Wing structure and method for manufacturing the same

Abstract

To provide a blade structure capable of improving erosion resistance performance, and a manufacturing method of the blade structure.SOLUTION: A blade structure comprises a blade body made of FRP, and an erosion suppression layer provided so as to cover at least a part of a front edge of the blade body. The erosion suppression layer comprises a sprayed layer having a predetermined surface roughness to maintain a liquid film formed on the erosion suppression layer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD The present disclosure relates to wing structures and methods of manufacturing wing structures. [Background technology]

[0002] It is known that wing structures, such as wind turbine blades, that move through high-speed fluids are subject to collisions with foreign matter in the air (e.g., raindrops, dust, etc.), causing erosion on the leading edge side. To protect the wing structure from this erosion, measures have been taken, such as forming an erosion-resistant protective film on the leading edge side of the wing structure (e.g., Patent Document 1).

[0003] Patent document 1 discloses that multiple resin shields that cover at least a portion of the leading edge of a wind turbine rotor blade are pre-formed into a shape that corresponds to the leading edge, and that these multiple shields are arranged side by side in the longitudinal direction of the rotor blade and attached to the rotor blade. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 219524 Summary of the Invention [Problem to be solved by the invention]

[0005] When droplets collide with the surface of an erosion-resistant protective film formed on the leading edge side of a wing structure, the impact pressure caused by the collision of the droplets causes erosion in the protective film, so it is desirable to improve the erosion resistance of the protective film. Generally, the surface of the protective film is formed to be smooth and free of irregularities in order to avoid a deterioration in the aerodynamic performance of the wing structure.

[0006] In view of the above circumstances, an object of at least one embodiment of the present disclosure is to provide a wing structure and a method for manufacturing a wing structure that can improve erosion resistance performance. [Means for solving the problem]

[0007] A wing structure according to an embodiment of the present disclosure includes: A wing body made of FRP, an erosion-suppressing layer provided to cover at least a portion of the leading edge of the blade body; The erosion-suppressing layer includes a thermal spray layer having a predetermined surface roughness, thereby maintaining a liquid film formed on the erosion-suppressing layer.

[0008] A method for manufacturing a wing structure according to an embodiment of the present disclosure includes: preparing a wing body formed of FRP; a thermal spray layer forming step of providing a thermal spray layer by thermal spraying so as to cover at least a portion of the leading edge of the blade body; After the sprayed layer forming step, a surface treatment step is provided in which the surface of the sprayed layer is treated so that the surface of the sprayed layer satisfies the condition of root mean square height Rq=5 to 40 μm. [Effects of the Invention]

[0009] According to at least one embodiment of the present disclosure, a wing structure and a method for manufacturing a wing structure capable of improving erosion resistance performance are provided. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view of a wing structure according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view of the vicinity of the leading edge of the wing structure shown in FIG. 1. [Figure 3] FIG. 1 is an explanatory diagram for explaining the erosion process. [Figure 4] FIG. 4 is an explanatory diagram for explaining the surface of the material in the incubation period shown in FIG. 3. [Figure 5] FIG. 4 is an explanatory diagram for explaining the surface of the material in the steady erosion rate period shown in FIG. 3. [Figure 6] FIG. 4 is an explanatory diagram for explaining the surface of the material in the final erosion stage shown in FIG. 3. [Figure 7] FIG. 1 is an explanatory diagram for explaining wettability. [Figure 8] FIG. 10 is an explanatory diagram for explaining the relationship between the area ratio r and the root mean square height Rq. [Figure 9] FIG. 1 is a flow diagram illustrating an example of a method for manufacturing a wing structure according to an embodiment of the present disclosure. [Figure 10] 1 is a schematic configuration diagram of a wind turbine generator including a wing structure according to an embodiment of the present disclosure. [Figure 11] FIG. 1 is a plan view of a wing structure according to an embodiment of the present disclosure. [Figure 12] FIG. 12 is a schematic cross-sectional view of the vicinity of the leading edge of the wing structure shown in FIG. 11. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," or "have" one element are not exclusive expressions that exclude the presence of other elements. Note that the same components will be denoted by the same reference numerals and the description thereof will be omitted.

[0012] (wing structure) Fig. 1 is a plan view of a wing structure according to one embodiment of the present disclosure. Fig. 2 is a schematic cross-sectional view of the vicinity of the leading edge of the wing structure shown in Fig. 1. Fig. 2 schematically shows a cross section perpendicular to the length direction (span direction) of the wing body. As shown in FIG. 1, a wing structure 1 according to some embodiments includes a wing body 2 and an erosion-suppressing layer 3 provided so as to cover at least a portion of a leading edge 21 of the wing body 2.

[0013] (Wing body) 1 , the blade body 2 extends along the blade span from the blade root 22 to the blade tip 23. The blade body 2 has a leading edge 21, a trailing edge 24, a pressure surface 25 which is one surface extending between the leading edge 21 and the trailing edge 24, and a suction surface 26 which is the other surface extending between the leading edge 21 and the trailing edge 24. The leading edge 21 and the trailing edge 24 each extend from the blade root 22 to the blade tip 23.

[0014] The blade body 2 is made of fiber reinforced plastic (FRP) such as carbon fiber reinforced plastic (CFRP) or glass fiber reinforced plastic (GFRP). As shown in Figure 2, the blade body 2 has a sprayed surface 27A on part of its surface (outer surface of the leading edge 21) 27, which is coated with an erosion-suppressing layer 3. The sprayed surface 27A is a part of the surface 27 that includes at least a part of the leading edge 21.

[0015] (Erosion prevention layer) As shown in Figure 2, the erosion-suppressing layer 3 includes a thermal spray layer 3A formed on the surface 27A of the blade main body 2 by thermal spraying. The thermal spray layer 3A is a coating formed on the surface 27 of the blade main body 2 by spraying a heated thermal spray material onto the surface 27 of the blade main body 2, which is the base material. The coating is formed when the thermal spray material solidifies and adheres to the surface. The erosion-suppressing layer 3 functions as a protective layer (outermost layer) to protect the blade main body 2 from droplet erosion caused by raindrops, dust, etc.

[0016] (erosion process) FIG. 3 is an explanatory diagram for explaining the erosion process. FIG. 3 schematically shows the relationship between the amount of damage caused by droplet erosion and time for a ductile metal. The vertical axis of FIG. 3 represents the amount of damage caused by droplet erosion, which is indicated by the mass loss of the ductile metal material. The horizontal axis of FIG. 3 represents the exposure time, which indicates the period during which the material was exposed to the droplets. Note that the vertical axis of FIG. 3 may also represent the volume loss or damage depth of the material, which indicate the degree of damage caused by droplet erosion. Alternatively, the horizontal axis of FIG. 3 may represent the amount of liquid impinging per unit area or the number of droplet collisions per unit area.

[0017] As shown in Figure 3, the erosion process is roughly divided into three regions (incubation period T1, steady erosion rate period T2, and final erosion period T3). Figure 4 is an explanatory diagram for explaining the surface of the material in the incubation period shown in Figure 3. Figure 5 is an explanatory diagram for explaining the surface of the material in the steady erosion rate period shown in Figure 3. Figure 6 is an explanatory diagram for explaining the surface of the material in the final erosion period shown in Figure 3. In Figures 4 to 6, the droplet is designated D, and the material exposed to droplet D is designated 4.

[0018] In the first region, the incubation period T1, as shown in Figure 4, the mass of the material 4 exposed to the droplet D does not decrease significantly, but elastic and plastic deformation occurs in the material 4. The plastic deformation causes small irregularities and depressions in the previously smooth surface 41, which increases the irregularity of the surface 41 and gradually increases the damage to the material 4 due to the stress concentration effect.

[0019] In the second region, the steady erosion rate period T2, the erosion rate is faster than in the incubation period T1 and the final erosion period T3, as shown in Figures 3 and 5, and the surface 41 of the material 4 is rapidly removed by droplet erosion, forming pits 42. As time passes, numerous pits 42 are formed on the surface 41, causing the surface 41 to become rough.

[0020] In the third region, the final erosion period T3, the erosion rate decreases compared to the steady erosion rate period T2. One possible reason for the decrease in erosion rate is that as the surface 41 of the material 4 becomes rougher, water W accumulates in deeper pits 42, and when droplets D collide with the water W accumulated in the pits 42, the impact of the droplets D is cushioned.

[0021] The inventors have found that when a liquid droplet D strikes the wing structure 1, the impact pressure caused by the collision of the liquid droplet D can be alleviated by maintaining the liquid film W1 formed by the liquid droplet D on the erosion-suppressing layer 3. The erosion-suppressing layer 3 described above is made of a sprayed layer 3A that has a predetermined surface roughness and is configured to maintain the liquid film W1 formed on the erosion-suppressing layer 3.

[0022] The surface 31 of the sprayed layer 3A is provided with an uneven shape having a predetermined surface roughness, and when droplets D hit the sprayed layer 3A, the uneven shape is able to maintain a liquid film W1. In the illustrated embodiment, the sprayed layer 3A is made of a material with excellent wear resistance, such as a cermet or a Co alloy, such as a Co (cobalt)-based alloy, so that the uneven shape is unlikely to be deformed by the droplets D and can maintain a shape that allows the liquid film W1 to be maintained for a long period of time.

[0023] As shown in Figure 2, a wing structure 1 according to some embodiments includes the above-described wing body 2 and the above-described erosion-suppressing layer 3. The erosion-suppressing layer 3 includes a thermal spray layer 3A having a predetermined surface roughness so as to maintain the liquid film W1 formed on the erosion-suppressing layer 3.

[0024] According to the above configuration, the thermal spray layer 3A having a predetermined surface roughness can maintain the liquid film W1 formed on the erosion-suppressing layer 3 by liquid droplets D when the liquid droplets D strike the wing structure 1. In this case, the liquid droplets D collide with the liquid film W1 formed on the erosion-suppressing layer 3, so the impact pressure caused by the collision of the liquid droplets D can be alleviated compared to when the liquid droplets D directly collide with the erosion-suppressing layer 3 on which no liquid film W1 is formed. By alleviating the impact pressure caused by the collision of the liquid droplets D, the progress of erosion in the erosion-suppressing layer 3 can be suppressed, and ultimately the progress of erosion in the leading edge 21 of the blade main body 2 covered with the erosion-suppressing layer 3 can be suppressed. In other words, the wing structure 1 maintains the liquid film W1 formed on the erosion-suppressing layer 3, and the liquid film W1 reduces the impact of the liquid droplets D, thereby improving erosion resistance.

[0025] When thermal spraying is performed on a blade body 2 made of FRP, the surface roughness of the sprayed layer 3A tends to be greater than when thermal spraying is performed on a blade body 2 made of a metallic material. For this reason, it is easier to form the surface 31 of the sprayed layer 3A into an irregular shape with a predetermined surface roughness when using a blade body 2 made of FRP than when using a blade body 2 made of a metallic material.

[0026] In some embodiments, the thermal spray layer 3A is made of a cermet or a Co alloy such as a Co-based alloy. The cermet includes at least one of alumina, tungsten carbide, silicon nitride, silicon carbide, zirconia, and chromium carbide. The thermal spray layer 3A is preferably made of a Co-based alloy, which has excellent corrosion resistance, wear resistance, and high-temperature strength. In one embodiment, the Co-based alloy constituting the thermal spray layer 3A contains at least Cr (chromium) and C (carbon), with the remainder being Co. The Co-based alloy constituting the thermal spray layer 3A may further contain at least one of Mo (molybdenum), Si (silicon), W (tungsten), Ni (nickel), and Fe (iron). According to the above configuration, the thermal spray layer 3A is made of a material with excellent heat resistance and wear resistance, such as a cermet or a Co alloy such as a Co-based alloy, and therefore exhibits high erosion resistance. In some other embodiments, the thermal spray layer 3A may be made of a material other than cermet or Co alloy.

[0027] In some embodiments, the surface roughness of the surface 31 of the thermal sprayed layer 3A described above satisfies the condition of root mean square height Rq = 5 to 40 μm. According to the above configuration, by making the surface 31 of the thermal sprayed layer 3A have a roughness that satisfies the condition of root mean square height Rq = 5 to 40 μm, the liquid film W1 formed on the surface 31 of the thermal sprayed layer 3A can be effectively maintained. Therefore, the liquid film W1 can mitigate the impact pressure caused by the collision of the droplets D.

[0028] If the surface roughness of surface 31 of sprayed layer 3A is too small (e.g., Rq<5 μm), it may be difficult to maintain liquid film W1. If the surface roughness of surface 31 of sprayed layer 3A is too large (e.g., Rq>40 μm), the frictional resistance experienced by sprayed layer 3A increases, which may result in a deterioration in the aerodynamic performance of wing structure 1. It is preferable that the surface roughness of surface 31 of sprayed layer 3A described above satisfies the condition of root mean square height Rq=10 to 30 μm.

[0029] (Wettability of the sprayed layer surface) The ability to maintain a liquid film W1 on the surface 31 of the thermal sprayed layer 3A depends on the wettability of the surface 31. FIG. 7 is an explanatory diagram illustrating wettability. As shown in FIG. 7, when a droplet D forms on the surface 44 of a solid 43, the surface tension between the solid 43 and the droplet D causes an equilibrium state in which the tangent to the outer edge (contact line) of the droplet D and the surface 44 form a contact angle. The smaller the contact angle, the better the wettability and the higher the affinity (ease of adhesion) of the liquid. In FIG. 7, θ represents the contact angle with respect to a rough surface, and θ represents the contact angle with respect to a flat surface made of the same material as the rough surface. As shown in FIG. 7, on a hydrophilic surface that satisfies the condition of a contact angle θ<90°, the contact angle θ tends to decrease as the surface roughness increases. In contrast, on a hydrophobic surface that satisfies the condition of a contact angle θ>90°, the contact angle θ tends to increase as the surface roughness increases.

[0030] The wettability of the surface 31 of the sprayed layer 3A can be expressed by the following Wenzel equation (1), where θw is the contact angle with respect to a rough surface of the sprayed layer 3A having the above-mentioned specified surface roughness, and θ is the contact angle with respect to a flat surface made of the same material as the sprayed layer 3A. cosθw=r·cosθ (1) In the above formula (1), r represents the area ratio of the rough surface to the flat surface, and the rougher the surface, the larger the area ratio r. The applicable range of the above formula (1) is an area ratio r of 1.7 or less.

[0031] In some embodiments, the surface roughness of the surface 31 of the thermal sprayed layer 3A satisfies the area ratio r = 1.1 to 1.7 in the above formula (1). FIG. 8 is an explanatory diagram illustrating the relationship between the area ratio r and the root-mean-square height Rq. In FIG. 8, the area ratio r is plotted on the vertical axis and the root-mean-square height Rq is plotted on the horizontal axis. FIG. 8 also shows a curve C illustrating the relationship between the area ratio r and the root-mean-square height Rq. The curve C was obtained by constructing a surface roughness using the root-mean-square height Rq as a parameter through numerical simulation, calculating the surface area of ​​the surface roughness, and then calculating the area ratio r from the calculated surface area. As shown in FIG. 8, the curve C rises after exceeding Rq = 10 μm (r = 1.1) and then monotonically increases. Furthermore, in FIG. 8, when the condition r = 1.7 is satisfied, Rq is 29 μm. Therefore, satisfying the area ratio r=1.1 to 1.7 can be rephrased as satisfying the root mean square height Rq=10 to 29 μm. By specifying the surface roughness of surface 31 of thermal sprayed layer 3A within the inflection point range of r=1.1 to r=1.7, the appropriate wettability can be obtained, and the liquid film W1 can be effectively maintained on surface 31.

[0032] According to the above configuration, by providing surface 31 of thermal sprayed layer 3A with a roughness that satisfies r = 1.1 to 1.7 in formula (1), it is possible to effectively maintain liquid film W1 formed on surface 31 of thermal sprayed layer 3A. As a result, the liquid film W1 can mitigate the impact pressure caused by the collision of droplets.

[0033] 9 is a flow diagram showing an example of a method 100 for manufacturing a wing structure according to an embodiment of the present disclosure. As shown in Fig. 9, the method 100 for manufacturing a wing structure 1 includes a preparation step S1 of preparing the above-described wing body 2, and a thermal sprayed layer formation step S2 of providing a thermal sprayed layer 3A by thermal spraying so as to cover at least a portion of the leading edge 21 of the wing body 2.

[0034] (Surface preparation) 9, the manufacturing method 100 for the wing structure 1 may further include a surface preparation step S3, prior to the thermal spray layer formation step S2, in which the surface 27A of the blade body 2 to be sprayed is subjected to a surface treatment so that the surface 27A has a predetermined surface roughness. In the surface preparation step S3, unevenness is formed on the surface 27A to be sprayed by at least one of a mechanical treatment such as blasting or shot peening, a thermal treatment such as laser processing, a chemical treatment such as etching, or a machining treatment such as grinding. In one embodiment, the surface treatment of the surface 27A to be sprayed is performed in the surface preparation step S3 so that the surface roughness of the surface 27A to be sprayed satisfies the condition of an arithmetic mean roughness Ra of 3.2 to 6.3 μm.

[0035] In some embodiments, the wing body 2 of the wing structure 1 described above has a sprayed surface 27A that is coated with an erosion-suppressing layer 3 (thermal sprayed layer 3A). The surface roughness of this sprayed surface 27A satisfies the condition of arithmetic mean roughness Ra = 3.2 to 6.3 μm. According to the above configuration, by making the surface 27A to be sprayed have a roughness that satisfies the condition of arithmetic mean roughness Ra = 3.2 to 6.3 μm, the sprayed layer 3A provided by thermal spraying on the surface 27A to be sprayed has a suitable roughness that reflects the surface roughness of the surface 27A to be sprayed, that is, a surface 31 having a roughness that can maintain a liquid film W1 on the sprayed layer 3A.

[0036] (Surface treatment of thermal sprayed layer) 9 , the manufacturing method 100 for the wing structure 1 may further include, after the thermal sprayed layer formation step S2, a surface treatment step S4 in which the surface 31 of the thermal sprayed layer 3A is treated so as to have a predetermined surface roughness. In the surface treatment step S4, unevenness is formed on the surface 31 of the thermal sprayed layer 3A by performing at least one of a mechanical treatment such as blasting or shot peening, a thermal treatment such as laser processing, a chemical treatment such as etching, or a machining treatment such as grinding. In one embodiment, the surface treatment step S4 is performed on the surface 31 of the thermal sprayed layer 3A so that the surface roughness of the surface 31 satisfies the condition Rq = 5 to 40 μm. Alternatively, the surface treatment step S4 may be performed on the surface 31 so that the surface roughness of the surface 31 of the thermal sprayed layer 3A satisfies either the condition Rq = 10 to 30 μm or Rq = 10 to 29 μm.

[0037] According to the above method, the surface of the sprayed layer 3A is treated to have a roughness (e.g., Rq = 5 to 40 μm) on the surface 31 of the sprayed layer 3A that allows the liquid film W1 to be maintained, and thus the liquid film W1 formed on the surface 31 of the sprayed layer 3A by the liquid droplets striking the wing structure 1 can be effectively maintained. Therefore, the liquid film W1 can mitigate the impact pressure caused by the collision of the liquid droplets D. Furthermore, according to the above method, the surface 31 of the sprayed layer 3A can be made to have a predetermined roughness (e.g., Rq = 5 to 40 μm) even after the formation of the sprayed layer 3A, so that the erosion resistance performance can be improved even after the formation of the sprayed layer 3A.

[0038] (wind power generation equipment) Fig. 10 is a schematic configuration diagram of a wind turbine generator including a wing structure according to an embodiment of the present disclosure. In some embodiments, as shown in Fig. 10, the above-mentioned wing structure 1 is made up of a wind turbine blade 1A. The wind turbine generator 10 includes at least one wind turbine blade 1A, a hub 11 to which the wind turbine blade 1A is attached, a generator (not shown) driven by rotation of the hub 11, a nacelle 13 that rotatably supports a rotor 12 (wind turbine rotor) including the wind turbine blade 1A and the hub 11, a tower 14 that supports the nacelle 13, and a base 15 that is provided on the ground G and supports the tower 14.

[0039] The wind turbine generator 10 may include a plurality of wind turbine blades 1A attached to the hub 11 in a radial arrangement. In other words, the at least one wind turbine blade 1A described above may include a plurality of wind turbine blades 1A attached to the hub 11 in a radial arrangement. Each of the plurality of wind turbine blades 1A has a blade root 22 fixed to the hub 11, and a blade tip 23 located radially outward from the blade root 22 with the hub 11 as the center. The tower 14 and base 15 are erected on land or offshore. Note that Fig. 10 illustrates a case where the tower 14 and base 15 are installed on land.

[0040] In the wind turbine generator 10, a rotor 12 including wind turbine blades 1A rotates when it receives wind, and the rotational force of the rotor 12 is transmitted to a generator (not shown), which generates electric power.

[0041] It should be noted that the wing structure 1 of the present disclosure can be applied to things other than wind turbine blades 1A. For example, in one embodiment, the wing structure 1 is made of an aircraft wing. When the wing structure 1 is used as a wind turbine blade 1A or an aircraft wing, measures to protect the wing structure 1 from lightning strikes are required.

[0042] (Lightning protection structure for wing structures) Fig. 11 is a plan view of a wing structure according to one embodiment of the present disclosure. Fig. 12 is a schematic cross-sectional view of the vicinity of the leading edge of the wing structure shown in Fig. 11. Fig. 12 schematically shows a cross section perpendicular to the length direction (span direction) of the wing body. In some embodiments, as shown in Figure 12, the above-mentioned wing structure 1 comprises the above-mentioned wing main body 2, the above-mentioned erosion-suppressing layer 3, and a conductive portion 5. The erosion-suppressing layer 3 includes the above-mentioned thermal sprayed layer 3A and an intermediate layer 3B formed between the wing main body 2 and the thermal sprayed layer 3A. The intermediate layer 3B has a lower electrical resistivity than the thermal sprayed layer 3A. As shown in Figure 10, the conductive portion 5 connects the intermediate layer 3B to ground G. In other words, the intermediate layer 3B is electrically connected to ground G via the conductive portion 5. Here, "ground" refers to a location to which current, such as a lightning current, generated in the wing structure 1 is ultimately discharged.

[0043] When lightning strikes the sprayed layer 3A, the intermediate layer 3B, which has a lower electrical resistivity than the sprayed layer 3A, exists directly below the sprayed layer 3A, and therefore the lightning current charged in the sprayed layer 3A can be quickly conducted to the ground G side via the intermediate layer 3B and the conductive portion 5. This makes it possible to suppress damage to the sprayed layer 3A, the intermediate layer 3B, and the blade body 2 caused by the lightning current. Note that the intermediate layer 3B does not necessarily have to be provided over the entire sprayed layer 3A, but by providing the intermediate layer 3B over the entire sprayed layer 3A, the lightning current charged in the sprayed layer 3A can be quickly conducted to the ground G side via the intermediate layer 3B.

[0044] The intermediate layer 3B is provided on the surface 27A to be sprayed of the blade body 2. The intermediate layer 3B is formed on the surface 27A to be sprayed of the blade body 2 before the formation of the thermal spray layer 3A. Like the thermal spray layer 3A, the intermediate layer 3B also functions as a protective layer to protect the blade body 2 from droplet erosion such as raindrops and dust. The intermediate layer 3B can be formed by various methods. For example, the intermediate layer 3B may be formed by thermal spraying, or a sheet-like intermediate layer 3B may be attached to the surface 27 of the blade body 2. The thermal spray layer 3A is provided on the intermediate layer 3B. It consists of a coating formed on the surface 32 of the intermediate layer 3B by spraying a heated thermal spray material onto the surface 32 of the intermediate layer 3B.

[0045] The manufacturing method 100 of the wing structure 1 described above may further include, prior to the sprayed layer forming step S2, an intermediate layer forming step of providing an intermediate layer 3B so as to cover at least a portion of the leading edge 21 of the wing body 2. The manufacturing method 100 of the wing structure 1 may further include, prior to the sprayed layer forming step S2, a surface treatment step of performing a surface treatment (priming) of the intermediate layer 3B so that the intermediate layer 3B has a predetermined surface roughness (e.g., Ra = 3.2 to 6.3 μm).

[0046] In some embodiments, the intermediate layer 3B is made of copper, a copper alloy, aluminum, or an aluminum alloy. An example of an aluminum alloy is duralumin. By using such a material with low electrical resistivity, the lightning current charged in the thermal spray layer 3A can be easily channeled to the ground G, improving the lightning current dissipation effect of the thermal spray layer 3A. Furthermore, by using the above-mentioned material, the intermediate layer 3B has a lower hardness and Young's modulus than the thermal spray layer 3A, making it less aggressive to the blade body 2 and providing strong adhesion to the blade body 2. Such an intermediate layer 3B can prevent the thermal spray layer 3A from peeling or falling off from the blade body 2.

[0047] 11 , the thermal spray layer 3A and intermediate layer 3B are each provided in at least a portion of the region from the tip 23 of the blade body 2 to half the length of the blade body 2 in the longitudinal direction (blade length direction) of the blade body 2. Because erosion depends on the peripheral speed, for example, in a wind turbine blade 1A, the tip 23 side of the blade body 2 is more susceptible to erosion than the root 22 side of the blade body 2. According to the above configuration, by providing the thermal spray layer 3A and intermediate layer 3B in at least a portion of the region from the tip 23 of the blade body 2 to half the length of the blade body 2 in the longitudinal direction of the blade body 2, it is possible to improve the erosion resistance of the region that is more susceptible to erosion.

[0048] In addition, when the wing structure 1 does not include an intermediate layer 3B, the sprayed layer 3A may be provided in at least a portion of the region from the blade tip 23 of the blade body 2 to 1 / 2 of the length of the blade body 2 in the longitudinal direction (blade length direction) of the blade body 2.

[0049] In some embodiments, the combined thickness of the thermal sprayed layer 3A and the intermediate layer 3B satisfies the condition of 200 μm to 2000 μm. In this case, the erosion resistance of the thermal sprayed layer 3A is ensured, while the thermal sprayed layer 3A and the intermediate layer 3B covering the thermally sprayed surface 27A of the blade body 2 are prevented from becoming too thick. Furthermore, the thickness can be adjusted with high precision so that there is no step between the surface 31 of the erosion-suppressing layer 3 and the surface 27 of the blade body 2, so the aerodynamic performance of the wing structure 1 can be maintained at a high level even after the erosion-suppressing layer 3 is formed.

[0050] The thickness of the sprayed layer 3A is determined primarily by the tip peripheral speed of the wing structure 1 (wind turbine blade 1A), while the thickness of the intermediate layer 3B is determined primarily by the required electrical resistivity. In one embodiment, the thickness of the sprayed layer 3A is in the range of 100 to 1000 μm, and the thickness of the intermediate layer 3B is in the range of 100 to 1000 μm. This allows the sprayed layer 3A to ensure erosion resistance and coating strength that can withstand the tip peripheral speed of the wing structure 1 (wind turbine blade 1A). The intermediate layer 3B can ensure a cross-sectional area that reduces electrical resistivity and ensures the required electrical conductivity.

[0051] When the wing structure 1 does not include the intermediate layer 3B, the thickness of the sprayed layer 3A may be in the range of 100 to 1000 μm.

[0052] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0053] The contents of the above-described embodiments can be understood, for example, as follows.

[0054] 1) A wing structure (1) according to at least one embodiment of the present disclosure comprises: A wing body (2) formed from FRP; an erosion-suppressing layer (3) provided so as to cover at least a part of the leading edge (21) of the blade body (2); The erosion-suppressing layer (3) includes a sprayed layer (3A) having a predetermined surface roughness, which is configured to maintain a liquid film formed on the erosion-suppressing layer (3).

[0055] According to the above configuration 1), the thermal spray layer 3A having a predetermined surface roughness can maintain a liquid film formed on the erosion-suppressing layer 3 by liquid droplets impinging on the wing structure 1. In this case, by having the liquid droplets impinge on the liquid film formed on the erosion-suppressing layer 3, the impact pressure caused by the droplets can be reduced compared to when the liquid droplets directly impinge on the erosion-suppressing layer 3 on which no liquid film is formed. By reducing the impact pressure caused by the droplets impinging, the progression of erosion in the erosion-suppressing layer 3 can be reduced, and ultimately, the progression of erosion in the leading edge 21 of the wing main body 2 covered with the erosion-suppressing layer 3 can be reduced. In other words, the wing structure 1 can improve its erosion resistance by maintaining a liquid film formed on the erosion-suppressing layer 3 and reducing the impact of the liquid droplets with the liquid film.

[0056] 2) In some embodiments, the wing structure (1) described in 1) above, The predetermined surface roughness of the thermal sprayed layer (3A) satisfies the condition of root mean square height Rq=5 to 40 μm.

[0057] According to the above configuration 2), by making the surface 31 of the sprayed layer 3A have a roughness satisfying the condition of root mean square height Rq = 5 to 40 μm, it is possible to effectively maintain a liquid film formed on the surface 31 of the sprayed layer 3A, and therefore, the liquid film can mitigate the impact pressure caused by the collision of liquid droplets.

[0058] 3) In some embodiments, the wing structure (1) according to 1) or 2) above, When the contact angle of the thermal sprayed layer (3A) with respect to a rough surface having the predetermined surface roughness is defined as θw and the contact angle of the thermal sprayed layer (3A) with respect to a flat surface made of the same material as the thermal sprayed layer (3A) is defined as θ, the predetermined surface roughness of the thermal sprayed layer (3A) is expressed by the following formula (1): cosθw=r·cosθ In this case, r=1.1~1.7 is satisfied.

[0059] According to the above configuration 3), by making the surface 31 of the sprayed layer 3A have a roughness that satisfies r=1.1 to 1.7 in the above formula (1), a liquid film formed on the surface 31 of the sprayed layer 3A can be effectively maintained. Therefore, the liquid film can mitigate the impact pressure caused by the collision of liquid droplets.

[0060] 4) In some embodiments, the wing structure (1) according to any one of 1) to 3) above, The blade body (2) has a sprayed surface (27A) coated with the erosion-suppressing layer (3), The surface roughness of the surface to be sprayed (27A) satisfies the condition of arithmetic mean roughness Ra=3.2 to 6.3 μm.

[0061] According to the above configuration 4), by making the surface to be sprayed (27A) have a roughness that satisfies the condition of arithmetic mean roughness Ra = 3.2 to 6.3 μm, the sprayed layer (3A) formed on the surface to be sprayed (27A) by thermal spraying has a suitable roughness that reflects the surface roughness of the surface to be sprayed (27A), that is, a surface (31) having a roughness that allows a liquid film to be maintained on the sprayed layer (3A) is formed.

[0062] 5) In some embodiments, the wing structure (1) according to any one of 1) to 4) above, The thermal spray layer (3A) is Alumina, tungsten carbide, silicon nitride, silicon carbide, zirconia or chrome carbide a cermet including at least one of the bites; Or, It was made of Co alloy.

[0063] According to the above configuration 5), the thermal spray layer (3A) is made of a material having excellent heat resistance and wear resistance, such as cermet or Co alloy, and therefore can exhibit high erosion resistance.

[0064] 6) In some embodiments, the wing structure (1) according to any one of 1) to 5) above, The erosion-suppressing layer (3) is The blade further includes an intermediate layer (3B) formed between the blade body (2) and the thermal sprayed layer (3A) and having an electrical resistivity lower than that of the thermal sprayed layer (3A), The wing structure (1) further comprises a conductive part (5) that electrically connects the intermediate layer (3B) to ground.

[0065] According to the above configuration 6), by providing the intermediate layer (3B) with low electrical resistivity between the sprayed layer (3A) which is an erosion-resistant film and the blade body (2), the lightning current charged in the sprayed layer (3A) can be quickly flowed to the ground side via the intermediate layer (3B), thereby suppressing damage to the sprayed layer (3A), the intermediate layer (3B) and the blade body (2) due to the lightning current.

[0066] 7) In some embodiments, the wing structure (1) described in 6) above, The sprayed layer (3A) and the intermediate layer (3B) are each provided in at least a portion of the region from the blade tip (23) of the blade body (2) to half the length of the blade body (2) in the longitudinal direction of the blade body (2).

[0067] Since erosion depends on the peripheral speed, the tip 23 side of the blade body 2 is more susceptible to erosion than the root 22 side of the blade body 2. According to the configuration of 7) above, by providing the thermal spray layer 3A and the intermediate layer 3B in at least a part of the region from the tip 23 of the blade body 2 to half the length of the blade body 2 in the longitudinal direction of the blade body 2, it is possible to improve the erosion resistance of the region that is susceptible to erosion.

[0068] 8) In some embodiments, the wing structure (1) according to 6) or 7) above, The total thickness of the thermal sprayed layer (3A) and the intermediate layer (3B) satisfies the condition of 200 μm or more and 2000 μm or less.

[0069] According to the configuration of 8) above, the total thickness of the thermal sprayed layer 3A and the intermediate layer 3B satisfies the condition of 200 μm to 2000 μm. In this case, the thermal sprayed layer 3A and the intermediate layer 3B covering the thermal sprayed surface 27A of the blade main body 2 can be prevented from becoming too thick while ensuring erosion resistance due to the thermal sprayed layer 3A. Furthermore, since the thickness can be adjusted with high precision so as to prevent a step from occurring between the surface 31 of the erosion-suppressing layer 3 and the surface 27 of the blade main body 2, the aerodynamic performance of the blade structure 1 can be maintained at a high level even after the erosion-suppressing layer 3 is formed.

[0070] 9) A method for manufacturing a wing structure (1) according to at least one embodiment of the present disclosure includes: A step of preparing a wing body (2) formed of FRP; a thermal spray layer forming step of providing a thermal spray layer (3A) by thermal spraying so as to cover at least a part of the leading edge (21) of the blade body (2); After the sprayed layer forming step, a surface treatment step is provided in which the sprayed layer (3A) is subjected to a surface treatment so that the surface (31) of the sprayed layer (3A) satisfies the condition of root mean square height Rq=5 to 40 μm.

[0071] According to the method of 9), the sprayed layer 3A is surface-treated to have a roughness on the surface 31 of the sprayed layer 3A that satisfies the condition of root mean square height Rq = 5 to 40 μm, which makes it possible to effectively maintain a liquid film formed on the surface 31 of the sprayed layer 3A by droplets striking the wing structure 1. This liquid film can therefore mitigate the impact pressure caused by the collision of droplets. Furthermore, according to the method of 9), the surface 31 of the sprayed layer 3A can be made to have a predetermined roughness (roughness that satisfies the condition of root mean square height Rq = 5 to 40 μm) even after the formation of the sprayed layer 3A, thereby improving erosion resistance even after the formation of the sprayed layer 3A. [Explanation of symbols]

[0072] 1 Wing structure 1A windmill blade 2 Wing body 3. Erosion-suppressing layer 3A sprayed layer 3B Middle layer 4 Materials 5 Conductive part 10. Wind power generation equipment 11. Hub 12 rotors 13 Nacelle 14. Tower 15 base 21 leading edge 22 Wing root 23 Wing Tip 24 Trailing edge 25 Pressure Surface 26 Suction surface 27 (wing body) surface 27A Sprayed surface 31 (Surface of thermal spray layer) 32 (intermediate layer) surface 41,44 surface 42 Pit 43 Solid 100 Wing structure manufacturing method C curve D droplet G Ground Ra: Arithmetic mean roughness Rq Root Mean Square Height S1 Preparation step S2 Thermal spray layer formation step S3 Surface preparation step S4 Surface treatment step T1 incubation period T2 Steady erosion rate period T3 Final erosion period W water W1 liquid film r area ratio θ Contact angle on a flat surface θw Contact angle on rough surface

Claims

1. a wing body formed of FRP; an erosion-suppressing layer provided to cover at least a portion of the leading edge of the blade body; The erosion-suppressing layer includes a thermal spray layer having a predetermined surface roughness, the predetermined surface roughness of the thermal spray layer satisfies the condition of root mean square height Rq = 5 to 40 μm; wing structure.

2. A wing body formed of FRP; an erosion-suppressing layer provided to cover at least a portion of the leading edge of the blade body; The erosion-suppressing layer includes a thermal spray layer having a predetermined surface roughness, When the contact angle of the thermal spray layer with respect to a rough surface having the predetermined surface roughness is defined as θw and the contact angle with respect to a flat surface made of the same material as the thermal spray layer is defined as θ, the predetermined surface roughness of the thermal spray layer can be calculated by the following formula (1): cosθw=r・cosθ In this case, r=1.1 to 1.7 is satisfied. wing structure.

3. The blade body has a sprayed surface coated with the erosion-suppressing layer, The surface roughness of the sprayed surface satisfies the condition of arithmetic mean roughness Ra = 3.2 to 6.3 μm. A wing structure according to claim 1 or 2.

4. The thermal spray layer is Alumina, tungsten carbide, silicon nitride, silicon carbide, zirconia or chrome carbide a cermet including at least one of the bites; Or, Consisting of a Co alloy, A wing structure according to any one of claims 1 to 3.

5. The erosion-suppressing layer is an intermediate layer formed between the blade body and the thermal spray layer and having an electrical resistivity lower than that of the thermal spray layer; The wing structure further includes a conductive portion electrically connecting the intermediate layer to ground. A wing structure according to any one of claims 1 to 4.

6. The thermal spray layer and the intermediate layer are each provided in at least a portion of a region from the blade tip of the blade body to half the length of the blade body in the length direction of the blade body.

6. A wing structure according to claim 5.

7. The total thickness of the thermal spray layer and the intermediate layer satisfies the condition of 200 μm or more and 2000 μm or less. A wing structure according to claim 5 or 6.

8. preparing a wing body formed of FRP; a thermal spray layer forming step of providing a thermal spray layer by thermal spraying so as to cover at least a portion of the leading edge of the blade body; and a surface treatment step of performing a surface treatment on the thermal sprayed layer after the thermal sprayed layer forming step so that the surface of the thermal sprayed layer satisfies the condition of root mean square height Rq = 5 to 40 μm. Method for manufacturing a wing structure.

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