A method for repairing the airbag blade tip of a wind turbine blade

Abstract

The present invention discloses a method for repairing the airbag blade tip of a wind turbine blade in the field of wind turbine blade design and manufacturing. First, a camera is used to take pictures for evidence, and the damaged position of the blade is determined in combination with the design drawings of the wind turbine blade and the position of the blade beacon paint. Then, the cutting position of the blade is determined. Then, a segmented airbag blade tip is manufactured by 3D printing technology, and each segmented airbag blade tip is firmly bonded. Finally, the airbag blade tip is installed on the blade body under appropriate meteorological conditions. The airbag blade tip repair method of the present invention retains a longer blade body, and at the same time removes the broken objects produced by the blade breakage to avoid damage to the airbag blade tip. While ensuring the strength of the airbag blade tip itself, its surface is polished smooth, and the wind field resistance requirements can also be met. The airbag blade tip of the present invention is simple and fast to manufacture, and the installation time with the blade body is short and the connection is reliable, which improves the reliability of the repair blade tip and is suitable for the rapid repair of the wind turbine blade tip.

Description

Technical Field

[0001] The invention relates to the field of design and manufacturing of wind turbine blades, and in particular to a method for repairing an airbag blade tip of a wind turbine blade. Background Art

[0002] During the operation of a wind turbine, if it encounters extreme wind conditions or the blades themselves have quality defects, the blades will produce a large amount of deformation during rotation and collide with the tower behind, causing the blade tips to be damaged and broken, greatly reducing the power generation. The tower will also be impacted and suffer structural damage, and even threaten the safety of the entire wind turbine.

[0003] At present, the maintenance plan for sweeping the blade tip requires a lot of manpower, financial resources and time. The operation process includes maintenance personnel taking a high-altitude hanging basket to reach the damaged position of the blade, first cutting off the damaged blade tip, and then hand-laying the composite material layer of the blade tip through the positioning tool, involving positioning, laying, pouring, bag pressing, insulation, bonding and other operations. Since the wind turbine is located in a windy area, the low wind speed window period suitable for manual high-altitude operations is short, and the entire maintenance process often takes several days. In addition, this solution for repairing the blade tip also has safety risks in the future. Under the action of long-term fatigue loads, the structural glue between the blade tip and the blade body is prone to fatigue failure, and there is a risk of the blade tip falling off and separating. However, it is difficult to evaluate the actual weight of the blade tip in the manual hand-layup process. There is a large mass moment deviation between the repaired blade and the normal blade. The three blades with unbalanced mass will cause the entire wind turbine to vibrate violently.

[0004] With the advancement and maturity of 3D printing technology, the wind power market has begun to explore and study 3D printed blades. The function of the blade is to capture wind energy through a specific aerodynamic shape. The use of glass fiber or carbon fiber composite materials is to meet the structural design requirements. According to the principle of moment balance, the load on the blade tip is small, and in theory, there is no need to use composite materials with good structural performance. The use of airbag blade tips can significantly reduce weight and maintain the corresponding aerodynamic shape. In addition, due to the advantages of simple manufacturing process, short installation time, and high structural reliability of 3D printed airbag blade tips, it can completely replace the existing blade tip maintenance solutions. However, in the existing 3D printing repair technology, the surface quality of flexible material parts manufactured by 3D printing is poor and cannot meet the requirements of wind field resistance. In addition, there is a large amount of deformation at the tip of the airbag blade, which is not conducive to the safe and stable operation of wind turbine blades. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects in the prior art and provide a method for repairing the airbag blade tip of a wind turbine blade. According to the geometric shape and fracture position of the original blade, a corresponding airbag blade tip is manufactured through 3D printing technology, and then the airbag blade tip is bonded to the damaged blade to complete the repair. The production of the airbag blade tip is simple and fast, the installation time with the damaged blade is short and the connection is reliable, which improves the reliability of the repair blade tip.

[0006] The object of the present invention is achieved by: a method for repairing the airbag blade tip of a wind turbine blade, comprising the following steps:

[0007] (1) Determine the damaged position of the blade: Determine the damaged position of the blade and the cutting position of the blade based on the blade design drawings, the position of the blade navigation paint, and the forensic photos of the damaged blade taken by the camera;

[0008] (2) Generate the 3D shape of the blade tip: Based on the 3D shape of the blade and the position of the blade cutting section determined in step 1, avoid the lightning arrester and down conductor of the blade, and manufacture the segmented airbag blade tip within the working space of the 3D printer, including the first segment airbag blade tip, the second segment airbag blade tip, and the third segment airbag blade tip. According to the finite element model of the blade, determine the size of the counterweight of each segment of the blade tip, and place the counterweight in the gap between the airbags;

[0009] (3) Check the air tightness of each segmented airbag blade tip: set an inflation hole at the trailing edge of the first segment airbag blade tip, the second segment airbag blade tip and the third segment airbag blade tip, and fill the inside of each segmented airbag blade tip with high-pressure air through the inflation hole to check the air tightness, and then seal the inflation hole;

[0010] (4) Bonding the segmented airbag blade tips: Bonding is performed according to the front-to-back spatial order of the first segment airbag blade tip, the second segment airbag blade tip, and the third segment airbag blade tip, and curing agent is applied to the bonding area of ​​each segmented airbag blade tip;

[0011] (5) Installation: Cut off the damaged blade according to the cutting position determined in step 1, and grind the cut section. Then pull the down conductor through the gap of the airbag blade tip and place it in the down conductor hole. Place the lightning receptor in the lightning receptor hole and place the metal blade tip at the tip.

[0012] (6) Bonding: Apply structural glue to the outer surface and cut section of the blade body, the tip bonding section of the airbag blade tip, the tip bonding inner surface, and the tip bonding inner section, wait for curing, fix the tip slot at the pore position of the blade, keep the bonding position fixed for a period of time, then apply curing glue to the outside of the bonding position, and use a scraper to scrape the blade until the surface is smooth;

[0013] (7) Follow-up monitoring: Continuously observe the appearance of the repaired blades, and monitor the power generation of the wind turbine and the load of the repaired blades.

[0014] Furthermore, the counterweight body in step 2 is a sandbox, a cured resin block or a bondable steel sheet.

[0015] Furthermore, the air tightness check in step 3 is performed by applying soapy water around the inflation hole. If there are no bubbles within 30 seconds, it means that the air tightness is good. The sealing inflation hole is inserted into the inflation hole by a plug, and structural glue is applied on the outer layer to fix it.

[0016] Furthermore, the curing agent described in step 4 is DP8700.

[0017] Furthermore, the sanding described in step 5 is first performed using 80-grit coarse sandpaper and then using 180-grit medium sandpaper.

[0018] Furthermore, the waiting time for curing in step 6 is 10 to 30 minutes, the fixing holding time is 30 to 60 minutes, and the structural adhesive is applied manually to ensure that the bonding surface is smooth and evenly applied; the waiting time for curing varies with the ambient temperature. When the ambient temperature is around 10°C, the waiting time for curing is 20 minutes, when the ambient temperature is around 30°C, the waiting time for curing is 10 minutes, and when the ambient temperature is around 0°C, the waiting time for curing is 30 minutes.

[0019] When the present invention is working, it first collects evidence by taking photos with a camera, and determines the damaged position of the blade in combination with the design drawings of the wind turbine blade and the position of the blade beacon paint, and then determines the cutting position of the blade. After that, a segmented airbag blade tip is manufactured through 3D printing technology, and then each segmented airbag blade tip is firmly bonded, and finally the airbag blade tip is installed on the blade body under appropriate meteorological conditions.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: first, the cutting position of the damaged blade in the present invention retains a longer blade body, and at the same time removes the broken objects generated by the blade breakage to avoid damaging the airbag blade tip. The airbag blade tip that matches the cut section of the blade body is accurately printed through 3D printing technology, and the cut section of the blade body is bonded to the airbag blade tip section, and the bonding is firm; second, the surface quality of the airbag blade tip obtained by 3D printing is rough. Through secondary manual polishing, sandpaper of different coarseness is used successively, while ensuring the strength of the airbag blade tip itself, its surface is polished smooth to meet the wind field resistance requirements; third, the blade tip part after repair in the prior art has a certain amount of deformation, which is not conducive to the stable and safe operation of the wind turbine blade. After the airbag blade tip is installed, the present invention applies a curing coating on the entire outer surface of the airbag blade tip and scrapes it to be smooth, which can keep the airbag blade tip as a whole with a small amount of deformation, and ensure the safe and stable operation of the wind turbine blade; fourth, the preparation method of the present invention is simple and easy to implement, fast to repair, low maintenance cost, and suitable for the rapid maintenance of the wind turbine blade tip. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of the airbag blade tip of the present invention.

[0022] Figure 2 Schematic diagram of the status of a wind turbine blade before and after repair.

[0023] Among them, 1 is the blade tip bonding section, 2 is the blade tip slot, 3 is the blade tip bonding inner surface, 4 is the blade tip bonding inner section, 5 is the down conductor hole, 6 is the counterweight, 7 is the first section of the airbag blade tip, 8 is the second section of the airbag blade tip, 9 is the lightning receptor hole, 10 is the third airbag blade tip, 11 is the gap, 12 is the inflation hole, and 13 is the metal blade tip. DETAILED DESCRIPTION

[0024] A method for repairing an airbag blade tip of a wind turbine blade comprises the following steps:

[0025] Step 1: Determine the damaged position of the blade: According to the blade design drawing, the position of the blade beacon paint and the forensic photos of the damaged blade taken by the camera, determine the damaged position of the blade and the cutting position of the blade.

[0026] Step 2: Generate the 3D shape of the blade tip: According to the 3D shape of the blade and the position of the blade cutting section determined in step 1, avoid the lightning arrester and down conductor of the blade, and manufacture a segmented airbag blade tip within the working space of the 3D printer, including the first segment airbag blade tip 7, the second segment airbag blade tip 8, and the third segment airbag blade tip 10. According to the finite element model of the blade, determine the size of the counterweight of each segment of the blade tip, and place a counterweight body 6 in the gap between the airbags. The counterweight body 6 can be a sandbox, a cured resin block, or a steel sheet pasted on the inner surface of the airbag.

[0027] Step 3: Check the air tightness of each segmented airbag blade tip: set an inflation hole 12 at the trailing edge of the first segment airbag blade tip 7, the second segment airbag blade tip 8 and the third segment airbag blade tip 10, and fill high-pressure air into each segmented airbag blade tip through the inflation hole 12 to check the air tightness, and then seal the inflation hole 12; the air tightness check is carried out by applying soapy water around the inflation hole 12, and no bubbles within 30 seconds indicate that the air tightness is good, insert a plug into the inflation hole 12 to seal the inflation hole 12, and apply structural adhesive on the outer layer to fix it.

[0028] Step 4: Bond the tips of the segmented airbags: Figure 1 As shown, bonding is performed according to the front-rear spatial positions of the first segment airbag blade tip 7, the second segment airbag blade tip 8 and the third segment airbag blade tip 10, and DP8700 curing agent is applied to the bonding area of ​​each segmented airbag blade tip. The curing agent on each bonding surface is required to be applied evenly. DP8700 curing agent is a curing agent that can be quickly cured even in a low temperature environment, which can greatly shorten the bonding time and increase the bonding speed.

[0029] Step 5: Installation: Cut off the damaged blade according to the cutting position determined in step 1, and grind the cut section. When grinding, first use 80-mesh coarse sandpaper, then use 180-mesh medium sandpaper to ensure the smoothness of the cut section; then pull the down conductor through the gap 11 of the airbag blade tip and place it in the down conductor hole 5, place the lightning receptor in the lightning receptor hole 9, and place the metal blade tip 13 at the tip;

[0030] Step 6: Bonding: Apply structural glue to the outer surface and cut section of the blade body, the blade tip bonding section 1 of the airbag blade tip, the blade tip bonding inner surface 3, and the blade tip bonding inner section 4, and wait for curing. The waiting time for curing varies with the ambient temperature. When the ambient temperature is around 10°C, the waiting time for curing is 20 minutes, when the ambient temperature is around 30°C, the waiting time for curing is 10 minutes, and when the ambient temperature is around 0°C, the waiting time for curing is 30 minutes. Fix the blade tip slot 2 at the pore position of the blade, and keep the bonding position fixed for 30 to 60 minutes. Then apply curing glue to the outside of the bonding position, and use a scraper to scrape the blade until the surface is smooth. This can keep the airbag blade tip with a small deformation and ensure the safe and stable operation of the wind turbine blade. The state structure diagram of the wind turbine blade before and after repair is shown as follows. Figure 2 shown.

[0031] Step 7: Tracking and monitoring: Continue to observe the appearance of the repaired blades, and monitor the power generation of the wind turbine and the load of the repaired blades.

[0032] Compared with the existing repair methods in enterprises, it takes at least 3 weeks from blade repair to installation and normal operation, and the repair procedure is complicated and costly; the method of the present invention only takes 2 to 3 days to repair the blade, and the installation work can be completed within one week, which greatly shortens the blade repair time, improves the repair efficiency and reduces the repair cost.

[0033] The airbag blade tip maintenance method of the present invention retains a longer blade body and removes broken materials produced by blade breakage to avoid damage to the airbag blade tip. In addition, the maintenance method of the present invention polishes the surface of the airbag blade tip smoothly while ensuring the strength of the airbag blade tip itself, and can also meet the wind field resistance requirements. After the airbag blade tip is installed, a curing coating is applied to the entire outer surface of the airbag blade tip and scraped until it is smooth, which can keep the airbag blade tip as a whole with a smaller deformation amount and ensure the safe and stable operation of the wind turbine blade. The preparation method of the present invention is simple and easy to implement, with fast repair and low maintenance cost, and is suitable for rapid maintenance of wind turbine blade tips.

[0034] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A method for repairing the airbag blade tip of a wind turbine blade, characterized in that: The steps include: (1) Determine the damaged position of the blade: Determine the damaged position of the blade and the cutting position of the blade based on the blade design drawings, the position of the blade navigation paint, and the forensic photos of the damaged blade taken by the camera; (2) Generate the 3D shape of the blade tip: Based on the 3D shape of the blade and the position of the blade cutting section determined in step 1, avoid the lightning arrester and down conductor of the blade, and manufacture the segmented airbag blade tip within the working space of the 3D printer, including the first segment airbag blade tip, the second segment airbag blade tip, and the third segment airbag blade tip. According to the finite element model of the blade, determine the size of the counterweight of each segment of the blade tip, and place the counterweight in the gap between the airbags; (3) Check the air tightness of each segmented airbag blade tip: set an inflation hole at the trailing edge of the first segment airbag blade tip, the second segment airbag blade tip and the third segment airbag blade tip, and fill the inside of each segmented airbag blade tip with high-pressure air through the inflation hole to check the air tightness, and then seal the inflation hole; (4) Bonding the segmented airbag blade tips: Bonding is performed according to the front-to-back spatial order of the first segment airbag blade tip, the second segment airbag blade tip, and the third segment airbag blade tip, and curing agent is applied to the bonding area of ​​each segmented airbag blade tip; (5) Installation: Cut off the damaged blade according to the cutting position determined in step 1, and grind the cut section. Then pull the down conductor through the gap of the airbag blade tip and place it in the down conductor hole. Place the lightning receptor in the lightning receptor hole and place the metal blade tip at the tip. (6) Bonding: Apply structural glue to the outer surface and cut section of the blade body, the tip bonding section of the airbag blade tip, the tip bonding inner surface, and the tip bonding inner section, wait for curing, fix the tip slot at the pore position of the blade, keep the bonding position fixed for a period of time, then apply curing glue to the outside of the bonding position, and use a scraper to scrape the blade until the surface is smooth; (7) Follow-up monitoring: Continuously observe the appearance of the repaired blades, and monitor the power generation of the wind turbine and the load of the repaired blades.

2. A method for repairing the airbag tip of a wind turbine blade according to claim 1, characterized in that: The counterweight body in step 2 is a sandbox, a cured resin block or a bondable steel sheet.

3. The method for repairing the airbag tip of a wind turbine blade according to claim 1, characterized in that: The air tightness check in step 3 is performed by applying soapy water around the inflation hole. If there are no bubbles within 30 seconds, it means that the air tightness is good. The plugged inflation hole is inserted into the inflation hole by a plug and fixed with structural glue on the outer layer.

4. The method for repairing the airbag tip of a wind turbine blade according to claim 1, characterized in that: The curing agent described in step 4 is DP8700.

5. The method for repairing the airbag tip of a wind turbine blade according to claim 1, characterized in that: The sanding described in step 5 is done first with 80-grit coarse sandpaper, then with 180-grit medium sandpaper.

6. The method for repairing the airbag tip of a wind turbine blade according to claim 1, characterized in that: The waiting time for curing in step 6 is 10 to 30 minutes, the fixing time is 30 to 60 minutes, and the structural adhesive is applied manually to ensure that the bonding surface is smooth and evenly applied.

Images