Method for determining protective layer range in wind turbine blade, and wind turbine blade

Abstract

To provide a method for determining a protective layer range in a wind turbine blade, which can properly set the range of a protective layer and prevent damage due to erosion as much as possible.SOLUTION: A method for determining a protective layer range in a wind turbine blade determines the range of a protective layer that is to be formed on a blade surface around a leading edge 16 in the blade length direction of a wind turbine blade body 5a made of FRP. The method has the steps of: setting the inflow direction and inflow velocity of raindrops heading toward the leading edge 16; obtaining surface orthogonal velocities V1, V2, which are velocity components in the normal direction at respective positions around the leading edge 16 of the blade surface in a plurality of cross sections perpendicular to the blade length direction, from the inflow direction and inflow velocity of the raindrops; setting a threshold value for the surface orthogonal velocity; and determining a range around the leading edge 16 where the surface orthogonal velocity becomes equal to or greater than the threshold value, as a range in which a protective layer is to be formed.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a method for determining a protective layer range for a wind turbine blade and a wind turbine blade. [Background technology]

[0002] As the wind turbine rotor rotates, the wind turbine blades collide with foreign objects in the air (for example, raindrops, dust particles, etc.) and are eroded, causing erosion on the leading edge side of the wind turbine blade. To protect the wind turbine blades from this erosion, it is known to form an erosion-resistant protective layer on the leading edge of the wind turbine blade (see Patent Document 1). [Prior art documents] [Patent documents]

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

[0004] However, the formation range of the protective layer is set to a predetermined range from the leading edge of the wind turbine blade body to the dorsal side and ventral side, and no particular consideration has been given to optimizing it. If the range of the protective layer is not set to an appropriate range, erosion may occur in the wind turbine blade body, and the wind turbine blade may need to be repaired or replaced.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a method for determining the protective layer range of a wind turbine blade, and a wind turbine blade, which can properly set the range of the protective layer and prevent damage due to erosion as much as possible. [Means for solving the problem]

[0006] A method for determining a protective layer range of a wind turbine blade according to one aspect of the present disclosure is a method for determining a protective layer range of a wind turbine blade that determines the range of a protective layer to be formed on a blade surface of a leading edge portion in a blade span direction of a wind turbine blade body formed from FRP, the method including the steps of: setting a collision direction and collision speed of particles heading toward the leading edge portion; obtaining a perpendicular velocity, which is a velocity component in the normal direction at each position at the leading edge portion of the blade surface in a plurality of cross sections perpendicular to the blade span direction, from the collision direction and collision speed of the particles; setting a threshold value for the perpendicular velocity; and determining a range of the leading edge portion where the perpendicular velocity is equal to or greater than the threshold value as a range in which the protective layer is to be formed.

[0007] A wind turbine blade according to one embodiment of the present disclosure comprises a wind turbine blade body formed of FRP, and a protective layer formed on a blade surface of a leading edge portion in a blade span direction of the wind turbine blade body, the protective layer having a smaller width in a ventral direction than a width in a suction direction of the blade surface in a cross section perpendicular to the blade span direction. Effect of the Invention

[0008] The range of the protective layer can be appropriately set, and damage due to erosion can be prevented as much as possible. [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 a wind turbine blade. [Diagram 3] FIG. 3 is a front view of the wind turbine blade of FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view of the wind turbine blade shown in FIGS. 2 and 3. [Diagram 5] FIG. 5 is a partially enlarged view of part D in FIG. [Figure 6] 1 is a graph showing perpendicular velocity. [Figure 7] 4A to 4C are cross-sectional views showing blade sections at various positions. [Figure 8] This is a graph in which a threshold value for the perpendicular velocity is added to the graph in FIG. [Figure 9] FIG. 2 is a plan view showing a schematic view of the range of a protective layer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 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 mounted on the nacelle 6 so as to be rotatable around a substantially horizontal axis.

[0011] A number of (e.g., three) wind turbine blades 5 are attached radially around the rotation axis of the rotor head 4. This allows the force of the wind hitting the wind turbine blades 5 from the direction of the rotation axis of the rotor head 4 to be converted into power that rotates the rotor head 4 around the rotation axis. The obtained power is converted into electricity by a generator (not shown) and supplied to the outside.

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

[0013] The wind turbine blade 5 has a leading edge 16 and a trailing edge 18 from the blade root 10 to the blade tip 12. The outer shape of the wind turbine blade 5 is determined by a ventral side surface 20 which is a pressure surface (positive pressure surface) and a suction side surface 22 which is a negative pressure surface facing the ventral side surface 20. The wind turbine blade 5 is made of FRP (Fiber-Reinforced Plastic). Examples of FRP that can be used include carbon fiber reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP). The entire length of the wind turbine blade 5 from the blade root 10 to the blade tip 12 is in the 100 m class, for example, 80 m or more and 150 m or less. A 200 m class wind turbine blade may be used as the wind turbine blade 5 of this embodiment.

[0014] 3, the wind turbine blade 5 is provided with a pre-bend PB that is bent in advance on the blade tip 12 side. The amount of bending of the pre-bend PB is determined in advance assuming that the wind turbine blade 5 receives wind pressure during operation. Therefore, the pre-bend PB is bent so that the ventral side surface 20 that receives wind pressure is concave and the suction side surface 22 is convex.

[0015] As shown in Fig. 2, a protective layer 30 is formed on the wind turbine blade main body 5a in a predetermined region (leading edge portion) including the blade tip portion 12 and leading edge 16 of the wind turbine blade 5. The formation range of the protective layer 30 is indicated by a thick line in Fig. 2. The formation range of the protective layer 30 in the blade length direction L1 is, for example, 20 m to 40 m, preferably about 30 m, from the tip 12a of the blade tip portion 12. Note that the formation range of the protective layer 30 is not limited to this, and for example, in a region where the peripheral speed exceeds 90 m / s, it is set to a range of about 1 / 3 of the total length from the tip of the wind turbine blade 5.

[0016] The protective layer 30 is made of a material having excellent wear resistance, such as a cermet or a Co (cobalt)-based alloy or other Co alloy.

[0017] Figure 4 shows a cross section of a wind turbine blade 5. In this figure, the horizontal direction indicates the chord direction (chord direction) C1. Arrow A1 indicates the collision direction of raindrops (particles) assuming that the raindrops are stationary relative to the rotation direction of the wind turbine blade 5. In reality, the raindrops also have a speed, so they form a velocity triangle with the speed of the wind turbine blade 5. However, since the speed of the raindrops is slower than the speed of the wind turbine blade 5, this angle is based on the assumption that the speed of the raindrops is zero. This figure shows the case where raindrops flow in from the front onto the leading edge 16 of the wind turbine blade 5.

[0018] Figure 5 shows an enlarged view of part D in Figure 4. The figure shows the normal velocity, which is the velocity component in the normal direction at each position of the leading edge of the blade surface in the blade section (cross section) of the wind turbine blade 5. At a position shifted from the leading edge 16 in the ventral side direction A2, the normal velocity V1 is oriented in an upward diagonal direction from the horizontal in the figure, and at a position shifted from the leading edge 16 in the suction side direction A3, the normal velocity V2 is oriented in a downward diagonal direction from the horizontal in the figure.

[0019] An example of the calculation results of the distribution of the perpendicular velocity in each cross section is shown in Figure 6. In this figure, the vertical axis indicates the perpendicular velocity [m / s], and the horizontal axis indicates the distance [mm] from the leading edge 16 in the ventral lateral direction A2 (see Figure 5) and the dorsal lateral direction A3 (see Figure 5). On the horizontal axis, 0.0 mm indicates the position of the leading edge 16, the distance from the leading edge 16 in the ventral lateral direction A2 is represented by a positive value, and the distance from the leading edge 16 in the dorsal lateral direction A3 is represented by a negative value.

[0020] The positions (1) to (6) shown in Fig. 6 correspond to the positions (1) to (6) in the blade span direction L1 shown in Fig. 2. Fig. 7 shows the blade cross sections (transverse sections) at the positions (1) to (6). If the rotation radius of the wind turbine blade 5 is R, the positions in the blade span direction L1 of the positions (1) to (6) and their specifications are as follows. Note that the rotation radius R of the wind turbine blade 5 is the distance from the center of rotation (the center of rotation of the rotor head 4 in Fig. 1) to the tip of the wind turbine blade 5. [Table 1]

[0021] The initial conditions for the calculation were a rotor diameter (rotation radius R of the wind turbine blades 5) of 95 m, a rotation speed of 15 rpm, and raindrops colliding head-on with the leading edge 16 (see Figures 4 and 5). The wind inflow speed with respect to the leading edge 16 was approximately 75 m / s.

[0022] As can be seen from the graph in Figure 6, the distribution of the perpendicular velocity at the tip position (1) is the steepest compared to the other positions (2) to (6). This is because the chord length C of the blade shape at position (1) is small (50.0 mm) and the thickness T is also small (11.2 mm). In addition, since position (1) is the farthest position in the radial direction of the wind turbine blade 5, the perpendicular velocity of the leading edge 16 at position (1) is the largest (about 75 m / s).

[0023] The distribution of the perpendicular velocity at position (2) is smaller than that at position (1) near the leading edge 16, but in the range of about + several mm (intersection +P12) or more and about - several mm or less (intersection -P12), the perpendicular velocity is larger than that at position (2), resulting in a distribution that spreads out compared to position (1). The chord length at position (2) is 11376 mm, and unlike position (1), the perpendicular velocity is present over the entire range of 150 mm on both sides of the leading edge 16. Comparing the distribution in the ventral side direction A2 and the dorsal side direction A3, the decrease in the perpendicular velocity in the ventral side direction A2 is greater as the distance from the leading edge 16 increases. Therefore, assuming that erosion progresses in proportion to the perpendicular velocity, the width (distance from the leading edge 16) of the protective layer 30 can be made smaller in the ventral side direction A2 than in the dorsal side direction A3. This tendency is also true for positions (3) to (6).

[0024] The distribution of the perpendicular velocity at position (3) is smaller in the vicinity of the leading edge 16 than at position (2). However, in the range of approximately +10 mm or more (intersection +P23) and approximately -15 mm or less (intersection -P23), the perpendicular velocity is larger than at position (2), and the spreading shape of the base is approximately similar.

[0025] The distribution of the perpendicular velocity at position (4) is smaller than that at position (3) in the vicinity of the leading edge 16. However, in the range of about +15 mm (intersection point +P34) or more and about -25 mm (intersection point -P34) or less, the perpendicular velocity is larger than that at position (3), and the spreading shape of the base is approximately similar.

[0026] The distribution of the perpendicular velocity at position (5) is smaller in the vicinity of the leading edge 16 than at position (4). However, in the range of about +40 mm or more (intersection point +P45) and about -50 mm or less (intersection point -P45), the perpendicular velocity is larger than at position (4), and the spreading shape of the base is approximately similar.

[0027] The distribution of the perpendicular velocity at position (6) is smaller in the vicinity of the leading edge 16 than at position (5). However, in the range of approximately +60 mm (intersection point +P56) or more and approximately -75 mm (intersection point -P56) or less, the perpendicular velocity is larger than at position (5), and the spreading shape of the base is approximately similar.

[0028] Next, a method for determining the range of the protective layer 30 from the graph shown in FIG. 6 will be described with reference to FIG.

[0029] First, set the inflow direction and inflow speed of the wind heading toward the leading edge 16. In the case of this embodiment, it is set based on the rotation speed of the wind turbine blade 5 that raindrops collide with the front surface of the leading edge 16 at the blade tip 12 at about 75 m / s.

[0030] Then, as shown in Figure 8, the normal velocity at each position around the leading edge 16 of the blade surface (±150 mm in Figure 8) is obtained from the shapes of multiple cross sections perpendicular to the blade length direction L1 (airfoil cross sections at positions (1) to (6) in Figure 8).

[0031] Next, the threshold value of the perpendicular velocity is set. In Fig. 8, the threshold value of the perpendicular velocity is set to 30 m / s.

[0032] Then, the range where the perpendicular velocity is equal to or greater than the threshold value is determined as the range for forming the protective layer 30. In Fig. 8, the range where the perpendicular velocity is equal to or greater than 30 m / s is the range for the protective layer 30. in particular, At position (1), the range is from about -15 mm to about +15 mm. At position (2), the range is from about -48 mm to about +20 mm. At position (3), the range is from about -70 mm to about +30 mm. At position (4), the range is from about -90 mm to about +40 mm. At position (5), the range is from about -90 mm to about +40 mm. At position (6), the range is from about -100 mm to about +30 mm. It becomes.

[0033] From the above, it can be seen that it is more appropriate for the width of the protective layer 30 to be smaller on the ventral side surface 20 than on the dorsal side surface 22 .

[0034] On the suction side surface 22, from the tip 12a in the blade length direction L1 toward the blade root 10 (see FIG. 2 for reference symbols), the area of ​​the protective layer 30 increases in distance (width) from the leading edge 16, the width of the protective layer 30 remains constant from position (4) to position (5), and the width of the protective layer 30 increases slightly from position (5) to position (6).

[0035] On the ventral side surface 20, the distance (width) of the protective layer 30 from the leading edge 16 increases from the tip 12a in the blade length direction L1 toward the blade root 10, and the width of the protective layer 30 is approximately constant on the blade root 10 side from position (4), and the width of the protective layer 30 becomes smaller at position (6). This is because, when comparing at the same perpendicular velocity (threshold value of 30 m / s), there is a region where the width (distance from the leading edge) is smaller at position (6) than at position (5). In other words, this is because the threshold value is set to a perpendicular velocity higher than the intersection point +P56 where the perpendicular velocities at positions (5) and (6) are reversed. In this way, when the threshold value of the perpendicular velocity is set to a perpendicular velocity higher than the intersection point where the perpendicular velocity is reversed, a region is generated where it is more appropriate to make the width of the protective layer 30 smaller at the position on the blade root 10 side than at the position on the blade tip 12 side.

[0036] Thus, taking into consideration the perpendicular velocity which depends on the blade shape, it is not appropriate for the width of the protective layer 30 to be constant in the blade length direction L1. Rather, it is preferable for the width to increase monotonically around the blade tip 12, and it is preferable for the width to be constant on the suction side surface 22, or to be constant on the pressure side surface 20 and then to become smaller as the width approaches the center in the blade length direction L1. There may be an area where the width of the protective layer 30 is smaller on the blade root 10 side than on the blade tip 12 side.

[0037] 9, it is not appropriate for the width of the protective layer 30 (the distance from the leading edge 16) to be constant in the spanwise direction L1, as shown by the boundary line N1 which indicates the range of the protective layer 30. It is also not appropriate for the width of the protective layer 30 to increase monotonically in the spanwise direction L1, as shown by the boundary line N2. It is also not appropriate for the range of the protective layer 30 to be symmetrical between the ventral side surface 20 and the suction side surface 22.

[0038] In contrast, in this embodiment, the protective layer 30 on the suction side surface 22 has a constant width after the distance from the leading edge 16 increases in the spanwise direction L1, as shown by the boundary line M1. In addition, the protective layer 30 on the ventral side surface 20 of this embodiment has a smaller width than the protective layer 30 on the suction side surface 22, and after the distance from the leading edge 16 increases in the spanwise direction L1, the protective layer 30 has a constant width and then further decreases in width, as shown by the boundary line M2.

[0039] The effects of the present embodiment described above are as follows. As a result of intensive research, the inventors of the present invention have found that erosion caused by raindrops around the leading edge 16 of the wind turbine blade main body 5a is greatly affected by the perpendicular velocity, which is the velocity component in the normal direction of the blade surface. Therefore, it was decided to determine the range in which the protective layer 30 should be formed from the perpendicular velocity. This makes it possible to appropriately set the area of ​​the protective layer 30, and to provide a wind turbine blade that can prevent damage caused by erosion as much as possible.

[0040] The perpendicular velocity of the airfoil-shaped wind turbine blade main body 5a is smaller on the ventral side surface 20 than on the suction side surface 22. Therefore, the width of the protective layer 30 formed on the blade surface in a cross section perpendicular to the blade length direction L1 is made smaller in the ventral side surface direction A2 than in the suction side surface direction A3. This makes it possible to appropriately set the range of the protective layer.

[0041] The wind turbine blade main body 5a has a blade width that increases monotonically from the blade tip 12 side toward the blade root 10 side. Therefore, in general, the width of the protective layer 30 formed around the leading edge 16 of the wind turbine blade main body 5a generally increases monotonically from the blade tip 12 toward the blade root 10 side (boundary line N2 in FIG. 9). Alternatively, the width of the protective layer 30 is generally constant over the blade length direction L1 (boundary line N1 in FIG. 9). However, after extensive research, the inventors of the present invention found that there exists a region in which the cross section on the blade root 10 side is smaller in width (distance from the leading edge) than the cross section on the blade tip 12 side when compared at the same perpendicular velocity. Therefore, as shown by the boundary line M2 in FIG. 9, the width of the protective layer 30 is set to a region in which the cross section on the blade root 10 side is smaller than the cross section on the blade tip 12 side. This allows the area of ​​the protective layer 30 to be appropriate.

[0042] In this embodiment, the direction of the wind flowing into the wind turbine blade 5 is in front of the leading edge 16, and the wind speed is about 75 m / s, but the present invention is not limited to this and can be appropriately determined depending on the installation conditions of the wind power generation device 1. For example, the collision angle and collision speed with raindrops that match the actual pitch angle of the blades can be used.

[0043] Furthermore, the blade shape is not limited to the shape shown in Fig. 7. The perpendicular velocity is calculated appropriately using the blade shape used at the time of design.

[0044] In addition, in FIG. 8, the threshold value of the perpendicular velocity is set to 30 m / s, but the present invention is not limited to this, and may be appropriately changed at the time of design.

[0045] The wind turbine blade protective layer range determination method and the wind turbine blade described in each of the above-described embodiments can be understood, for example, as follows.

[0046] A protective layer range determination method for a wind turbine blade (5) according to a first aspect of the present disclosure is a method for determining a protective layer range of a wind turbine blade that determines a range of a protective layer (30) to be formed on a blade surface of a leading edge portion in a blade length direction (L1) of a wind turbine blade body (5a) formed from FRP, and includes the steps of: setting a collision direction and collision speed of particles heading toward the leading edge portion; obtaining a perpendicular velocity, which is a velocity component in the normal direction at each position at the leading edge portion of the blade surface in a plurality of cross sections perpendicular to the blade length direction, from the collision direction and collision speed of the particles; setting a threshold value for the perpendicular velocity; and determining a range of the leading edge portion where the perpendicular velocity is equal to or greater than the threshold value as a range in which the protective layer is to be formed.

[0047] After extensive research, the inventors found that erosion caused by particles (raindrops) occurring at the leading edge of the wind turbine blade body is significantly affected by the perpendicular velocity, which is the velocity component in the normal direction of the blade surface. Therefore, it was decided to determine the range in which the protective layer should be formed from the perpendicular velocity. This makes it possible to appropriately set the range of the protective layer, and provide a wind turbine blade that can prevent damage caused by erosion as much as possible. Note that the particles refer to particles that can cause erosion in the wind turbine blade body, and typically include raindrops, but also dust and the like.

[0048] A wind turbine blade (5) according to a first aspect of the present disclosure comprises a wind turbine blade body (5a) made of FRP, and a protective layer (30) formed on a blade surface of a leading edge portion in a blade length direction (L1) of the wind turbine blade body, the protective layer having a smaller width in a ventral direction than in a suction direction of the blade surface in a cross section perpendicular to the blade length direction.

[0049] Through extensive research, the inventors have found that erosion caused by particles (raindrops) generated at the leading edge of the wind turbine blade body is greatly affected by the normal velocity, which is the velocity component in the normal direction of the blade surface. The normal velocity of an airfoil-shaped wind turbine blade is smaller on the ventral side than on the suction side. Therefore, the protective layer formed on the blade surface in a cross section perpendicular to the blade length direction is made smaller in width in the ventral direction than in the suction side. This makes it possible to appropriately set the range of the protective layer, and provide a wind turbine blade that can prevent damage caused by erosion as much as possible.

[0050] A wind turbine blade (5) according to a second aspect of the present disclosure is the first aspect, wherein a region exists in which the width of the protective layer in the cross section on the blade root side is smaller than the width of the cross section on the blade tip side.

[0051] The blade width of the wind turbine blade body increases monotonically from the blade tip side to the blade root side. Therefore, in general, the width of the protective layer formed on the leading edge of the wind turbine blade body increases monotonically from the blade tip to the blade root side or is the same. However, after extensive research, the inventors found that there is a region where the cross section of the blade root is smaller in width (distance from the leading edge) than the cross section of the blade tip side when compared at the same perpendicular speed. Therefore, a region is provided in which the width of the protective layer is smaller in the cross section of the blade root side than in the cross section of the blade tip side. This makes it possible to provide a wind turbine blade with an appropriate range of the protective layer. [Explanation of symbols]

[0052] 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 (tip) 12a Tip 14 Airfoil section 16 Leading Edge 18 Trailing edge 20 Ventral aspect 22 Dorsal aspect 30 protective layer A1 Inflow direction A2 Ventral direction A3 Dorsal direction B Installation surface C1 Chord direction (chord direction) L1 Span direction PB Pre-bend

Claims

1. A method for determining a protective layer range of a wind turbine blade, which determines a range of a protective layer to be formed on a blade surface of a leading edge portion in a blade span direction of a wind turbine blade body formed of FRP, comprising: setting an impact direction and impact velocity of particles toward the leading edge; A step of obtaining a normal velocity, which is a velocity component in a normal direction at each position of the leading edge of the blade surface in a plurality of cross sections perpendicular to the blade span direction, from the collision direction and the collision velocity of the particle; setting the threshold value of the perpendicular velocity; determining a range of the leading edge portion where the perpendicular velocity is equal to or greater than the threshold value as a range in which the protective layer is to be formed; A method for determining a protective layer range of a wind turbine blade having the following:

2. A wind turbine blade body formed of FRP; a protective layer formed on a blade surface of a leading edge portion in a blade span direction of the wind turbine blade body; Equipped with The protective layer has a width in a pressure direction smaller than a width in a suction direction of the blade surface in a cross section perpendicular to the blade span direction.

3. The wind turbine blade according to claim 2 , wherein there is a region in which a width of the protective layer in the cross section is smaller on a blade root side than on a blade tip side.

Images