JP2023115519A - Windmill and wind power generating device - Google Patents

Abstract

To provide a windmill which can improve the conversion efficiency of rotational energy.SOLUTION: A windmill comprises a shaft, a blade and a support material. The windmill is rotatable around a center axis of the shaft. The blade has a blade main body part extending along an axial direction being a direction of the center axis. The blade main body part includes a front edge being an end of a front side in a rotation direction of the windmill, and a rear edge being an end of a rear side in the rotation direction in a cross-sectional view perpendicular to the axial direction. The support material connects the shaft and the blade main body part. The support material has a front end being an end of a front side in the rotation direction, and a rear end being an end of a rear side in the rotation direction. A linear line passing an intermediate point between the front end and the rear end, and parallel with an extension direction of the support material intersects with a blade chord line at the rear edge side rather than a center point of the blade chord line which connects the front edge and the rear edge.SELECTED DRAWING: Figure 1

Description

The present invention relates to wind turbines and wind turbine generators.

Japanese Patent Laying-Open No. 2011-169292 (Patent Document 1) describes a vertical wind turbine for wind power generation. The vertical wind turbine described in Patent Document 1 has a rotor, blades (wings), and horizontal support arms (support members). The rotating body is rotatable around the central axis. The blade has a main portion extending along the direction of the central axis of the rotating body (axial direction). The support member connects the main portion of the blade and the rotor by extending along a direction (radial direction) perpendicular to the axial direction and passing through the central axis of the rotor. The support is generally fish-shaped in cross-section perpendicular to the radial direction.

Japanese Patent No. 5527783 (Patent Document 2) describes a rotor for wind power generation. The rotor described in Patent Literature 1 has a rotating shaft, blades (wings), and supports (supporting members). The rotary shaft is rotatable around the central axis. The blade extends along the central axis direction (axial direction) of the rotating shaft. The support member connects the blade and the rotating shaft by extending along a direction (radial direction) perpendicular to the axial direction and passing through the central axis of the rotating shaft. The support is streamlined in cross-section perpendicular to the radial direction.

JP 2011-169292 A Japanese Patent No. 5527783

In the wind turbine described in Patent Document 1 and the rotor described in Patent Document 2, the cross-sectional shape of the support material perpendicular to the radial direction is substantially fish-shaped or streamlined, thereby reducing the air resistance of the support material itself. thus improving the rotational energy conversion efficiency. However, in the wind turbine described in Patent Document 1 and the rotor described in Patent Document 2, attention is not paid to the turbulence of the airflow at the connecting portion between the supporting member and the blade. Therefore, the wind turbine described in Patent Document 1 and the rotor described in Patent Document 2 have room for improvement in rotational energy conversion efficiency.

The present invention has been made in view of the problems of the prior art as described above. More specifically, the present invention provides a wind turbine and a wind turbine generator capable of improving rotational energy conversion efficiency.

The wind turbine of the present invention comprises a shaft, blades and supports. The windmill is rotatable around the central axis of the shaft. The wing has a wing body extending along an axial direction, which is the direction of the central axis. In a cross-sectional view perpendicular to the axial direction, the blade main body includes a front edge that is the front end in the rotation direction of the wind turbine and a rear edge that is the rear end in the rotation direction. A support connects the shaft and the wing body. The support has a front end, which is the forward end in the rotational direction, and a rear end, which is the rearward end in the rotational direction. A straight line passing through the midpoint between the leading edge and the trailing edge and parallel to the direction of extension of the support material intersects the chord line on the trailing edge side of the midpoint of the chord line connecting the leading edge and the trailing edge. ing. The support member has a first portion that is an end on the wing main body side and a second portion that extends from the first portion toward the center axis side. The leading edge of the first portion is, in the direction of the chord line, on the trailing edge side of the distance from the trailing edge that is 2/3 of the length of the chord line. The boundary between the first portion and the second portion is inside a circle centered on the central axis and passing through the front end connected to the wing body.

In the wind turbine described above, the boundary between the first portion and the second portion may pass through an intermediate position between the front end and the rear end and may be orthogonal to a straight line parallel to the extending direction of the support member.

A wind turbine generator according to the present invention includes the windmill described above and a generator that generates power by rotating the windmill about its central axis.

According to the windmill and wind power generator of the present invention, the rotational energy conversion efficiency can be improved.

1 is a front view of a wind turbine generator 100; FIG. FIG. 2 is a cross-sectional view along II-II in FIG. 1; 4 is a schematic diagram showing the relationship between the azimuth angle of the blade main body 12a and the wind direction. FIG. 5 is a schematic graph showing the relationship between the rotation time of the wind turbine 10 and the rotation torque applied to the wind turbine 10 when there are two blades 12; 2 is a cross-sectional view of the wind turbine generator 200. FIG. 4 is a graph showing the relationship between the circumferential speed ratio in the wind power generator 100 and the output increase rate of the wind turbine 10. FIG.

Details of embodiments of the present invention will be described with reference to the drawings. In the drawings below, the same or corresponding parts are denoted by the same reference numerals, and redundant description will not be repeated. The wind power generator according to the embodiment is referred to as a wind power generator 100 .

(Configuration of wind turbine generator 100)
The configuration of the wind turbine generator 100 will be described below.

FIG. 1 is a front view of the wind turbine generator 100. FIG. As shown in FIG. 1 , the wind turbine generator 100 has a windmill 10 and a generator 20 . The generator 20 generates power as the wind turbine 10 rotates around a central axis A, which will be described later. The wind turbine generator 100 is installed at a high place by being mounted on a pillar (not shown).

The wind turbine 10 is a vertical axis wind turbine (vertical wind turbine). The windmill 10 has a shaft 11 , blades 12 and supports 13 . Let the central axis of the shaft 11 be central axis A. As shown in FIG. Let the direction of the central axis A be the axial direction. A direction orthogonal to the axial direction and passing through the central axis A is defined as a radial direction. The windmill 10 is rotatable around a central axis A. In the example shown in FIG. 1, the wind turbine 10 has two blades 12 arranged symmetrically with respect to the central axis A. As shown in FIG. However, the number of blades 12 is not limited to this.

The shaft 11 extends axially. The shaft 11 is rotatable around the central axis A. In the example shown in FIG. 1, the blade 12 has a blade body portion 12a, a blade tip slope portion 12b, and a blade tip slope portion 12c. However, the shape of the end portion of the blade 12 is not limited to the inclined blade tip portion 12b and the inclined blade tip portion 12c, and may be other shapes. The wing body portion 12a extends along the axial direction. FIG. 2 is a cross-sectional view along II-II in FIG. As shown in FIG. 2, the wing main body 12a has a lift shape, for example, in a cross-sectional view perpendicular to the axial direction.

In a cross-sectional view perpendicular to the axial direction, the blade main body 12a has a leading edge 12aa and a trailing edge 12ab. The leading edge 12aa is the end of the blade body 12a on the forward side in the direction of rotation of the wind turbine 10 (indicated by the arrow in FIG. 2). The trailing edge 12ab is the end of the blade main body 12a on the rear side in the rotation direction of the wind turbine 10 . A virtual line connecting the leading edge 12aa and the trailing edge 12ab is defined as a chord line 12ac. The direction of the chord line 12ac is defined as the chord direction.

A point on the chord line 12ac at an intermediate position between the leading edge 12aa and the trailing edge 12ab is defined as an intermediate position MP. The chordwise distance between the intermediate position MP and the leading edge 12aa is equal to the distance between the chordwise intermediate position MP and the trailing edge 12ab. A position P1 is a position where the distance from the trailing edge 12ab in the chord direction is 2/3 of the chord length (the length of the chord line 12ac). The position P1 is closer to the leading edge 12aa than the intermediate position MP in the chord direction.

The wing body portion 12a has an inner side surface 12ad and an outer side surface 12ae. The inner side surface 12ad is a surface of the surface of the blade main body 12a facing the central axis A side (radially inward). The outer side surface 12ae is a surface of the surface of the blade main body 12a facing the opposite side (radially outward) of the central axis A. From another point of view, the outer surface 12ae is the opposite surface of the inner surface 12ad in the radial direction.

In the example of FIG. 1, the blade tip inclined portion 12b is connected to one axial end (upper end) of the blade body portion 12a. The blade tip inclined portion 12b extends upward from the upper end of the blade body portion 12a while being inclined radially inward. The blade tip inclined portion 12c is connected to the other axial end (lower end) of the blade body portion 12a. The blade tip inclined portion 12c extends downward from the lower end of the blade body portion 12a while being inclined radially inward.

The support member 13 extends along the radial direction. The support member 13 may extend along the radial direction when viewed from a direction parallel to the axial direction, and may be inclined with respect to a plane orthogonal to the axial direction. A support member 13 connects the shaft 11 and the blade 12 (the blade body 12a). The support member 13 is connected to the inner side surface 12ad side of the blade body portion 12a. As shown in FIG. 2, the support member 13 has a front end 13a and a rear end 13b in plan view (when viewed along the axial direction). The front end 13 a is the end of the support member 13 on the front side in the rotation direction of the wind turbine 10 . The rear end 13b is the end of the support member 13 on the rear side in the rotation direction of the wind turbine 10 .

An imaginary straight line passing through the intermediate position between the front end 13a and the rear end 13b and parallel to the extending direction of the support member 13 is defined as a straight line 13c. The straight line 13c and the chord line 12ac intersect at the intersection point CP. The intersection CP is closer to the trailing edge 12ab than the intermediate position MP in the chord direction. The straight line 13c forms an angle θ with the chord line 12ac. Angle θ is, for example, less than 90°.

The support member 13 has a first portion 13d and a second portion 13e. The first portion 13d is the end of the support member 13 connected to the wing main body 12a. The second portion 13e extends toward the central axis A from the first portion 13d. The width of the second portion 13e in the direction perpendicular to the extending direction of the support member 13 is greater than the width of the first portion 13d in the direction perpendicular to the extending direction of the support member 13. As shown in FIG. A boundary between the first portion 13d and the second portion 13e is defined as a boundary 13f. Boundary 13f is preferably orthogonal to straight line 13c.

The front end 13a in the first portion 13d is closer to the trailing edge 12ab than the position P1 in the chord direction. The position of the front end 13a connected to the blade main body 12a is defined as position P2. A circle C is defined as the trajectory of the position P2 along with the rotation of the wind turbine 10, that is, the circle passing through the position P2 and having the central axis A as its center. The boundary 13f is inside the circle C. Boundary 13f is preferably orthogonal to straight line 13c.

Although not shown, in a cross-sectional view perpendicular to the extending direction of the support member 13, the support member 13 preferably has a smooth shape such as a streamlined shape or an elliptical shape.

FIG. 3 is a schematic diagram showing the relationship between the azimuth angle of the blade body 12a and the wind direction. The azimuth angle of the blade main body 12a is 0° when the wind direction is rotated 90° with respect to the direction from the trailing edge 12ab toward the leading edge 12aa. In the example of FIG. 3, the azimuth angle of the blade body 12a increases as the wind turbine 10 rotates counterclockwise. The azimuth angle returns to 0°.

FIG. 4 is a schematic graph showing the relationship between the rotation time of the wind turbine 10 and the rotation torque applied to the wind turbine 10 when the number of blades 12 is two. As shown in FIG. 4, the rotational torque applied to the wind turbine 10 becomes maximum when the azimuth angle of the blade body 12a is near 0°.

(Effect of wind turbine generator 100)
The effect of the wind power generator 100 will be described below in comparison with the wind power generator according to the comparative example. A wind turbine generator according to a comparative example is referred to as a wind turbine generator 200 .

FIG. 5 is a cross-sectional view of the wind turbine generator 200. As shown in FIG. FIG. 5 shows a cross section of the wind turbine generator 200 at a position corresponding to II-II in FIG. As shown in FIG. 5, in the wind turbine generator 200, the boundary 13f is outside the circle C. As shown in FIG. Except for this point, the configuration of the wind turbine generator 200 is common to the configuration of the wind turbine generator 100 .

What produces the rotational force of the wind turbine 10 is the negative pressure generated mainly around the inner side surface 12ad (hereinafter referred to as the "negative pressure generation area") near the front edge 12aa. When the position of the connecting portion between the support member 13 and the blade main body portion 12a is close to the negative pressure generation region, the airflow turbulence is likely to occur at the connecting portion between the support member 13 and the blade main body portion 12a. As a result of this airflow turbulence interfering with the airflow flowing in the negative pressure generating region, the airflow flowing in the negative pressure generating region is separated from the inner surface 12ad, and the rotational force of the wind turbine 10 is reduced.

In the wind turbine generator 100 and the wind turbine generator 200, the intersection point CP between the straight line 13c and the chord line 12ac is closer to the trailing edge 12ab than the intermediate position MP. In the wind turbine generator 100 and the wind turbine generator 200, the front end 13a of the first portion 13d is closer to the trailing edge 12ab than the position P1 in the chord direction. Therefore, in the wind turbine generator 100 and the wind turbine generator 200, the connecting portion between the support member 13 and the blade main body portion 12a can be separated from the negative pressure generation region, and the negative pressure generated at the connecting portion between the support member 13 and the blade main body portion 12a can be separated. The turbulence of the airflow that occurs is less likely to interfere with the negative pressure generation area.

However, in the wind turbine generator 200, since the boundary 13f is outside the circle C, separation of the airflow is likely to occur at the boundary 13f. On the other hand, in the wind turbine generator 100, since the boundary 13f is located inside the circle C, the negative pressure gradient suppresses the separation of the airflow (the separation position of the airflow is closer to the trailing edge 12ab than in the wind turbine generator 200). ), making it more difficult for turbulent airflow to interfere with the negative pressure generation area. Therefore, according to the wind power generator 100, compared with the wind power generator 200, the rotational energy conversion efficiency can be improved. When the boundary 13f is orthogonal to the straight line 13c, manufacturing of the wind turbine 10 is facilitated. More specifically, in this case, it is possible to facilitate management of the angle of the blade 12 with respect to the support member 13, improve the ease of assembly of the wind turbine 10, and improve the weldability of the support member 13 to the blade 12.

(Example)
FIG. 6 is a graph showing the relationship between the circumferential speed ratio in the wind turbine generator 100 and the output increase rate of the wind turbine 10. As shown in FIG. The horizontal axis in FIG. 6 is the peripheral speed of the wind turbine 10, and the vertical axis in FIG. The peripheral speed ratio of the windmill 10 is ω×R/V, where ω (unit: s ⁻¹ ) is the angular velocity of the windmill 10, R (unit: m) is the radius of the windmill 10, and V (unit: m) is the wind speed. becomes. If the rotation speed of the windmill 10 is n (unit: rps), the peripheral speed ratio of the windmill 10 is 2π×R×n/V.

The output increase rate of the wind turbine 10 in the wind turbine generator 100 is obtained by dividing the difference between the output of the wind turbine 10 in the wind turbine generator 100 and the output of the wind turbine 10 in the wind turbine generator 200 by the output of the wind turbine 10 in the wind turbine generator 200. It is a value multiplied by 100.

As shown in FIG. 6 , the output of the wind turbine 10 in the wind turbine generator 100 exceeded the output of the wind turbine 10 in the wind turbine generator 200 at any peripheral speed ratio. From this, it has been experimentally clarified that the wind turbine generator 100 can improve the rotational energy conversion efficiency.

Although the embodiment of the present invention has been described as above, it is also possible to modify the above-described embodiment in various ways. Also, the scope of the present invention is not limited to the embodiments described above. The scope of the present invention is indicated by the scope of claims, and is intended to include all changes within the meaning and scope of equivalence to the scope of claims.

The above embodiments are particularly advantageously applied to vertical axis wind turbines and wind power installations with vertical axis wind turbines.

100 wind turbine generator 10 wind turbine 11 shaft 12 blade 12a blade main body 12aa leading edge 12ab trailing edge 12ad inner surface 12ae outer surface 12b, 12c blade tip inclined portion 13 support member 13a front end 13b back end, 13c straight line, 13d first part, 13e second part, 13f boundary, 20 generator, 200 wind turbine generator, A central axis, C circle, CP intersection point, MP intermediate position, P1, P2 position.

Claims (3)

a windmill,
comprising a shaft, wings and a support,
The windmill is rotatable around the central axis of the shaft,
The blade has a blade body extending along an axial direction that is the direction of the central axis,
In a cross-sectional view orthogonal to the axial direction, the blade main body includes a leading edge that is a front end in the rotation direction of the wind turbine and a rear edge that is a rear end in the rotation direction,
The support member connects the shaft and the blade body,
The support member has a front end that is a front end in the rotation direction and a rear end that is a rear end in the rotation direction,
A straight line passing through an intermediate position between the front end and the rear end and parallel to the extending direction of the support member is on the trailing edge side of the midpoint of the chord line connecting the leading edge and the trailing edge. intersecting the chord line,
The support member has a first portion that is an end on the wing main body side and a second portion that extends from the first portion toward the central axis,
the leading edge of the first portion being in the direction of the chord line, on the trailing edge side of a distance from the trailing edge of two-thirds of the length of the chord line;
A wind turbine in which a boundary between the first portion and the second portion is inside a circle centered on the central axis and passing through the front end connected to the blade main body. The wind turbine according to claim 1, wherein said boundary is orthogonal to said straight line. The wind turbine according to claim 1 or claim 2;
and a generator that generates power by rotating the wind turbine around the central axis.

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