Wind turbine blade, and design method for wind turbine blade

Abstract

To provide a wind turbine blade that can reduce cost involved in formation of protective layers, and can improve workability of construction and repair.SOLUTION: A wind turbine blade 5 is attached to a hub of a wind power generation device, and comprises: a blade body 5a extending in a blade length direction L1; a tip part 12 provided in the blade body 5a, and formed of a metal material; a second region protective layer 30a covering a front edge part 16 in a second region R2 of the blade body 5a located closer to the side of the hub than a first region R1 including the tip part; and a third region protective layer 30b covering the front edge part 16 in a third region R3 of the blade body 5a located closer to the side of the hub than the second region R2. The hardness of a material forming the second region protective layer 30a is larger than the hardness of a material forming the third region protective layer 30b.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a wind turbine blade and a method for designing a wind turbine blade. [Background technology]

[0002] As the wind turbine rotor rotates, the wind turbine blades collide with foreign objects in the air (e.g., raindrops, dust, etc.) and are eroded, causing erosion at the leading edge of the wind turbine blade. To protect the wind turbine blades from this erosion, it is known to form an erosion-resistant protective layer at the leading edge of the wind turbine blade (see Patent Document 1). Regarding the configuration of a wind turbine blade, a configuration is known in which a metal layer with low electrical resistivity is provided in at least a partial area of ​​the wind turbine blade, thereby quickly dissipating lightning current when the wind turbine blade is struck by lightning (see Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-175830 [Patent Document 2] Patent No. 6838181 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent wind turbines (e.g., offshore wind turbines), the rotor diameter has become larger as the turbine size increases, and the circumferential speed at the tip of the wind turbine blade tends to increase. Therefore, in order to prevent erosion at the tip, measures such as lowering the rotation speed to lower the circumferential speed and expanding the range of the erosion-resistant protective layer in the blade length direction are required. In Patent Document 2, a layer (e.g., sprayed film) that is erosion resistant and protects the blade body is provided in the hub side area next to a metal (e.g., copper) receptor at the very tip that has high erosion resistance and is intended mainly for attracting lightning. However, forming the sprayed metal film uniformly requires excessive costs and labor during construction and repair.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a wind turbine blade and a method for designing a wind turbine blade that can reduce the costs of forming a protective layer and improve the workability of construction and repair work. [Means for solving the problem]

[0006] A wind turbine blade according to one embodiment of the present disclosure is a wind turbine blade that is attached to the hub of a wind power generation device, and comprises a blade body, a tip portion provided on the blade body and formed of a metal material, a second region protective layer covering a leading edge portion of a second region of the blade body that is located closer to the hub than a first region including the tip portion, and a third region protective layer covering a leading edge portion of a third region of the blade body that is located closer to the hub than the second region, wherein the hardness of the material forming the second region protective layer is greater than the hardness of the material forming the third region protective layer.

[0007] A design method for a wind turbine blade according to one aspect of the present disclosure is a design method for a wind turbine blade to be attached to a hub of a wind power generation device, the wind turbine blade comprising: a blade body extending in a blade span direction; a tip portion provided on the blade body and formed of a metal material; a second region protective layer covering a leading edge portion of a second region of the blade body located closer to the hub than a first region including the tip portion; and a third region protective layer covering a leading edge portion of a third region of the blade body located closer to the hub than the second region, wherein the second region is a range in the blade span direction in which the circumferential speed of the leading edge portion is equal to or greater than a first threshold, the third region is a range in the blade span direction in which the circumferential speed of the leading edge portion is equal to or greater than a second threshold that is less than the first threshold and smaller than the first threshold, and the hardness of the material forming the second region protective layer is greater than the hardness of the material forming the third region protective layer, and / or the thickness of the material forming the second region protective layer is greater than the thickness of the material forming the third region protective layer. Effect of the Invention

[0008] The cost of forming the protective layer can be reduced, and the workability of construction and repair can be improved. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram showing a wind power generation device using a wind turbine blade according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a plan view showing the general shape of a wind turbine blade. [Diagram 3] FIG. 4 is a cross-sectional view in the stacking direction of a second region of the wind turbine blade. [Figure 4] FIG. 11 is a cross-sectional view in the lamination direction of a third region of the wind turbine blade. [Diagram 5] FIG. 3 is a cross-sectional view of the wind turbine blade shown in FIG. 2. [Figure 6] 1 is a graph showing the relationship between the position in the blade length direction and the peripheral speed of a wind turbine blade used on land. [Figure 7] 1 is a graph showing the relationship between the position in the blade length direction and the circumferential speed of a wind turbine blade used offshore. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Wind turbine blade configuration) Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. As shown in FIG. 1, the wind turbine generator 1 has a tower 3 erected on an installation surface B, a nacelle 6 installed at the upper end of the tower 3, and a rotor head 4 (hub 4) mounted on the nacelle 6 so as to be rotatable around a substantially horizontal axis.

[0011] A plurality of (e.g., three) wind turbine blades 5 are attached radially around the rotation axis of the rotor head 4. A part of the energy of the wind that strikes the wind turbine blades 5 from the direction of the rotation axis of the rotor head 4 is converted into energy that rotates the rotor head 4 around the rotation axis, and the obtained rotational energy is further converted into electrical energy by a generator (not shown) and supplied to the outside.

[0012] 2, the wind turbine blade 5 includes a wind turbine blade body (blade body) 5a extending in a blade span direction L1, a blade root 10 attached to the rotor head 4, a blade tip (tip) 12 located farthest from the rotor head 4, and an airfoil portion 14 extending between the blade root 10 and the blade tip 12. The blade span direction L1 extends horizontally in FIG. 2.

[0013] The wind turbine blade 5 has a leading edge (leading edge portion) 16 and a trailing edge 18 from the blade root portion 10 to the blade tip portion (tip portion) 12. The outer shape of the wind turbine blade 5 is defined by a ventral side surface 20 which is a pressure surface (positive pressure surface) and a suction side surface 22 which is opposed to the ventral side surface 20 and is a negative pressure surface. The wind turbine blade 5 is made of FRP (Fiber-Reinforced Plastic). As the FRP, carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP), or the like is used. The overall length of the wind turbine blade 5 from the blade root 10 to the blade tip 12 has tended to increase in recent years, and currently, for example, is up to about 85 m for onshore wind turbines and up to about 130 m for offshore wind turbines. The wind turbine blade 5 of this embodiment can be, for example, from 25 m to 150 m. However, these values ​​are merely examples and can be changed as appropriate.

[0014] As shown in FIG. 2, in this embodiment, the wind turbine blade 5 is divided along the blade span direction L1 of the wind turbine blade 5 into a first region R1 to a fourth region R4. For example, the first region R1 to the fourth region R4 are regions divided into a plurality of regions (four regions in this case) in sequence from the tip of the wind turbine blade 5 according to the circumferential speed that changes in the blade length direction of the wind turbine blade 5.

[0015] The second region R2 is a region where a second region protective layer 30a is formed by, for example, thermal spraying or a metal plate LEP (Leading Edge Protection). As described later, the third region R3 is a region where the third region protective layer 30b is formed. The details of each area will be described later.

[0016] Specifically, the blade tip 12 is a receptor. The receptor is made of, for example, copper-tungsten, which is an alloy of copper and tungsten. Not limited to this example, the blade tip 12 is made of a metal material with low electrical resistivity and is provided as a part that induces lightning. Furthermore, the blade tip 12 is connected to a sprayed layer 32 and a metal layer 34 in the second region R2, which will be described later. The sprayed layer 32 and the metal layer 34 are made of a material with low electrical resistivity. With this configuration, the lightning current that strikes the blade can be passed to the ground G via the downstream conductive path while utilizing the low electrical resistance portion provided inside the wind turbine blade main body 5a as the conductive path. The material constituting the blade tip 12 is not limited to copper tungsten, but may be any metal material having a desired electrical resistivity. The region formed by the blade tip portion 12 corresponds to the first region R1. The first region R1 is, for example, a region extending from the tip 12a of the wind turbine blade 5 to approximately 1 m in the blade span direction L1. Furthermore, at the blade tip portion 12, a conductive portion, which will be described later, is provided inside the wind turbine blade 5.

[0017] The first region R1 is formed using a metal material, such as copper tungsten, as a base material. Specifically, the first region R1 is a region where the blade tip portion 12 is formed.

[0018] As shown in FIG. 2, in a predetermined region (leading edge region, see also part D in FIG. 5) including the leading edge portion 16 of the second region R2 and the leading edge portion 16 corresponding to the third region R3, a protective layer 30 (second region protective layer 30a and third region protective layer 30b) is formed on the wind turbine blade main body 5a. The range in which the protective layer 30 is formed is set according to the circumferential speed at a position in the blade length direction L1 of the wind turbine blade 5. Furthermore, the material of the protective layer 30 differs depending on the circumferential speed at the position (region) where the protective layer 30 is formed. In Fig. 2, the second region protective layer 30a is indicated by a thick solid line, and the third region protective layer 30b is indicated by a thick dashed line.

[0019] The configuration of the wind turbine blade 5 in the second region R2 will be described. In the blade length direction of the wind turbine blade 5, the peripheral speed is faster in the second region R2 close to the blade tip 12, and therefore stronger erosion resistance is required. For this reason, the second region protective layer 30a made of a material harder than the third region protective layer 30b is formed in the leading edge portion 16 corresponding to the second region R2. The formation range of the second region protective layer 30a in the blade length direction L1 (the thick solid line portion in FIG. 2) is set according to the circumferential speed at the position in the blade length direction L1 of the wind turbine blade 5. Note that, when the formation range of the second region protective layer 30a having high erosion resistance is large, it must be considered that it becomes an excessive specification and becomes expensive.

[0020] FIG. 3 is a cross-sectional view of the wind turbine blade 5 in the second region R2 in the stacking direction. The wind turbine blade 5 in the second region R2 is composed of a second region protective layer 30a, a thermal spray layer 32, a metal layer , and a main body material layer . The second region R2 is located closer to the hub than the blade tip 12 of the wind turbine blade 5. In the second region R2, a conductive portion is formed on the outer layer of the main body material layer 36 whose base material is a resin material such as FRP. The conductive portion is made of a material (e.g., copper) having a lower electrical resistivity than the second region protection layer 30a, and includes a sprayed layer 32 that functions as a part of a conductive path for passing a lightning current to ground G. The conductive portion further includes a metal layer 34 in partial contact with the sprayed layer 32, and a down conductor 35 connected to the metal layer 34. 3 corresponds to the hub side (the direction approaching the hub), and down conductor 35 extends toward the hub side and is connected to a conductive path that passes a lightning current to ground G via hub 4, nacelle 6, and tower 3, and functions as a part of the conductive path. Down conductor 35 is also connected to blade tip 12, which is located on the front side of the paper in FIG. 3 (the direction away from the hub).

[0021] The second region protection layer 30a is made of a material having excellent erosion resistance, such as a cermet containing at least one of alumina, tungsten carbide, silicon nitride, silicon carbide, zirconia, and chromium carbide, or a Co alloy such as a Co (cobalt)-based alloy. The second region protective layer 30a is made of a material having excellent heat resistance and erosion resistance, and thus exhibits high erosion resistance. The protective layer 30 is formed by, for example, HVOF (High Velocity Oxy-Fuel) spraying. The second region protective layer 30a is directly sprayed onto the sprayed layer 32, which is made of a metallic material, and thus achieves excellent adhesion without requiring any other configuration. The second region protective layer 30a may be formed by spraying a metal material or by attaching a metal plate LEP.

[0022] The thermal spray layer 32 is made of copper, a copper alloy, aluminum, or an aluminum alloy (for example, duralumin). In this way, by forming the sprayed layer 32 from a material with low electrical resistivity, the sprayed layer 32 can function as a conductive path for quickly passing the charged lightning current to the ground G. Furthermore, when forming the sprayed layer 32 from the above material, a material with a lower hardness and Young's modulus than the second region protective layer 30a is used, so that the sprayed layer 32 is less aggressive to the blade body and has a high adhesion to the wind turbine blade body 5a. This makes it possible to prevent the second region protective layer 30a from peeling off or falling off from the wind turbine blade body 5a.

[0023] The metal layer 34 is a metallic mesh made of, for example, copper, a copper alloy, aluminum, or an aluminum alloy. As the aluminum alloy, for example, duralumin can be used. By making the metal layer 34 out of a material with low electrical resistivity, the current that strikes the second region protection layer 30a can flow in this order through the sprayed layer 32, the metal layer 34, and the down conductor 35, and can quickly flow to the ground G side. The metal layer 34 is in contact with at least the sprayed layer 32. For example, the metal layer 34 has a mesh shape, and is in partial contact with the sprayed layer 32 extending in the spanwise direction L1 of the main body material layer 36. This improves the electrical conductivity between the sprayed layer 32 and the metal layer 34, and allows the lightning current charged in the sprayed layer 32 to flow quickly to the ground G. It is also preferable to make the area of ​​contact (contact area) between the sprayed layer 32 and the metal layer 34 as large as possible. By making the contact area large, the electrical conductivity between the sprayed layer 32 and the metal layer 34 can be maintained high.

[0024] In addition to the metal layer 34, a conductive part extending to the ground G is provided on the wind turbine blade main body 5a, and the blade tip 12 corresponding to the receptor is connected to the conductive part (more specifically, the down conductor 35). As a result, a conductive path is formed in the wind turbine blade main body 5a, which extends from the second region protection layer 30a to the ground G via the sprayed layer 32, the metal layer 34, and the down conductor 35, and which extends to the ground G via the blade tip portion 12 corresponding to the receptor and the down conductor 35. By forming the metal layer 34 having a low electrical resistivity on the surface of the main body material layer 36 in this manner, the conductivity of the conductive path between the sprayed layer 32 and the metal layer 34 can be increased. Then, the lightning strike current generated when lightning strikes the second region protection layer 30a can be quickly conducted to the ground G via the conductive path which passes through the sprayed layer 32, the metal layer 34, and the down conductor 35 in this order. Also, a conductive path may be formed that directly connects the thermal spray layer 32, which has a low electrical resistivity, to the down conductor 35. This makes it possible to effectively prevent damage to the second region protection layer 30a.

[0025] The main body material layer 36 is a layer configured from a material that becomes the base material of the wind turbine blade 5, and in this embodiment, is formed from FRP as described above.

[0026] Next, the configuration of the wind turbine blade 5 in the third region R3 will be described. The peripheral speed in the third region R3, which is closer to the hub than the second region R2 in the blade length direction L1 of the wind turbine blade 5, is slower than the peripheral speed in the second region R2. Therefore, the erosion resistance required for the leading edge portion 16 corresponding to the third region R3 is less stringent than that required for the second region R2. Therefore, the third-region protective layer 30b can be formed in the leading edge portion 16 corresponding to the third region R3 using a material that is less hard than the material of the second-region protective layer 30a.

[0027] In this way, the ranges in which the second region protective layer 30a and the third region protective layer 30b are formed are determined by their respective erosion resistance performances and the peripheral speed in the blade length direction L1 of the installation range.

[0028] FIG. 4 is a cross-sectional view of the wind turbine blade 5 in the third region R3 in the stacking direction. The third region R3 is composed of a third region protective layer 30b and a main body material layer . The third region R3 is located closer to the hub side than the second region R2 of the wind turbine blade 5. In the third region R3, a third region protective layer 30b (e.g., a resin coating) which is lower in hardness than the second region protective layer 30a and is not made of a metal material is formed on the outer layer of the main body material layer 36, which has a base material of a resin material such as FRP. Since the third region R3 has a slower peripheral speed than the second region R2, the desired erosion resistance can be ensured even if the wind turbine blade 5 is protected by a resin coating having a lower hardness than the second region protective layer 30a. The third region R3 has a lower possibility of being struck by lightning than the blade tip 12 (receptor) which is a lightning attracting portion and the second region R2, so there is no need to provide a conductive path therein.

[0029] The third region protective layer 30b is, for example, a material containing polyurethane, and is formed, for example, from friction paint LEP, tape material LEP, polyurethane LEP, or the like.

[0030] Next, the fourth region R4 is a region extending from the hub side end of the third region R3 of the wind turbine blade 5 to the blade root portion 10. Since the peripheral speed of the fourth region R4, which is located closer to the hub than the third region R3, is slower than the peripheral speed of the third region R3, there is no need to provide a protective layer 30 for improving erosion resistance at the leading edge 16 of the wind turbine blade 5. That is, as described above, the fourth region R4 is formed from a base material such as FRP (Fiber-Reinforced Plastic) such as carbon fiber reinforced plastic (CFRP) or glass fiber reinforced plastic (GFRP). Further, inside the wind turbine blade 5, a down conductor 35 is provided along the blade length direction L1, part of which is connected to the metal material constituting the blade tip portion 12, for conducting a lightning current due to a lightning strike to the ground G.

[0031] As described above, in the wind turbine blade 5, in the range from the first region R1 to the fourth region R4, a protective layer 30 (second region protective layer 30a and third region protective layer 30b) is formed on the outermost layer on the front edge portion 16 side of the second region R2 and the third region R3 located on the hub side of the first region R1, which corresponds to the lightning attracting portion. Specifically, the protective layer 30 is formed in an area where the peripheral speed of the leading edge 16 of the wind turbine blade 5 is equal to or higher than a predetermined threshold value when the wind turbine blade 5 rotates. In other words, by forming the protective layer 30 only in areas where erosion is likely to occur when the wind turbine blade 5 rotates, the erosion resistance of the wind turbine blade 5 can be efficiently improved.

[0032] Next, an example of a method (design method) for setting the range of the second region-protection layer 30a and the range of the third region-protection layer 30b will be described.

[0033] 5, 6 and 7, the circumferential speed of the leading edge 16 at each position in the spanwise direction L1 of the wind turbine blade 5 and the range in which the second region protective layer 30a and the third region protective layer 30b are formed in the spanwise direction L1 of the wind turbine blade 5 are set based on the circumferential speed of the leading edge 16 of the wind turbine blade 5.

[0034] In FIG. 5 a cross section of a wind turbine blade 5 is shown. In FIG. 5, the horizontal direction indicates the chord direction (the chord direction) C1. An arrow A1 indicates the direction in which the wind turbine blade 5 collides with foreign matter in the air (for example, raindrops, dust, etc.). FIG. 5 shows a case where a foreign object collides head-on against the leading edge 16 of the wind turbine blade 5.

[0035] Fig. 6 is a graph illustrating the relationship between the distance from the center of rotation in the blade span direction L1 of a wind turbine blade 5 used on land and the peripheral speed of the leading edge 16 of the wind turbine blade 5. Meanwhile, Fig. 7 is a graph illustrating the relationship between the distance from the center of rotation in the blade span direction L1 of a wind turbine blade 5 used offshore and the peripheral speed of the leading edge 16 of the wind turbine blade 5. The plotted points shown in Figs. 6 and 7 indicate the peripheral speed of the leading edge of the wind turbine blade 5 relative to the distance from the center of rotation in the blade span direction L1 of the wind turbine blade 5. As can be seen from Figs. 6 and 7, the peripheral speed of the wind turbine blade 5 is proportional to the distance from the center of rotation in the blade span direction L1, and the peripheral speed increases as the distance from the center of rotation in the blade span direction L1 increases. The dashed lines shown in Figures 6 and 7 indicate a first threshold value for defining the range of the second region-protection layer 30a and a second threshold value (smaller than the first threshold value) for defining the range of the third region-protection layer 30b.

[0036] In the range where the peripheral speed of the wind turbine blade 5 is equal to or higher than a preset first threshold value, the leading edge 16 will collide with raindrops or dust in the air at high speed, making it highly likely that damage due to erosion will occur, and if damage does occur, the extent of the damage will be greater. For this reason, it is preferable to set this range as the second region R2 including the second region protective layer 30a formed of a metal material having high erosion resistance. In this way, by forming the second region protective layer 30a in a location where stronger erosion resistance is required, the possibility that the wind turbine blade 5 will be damaged by erosion can be reduced.

[0037] Furthermore, in a position where the circumferential speed of the wind turbine blade 5 is slower than that in the second region, i.e., in a range where the circumferential speed of the wind turbine blade 5 is less than a preset first threshold value, the leading edge 16 collides with raindrops and dust in the air at a slower speed than in the second region R2. Therefore, the possibility of damage due to erosion occurring is lower than in the second region R2, and if damage does occur, the degree of damage also tends to be smaller. However, in a range in which the peripheral speed is equal to or greater than a preset second threshold value, erosion may occur. Therefore, it is preferable to set such a range (the range where the circumferential speed is less than the first threshold value and greater than or equal to the second threshold value) as the third region R3 having a third region protection layer 30b formed of a resin material that is less hard than a metal material. In this way, in areas where it is not necessary to form the protective layer 30a using a metal material, by forming the third region protective layer 30b using a resin material, it is possible to reduce damage to the wind turbine blade body 5a in the low circumferential speed range where erosion occurs, while reducing the cost of forming the protective layer 30 and the labor burden during construction and repair.

[0038] As described above, threshold values ​​(a first threshold value and a second threshold value smaller than the first threshold value) for the circumferential speed of the wind turbine blades 5 are set in advance according to the rotation radius and rotation speed of the wind power generation device 1, and the ranges of the second area protection layer 30a and the third area protection layer 30b are set based on the first threshold value and the second threshold value.

[0039] (For wind turbine blades used on land) The total length of the wind turbine blade body 5a of a wind turbine blade used offshore is, for example, about 46 m. In the case of wind turbine blades used on land, as shown in FIG. 6, the first threshold is set to 65 m / s and the second threshold is set to 50 m / s. In this case, a position about 32 m from the center of rotation where the peripheral speed of the leading edge 16 of the wind turbine blade 5 is 50 m / s (second threshold) is set as the boundary position of the hub side end of the third region R3. Also, a position about 41 m from the center of rotation where the peripheral speed of the leading edge 16 of the wind turbine blade 5 is 65 m / s (first threshold) is set as the boundary position of the hub side end of the second region R2. The third region protection layer 30b of the third region R3 is installed between the boundary position derived from the first threshold value and the second threshold value, and the second region protection layer 30a of the second region R2 is installed between the boundary position derived from the first threshold value and the hub side end of the blade tip 12, which is installed for the purpose of attracting lightning.

[0040] (For offshore wind turbine blades) In the above explanation, an example was given of a wind turbine blade that is a large wind turbine blade used on land, but even in the case of a large wind turbine blade used offshore, the range of each region may be determined according to a threshold value corresponding to the circumferential speed. The total length of the wind turbine blade body 5a of a wind turbine blade used offshore is, for example, about 116 m.

[0041] In the case of a wind turbine blade used offshore, as shown in FIG. 7, the first threshold is set to 65 m / s and the second threshold is set to 50 m / s. In this case, a position about 57 m from the center of rotation where the circumferential speed of the leading edge 16 of the wind turbine blade 5 is 50 m / s (second threshold) is set as the boundary position of the hub side end of the third region R3. Also, a position about 74 m from the center of rotation where the circumferential speed of the leading edge 16 is 65 m / s (first threshold) is set as the boundary position of the hub side end of the second region R2. The protective layer 30b of the third region R3 is installed between the boundary position derived from the first threshold value and the second threshold value, and the second region protective layer 30a of the second region R2 is installed between the boundary position derived from the first threshold value and the hub side end of the blade tip 12, which is installed for the purpose of attracting lightning.

[0042] As in these two examples, the second region-protecting layer 30a and the third region-protecting layer 30b are formed in ranges in the blade length direction L1 of the wind turbine blade 5 where the peripheral speed is based on each of the preset threshold values. This makes it possible to prevent damage due to erosion, and also to form an appropriate protective layer 30 on the leading edge portion 16 corresponding to each region of the wind turbine blade 5 depending on the possibility of erosion occurring. Furthermore, the first and second thresholds, which are thresholds for the circumferential speed of the wind turbine blade 5, may be set to appropriate values ​​taking into consideration parameters such as erosion resistance depending on the material of each of the second region protective layer 30a and / or the third region protective layer 30b employed, repair details corresponding to the erosion resistance, replacement cycles, costs, etc. This makes it possible to optimize the range and specifications for forming the protective layer 30 that requires erosion countermeasures.

[0043] The effects of this embodiment are as follows. The protective layer 30 covers the leading edge 16 of the wind turbine blade 5 at the second region R2 located closer to the hub than the first region R1 and at the third region R3 located closer to the hub than the second region R2. In addition, the second region protective layer 30a is formed on the front edge portion 16 of the second region R2, and the third region protective layer 30b is formed on the front edge portion 16 of the third region. The hardness of the material constituting the second region protective layer 30a is greater than the hardness of the material constituting the third region protective layer 30b, and the erosion resistance is high. This makes it possible to reduce the cost of forming the protective layer 30 and facilitate repair in the installation environment of the wind power generation device 1. Furthermore, the construction time related to the formation of the protective layer can be shortened, and the workability during construction and repair can be improved. In particular, the third region protective layer 30b formed of a resin material can reduce the cost and facilitate repair in the installation environment of the wind power generation device 1, compared to the second region protective layer 30a formed of a metal material. In addition, the construction time related to the formation of the third region protective layer 30b is shorter than the construction time related to the formation of the second region protective layer 30a.

[0044] (Variation 1) The range in which the protective layer 30 is to be formed may be determined from the perpendicular velocity, which is the velocity component in the normal direction of the blade surface. This makes it possible to more appropriately set the area of ​​the protective layer 30, thereby providing a wind turbine blade that can prevent damage due to erosion as much as possible.

[0045] (Variation 2) The first and second thresholds are changed as appropriate depending on the installation conditions and installation location (installation environment) of the wind turbine power generation device 1, the overall length of the wind turbine blade main body 5a, the specifications of the wind turbine blade main body 5a, the operating conditions (e.g., rotation speed), the specifications of the protective layer 30, the impact on costs, etc. Also, it is of course not necessary to use the same thresholds for onshore and offshore wind turbines.

[0046] (Variation 3) The airfoil shape is not limited to a unique shape. The peripheral speed threshold may be set using the blade shape used at the time of design.

[0047] (Variation 4) The thicknesses of the second region-protecting layer 30a and the third region-protecting layer 30b may be determined according to the peripheral speed of the wind turbine blade 5. For example, the second region protection layer 30a and the third region protection layer 30b may be formed of the same material, and the thickness of the third region protection layer 30b may be smaller than the thickness of the second region protection layer 30a, thereby reducing costs.

[0048] (Variation 5) The thickness of the second region-protecting layer 30a at each position may be set according to the peripheral speed at each position within the second region R2. In the second region R2, the peripheral speed of the leading edge 16 on the blade tip 12 side is greater than the peripheral speed of the leading edge 16 on the hub 4 side. Therefore, by making the thickness of the second region protective layer 30a on the blade tip 12 side of the wind turbine blade 5 thicker than the thickness of the second region protective layer 30a on the hub 4 side, appropriate erosion resistance according to the peripheral speed distribution of the wind turbine blade 5 can be obtained. Similarly, the thickness of the third region protective layer 30b at each position may be set according to the circumferential speed at each position in the third region R3. In the third region R3, the thickness of the third region protective layer 30b on the second region R2 side may be set to be thicker than the thickness of the third region protective layer 30b on the hub 4 side, thereby more effectively improving the erosion resistance.

[0049] (Additional Note) The wind turbine blade and the design method of the wind turbine blade described in each of the above-described embodiments can be understood, for example, as follows. A wind turbine blade (5) according to a first aspect of the present disclosure is a wind turbine blade to be attached to a hub (4) of a wind power generation device (1), and comprises a blade body (5a) extending in the blade span direction, a tip portion (12) provided on the blade body and formed of a metal material, a second region protective layer (30a) covering a leading edge portion of a second region (R2) of the blade body located closer to the hub than a first region (R1) including the tip portion, and a third region protective layer (30b) covering a leading edge portion of a third region (R3) of the blade body located closer to the hub than the second region, wherein the hardness of the material forming the second region protective layer is greater than the hardness of the material forming the third region protective layer.

[0050] According to the wind turbine blade of the present disclosure, the leading edge of the second region of the blade body, which is located closer to the hub of the wind power generating device than the first region including the tip provided on the blade body, is covered by the second region protective layer, and the leading edge of the third region of the blade body, which is located closer to the hub than the second region, is covered by the third region protective layer. The hardness of the second region protective layer is greater than the hardness of the third region protective layer. That is, the leading edge of the second region, which is installed on the hub side of the first region installed for the purpose of attracting lightning and has a high circumferential speed and requires high erosion resistance, is protected by the second region protective layer formed of a material with a high hardness, and the third region protective layer, which protects the leading edge of the third region, which has a low circumferential speed and does not require erosion resistance as much as the tip side of the blade body, is formed of a material with a lower hardness than the material forming the second region protective layer. In this way, the material of the protective layer is changed according to the position in the blade length direction of the blade body, taking into consideration the erosion resistance required in each region in response to the operating conditions of the wind turbine blade (for example, the length and circumferential speed of the wind turbine blade, etc.). This makes it possible to reduce the cost of forming the protective layer and improve the workability of construction and repair work.

[0051] A wind turbine blade according to a second aspect of the present disclosure is such that, in the first aspect, the second region protective layer is formed in a range in the blade length direction where the circumferential speed of the leading edge portion is equal to or greater than a first threshold, and the third region protective layer is formed in a range in the blade length direction where the circumferential speed of the leading edge portion is less than the first threshold and equal to or greater than a second threshold that is smaller than the first threshold.

[0052] According to the wind turbine blade of the present disclosure, the second region protective layer is formed in a range in the blade length direction where the circumferential speed of the leading edge portion is equal to or greater than a first threshold, and the third region protective layer is formed in a range in the blade length direction where the circumferential speed of the leading edge portion is less than the first threshold and equal to or greater than a second threshold smaller than the first threshold. That is, the second region protective layer is formed in a range where raindrops or dust in the air collide with the wind turbine blade at high speed and damage due to erosion is likely to occur. Also, the third region protective layer is formed in a range where raindrops or dust in the air do not collide with the wind turbine blade at high speed compared to the second region and where the possibility of damage due to erosion is lower than that of the second region. This makes it possible to prevent damage due to erosion as much as possible, and to form an appropriate protective layer for the leading edge portion of each region of the wind turbine blade depending on the possibility of erosion occurring.

[0053] In a wind turbine blade according to a third aspect of the present disclosure, in the first aspect, the layer thickness at each position of the second region protective layer is set according to the circumferential speed at each position within the second region, and the layer thickness at each position of the third region protective layer is set according to the circumferential speed at each position within the third region.

[0054] According to the wind turbine blade of the present disclosure, the layer thickness at each position of the second region protective layer is set according to the peripheral speed at each position in the second region, and the layer thickness at each position of the third region protective layer is set according to the peripheral speed at each position in the third region. This makes it possible to obtain appropriate erosion resistance according to the peripheral speed distribution of the wind turbine blade 5.

[0055] A wind turbine blade (5) according to a fourth aspect of the present disclosure is a wind turbine blade to be attached to a hub (4) of a wind power generation device (1), and comprises a blade body (5a) extending in the blade span direction, a tip portion (12) provided on the blade body and formed of a metal material, a second region protective layer (30a) covering a leading edge portion of a second region (R2) of the blade body located closer to the hub than a first region (R1) including the tip portion, and a third region protective layer (30b) covering a leading edge portion of a third region (R3) of the blade body located closer to the hub than the second region, wherein the second region protective layer and the third region protective layer are formed of the same material, and the thickness of the second region protective layer is greater than the thickness of the third region protective layer.

[0056] According to the wind turbine blade of the present disclosure, a wind turbine blade to be attached to a hub of a wind power generating device includes a blade body, a tip portion formed of a metal material on the blade body, a second region protective layer covering a front edge portion of a second region of the blade body located closer to the hub than a first region including the tip portion, and a third region protective layer covering a front edge portion of a third region of the blade body located closer to the hub than the second region, the second region protective layer and the third region protective layer being made of the same material, and the thickness of the second region protective layer being greater than the thickness of the third region protective layer, thereby enabling cost reduction.

[0057] A design method for a wind turbine blade (5) according to a fourth aspect of the present disclosure is a design method for a wind turbine blade to be attached to a hub of a wind power generation device, the wind turbine blade comprising: a blade body extending in a blade span direction; a tip portion provided on the blade body and formed of a metal material; a second region protective layer covering a leading edge portion of a second region of the blade body located closer to the hub than a first region including the tip portion; and a third region protective layer covering a leading edge portion of a third region of the blade body located closer to the hub than the second region, wherein the second region is a range in the blade span direction in which the circumferential speed of the leading edge portion is equal to or greater than a first threshold, the third region is a range in the blade span direction in which the circumferential speed of the leading edge portion is equal to or greater than a second threshold that is less than the first threshold and smaller than the first threshold, the hardness of the material forming the second region protective layer is greater than the hardness of the material forming the third region protective layer, and / or the thickness of the material forming the second region protective layer is greater than the thickness of the material forming the third region protective layer. [Explanation of symbols]

[0058] 1. Wind power generation equipment 3. Tower 4 Rotor Head 5 windmill blade 5a Wind turbine blade body 6. Nacelle 10 Wing root 12 Wing tip 12a Tip 14 Airfoil section 16 Leading edge 18 Trailing edge 20 Ventral aspect 22 Dorsal aspect 30 protective layer 30a 2nd area protective layer 30b Third area protective layer 32 Thermal spray layer 34 Metal layer 35 Down Conductor 36 Body material layer B Installation surface C1 Chord direction (chord direction) L1 spanwise direction R1 1st area R2 Second area R3 3rd Area R4 4th Area

Claims

1. A wind turbine blade attached to a hub of a wind turbine generator, A blade body extending in a span direction; a tip portion provided on the blade body and made of a metal material; a second region protective layer covering a leading edge portion of a second region of the blade body located closer to the hub than a first region including the tip portion; a third region protective layer covering a leading edge portion of a third region of the blade body located closer to the hub than the second region; Equipped with The hardness of the material forming the second region protection layer is greater than the hardness of the material forming the third region protection layer. windmill blade.

2. The second region protective layer is formed in a range in the span direction where a peripheral speed of the leading edge portion is equal to or greater than a first threshold value, The third region protective layer is formed in a range in the span direction where the peripheral speed of the leading edge portion is less than the first threshold value and is equal to or greater than a second threshold value that is smaller than the first threshold value. The wind turbine blade according to claim 1.

3. a thickness of the second region protection layer at each position is set according to a peripheral speed at each position in the second region; The thickness of the third region protection layer at each position is set according to the peripheral speed at each position within the third region. The wind turbine blade according to claim 1.

4. A wind turbine blade attached to a hub of a wind turbine generator, A blade body extending in a span direction; a tip portion provided on the blade body and made of a metal material; a second region protective layer covering a leading edge portion of a second region of the blade body located closer to the hub than a first region including the tip portion; a third region protective layer covering a leading edge portion of a third region of the blade body located closer to the hub than the second region; Equipped with The second region protection layer and the third region protection layer are formed of the same material, and the thickness of the second region protection layer is greater than the thickness of the third region protection layer. windmill blade.

5. A method for designing a wind turbine blade to be attached to a hub of a wind turbine generator, comprising the steps of: The wind turbine blade is A blade body extending in a span direction; a tip portion provided on the blade body and made of a metal material; a second region protective layer covering a leading edge portion of a second region of the blade body located closer to the hub than a first region including the tip portion; a third region protective layer covering a leading edge portion of a third region of the blade body located closer to the hub than the second region; Equipped with A range in the span direction in which the peripheral speed of the leading edge portion is equal to or greater than a first threshold is defined as the second region, A range in the span direction in which the peripheral speed of the leading edge portion is less than the first threshold value and is equal to or greater than a second threshold value that is smaller than the first threshold value is defined as the third region, The hardness of the material forming the second region protection layer is set to be greater than the hardness of the material forming the third region protection layer, and / or the thickness of the material forming the second region protection layer is set to be greater than the thickness of the material forming the third region protection layer. How wind turbine blades are designed.

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