A comprehensive pipe laying and infusion method for megawatt-level wind turbine blades

Abstract

The present invention belongs to the technical field of wind turbine blade manufacturing, and provides a comprehensive pipe laying and infusion method for megawatt-level wind turbine blades, including structural layer pipe laying. First, according to the number of fiberglass cloth structural layers above the sandwich structure of the windward surface and the leeward surface, infusion pipeline diversion grooves in different directions are arranged; PET foam materials are placed in the PET area, and diversion grooves are arranged in the PET area; the PET foam materials have good fatigue performance and mechanical properties, and the production process is environmentally friendly; circumferential diversion grooves are arranged in the balsa wood area, and a diversion net is laid at the balsa wood position. The balsa wood can play a role in locally strengthening the blade shell, and the balsa wood will not excessively increase the weight of the blade; main diversion grooves need to be placed on both sides of the front and rear edges of the girder, and the glue injection ports of all circumferential diversion grooves need to be placed at the positions of the main diversion grooves; through comprehensive pipe laying, the problems that it is difficult to fix the diversion grooves in the areas with large chord lengths and curvatures of the windward surface and the leeward surface of the blade and the positioning is prone to deviation are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of wind turbine blade manufacturing, and more specifically, it is a comprehensive pipe laying and infusion method for megawatt-level wind turbine blades. Background Art

[0002] With the gradual depletion of non-renewable energy on the earth, and at the same time, a large amount of pollution is generated during the combustion of non-renewable energy, causing the deterioration of the entire environment. Therefore, there is an urgent need for an environmentally friendly and renewable energy source. Among them, wind power is a very widely promoted clean energy source at present. Wind turbines generate electricity mainly by relying on the wind to drive the blades to rotate, thereby realizing the process of converting wind energy into electrical energy. A wind turbine blade with excellent design, reliable quality and high efficiency is a key factor to ensure the normal operation of the entire wind turbine.

[0003] As one of the core components of wind turbines, with the increasingly fierce competition in the industry, it is particularly important to improve the production efficiency of blades and ensure the reliable quality of blades. Among them, the blade vacuum infusion process is the main process flow in the blade forming process. Although the current infusion process can ensure the completion of blade infusion production, there are still the following problems:

[0004] 1. The existing infusion process cannot well solve the problems of the downward sliding of the flow guide groove in the large chord and large curvature areas and inaccurate positioning.

[0005] 2. It cannot well solve the problem of a large number of axial pipe laying injection ports and the risk of air leakage.

[0006] 3. It cannot well solve the problems of slow gluing in the large curvature rear yard of the blade and the increase in the cost of infusion resin due to the large amount of resin used. Summary of the Invention

[0007] In order to solve the above technical problems, the invention provides a comprehensive pipe laying and infusion method for megawatt-level wind turbine blades. By adopting the method of axial and chordal pipe laying, it includes a combination of structures such as an anti-indentation flow guide groove, a tee joint, a tee injection port, an anti-indentation injection port, an anti-indentation joint, etc., to solve the problems of inaccurate positioning, air leakage risk and high material cost during the infusion process.

[0008] The specific technical solution of the invention is as follows:

[0009] A comprehensive pipe laying and infusion method for megawatt-level wind turbine blades, comprising the following steps:

[0010] S1: Structural layer pipe laying. First, according to the number of fiberglass cloth structural layers above the sandwich structure of the windward side and the leeward side, lay the perfusion pipeline diversion grooves in different directions. Before the perfusion of the wind turbine blade, it is necessary to clean the perfusion mold with a mold cleaning agent and seal the small air holes on the surface of the mold with a sealing agent to prevent the large porosity of the wind turbine blade caused by the air leakage of the mold during the vacuum perfusion process.

[0011] S2: PET area. Place PET foam material in the PET area and lay diversion grooves in the PET area. PET foam material has good fatigue performance and mechanical properties, and the production process is environmentally friendly. Through PET, it has gradually replaced PVC foam material.

[0012] S3: Balsa wood area. Lay circumferential diversion grooves in the balsa wood area and lay a diversion net at the balsa wood position. Balsa wood can play a role in locally strengthening the blade shell, and balsa wood will not increase the weight of the blade too much.

[0013] S4: Girder area. It is necessary to place main diversion grooves on both sides of the front and rear edges of the girder, and all the injection ports of the circumferential diversion grooves need to be placed at the position of the main diversion grooves. The girder is equivalent to the backbone of a person, and the long wind turbine blade needs to be supported by the girder.

[0014] S5: Perfusion completed. After the diversion grooves in each area of the blade are arranged, start to perfuse the resin inside the blade and heat the blade to accelerate the curing of the resin. The resin uses epoxy resin, the curing temperature is controlled at 40°C and maintained for 10h, and then at 70°C and maintained for 3h, so as to complete the curing of the resin.

[0015] As a further improvement of this solution, in step S1, when the number of fiberglass cloth structural layers > 8 layers, the diversion grooves are laid in the axial direction, and when the number of fiberglass cloth structural layers ≤ 8 layers, the diversion grooves are laid in the chordal direction.

[0016] As a further improvement of this solution, the distance between the end position of the axially laid diversion grooves and the chordally laid diversion grooves is 1.5m, and a glue blocking strip is placed chordally in the 1.5m distance.

[0017] As a further improvement of this solution, in step S2, the distance between the diversion grooves in the PET area is set to 2m.

[0018] As a further improvement of this solution, in step S3, the direction of the circumferential diversion grooves laid in the middle of the balsa wood area is chordal, and the number of circumferential diversion grooves is one.

[0019] As a further improvement of this solution, the circumferential diversion grooves and the main diversion grooves in the girder area are connected by a tee.

[0020] As a further improvement of this solution, the circumferential flow guide groove is cut off 10 cm away from the leading edge of the prefabricated auxiliary beam of the blade, and the circumferential flow guide groove is laid flush with the edge of the core material from the leading edge of the prefabricated auxiliary beam of the blade.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. After comprehensively arranging the flow guide grooves in the axial, chordal and circumferential directions, the present invention solves the problems that it is difficult to fix the flow guide grooves in the regions with large chord lengths and curvatures on the windward and leeward sides of the blade and the positioning is prone to deviation, improves the laying efficiency of the flow guide system; reduces the number of injection ports, reduces the quality risk caused by air leakage due to improper connection of the injection ports; solves the problem of defects in the flow guide grooves caused by poor coverage of the heat preservation cotton quilt. Description of the Drawings

[0023] Figure 1 is a cross-sectional view of the front section of the blade of the present invention;

[0024] Figure 2 is a cross-sectional view of the middle section of the blade of the present invention;

[0025] Figure 3 is a cross-sectional view of the tail section of the blade of the present invention;

[0026] Figure 4 is a schematic diagram of the structural composition of the blade of the present invention;

[0027] Figure 5 is a process flow chart of the blade perfusion of the present invention. Specific Embodiments

[0028] The following further describes in detail the embodiments of the present invention in conjunction with the drawings and embodiments. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0029] As Figures 1-5 shown, a comprehensive pipe laying and perfusion method for megawatt-level wind turbine blades. The current wind turbine blade structure is mainly composed of two upper and lower half shells. The blade structure includes a leading edge, a blade girder, a trailing edge auxiliary beam, a foam board and blade ribs; according to the characteristics of the megawatt-level airfoil layup structure, the layout of the perfusion flow guide grooves is mainly axial and chordal. To solve the problems regarding blade perfusion in the background art, the perfusion process of the megawatt-level wind turbine blades of the present invention is as follows:

[0030] First, prepare well before blade infusion. Clean the surface of the mold with a mold cleaner to remove surface stains. At the same time, use a hole sealer to seal the small pores on the mold surface to prevent large porosity of the product caused by air leakage of the mold during the vacuum infusion process. Then, lay a release agent on the mold surface to form a dense layer on the mold surface, making it easier for the blade to separate from the mold after infusion. Then, lay the embedded parts. The embedded parts mainly include the blade girder, foam core, root embedded block, and fiberglass cloth. Among them, the blade girder is formed on a separate mold, and a special tooling equipment is required for precise positioning during laying. The foam core preferably uses a PET foam board, which has the function of being lightweight and high-strength and can improve the overall stiffness of the blade. During the laying process, it is necessary to ensure that the connection between each board is tight. Lay the fiberglass cloth in the upper and lower shells of the blade and stagger it from the laid embedded parts. After the previous preparation work is completed, start laying the flow guide grooves / flow guide pipes inside the blade and prepare for the formal infusion. The specific steps are as follows:

[0031] Step 1: Pipe laying for the structural layer

[0032] 1.1 When the fiberglass cloth structural layer above the sandwich structure of the windward and leeward sides of the wind turbine blade > 8 layers, the flow guide grooves start to be laid in the axial direction;

[0033] 1.2 When the fiberglass cloth structural layer above the sandwich structure of the windward and leeward sides of the wind turbine blade ≤ 8 layers, the flow guide grooves start to be laid in the chordal direction;

[0034] And the distance between the end position of the axially laid flow guide grooves and the chordally laid flow guide grooves is 1.5 m, and a glue blocking strip is placed chordally in the 1.5 m interval to ensure that the glue liquids do not affect each other. The glue blocking strip is butt-jointed with the leading edge or trailing edge of the girder and butt-jointed with the leading edge of the auxiliary girder for laying.

[0035] Generally, the length of one flow guide groove is 4 m. According to the previous axial pipe laying method, in the area with a larger chord length, the flow guide grooves are prone to sliding. By adopting chordal pipe laying: that is, one person inside the shell locates according to the girder marking line, and one person outside locates according to the mold flange platform marking line. In this way, according to the positioning method of two points determining a line, it not only meets the positioning accuracy of the flow guide grooves but also solves the problem of sliding and offset of the flow guide groove positioning.

[0036] It should be noted that: the windward and leeward sides of the blade refer to the upper and lower shells of the blade;

[0037] In addition, when the diversion system arranges pipes according to the axial diversion grooves, the width of the cotton quilt is greater than the distance between the diversion grooves. When the cotton quilt covers in the circumferential direction, all the diversion grooves are under the cotton quilt, making it difficult to observe the heat release process and lift the cotton quilt to release heat. When the cotton quilt covers in the axial direction, due to the large chord length and curvature of the trailing edge, each piece of the cotton quilt needs to be placed closely when covering. During the heat release process, when the lower cotton quilt is lifted, the upper cotton quilt is likely to slide down. After the diversion grooves are arranged in the circumferential direction, the cotton quilt can be placed between two circumferential diversion grooves along the circumferential direction. There is no diversion groove under the cotton quilt, and when the cotton quilt is lifted to release heat, the cotton quilt can be removed as a whole. After arranging the pipes according to the comprehensive pipe layout plan according to the diversion grooves, the problem of the high-temperature white defect under the diversion grooves caused by poor coverage of the thermal insulation cotton quilt is solved.

[0038] Step 2: PET area

[0039] The main component of the PET foam board is polybutylene terephthalate, which is mainly used to manufacture synthetic fibers, films, bottles, etc. The PET foam formed after foaming has good heat resistance and mechanical properties. Therefore, at present, the original PVC foam board is gradually replaced by the PET foam board;

[0040] The distance between the circumferential diversion grooves in the PET area is controlled at 2m.

[0041] Step 3: Balsa wood area

[0042] Balsa wood is laid in the part that needs to be strengthened at the root of the wind turbine blade to strengthen the local strength of the shell. A circumferential diversion groove is laid in the middle of the balsa wood area and in the circumferential direction, and a diversion net is laid at the balsa wood position. During vacuum infusion, the resin flow rate in the fiberglass cloth is much lower than that on the diversion net. Therefore, the diversion net can soak a larger area of fiberglass cloth faster. By laying balsa wood in the core material of the root strengthening area and PET in other areas, the structural strength of the wind turbine blade is further enhanced.

[0043] It should be noted that: the specific gravity of balsa wood is only 0.10 - 0.20 g / cm³, and it has good strength, especially good sound insulation and heat insulation performance. By combining balsa wood with nylon filaments to make a balsa wood sandwich panel, it can also be bent into shape. After coating fiberglass cloth and high-strength epoxy resin on the outside, the strength of the blade after consolidation is 30 times higher than that of the balsa wood itself.

[0044] Step 4: Beam area

[0045] By placing main diversion grooves on both sides of the leading and trailing edges of the blade beam, and placing all the injection ports of the circumferential diversion grooves in the balsa wood area at the main diversion groove positions, where the circumferential diversion groove and the main diversion groove are connected by a tee. The circumferential diversion groove is cut and placed 10 cm away from the leading edge of the prefabricated auxiliary beam, and the circumferential diversion groove is laid flush with the leading edge and the edge of the core material.

[0046] Step 5: Completion of perfusion

[0047] After the laying of the flow guiding grooves is completed, the mold and the entire product are sealed with a vacuum bag to make the entire system in a negative pressure state, so that the resin can be sucked in, thus achieving the process of vacuum perfusion. During the perfusion process, it is required that no air enters, so the airtightness of the entire perfusion system needs to be detected, and it is necessary to ensure that there is enough resin at each resin injection port, and the opening and closing time of each resin injection port also needs to be strictly limited;

[0048] Among them, the number of resin injection ports in the housing is reduced from 69 in the original process to 43, and the number of resin injection ports is reduced by 37%. The connection of the resin injection ports is manually wound with a sealing strip, reducing the probability of air leakage caused by improper connection of the resin injection ports;

[0049] Then start injecting the resin. After the injection is completed, start heating the resin. First, heat it to 40°C and maintain it for 10 hours, and then heat it to 70°C and maintain it for 3 hours to complete the curing of the resin, ensuring that the blade meets the relevant performance requirements after perfusion.

[0050] After the perfusion is completed, then demold the blade and perform some post-treatment on the blade to complete the production of the blade.

[0051] After adopting the above comprehensive layout of the flow guiding grooves, the problems that it is difficult to fix the flow guiding grooves in the areas with large chord lengths and curvatures on the windward side and the leeward side of the blade and the positioning is prone to deviation are solved, and the laying efficiency of the flow guiding system is improved; the number of resin injection ports is reduced, reducing the quality risk caused by air leakage due to improper connection of the resin injection ports; the problem of flow guiding groove defects caused by poor coverage of the heat preservation cotton is solved; the consumption of auxiliary materials for the housing is reduced, achieving the effect of cost reduction, and the perfusion efficiency is improved while reducing the resin consumption.

[0052] The embodiments of the present invention are given for the purpose of illustration and description, and are not exhaustive or limit the present invention to the disclosed form. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features.

Claims

1. A comprehensive pipe laying and infusion method for megawatt-level wind turbine blades, characterized in that, It includes the following steps: S1: Structural layer pipe laying. First, according to the number of fiberglass cloth structural layers above the sandwich structure of the windward side and the leeward side, arrange the perfusion pipeline diversion grooves in different directions; When the number of fiberglass cloth structural layers > 8 layers, the diversion grooves are arranged in the axial direction for pipe laying; When the number of fiberglass cloth structural layers ≤ 8 layers, the diversion grooves are arranged in the chordal direction for pipe laying; The cotton quilt is placed in the middle of two chordal diversion grooves, and there is no diversion groove below the cotton quilt; S2: PET area. Place PET foam material in the PET area and arrange diversion grooves in the PET area; S3: Balsa wood area. Arrange circumferential diversion grooves in the balsa wood area and lay a diversion net at the balsa wood position; S4: Girder area. Place main diversion grooves on both sides of the front and rear edges of the girder. All the injection ports of the circumferential diversion grooves need to be placed at the positions of the main diversion grooves; S5: After perfusion is completed, after the diversion grooves in each area of the blade are arranged, start to pour resin into the blade interior and heat the blade to accelerate the resin curing.

2. The integrated pipe laying and infusion method for megawatt-level wind turbine blades according to claim 1, characterized in that: The distance between the end position of the axially arranged pipe laying diversion groove and the chordally arranged pipe laying diversion groove is 1.5 m, and a glue blocking strip is placed chordally in the 1.5 m interval.

3. The integrated pipe laying and infusion method for megawatt-level wind turbine blades according to claim 2, wherein: In step S2, the spacing of the diversion grooves in the PET area is set to 2 m.

4. The integrated pipe laying and infusion method for megawatt-level wind turbine blades according to claim 1, wherein: In step S3, the direction of the circumferential diversion groove laid in the middle of the balsa wood area is chordal, and the number of the circumferential diversion grooves is one.

5. The integrated pipe laying and infusion method for megawatt-level wind turbine blades according to claim 4, characterized in that: The circumferential diversion groove and the main diversion groove in the girder area are connected by a tee.

6. The integrated pipe laying and perfusion method for megawatt-level wind turbine blades according to claim 4, characterized in that: The circumferential diversion groove is cut off 10 cm from the leading edge of the prefabricated auxiliary beam of the blade, and the circumferential diversion groove is laid flush with the leading edge of the prefabricated auxiliary beam of the blade and the edge of the core material.

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