etc. Specifically, the preset parameters of the wind turbine blade include the local outer skin infusion liquid mass corresponding to the structural preform per unit time, the cross-sectional area of the flow guide structure of the structural preform, the surface area of the side of the structural preform with the flow guide structure, and the infusion liquid density.

[0100] By adjusting the size of the cross-sectional area of the flow guide structure of the structural preform, the corresponding structural strength parameters and slotting rates are obtained, thereby establishing a corresponding relationship table of the structural strength parameters and the slotting rate of the structural preform of the wind turbine blade.

[0101] In addition, in the optional embodiment of the present application, the calculation formula of the local outer skin infusion liquid mass corresponding to the structural preform per unit time in step S2 includes:

[0102] G is the local outer skin infusion liquid mass corresponding to the structural preform per unit time; S3 is the surface area of the side of the structural preform corresponding to the outer skin; N is the number of fiber layers of the outer skin; ρ2 is the fiber area density; G 总 is the total content of the infusion liquid; G 纤 is the fiber content; T is the total infusion time.

[0103] The above formula (2) is analyzed.

[0104] wherein the total fiber mass of the outer skin Gouter: G 外 = S3 x N x p2. The surface area multiplied by the number of fiber layers gives the total area of all the fibers on the outer skin, and then multiplied by the fiber areal density (mass of fiber per unit area) gives the total mass of all the fibers on the outer skin.

[0105] The mass of the fibers in the perfusion liquid:

[0106] This part is calculated by "total content of perfusion liquid / fiber content", i.e. G 总 / G 纤 The total content of perfusion liquid is the total mass of the perfusion liquid, and the fiber content is the proportion (or mass fraction) of the fibers in the perfusion liquid. Dividing the two gives the total mass of the fibers in the perfusion liquid.

[0107] The mass of the liquid perfused per unit time:

[0108] Finally, dividing the total fiber mass of the outer skin by the mass of the fibers in the perfusion liquid gives the mass of the perfusion liquid needed to cover all the fibers on the outer skin (without considering the loss and waste during the perfusion process). However, the mass of the perfusion liquid is accumulated during the entire perfusion process, so we also need to divide by the total perfusion time T to get the actual mass of the liquid perfused per unit time.

[0109] The above merely provides a specific implementation of the present application, and those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, modules and units can refer to the corresponding processes in the foregoing method embodiments, which will not be described again herein. It should be understood that the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered within the protection scope of the present application.

Claims

1. A wind turbine blade structural preform, wherein, The structure surface comprises alternating first and second flow guiding regions, the flow guiding directions of the flow guiding structures of the first and second flow guiding regions are arranged in opposite directions, and the flow guiding structures of the first flow guiding regions are arranged in a mesh shape.

2. A wind power blade structural preform according to claim 1, wherein, The flow guiding structures of the first and second flow guiding regions are arranged in opposite directions relative to the structure forming direction of the structure surface.

3. A wind power blade structural preform according to claim 1, wherein, The flow guiding structures of the second flow guiding regions are arranged along the spanwise direction of the wind turbine blade.

4. A wind turbine blade structural preform according to any of claims 1 to 3, wherein, The included angle between the flow guiding structures of the first flow guiding regions and the spanwise direction of the wind turbine blade ranges from ±30° to ±45°.

5. A wind turbine blade structural preform according to claim 2, wherein, The flow guiding structures of the first flow guiding regions comprise flow guiding portions arranged in sequence, and each flow guiding portion comprises a pair of grooves in cross communication. The flow guiding structures of the second flow guiding regions comprise protrusions, the flow guiding portions are arranged along the length direction of the protrusions, and the protrusions of each second flow guiding region are arranged in parallel.

6. A wind turbine blade structural preform according to claim 2, wherein, The flow guiding structures of the first flow guiding regions comprise grooves, the depth of each groove ranges from 2±0.5 mm, and the width of each groove ranges from 2 mm to 3 mm. The flow guiding structures of the second flow guiding regions comprise protrusions, the height of each protrusion ranges from 2 mm to 3 mm, and the width of each protrusion ranges from 2 mm to 3 mm.

7. A wind turbine blade, wherein, The wind turbine blade structure preform comprises: an outer skin; an inner skin; a structure layer arranged between the outer skin and the inner skin, the structure layer comprising the wind turbine blade structure preform according to any one of claims 1 to 6, and the structure surface of the wind turbine blade structure preform facing away from the inner skin.

8. A wind power blade according to claim 7, wherein, The outer skin comprises a fiber layer, and the flow guiding structures of the first flow guiding regions of the wind turbine blade structure preform are arranged along the fiber direction of the fiber layer.

9. A method of designing a wind turbine blade structural preform according to any of claims 1 to 6, wherein, The method comprises: determining the slotting rate of the structure preform based on the structure strength parameter of a specified position of the wind turbine blade and a corresponding relationship table between the structure strength parameter and the slotting rate of the structure preform; determining the cross-sectional area of the flow guiding structure of the structure preform based on the slotting rate and a corresponding relationship formula between the slotting rate and the cross-sectional area of the flow guiding structure of the structure preform, wherein the slotting rate is proportional to the local outer skin resin mass of the structure preform per unit time, and inversely proportional to the surface area of the structure preform having the flow guiding structure, the cross-sectional area of the flow guiding structure, and the resin density; determining the design parameter of the flow guiding structure of the structure preform based on the cross-sectional area of the flow guiding structure of the structure preform and the structure layout of the flow guiding structure.

10. The method of designing a structural preform according to claim 9, wherein, The method comprises: simulating the structure strength parameter of the specified position based on preset parameters and a preset structure layout of the wind turbine blade, wherein the preset parameters of the wind turbine blade comprise the local outer skin resin mass of the structure preform per unit time, the cross-sectional area of the flow guiding structure of the structure preform, the surface area of the structure preform having the flow guiding structure, and the resin density. determining a slotting rate of the structural preform at the specified location based on the following relationship of slotting rate: Wherein, W is the slotting rate, G is the local outer skin perfusion liquid mass corresponding to the structural preform per unit time; S1 is the surface area of the structural preform having a flow guide structure; S2 is the cross-sectional area of the flow guide structure; and p is the density of the perfusion liquid; Based on the structural strength parameter of the specified position and the slotting rate of the structural preform, a corresponding relationship table of the structural strength parameter under the cross-sectional area of the flow guide structure of different structural preforms and the slotting rate of the structural preform of the wind power blade is established.

11. The method of designing a structural preform according to claim 9, wherein, The calculation formula of the local outer skin perfusion liquid quality corresponding to the structural prefabricated part in the unit time comprises: G is the local outer skin infusion liquid mass corresponding to the structural preform per unit time; S3 is the surface area of one side of the outer skin corresponding to the structural preform; N is the number of fiber layers of the outer skin; p2 is the fiber area density; G 总 is the total content of the infusion liquid; G 纤 is the fiber content; T is the total infusion time.

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