Blade perfusion cork wood air filament defect elimination method and blade

Abstract

The invention relates to the field of wind power generation, and discloses a method for eliminating the air filament defect of blade perfusion cork wood and a blade, and the method comprises the following steps: S1: a cork wood processing process: adding a set amount of hole sealing agent on the surface of the cork wood, and selecting a set groove width and cutting through to process the cork wood; s2, baking treatment is conducted, specifically, the balsa wood is baked, and the balsa wood is rolled up and placed in a drying room and lasts for a set time at the set temperature; s3, in the laying process, a continuous felt is arranged in the middle area of the mold surface, a layer of demolding cloth is additionally arranged between the continuous felt and the skin, and a VAP film is laid in the edge area of the blade; and S4, pouring is completed, water is sprayed to the part, with the surface temperature higher than the set temperature, of the balsa wood for cooling, and precipitation of water in the balsa wood is reduced. By optimizing the drying, slotting, chemical treatment and pouring processes, the moisture content and gas residues of cork wood are remarkably reduced, and the surface quality and stability of the wind power blade are improved.

Description

Technical Field

[0001] The invention relates to the field of wind power generation, and in particular to a method for eliminating defects of balsa wood gas fibers infused into a blade and a blade. Background Art

[0002] In the fine manufacturing process of wind turbine blades, the requirements for the structural strength of the blades are becoming increasingly stringent. Balsa wood, with a density between 100 and 150 kg / m³, has excellent mechanical strength and modulus, far exceeding the performance of various foam materials. Balsa wood can maintain stable physical properties within an extremely wide temperature range (-212°C to 163°C), coupled with its unique honeycomb pore structure, these characteristics together give balsa wood a unique advantage in the field of structural sandwich materials, making it an ideal choice for making wind turbine blade sandwich materials.

[0003] However, in the key stage of primary molding and pouring, the balsa wood surface area of ​​the blade and the core material grooves are often plagued by defects such as air filaments and bubbles. These defects are like invisible cracks, which not only erode the overall quality of the blade, but also weaken its strength, posing a potential threat to the stable operation of the wind turbine.

[0004] In the face of this challenge, current technology mainly focuses on trying to alleviate the air-thread problem by finely controlling the moisture content of balsa wood. Unfortunately, however, this method has not been able to effectively and thoroughly solve this problem, and we still need to continue to explore more efficient and comprehensive solutions. Summary of the invention

[0005] In view of the above-mentioned technical deficiencies, the technical problem to be solved by the present invention is to provide a method for eliminating air thread defects in balsa wood infusion of blades and a blade, aiming to solve the problems of air threads, bubbles and other defects often encountered in the balsa wood surface area and core material grooves of the blades in the key link of the main molding infusion.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a method for eliminating air-thread defects of balsa wood in a blade, comprising: S1: a balsa wood processing process, adding a set amount of sealing agent to the surface of the balsa wood and selecting a set groove width and cutting through to process the balsa wood; S2: baking treatment, wherein the balsa wood is rolled up and placed in a drying room at a set temperature for a set time; S3: during the laying process, a continuous felt is arranged in the middle area of ​​the mold profile, a layer of release cloth is added between the continuous felt and the skin, and a VAP film is laid in the edge area of ​​the blade; Among them, before the balsa wood is laid, the mold is preheated to the set temperature until the laying is completed; S4: After the infusion is completed, water is sprayed on the part of the balsa wood surface whose temperature is higher than the set temperature to cool it down, so as to reduce the precipitation of moisture in the balsa wood.

[0007] Further, the balsa wood is rolled and placed in a drying room at a temperature greater than 85° C. for at least 10 hours.

[0008] Furthermore, it also includes baking in a high temperature environment that meets the set temperature.

[0009] Furthermore, the method further includes separating the balsa wood layers and baking them.

[0010] Furthermore, 18-20 g / ㎡ of sealing agent is added to the surface of the balsa wood, and a groove width of 0.1-0.5 mm and a through cut are selected to process the balsa wood.

[0011] Furthermore, after the mold is preheated to a set temperature, the balsa wood area is covered with thermal insulation cotton to maintain the temperature of the balsa wood area, and at the same time, an external steel wire pipe is used to intermittently evacuate the air in the mold.

[0012] Furthermore, the VAP film laid on the edge area of ​​the blade exceeds the defective area by 30-50mm, and a suction ear with a width of 200mm is set at a set interval. The suction ear cavity is overlapped with the VAP film and the trailing edge side is laid on the guide net of the flange platform to increase the power of suction after the resin covering of the air thread area, so as to improve the balsa wood air thread.

[0013] Furthermore, before laying the balsa wood, the mold is preheated to 45°C to reduce the risk of the balsa wood absorbing moisture due to temperature differences.

[0014] Furthermore, it also includes: taking out the balsa wood from the baking room half an hour before laying or directly placing the balsa wood taken out from the baking room in a vacuum negative pressure environment for cooling.

[0015] A blade is manufactured by a blade infusion balsa wood gas-fiber defect elimination method.

[0016] The beneficial effects of the present invention are: 1. Control the placement of balsa wood, drying room temperature and drying time to minimize the moisture content of balsa wood.

[0017] 2. By controlling the width and depth of the balsa wood grooves, the molecular force between the bubbles and the balsa wood grooves can be weakened to reduce the residual gas during the infusion process.

[0018] 3. By adding an appropriate amount of chemical substances to the surface of balsa wood, the porosity in the balsa wood structure and the explosion problem caused by the infusion resin penetrating into the balsa wood during the infusion process have been improved.

[0019] 4. Laying a layer of continuous felt or VAP membrane outside the skin can guide the water vapor to the continuous felt or VAP membrane during the infusion process, thereby eliminating the problem of balsa wood gas fibers in the FRP layer.

[0020] 5. Open the mold in advance to preheat at 45℃, cover the balsa wood area with insulation cotton to increase the temperature of the balsa wood area, and at the same time, intermittently switch on and off the external steel wire tube to effectively avoid the problem of excessive moisture content caused by moisture absorption by balsa wood.

[0021] 6. After the pouring is completed, local resin top glue is applied to prevent the formation of explosion and reduce the degree of explosion. At the same time, the surface temperature of the balsa wood is checked to be no higher than 45°C, and water is sprayed to cool the high-temperature area to reduce the precipitation of moisture in the balsa wood. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic flow chart of a method for eliminating defects of balsa wood gas fibers in blade infusion provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] like Figure 1 As shown, this embodiment provides a method for eliminating defects of balsa wood gas fibers in a blade, comprising: S1: Balsa wood processing, add 18-20g / ㎡ sealing agent on the surface of balsa wood, select 0.1-0.5mm groove width and cut through to process balsa wood. It should be noted that: Choosing the appropriate groove width and depth can weaken the surface tension between the gas and the core material groove, which is beneficial to the discharge of gas during the infusion process. By adding an appropriate amount of chemical substances during the balsa wood production process, on the one hand, the microporous structure in the balsa wood structure can be effectively filled to avoid water vapor enrichment. On the other hand, the infusion resin can be effectively blocked from penetrating into the balsa wood during infusion, thereby avoiding abnormally high temperature of the balsa wood and forming balsa wood explosion.

[0027] S2: Baking treatment, the balsa wood is baked, wherein the balsa wood is rolled up and placed in a drying room at a set temperature for a set time. It should be noted that: The balsa is rolled or separated into layers and placed in a drying room at a temperature greater than 85°C for at least 10 hours.

[0028] Different placement methods of balsa wood will result in different evaporation rates of moisture during the baking process. All cartons and films should be removed, and the balsa wood boards should be rolled up for baking. The water removal quality of the rolled boards for baking is much greater than the water removal quality of the boards laid flat. When baking balsa wood, measure and ensure that the baking temperature of the balsa wood surface is greater than 85°C and the duration is greater than 10 hours, which can effectively remove moisture from thicker balsa wood.

[0029] After the mold is preheated to the set temperature, the balsa wood area is covered with insulation cotton to maintain the temperature of the balsa wood area. At the same time, an external steel wire pipe is used to intermittently evacuate the air in the mold.

[0030] S3: During the laying process, a continuous felt is arranged in the middle area of ​​the mold surface, a layer of demoulding cloth is added between the continuous felt and the skin, and a VAP film is laid in the edge area of ​​the blade; before laying the balsa wood, the mold is preheated to 45°C until the laying is completed to reduce the risk of balsa wood absorbing moisture due to temperature difference; at the same time, the balsa wood is taken out of the baking room half an hour before laying or directly placed in a vacuum negative pressure environment to cool. It should be explained that: For the area where VAP film cannot be arranged in the middle of the mold surface, a three-dimensional porous structure of continuous felt or surface felt or other porous gas-conducting materials is used. By placing the continuous felt outside the skin and adding a layer of demoulding cloth between the continuous felt and the skin, the gas produced by the balsa wood during the exothermic peak of infusion and curing is introduced into the porous structure of the continuous felt through the enrichment effect of the continuous felt. After the curing is completed, the continuous felt is torn off to achieve the purpose of eliminating the balsa wood gas threads in the skin cloth layer. For the edge area of ​​the blade, VAP film can be laid, and the laying width of the VAP film is determined according to the gas thread defect area. The VAP film exceeds the defect area by 30-50mm. A 200mm wide exhaust ear is laid every 4m in the chord direction. The exhaust ear cavity is overlapped with the VAP film and laid on the guide net of the flange platform on the trailing edge side to increase the power of exhaust after the gas thread area is covered with resin, thereby improving the balsa wood gas threads.

[0031] Preferably, during the balsa wood laying operation, the balsa wood that has been baked at high temperature for a long time is in an ultra-dry balsa wood state. Affected by the working environment, i.e., high humidity environment, the balsa wood is very easy to absorb moisture. Therefore, the balsa wood is taken out of the baking room half an hour before laying, or the taken out balsa wood is placed in a vacuum negative pressure state for cooling to reduce the moisture absorption of the balsa wood. Before laying the balsa wood, the mold is opened at 45°C to preheat the mold until the laying is completed, so as to further reduce the moisture absorption caused by the sudden change of the balsa wood temperature.

[0032] S4: After the infusion is completed, water is sprayed on the part of the balsa wood surface that is higher than the set temperature to reduce the temperature and reduce the precipitation of moisture in the balsa wood. The balsa wood gas thread problem caused by balsa wood glue seepage during the infusion process can be solved by local resin infusion after the large surface of the shell is infused, based on the gas return phenomenon of the balsa wood on the inner surface. The moisture in the balsa wood is in a low-pressure state after vacuum sealing, and its boiling point is low. During the infusion and curing process, the temperature of the balsa wood area is detected multiple times through temperature measuring equipment. For areas where the surface temperature of the balsa wood is higher than 45°C, water is sprinkled to cool down, so as to achieve the purpose of avoiding the evaporation of moisture in the balsa wood.

[0033] Example 2

[0034] Based on the fact that the balsa wood is rolled up or the layers of balsa wood are separated and placed in a drying room for baking in Example 1, this embodiment also provides another method for baking balsa wood, that is, in addition to a special baking room, other high-temperature links in the blade manufacturing process, such as the blade post-curing process, can also be used to complete the baking of the balsa wood, thereby achieving the purpose of removing moisture.

[0035] Example 3

[0036] Based on Example 1, this example also provides a blade manufactured based on a method for eliminating defects of balsa wood gas fibers infused into blades.

[0037] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for eliminating defects of balsa wood gas fibers in a blade, characterized in that: include: S1: Balsa wood processing, adding a set amount of sealer to the surface of the balsa wood and selecting a set groove width and cut-through to process the balsa wood; S2: baking treatment, wherein the balsa wood is rolled up and placed in a drying room at a set temperature for a set time; S3: during the laying process, a continuous felt is arranged in the middle area of ​​the mold profile, a layer of release cloth is added between the continuous felt and the skin, and a VAP film is laid in the edge area of ​​the blade; Among them, before the balsa wood is laid, the mold is preheated to the set temperature until the laying is completed; S4: After the infusion is completed, water is sprayed on the part of the balsa wood surface whose temperature is higher than the set temperature to cool it down, so as to reduce the precipitation of moisture in the balsa wood.

2. A method for eliminating defects of balsa wood gas fibers in blade infusion according to claim 1, characterized in that: The balsa wood is rolled and placed in a drying room at a temperature greater than 85°C for at least 10 hours.

3. A method for eliminating defects of balsa wood gas fibers in blade infusion as claimed in claim 1, characterized in that: It also includes baking in a high temperature environment that meets the set temperature.

4. A method for eliminating defects of balsa wood gas fibers in blade infusion as claimed in claim 1, characterized in that: It also involves baking the balsa wood layers after spacing them apart.

5. A method for eliminating defects of balsa wood gas fibers in blade infusion as claimed in claim 1, characterized in that: Add 18-20g / ㎡ sealer to the balsa wood surface and select 0.1-0.5mm groove width and cut through to process the balsa wood.

6. A method for eliminating defects of balsa wood gas fibers in blade infusion as claimed in claim 1, characterized in that: After the mold is preheated to the set temperature, the balsa wood area is covered with insulation cotton to maintain the temperature of the balsa wood area. At the same time, an external steel wire pipe is used to intermittently evacuate the air in the mold.

7. A method for eliminating defects of balsa wood gas fibers in a blade according to claim 1, characterized in that: The VAP film laid in the edge area of ​​the blade exceeds the defective area by 30-50mm. A suction ear with a width of 200mm is set at a set distance at each interval. The suction ear cavity is overlapped with the VAP film and laid on the guide net of the flange platform on the trailing edge side to increase the power of suction after the resin covering the air thread area, so as to improve the balsa wood air thread.

8. A method for eliminating defects of balsa wood gas fibers in a blade according to claim 1, characterized in that: Before laying the balsa wood, preheat the mold to 45°C to reduce the risk of the balsa wood absorbing moisture due to temperature difference.

9. A method for eliminating defects of balsa wood gas fibers in blade infusion as claimed in claim 1, characterized in that: Also includes: Take out the balsa wood from the baking room half an hour before laying, or directly place the balsa wood taken out from the baking room in a vacuum negative pressure environment to cool it.

10. A blade, characterized in that: The blade is made by a method for eliminating defects of balsa wood gas fibers in a blade as described in any one of claims 1 to 9.

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