JP2015222021A - Blade and windmill for wind power generation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further reduce noises in a blade of a windmill for wind power generation and the like.SOLUTION: A blade includes a wing-shaped cross-section body part, and a device which has a plurality of protrusions and a plurality of notched parts, arranged alternately in the wing height direction of the body part, and which is provided at a rear edge of the body part. The blade comprises a mesh material that is provided in the state of covering the notched part.

Description

  The present invention relates to a blade and a wind turbine for wind power generation.

  In wind turbines for wind power generation and the like, it is known that noise is generated by rotation of blades. Such noise is generated in proportion to the 5th or 6th power of the peripheral speed of the blade, and thus increases particularly on the tip side of the blade. There are a plurality of possible causes of noise, but the trailing edge noise generated by interference between the turbulent boundary layer formed around the blade and the trailing edge of the blade is considered to be the main cause.

  In order to reduce such trailing edge noise, for example, as shown in Patent Documents 1 to 3, a structure in which a device having a saw-tooth shape is attached to the trailing edge side of the blade has been proposed.

US Pat. No. 8,267,657 US Patent Application Publication No. 2012/0141277 US Patent Application Publication No. 2012/0134837

  Although a certain noise reduction effect can be obtained by attaching a device having a saw-tooth shape to the trailing edge side of the blade, the noise of wind turbines for wind power generation is preferably as small as possible, and further noise reduction is required.

  The present invention has been made in view of the above-described problems, and an object thereof is to further reduce noise in a blade such as a wind turbine for wind power generation.

  The present invention adopts the following configuration as means for solving the above-described problems.

  A first invention includes a main body portion having a wing-shaped cross section, a plurality of protrusions and notches arranged alternately in the blade height direction of the main body portion, and a device provided at a rear edge portion of the main body portion. A configuration is adopted in which the blade includes a mesh material provided so as to cover the notch.

  A second invention adopts a configuration in the first invention in which the mesh material is a glass cloth.

  A third invention is a wind turbine for wind power generation having a plurality of blades provided radially with respect to a rotating shaft, and employs a configuration in which the blade according to the first or second invention is provided as the blade.

  According to the present invention, the mesh material reduces the amount of air that passes from the ventral side to the back side of the blade, thereby reducing the amplitude of the pressure fluctuation pattern in the height direction of the blade, thereby reducing noise. Is possible. Therefore, according to the present invention, it is possible to further reduce noise in a blade of a wind turbine for wind power generation or the like.

It is a schematic diagram of the windmill for wind power generation provided with the braid | blade of one Embodiment of this invention. It is the schematic diagram which expanded the site | part on the chip | tip side and downstream of the braid | blade of one Embodiment of this invention, (a) is a top view, (b) is sectional drawing. (A) is an experimental result when the elevation angle is 0 ° in the wind tunnel experiment, and (b) is an experimental result when the elevation angle is 6 ° in the third wind tunnel experiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a blade and a wind turbine for wind power generation according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

  FIG. 1 is a schematic diagram of a wind turbine 1 for wind power generation provided with a blade 4 of the present embodiment. A wind turbine 1 for wind power generation includes a column 2 standing on the ground, a rotating shaft 3 attached to the tip of the column, a plurality of blades 4 provided radially with respect to the rotating shaft 3, and a glass cloth 5 (mesh Material). The wind turbine 1 for wind power generation includes a generator (not shown) connected to the rotary shaft 3, and transmits power generated by the blade 4 receiving wind through the rotary shaft 3 to the generator. Generate electricity.

  In the following description, the radial direction centered on the rotating shaft 3 is referred to as a blade height direction, the tip of the blade 4 in the blade height direction is referred to as a tip, and the root of the blade 4 is referred to as a hub. Further, as shown in FIG. 1, the blade 4 is rotated clockwise, and the front in the rotational direction is referred to as upstream and the rear in the rotational direction is referred to as downstream.

  2A and 2B are schematic views in which a portion on the tip side and the downstream side of the blade 4 is enlarged, (a) is a plan view, and (b) is a cross-sectional view. As shown in these drawings, the blade 4 of the present embodiment includes a main body portion 4a having a wing-shaped cross section and a device 4b attached to the rear edge portion 4a1 of the main body portion 4a.

  As shown in FIG. 2A, the device 4b has protrusions 4b1 and cutouts 4b2 that are alternately arranged in the height direction of the main body 4a at equal intervals. In such a device 4b, for example, when the chord length of the main body portion 4a is C and the length of the protrusion 4b1 in the chord length direction is L, L / C is 2.3%, and the protrusion The tip thickness of 4b1 is 1.2 mm. Further, L / λ is set to 1.5 when the distance between the protrusions 4b1 is λ. Furthermore, the tip of the protrusion 4b1 has an arc shape with a radius of curvature of 2 mm. Note that these values are merely examples, and it is naturally possible to use devices having other values.

  As shown in FIG. 2B, the device 4b has a protruding portion on the abdomen side of the main body portion 4a so as to be easily positioned with respect to the main body portion 4a. It is desirable to remove this protruding portion by processing such as cutting in order to improve aerodynamic performance.

The glass cloth 5 is stuck on the ventral side of the device 4b. The glass cloth 5 is provided so as to cover the notch 4b2. Such a glass cloth 5 is based on, for example, the standard of “JIS R 3414”, has a count and a width of 67.5 tex, a weaving density of 32/25 mm, and a width of 25. / 25 mm, the thickness is 0.16 mm, the mass is 139 g / m ² or more, the tensile strength is 657 or more, the width is 510 or more, and the woven structure is plain weave.

  Next, the results of wind tunnel experiments using different types of blades will be described. In this experiment, an experiment was performed using the blade of the present invention and the first to fifth blades as the blade. The first blade has L / C of 2.3%, the tip thickness of the protrusion 4b1 is 1.2 mm, L / λ is 1.5, and the tip of the protrusion 4b1 has a radius of curvature of 2 mm. A blade including a device having an arc shape. The second blade is a blade having a device in which L / C is changed to 4.3% and L / λ is changed to 2.83 with respect to the first blade. The third blade is a blade in which a mesh material having a significantly lower weaving density than the glass cloth 5 is attached to the second blade instead of the glass cloth 5. The fourth blade is a blade obtained by attaching the glass cloth 5 to the second blade. The fifth blade is a blade obtained by attaching the glass cloth 5 to the first blade.

  FIG. 3A shows experimental results when the wind speed is 50 m / s and the elevation angle is 6 °. FIG. 3B shows the experimental results when the wind speed is 50 m / s and the elevation angle is 10 °. In the graph of FIG. 3, the horizontal axis indicates the frequency, and the vertical axis indicates the difference from the sound pressure level of noise when a device (rectangular device) whose trailing edge side is not thinned is used. In FIG. 3, the graph indicated by the black circle indicates the experimental result using the first blade, the graph indicated by the black triangle indicates the experimental result using the second blade, and the graph indicated by the black square uses the third blade. The graphs indicated by white circles indicate the experimental results using the fourth blade, and the graphs indicated by white triangles indicate the experimental results using the fifth blade.

  As shown in these figures, it can be seen that when the fourth blade is used, the sound pressure level of the noise on the high frequency side is lower than when the second blade is used. In addition, it can be seen that when the fifth blade is used, the sound pressure level of the noise on the high frequency side is lower than when the first blade is used. Therefore, it can be seen that the sound pressure level of the noise on the high frequency side is further lowered by applying the glass cloth 5. This is because the glass cloth 5 reduces the amount of air that passes from the ventral side to the back side of the blade through the cutout portion 4b2, so that the pressure fluctuation pattern in the height direction of the blade has a period corresponding to the position of the cutout portion 4b2. It is considered that the amplitude of the noise is reduced, thereby reducing the noise. When the third blade was used, the noise on the low frequency side was only slightly reduced compared to the case where the second blade was used. For further reduction, it is desirable that the weaving density is high.

  According to the blade 4 and the wind turbine for wind power generation of the present embodiment as described above, the pressure in the height direction of the blade is reduced by reducing the amount of air that flows from the ventral side to the back side of the blade 4 by the glass cloth 5. The amplitude of the fluctuation pattern is reduced, which makes it possible to reduce noise.

  Moreover, the blade 4 of this embodiment uses the glass cloth 5 as a mesh material of this invention. According to the blade 4 of this embodiment, a mesh material with high weaving density can be obtained, and noise can be further reduced.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

  For example, in the above embodiment, an example in which the blade of the present invention is applied to a wind turbine for wind power generation has been described. However, the present invention is not limited to this, and can be applied to general wind turbines for obtaining rotational power, and can also be applied to gas turbine engines.

  Moreover, in the said embodiment, the structure which uses the glass cloth 5 as a mesh material was demonstrated. However, the present invention is not limited to this, and other materials can be used as the mesh material. Even in such a case, although the effect is large or small, noise can be further reduced.

  Moreover, in the said embodiment, the structure which sticks the glass cloth 5 only to the ventral side of the braid | blade 4 was employ | adopted. However, the present invention is not limited to this, and the glass cloth 5 may be attached only to the back side of the blade 4 or the glass cloth 5 may be attached to both the back side and the abdomen side.

  Moreover, the glass cloth 5 may be fixed to the device 4b by embedding a part of the glass cloth 5 in the device 4b, and the glass cloth 5 may be provided only in the notch 4b2.

  DESCRIPTION OF SYMBOLS 1 Windmill for wind power generation, 2 props, 3 rotating shafts, 4 blades, 4a body part, 4a1 rear edge part, 4b device, 4b1 projecting part, 4b2 notch part, 5 glass cloth (mesh material)

Claims (3)

A blade having a cross-sectionally wing-shaped main body, a plurality of protrusions and notches arranged alternately in the blade height direction of the main body, and a device provided at a rear edge of the main body ,
A blade comprising a mesh material provided to cover the notch.   The blade according to claim 1, wherein the mesh material is a glass cloth. A wind turbine for wind power generation having a plurality of blades provided radially with respect to a rotating shaft
A wind turbine for wind power generation, comprising the blade according to claim 1 or 2 as the blade.

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