JP2004137910A - Wind mill for horizontal axis type wind power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wind mill for a horizontal axis type wind power generator, in which a wind speed range where power generation can be performed by increasing rotating torque even in a low wind speed is enlarged, and which can be mass-produced at low cost. <P>SOLUTION: The wind mill for a horizontal axis type wind power generator has a rotating shaft in an approximately wind force direction, and is constituted by radially connecting a plurality of blades to the rotating shaft through a connection member. In the wind mill, wind receiving faces of the blades are formed in such a manner that base end sides thereof are rectangular blade parts of an aspect ratio of 1.5 or more, and delta blade parts of an aspect ratio of 1.5 or less are connected to the outside of the rectangular blade parts. A twist angle of 10 to 20 degrees is set between both side parts of the rectangular blade part, and the delta blade parts is in a flat shape. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wind turbine for a horizontal axis wind power generator having a rotation axis substantially in the direction of wind, and a plurality of blades radially connected to the rotation axis, and more particularly to a wind receiving surface of the blade. The present invention relates to a wind turbine for a horizontal axis wind power generator, in which the shape of a blade is changed to change the aerodynamic properties of the blade, thereby increasing the rotational torque at low wind speeds and expanding the wind speed range in which power can be generated.
[0002]
[Prior art]
Generally, a horizontal axis type windmill used for a wind power generator has a rotation axis in a horizontal direction, that is, a wind direction, so that a natural wind energy can be efficiently used, and a hub fixed to the rotation axis. A plurality of blades are radially connected to a connecting member such as the above, and are used at a high place such as a rooftop. (For example, see Patent Document 1)
[0003]
[Patent Document 1]
JP-A-2000-310179 (page 2, FIG. 6)
[0004]
[Problems to be solved by the invention]
By the way, when wind power is generated, a constant air volume is required, but in Japan there are many mountains and the average annual wind speed in most areas is 10 m / sec or less, and the actual air volume cannot be obtained. It is. This wind speed increases as the height from the ground increases, but installing this wind turbine at a high place requires large-scale equipment and cost.For example, a medium-sized or small horizontal shaft for private residences There was a problem as a windmill for wind turbines.
[0005]
In addition, a horizontal axis type wind turbine having a fixed blade mounting angle (pitch) has a limitation on the maximum number of rotations of the wind turbine, and the range in which effective power generation is possible is limited by the rotational torque generated in the wind turbine. As a result, there is a problem in practical use because the blade is stalled at an effective angle of attack of about 15 degrees and at a low wind speed of 5 m / sec or less and does not effectively generate rotational torque.
[0006]
Therefore, conventionally, in order to cope with such a low speed region, auxiliary blades or auxiliary wings which advance and retreat toward the tip of each blade are built in, and these auxiliary blades or auxiliary wings are extended at low wind speed. There has been proposed a windmill for a horizontal axis type wind generator in which the lift of the wing is increased to increase the rotational torque. (For example, see Patent Document 2)
[0007]
[Patent Document 2]
JP 2001-231615 A (page 1, FIG. 2, FIG. 11)
[0008]
However, when an auxiliary blade or an auxiliary wing is incorporated in each blade main body in this way, the structure of the wind turbine itself becomes complicated and large, and therefore the number of parts and man-hours increase, and the manufacturing cost increases. There was a concern that it would be damaged in the event of a strong wind.
[0009]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to increase the rotational torque and expand the wind speed range in which power can be generated even at a low wind speed, and to mass-produce at low cost. It is another object of the present invention to provide a wind turbine for a horizontal axis type wind power generator.
[0010]
[Means for Solving the Problems]
The object of the present invention is to provide a wind turbine for a horizontal axis wind power generator having a rotating shaft in a direction of substantially wind and connecting a plurality of blades radially to the rotating shaft via a connecting member. The basic shape of the wind receiving surface, the base end side is a rectangular wing portion having an aspect ratio of 1.5 or more, and a delta wing portion having an aspect ratio of 1.5 or less is formed outside the rectangular wing portion, and formed. In addition, this is achieved by setting a twist angle of 10 to 20 degrees between both side portions of the rectangular wing portion and making the delta wing portion a planar shape.
[0011]
Further, the object of the present invention is that the airfoil of the rectangular airfoil has a shape in a range of 20% to 80% of a chord length of a airfoil having a straight line or a high lift coefficient at a low Reynolds number. Is more effectively achieved.
[0012]
Further, the above object of the present invention can be more effectively achieved by setting a mounting angle of 20 degrees to 25 degrees with respect to a plane orthogonal to the rotation axis at the connecting portion of the blade.
[0013]
Still further, the above object of the present invention is more effectively achieved when the blade is formed of an aluminum alloy or a plastic material.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 is a front view of a wind turbine 1 for a horizontal axis type wind power generator according to an embodiment of the present invention, that is, a view as viewed from a wind receiving surface side. As shown in the figure, in the wind turbine 1, a hub 3 is fixed to a rotating shaft 2 arranged substantially in the direction of wind, that is, in a horizontal direction, and a plurality of hubs 3 are connected to the hub 3 via a blade root connecting member 4 (this embodiment). (Four blades) are connected at equal intervals in a radial (radial) direction on a plane orthogonal to the axis of the rotating shaft 2. This blade 5 is rotated in the direction of arrow N by wind power. The rear end of the rotating shaft 2 is connected to the generator via a known means such as a support member (not shown).
[0016]
In this embodiment, the basic planar shape of the blade 5, that is, the basic shape of the wind receiving surface is formed by a rectangular wing portion 5X formed of abcd and efg, as schematically shown in FIG. And a delta wing 5Y. Here, the rectangular wing 5X has an aspect ratio of 1.5 or more, and the delta wing 5Y has an aspect ratio of 1.5 or less. In the drawings, O indicates the axis of the rotating shaft 2.
[0017]
As shown by the solid line in FIG. 2 (B), one end of the rectangular blade portion 5X, that is, the blade root portion 5Xa side is formed in a fan shape, and the central portion thereof is connected to the hub 3 in the form of an elongated plate-shaped blade root connecting member. 4 is fixed by screws 6. On the other hand, the other end of the rectangular wing 5X is connected to the delta wing 5Y at a position where the corner d intersects the approximate middle point of the left inclined side ef of the delta wing 5Y. The connecting portion between the rectangular wing portion 5X and the delta wing portion 5Y and the corners e, f, and g of the delta wing portion 5Y are rounded as shown in the figure, and the overall shape of the blade 5 is modified. I have.
[0018]
In the wind turbine 1, since the wind receiving surface shape of the blade 5 is formed as described above, the effective angle of attack until the wing, especially the delta wing 5Y stalls, becomes as large as 30 to 40 degrees. In some portions, an effective lift can be generated even at a low wind speed of 5 m / sec or less to increase the rotational torque, thereby expanding the wind speed range in which power can be generated.
[0019]
In the wind turbine 1, the rectangular wings 5X and the delta wings 5Y forming the blades 5 are integrally formed by pressing an aluminum alloy plate having a thickness of about 3 to 5 mm. In addition, it is also possible to integrally mold with, for example, a plastic (including FRP) material. As described above, since the blade 5 of the present wind turbine 1 is designed to have a simple structure by using a lightweight material, the blade 5 can be mass-produced at low cost, thereby greatly reducing the manufacturing cost of the present wind turbine 1 itself. be able to.
[0020]
As described above, the blade 5 composed of the rectangular wing portion 5X and the delta wing portion 5Y is, as shown in FIG. 1, arranged in a radial direction on a plane orthogonal to the axis of the rotating shaft 2 via the blade root connecting member 4. The blade roots 5Xa are arranged at intervals and are attached to the hub 3. The blade roots 5Xa are provided at an attachment angle α of 20 to 25 degrees with respect to a plane orthogonal to the rotation shaft 2 in the wind turbine 1. .
[0021]
FIG. 3A is a sectional view taken along the line AA of FIG. 2B showing this state. As shown in the figure, the cross-sectional side end (the inner cross-sectional end of the rectangular wing 5X) of the blade root 5Xa whose ends are indicated by a and b is attached to a plane F orthogonal to the rotation axis 2 by an attachment angle α (20). ° to 25 °>α> 0 °).
[0022]
Further, in the wind turbine 1, a twist angle β of 10 to 20 degrees is formed between the both sides of the rectangular wing 5X, that is, between the short side ab and the short side cd of the rectangular wing 5X shown in FIG. Is set.
[0023]
FIG. 3B is a cross-sectional view taken along the line BB of FIG. 2B showing this state. As shown in the figure, the outer cross-sectional end of the rectangular wing portion 5X whose cross-sectional end is indicated by c and d has a torsion angle β (10 ° to 20 °>β> 0 °) with respect to the mounting angle α of the blade root 5Xa. ).
[0024]
Furthermore, in the wind turbine 1, the airfoil of the rectangular airfoil portion 5X has a low Reynolds number and a high lift coefficient represented by the NACA 4-shaped airfoil, the RAF airfoil, the Göttingen airfoil, and is used for airplanes and the like. It is formed in part of a streamlined airfoil.
[0025]
That is, as shown by the bold line in FIG. 4, the airfoil of the rectangular wing portion 5X is in the range of 20% to 80% of the chord length L from the leading edge G in the streamlined airfoil 6 (see FIG. 4). 4 (indicated by curve L1L2).
[0026]
In addition, with respect to the rectangular wing portion 5X having such an airfoil, the delta wing portion 5Y provided to be connected to the rectangular wing portion 5X is formed in a planar shape. By providing such a delta wing portion 5Y outside the rectangular wing portion 5X, as described above, the effective angle of attack until stall can be increased to 30 to 40 degrees. Even at a low wind speed of not more than / sec, an effective lift can be generated to increase the rotational torque, thereby expanding the wind speed range in which power can be generated.
[0027]
As described above, by setting the attachment angle α to 20 to 25 degrees and the torsion angle β to 10 to 20 degrees with respect to the blade 5, the entire surface of the wind receiving surface of the blade 5 can be effectively used. The generation of lift has been confirmed by experiments performed by the present inventors.
[0028]
As described above, the content of the present invention has been described based on one embodiment. However, the present invention is not necessarily limited to the above-described embodiment, and for example, the configuration can be changed as follows.
[0029]
In the above embodiment, the number of blades is four, but the number is not limited as long as the number is two or more, that is, a plurality of blades. In consideration of the balance from the start of the wind turbine to the rotation thereof, it is desirable to set the number of sheets to an even number.
[0030]
In the above-described embodiment, the airfoil of the rectangular wing portion 5X of the blade has a shape in the range of 20% to 80% of the chord length of the airfoil having a low Reynolds number and a high lift coefficient. It has been confirmed that the same effects as described above can be obtained even with a linear shape.
[0031]
Furthermore, as means for connecting the blade to the rotating shaft, the hub, the connecting member, and the blade may be formed as a single plate or by integral molding or the like, and this may be directly attached to the rotating shaft. It is.
[0032]
【The invention's effect】
As described in detail above, according to the invention relating to the improvement of the wind receiving surface shape and the mounting structure of the blades described in the claims and claims 1 to 3, by changing the aerodynamic property Even at a low wind speed, an effective lift can be generated to increase the rotational torque, and the wind speed range in which power can be generated can be expanded. Therefore, the wind turbine for a horizontal axis type wind power generator according to the present invention can be installed and used in a low place such as a middle / low-rise building or the roof of a private house, and used as a generator for constructing a power saving system. Can be widely used.
[0033]
In particular, since the blade itself can be manufactured in a compact structure using a lightweight material, the blade can be mass-produced at a low cost, thereby reducing the manufacturing cost of the entire wind turbine for a horizontal axis wind power generator. Also, there is no need to worry about damage due to strong winds.
[Brief description of the drawings]
FIG. 1 is a front view of a wind turbine 1 for a horizontal axis type wind power generator according to an embodiment of the present invention.
FIG. 2A is a diagram schematically showing a basic plane shape of a blade 5 in the present embodiment, that is, a basic shape of a wind receiving surface, and FIG. 2B is a diagram showing that the overall shape of the blade 5 is modified. FIG.
3A is a sectional view taken along the line AA in FIG. 2B, and FIG. 3B is a sectional view taken along the line BB in FIG.
FIG. 4 is a view showing the shape of a rectangular wing in the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Horizontal axis type wind turbine (according to the present invention) 2 Rotary shaft 3 Hub 4 Blade connecting member 5 Blade 5X Rectangular wing 5Xa Blade root 5Y Delta wing 6 Streamline airfoil

Claims (4)

In a wind turbine for a horizontal axis wind power generator having a rotating shaft in a direction of substantially wind and connecting a plurality of blades radially to the rotating shaft via a connecting member, a basic shape of a wind receiving surface of the blade The base end side is a rectangular wing part having an aspect ratio of 1.5 or more, and a delta wing part having an aspect ratio of 1.5 or less is formed continuously outside the rectangular wing part. A windmill for a horizontal axis wind power generator, wherein a twist angle of 10 to 20 degrees is set between both side portions and the delta wing portion is formed in a plane shape. The airfoil of the rectangular wing portion has a shape ranging from 20% to 80% of a chord length of a straight or an airfoil having a high lift coefficient at a low Reynolds number. Wind turbine for horizontal axis type wind generator. 3. The horizontal axis type wind power generator according to claim 1, wherein an attachment angle of 20 ° to 25 ° with respect to a plane orthogonal to the rotation axis is set in the connection portion of the blade. 4. Windmill. The windmill for a horizontal axis type wind power generator according to claim 1, wherein the blade is formed of an aluminum alloy or a plastic material.

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