JP6500346B2 - Blades and wind turbines - Google Patents

Description

  The present invention relates to blades and wind turbines for wind power generation.

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

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

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

  Although a certain noise reduction effect can be obtained by attaching a device having a saw blade shape to the trailing edge side of the blade, the noise of a wind turbine 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-mentioned problems.

  According to a first aspect of the present invention, there is provided a main body having a cross-sectional wing shape, and a device provided with a plurality of protrusions and notches alternately arranged in the wing height direction of the main body at the rear edge of the main body. A blade having a mesh material provided to cover the notch.

  According to a second invention, in the first invention, the mesh material is a glass cloth.

  A third aspect of the present invention is a wind turbine for wind power generation having a plurality of blades provided radially with respect to a rotation axis, and employing a configuration including the blade of the first or second invention as the blade.

  According to the present invention, the mesh material reduces the amount of air coming from the ventral side to the dorsal 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, noise can be further reduced in a blade such as a wind turbine for wind power generation.

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

  An embodiment of a blade and a wind turbine for wind power generation according to the present invention will be described below 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 view of a wind turbine 1 for wind power generation provided with a blade 4 of the present embodiment. The wind turbine 1 for wind power generation includes a support 2 erected on the ground, a rotary shaft 3 attached to the tip of the support, a plurality of blades 4 provided radially with respect to the rotary shaft 3, and a glass cloth 5 (mesh Materials). In addition, the wind turbine 1 for wind power generation includes a generator (not shown) connected to the rotating shaft 3, and transmits power generated by the blade 4 receiving the wind to the generator via the rotating shaft 3. Generate electricity.

  In the following description, the radial direction centering on the rotation axis 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 the upstream, and the rear in the rotational direction is referred to as the downstream.

  FIG. 2 is a schematic view 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 figures, the blade 4 of the present embodiment is configured of a main body 4 a having a wing-shaped cross section and a device 4 b attached to the rear edge 4 a 1 of the main body 4 a.

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

  In addition, as shown in FIG.2 (b), the device 4b has a projection-shaped site | part on the belly side of the main-body part 4a so that it may be easy to position with respect to the main-body part 4a. It is desirable to remove this projecting portion by processing such as cutting in order to improve aerodynamic performance.

The glass cloth 5 is attached to 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", and both the count and weight are 67.5 tex, and the weave density is 32 threads / 25 mm, 25 threads / 25 mm, thickness is 0.16 mm, weight is 139 g / m ² or more, tensile strength is 657 or more, weft 510 or more, and the weave structure is a plain weave.

  Next, the result of conducting a wind tunnel experiment using different types of blades will be described. In this experiment, experiments were 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 curvature radius of 2 mm. It is a blade comprising a device in the form of an arc. The second blade is a blade having a device in which L / C is 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 weave density extremely lower than that of the glass cloth 5 is changed to the glass cloth 5 and attached to the second blade. The fourth blade is a blade in which the glass cloth 5 is attached to the second blade. The fifth blade is a blade in which the glass cloth 5 is attached to the first blade.

  FIG. 3 (a) is an experimental result when the wind speed is 50 m / s and the elevation angle is 6 °. FIG.3 (b) is an experimental result in case the wind speed is 50 m / s and an elevation angle is 10 degrees. In the graph of FIG. 3, the horizontal axis represents frequency, and the vertical axis represents the difference between the noise pressure level and the noise level when using a device (rectangular device) whose trailing edge side is not thinned. 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 indicates the third blade. The result of the experiment is shown, the graph shown by the white circle shows the result of the experiment using the fourth blade, and the graph shown by the white triangle shows the result of the experiment 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 further reduced as compared with the case where the second blade is used. Further, it can be seen that when the fifth blade is used, the sound pressure level of the noise on the high frequency side is further reduced as compared with the case where the first blade is used. Therefore, by sticking the glass cloth 5, it turns out that the sound pressure level of the noise by the side of high frequency is falling further. This is because the glass cloth 5 reduces the amount of air coming from the ventral side to the dorsal side of the blade through the notch portion 4b2, thereby causing a pressure fluctuation pattern in the height direction of the blade having a cycle corresponding to the position of the notch portion 4b2. It is believed that the amplitude of the noise is reduced, thereby reducing the noise. When the third blade is used, the noise on the low frequency side is only slightly reduced compared to the case where the second blade is used, so the sound pressure level of the noise on the high frequency side is In order to further reduce, it is desirable that the weave density be high.

  According to the blade 4 and 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 which falls from the ventral side to the dorsal 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 the present embodiment, a mesh material with high weave density can be obtained, and noise can be further reduced.

  Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above embodiments. The shapes, combinations, and the like of the constituent members shown in the above-described embodiment are merely examples, and various changes can be made based on design requirements and the like without departing from the spirit of the present invention.

  For example, in the said embodiment, the example which applies the braid | blade of this invention to the windmill for wind power generation was demonstrated. However, the present invention is not limited to this, and can be applied to wind turbines in general for obtaining rotational power, and also 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 it is also possible to use other materials as the mesh material. Even in such a case, although the effect is large and small, noise can be further reduced.

  Moreover, in the said embodiment, the structure which affixes the glass cloth 5 only to the belly 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 ventral side.

  Alternatively, 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.

  1 Wind turbine for wind power generation, 2 columns, 3 rotating shafts, 4 blades, 4a main body, 4a1 rear edge, 4b device, 4b1 protrusion, 4b2 notch, 5 glass cloth (mesh material)

Claims (3)

A blade having a main body having a wing shape in cross section, and a plurality of protrusions and notches alternately arranged in the wing height direction of the main body, and a device provided at a rear edge of the main body. ,
It has a mesh material provided covering the entire area of the notch,
The edge of the mesh material connects the tips of the adjacent protrusions in a straight line .   The blade according to claim 1, wherein the mesh material is a glass cloth.   It is a windmill for wind power generation which has a braid | blade provided with multiple radial with respect to the rotating shaft, Comprising: The wind turbine for wind power generation characterized by including the braid | blade of Claim 1 or 2 as said braid | blade.

Images