Windmill and wind power plant

Abstract

A windmill (10) includes a shaft (11), a blade (12), and a support member (13). The windmill is rotatable about a central axis (A) of the shaft. The blade has a blade body portion (12a) extending in a direction along the central axis, that is, in an axial direction. The blade body portion includes a leading edge (12aa) which is an end portion on a front side in a direction of rotation of the windmill when viewed in a cross section orthogonal to the axial direction, and a trailing edge (12ab) which is an end portion on a rear side in the direction of rotation. The support member extends in a radial direction orthogonal to the axial direction and passing through the central axis, thereby connecting the shaft and the blade body portion. The support member has a leading end (13a) which is an end portion on a front side in the direction of rotation, and a trailing end (13b) which is an end portion on a rear side in the direction of rotation. A straight line (13c) passing through a middle position between the leading end and the trailing end and parallel to the radial direction intersects a blade chord line (12ac) connecting the leading edge and the trailing edge at a position on a trailing edge side than a midpoint (MP) of the blade chord line.

Description

Technical Field

[0001] This invention relates to a windmill and a wind power generation device. Background Technology

[0002] Japanese Patent Application Publication No. 2011-169292 (Patent Document 1) discloses a vertical wind turbine for wind power generation. The vertical wind turbine described in Patent Document 1 has a rotating body, blades (wings), and a horizontal support arm (support member). The rotating body is capable of rotating about a central axis. The blades have a main portion extending in the direction (axial direction) along the central axis of the rotating body. The support member extends in a direction orthogonal to the axial direction and passing through the central axis of the rotating body (radial direction), thereby connecting the main portion of the blade to the rotating body. The support member is approximately fish-shaped in a cross-section orthogonal to the radial direction.

[0003] Japanese Patent Publication No. 5527783 (Patent Document 2) discloses a rotor for wind power generation. The rotor described in Patent Document 1 has a rotating shaft, blades (wings), and a support platform (support member). The rotating shaft is capable of rotating about a central axis. The blades extend along the direction (axial direction) of the central axis of the rotating shaft. The support member extends along a direction orthogonal to the axial direction and passing through the central axis of the rotating shaft (radial direction), thereby connecting the blades to the rotating shaft. The support member is streamlined in a cross-section orthogonal to the radial direction. Existing technical documents Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2011-169292 Patent Document 2: Japanese Patent No. 5527783 Summary of the Invention The technical problem that the invention aims to solve

[0005] In the windmill described in Patent Document 1 and the rotor described in Patent Document 2, the air resistance of the support member itself is reduced by making its cross-sectional shape approximately fish-shaped or streamlined, thereby improving the rotational energy conversion efficiency. However, in the windmill described in Patent Document 1 and the rotor described in Patent Document 2, the turbulence of airflow at the connection between the support member and the blades is not addressed. Therefore, there is room for improvement in the rotational energy conversion efficiency of the windmill described in Patent Document 1 and the rotor described in Patent Document 2.

[0006] This invention was made in view of the problems of the prior art as described above. More specifically, it provides a windmill and wind power generation device capable of improving the conversion efficiency of rotational energy. Technical solutions adopted to solve technical problems

[0007] The windmill of the present invention includes a shaft, blades, and a support member. The windmill is rotatable about the central axis of the shaft. The blade has a blade body portion extending axially along the direction of the central axis. The blade body portion includes a leading edge at an end on the front side of the direction of rotation (when viewed in cross-section orthogonal to the axial direction) and a trailing edge at an end on the rear side of the direction of rotation of the windmill. The support member extends radially along a direction orthogonal to the axial direction and passing through the central axis, thereby connecting the shaft to the blade body portion. The support member has a front end at the front side of the direction of rotation and a rear end at the rear side of the direction of rotation. A straight line passing through the midpoint between the front and rear ends and parallel to the radial direction intersects the blade chord line at a position further towards the trailing edge than the midpoint of the blade chord line connecting the leading and trailing edges.

[0008] In the aforementioned windmill, the front end of the end located on the side of the blade body is positioned further from the trailing edge than the position at a distance of 2 / 3 of the blade chord length from the trailing edge.

[0009] In the aforementioned windmill, the straight line passing through the middle of the front and rear ends and parallel to the radial direction can form an angle of less than 90° with the blade chord.

[0010] In the aforementioned windmill, the leading edge of the end located on the side of the blade body can also be positioned further along the trailing edge than the center of gravity of the blade body in the direction of the blade chord.

[0011] The wind power generation device of the present invention includes the windmill described above and a generator that generates electricity by rotating about the central axis of the windmill. Invention Effects

[0012] The windmill and wind power generation device according to the present invention can improve the rotational energy conversion efficiency. Attached Figure Description

[0013] Figure 1 This is the front view of the wind power generation device 100. Figure 2 yes Figure 1 Sectional view at I II I. Figure 3 This is a schematic diagram showing the relationship between the azimuth angle of the blade body 12a and the wind direction. Figure 4 This is a schematic graph showing the relationship between the rotation time of the wind turbine 10 and the rotational torque applied to the wind turbine 10 when there are two blades 12. Figure 5 This is a cross-sectional view of a wind power generation device 200. Detailed Implementation

[0014] The embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following drawings, the same or equivalent parts are labeled with the same reference numerals, and the descriptions are not repeated.

[0015] (Structure of the wind power generation device according to the embodiment) The structure of the wind power generation device (hereinafter referred to as "wind power generation device 100") according to the first embodiment will be described.

[0016] Figure 1 This is a front view of the wind power generation device 100. (Example) Figure 1 As shown, the wind power generation device 100 includes a windmill 10 and a generator 20. The generator 20 generates electricity by rotating the windmill 10 about a central axis A (described later). The wind power generation device 100 is mounted at a high position on a support column (not shown).

[0017] Windmill 10 is a vertical axis windmill (vertical windmill). Windmill 10 has a shaft 11, blades 12, and a support 13. The central axis of shaft 11 is designated as central axis A. The direction of central axis A is designated as axial. The direction orthogonal to the axial direction and passing through central axis A is designated as radial. Windmill 10 is capable of rotating about central axis A. Figure 1 In the example shown, the windmill 10 has two blades 12 arranged symmetrically with respect to the central axis A. However, the number of blades 12 is not limited to this.

[0018] Shaft 11 extends axially. Shaft 11 is rotatable about central axis A. Blade 12 has blade body portion 12a, blade tip inclined portion 12b, and blade tip inclined portion 12c. Blade body portion 12a extends axially. Figure 2 yes Figure 1 A sectional view at point I II I. (See image below.) Figure 2 As shown, the blade body 12a is, for example, in a cross-sectional view orthogonal to the axial direction, in a lift-shaped form.

[0019] In a cross-sectional view orthogonal to the axial direction, the blade body 12a has a leading edge 12aa and a trailing edge 12ab. The leading edge 12aa is located in the direction of rotation of the wind turbine 10. Figure 2 The leading edge 12aa is the end of the blade body 12a on the front side (indicated by the arrow). The trailing edge 12ab is the end of the blade body 12a on the rear side in the direction of rotation of the wind turbine 10. The imaginary line connecting the leading edge 12aa and the trailing edge 12ab is defined as the blade chord line 12ac. The direction of the blade chord line 12ac is defined as the blade chord direction.

[0020] The point on the blade chord line 12ac, located midway between the leading edge 12aa and the trailing edge 12ab, is designated as the midpoint MP. The distance between the midpoint MP in the blade chord direction and the leading edge 12aa is equal to the distance between the midpoint MP in the blade chord direction and the trailing edge 12ab.

[0021] The center of gravity of the blade body 12a, viewed in a cross-section orthogonal to the axial direction, is designated as the center of gravity position GP. The width of the blade body 12a in a direction orthogonal to the blade chord direction is greatest at the leading edge 12aa and decreases towards the trailing edge 12ab. Therefore, the center of gravity position GP is located further towards the leading edge 12aa in the blade chord direction than the intermediate position MP. The center of gravity position GP may or may not be located on the blade chord line 12ac. Furthermore, Figure 2 An example is shown where the center of gravity GP is located on the blade chord 12ac.

[0022] Position P is defined as the point on the blade chord direction where the distance from the trailing edge 12ab is 2 / 3 of the blade chord length (the length of the blade chord line 12ac). Position P is also located on the blade chord direction further from the leading edge 12aa than the intermediate position MP and the center of gravity position GP.

[0023] The blade body 12a has an inner surface 12ad and an outer surface 12ae. The inner surface 12ad is the surface of the blade body 12a facing the central axis A (radially inward). The outer surface 12ae is the surface of the blade body 12a facing the side opposite to the central axis A (radially outward). From another viewpoint, the outer surface 12ae is the radially opposite surface to the inner surface 12ad.

[0024] like Figure 1 As shown, 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.

[0025] Support member 13 extends radially. Support member 13 extends radially, thereby connecting shaft 11 to blade 12 (blade body 12a). Support member 13 is connected to the inner surface 12ad side of blade body 12a. Figure 2As shown, in a top view (when viewed axially), the support member 13 has a front end 13a and a rear end 13b. The front end 13a is the end of the support member 13 located on the front side in the rotation direction of the windmill 10. The rear end 13b is the end of the support member 13 located on the rear side in the rotation direction of the windmill 10.

[0026] A straight line passing through the midpoint between the front end 13a and the rear end 13b, and parallel to the radial direction, is designated as line 13c. Line 13c intersects the blade chord 12ac at point CP. Point CP is located in the blade chord direction further from the trailing edge 12ab than the midpoint MP. An angle θ is formed between line 13c and the blade chord 12ac. Angle θ is, for example, less than 90°.

[0027] The front end 13a of the end portion of the blade body 12a on the support member 13 is located further toward the trailing edge 12ab in the blade chord direction than position P. Preferably, the front end 13a of the end portion of the blade body 12a on the support member 13 is located further toward the trailing edge 12ab in the blade chord direction than the center of gravity position GP.

[0028] Although not shown in the figure, when viewed in a cross-sectional view orthogonal to the radial direction, the support member 13 is formed in a smooth shape such as a streamline or ellipse.

[0029] Figure 3 This is a schematic diagram showing the relationship between the azimuth angle of the blade body 12a and the wind direction. When the wind direction is rotated 90° relative to the direction from the trailing edge 12ab towards the leading edge 12aa, the azimuth angle of the blade body 12a is 0°. Figure 3 In the example, regarding the azimuth angle of the blade body 12a, the azimuth angle of the blade body 12a increases as the windmill 10 rotates counterclockwise, and the azimuth angle of the blade body 12a returns to 0° when the windmill 10 rotates one revolution.

[0030] Figure 4 This is a schematic graph showing the relationship between the rotation time of the wind turbine 10 and the rotational torque applied to the wind turbine 10 when there are two blades (12). Figure 4 As shown, the rotational torque applied to the wind turbine 10 is at its maximum when the azimuth angle of the blade body 12a is near 0°.

[0031] (Effects of the wind power generation device according to the implementation method) The effects of the wind power generation device 100 will be described below in comparison with a comparative example wind power generation device (hereinafter referred to as "wind power generation device 200").

[0032] The wind power generation device 200 has a wind turbine 10 and a generator 20. Figure 5 This is a cross-sectional view of a wind power generation device 200. Figure 5 It shows the relationship with Figure 1 The cross-section at the position corresponding to I, II, and I in the diagram. For example... Figure 5 As shown, in the wind power generation device 200, the wind turbine 10 has a shaft 11 (in Figure 5 (Not shown in the figure), blade 12 and support 13. Regarding these points, the structure of the wind power generation device 200 is the same as that of the wind power generation device 100.

[0033] However, in the wind power generation device 200, the center of gravity GP is located on the straight line 13c. That is, in the wind power generation device 200, the intersection CP of the straight line 13c and the blade chord line 12ac is located further towards the leading edge 12aa than the middle position MP. In this respect, the structure of the wind power generation device 200 differs from that of the wind power generation device 100. Furthermore, in the wind power generation device 200, the straight line 13c and the blade chord line 12ac, for example, form a right angle.

[0034] In the wind power generation device 200, since the center of gravity GP is located on the straight line 13c, the centrifugal force applied to the blade 12 (blade body 12a) can be easily supported by the support member 13. However, in the wind power generation device 200, there is still room for improvement in the conversion efficiency of rotational energy.

[0035] More specifically, the rotational force of the windmill 10 is mainly generated around the inner side 12ad near the leading edge 12aa. Figure 5 The area indicated by the dashed line (hereinafter referred to as the "negative pressure generation area") generates negative pressure. In the wind power generation device 200, since the support member 13 is connected to the blade body 12a with the center of gravity GP located on the straight line 13c, the connection between the support member 13 and the blade body 12a is close to the negative pressure generation area. Turbulence in the airflow is easily generated at the connection between the support member 13 and the blade body 12a. As a result of the interference between this turbulence and the airflow flowing in the negative pressure generation area, the airflow flowing in the negative pressure generation area is separated from the inner surface 12ad, and the rotational force of the wind turbine 10 is reduced.

[0036] On the other hand, in the wind power generation device 100, since the intersection point CP of the straight line 13c and the blade chord line 12ac is located further along the trailing edge 12ab than the middle position MP, the connection between the support member 13 and the blade body 12a can be moved away from the negative pressure generation area, and the turbulence of the airflow generated at the connection between the support member 13 and the blade body 12a is less likely to interfere with the negative pressure generation area. Thus, according to the wind power generation device 100, the reduction in the rotational force of the wind turbine 10 caused by the turbulence of the airflow generated at the connection between the support member 13 and the blade body 12a can be suppressed, thereby improving the rotational energy conversion efficiency.

[0037] When the front end 13a of the support member 13 located on the blade body 12a side in the wind power generation device 100 is located on the trailing edge 12ab side in the blade chord direction, it is possible to further move the connection between the support member 13 and the blade body 12a away from the negative pressure generation area, thereby further improving the conversion efficiency of rotational energy.

[0038] When the angle (angle θ) between the straight line 13c in the wind power generation device 100 and the blade chord 12ac is less than 90°, the rotational trajectories of the leading edge 12aa and the trailing edge 12ab can be arranged on the same diameter. Therefore, the projected area when viewed from the side of the blade body 12a is reduced. Thus, in this case, the rotational drag of the wind turbine 10 can be reduced, and the rotational energy conversion efficiency can be improved.

[0039] As described above, embodiments of the present invention have been presented, but various modifications can be made to these embodiments. Furthermore, the scope of the present invention is not limited to the above embodiments. The scope of the present invention is defined by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims. Industrial availability

[0040] The above-described embodiments are particularly advantageous for use with vertical axis wind turbines and wind power generation devices having vertical axis wind turbines. Symbol Explanation

[0041] 10 Windmill, 11 Shaft, 12 Blade, 12a Blade Body, 12aa Leading Edge, 12ab Trailing Edge, 12ad Inner Surface, 12ae Outer Surface, 12b Blade Tip Inclined Part, 12c Blade Tip Inclined Part, 13 Support Component, 13a Front End, 13b Rear End, 13c Straight Line, 20 Generator, 100, 200 Wind Power Generation Unit, A Central Axis, CP Intersection, GP Center of Gravity Position, MP Middle Position, P Position.

Claims

1. A windmill, comprising a shaft, blades, and support components, The windmill is capable of rotating about the central axis of the shaft, and the blades have blade body portions extending axially along the direction of the central axis. The blade body includes a leading edge at the front side of the windmill in the direction of rotation, and a trailing edge at the rear side of the windmill in the direction of rotation, when viewed in a cross-sectional view orthogonal to the axial direction. The support member extends radially along a direction orthogonal to the axial direction and passing through the central axis, thereby connecting the shaft to the blade body. The support member has a front end (i.e., a front end) in the direction of rotation and a rear end (i.e., a rear end) in the direction of rotation. A straight line passing through the midpoint between the front and rear ends and parallel to the radial direction intersects the blade chord line at a position closer to the trailing edge than the midpoint of the blade chord line, the blade chord line connecting the front and rear edges. The rear end located at the end of the blade body is positioned closer to the leading edge than the trailing edge in the direction of the blade chord.

2. The windmill as described in claim 1, characterized in that, The front end of the end located on the side of the blade body is positioned further from the trailing edge than a position at a distance of 2 / 3 of the length of the blade chord in the direction of the blade chord.

3. The windmill as described in claim 1, characterized in that, The straight line forms an angle of less than 90° with the blade chord.

4. The windmill as described in claim 1, characterized in that, The front end of the end located on the side of the blade body is positioned further toward the trailing edge than the center of gravity of the blade body in the direction of the blade chord.

5. A wind power generation device, comprising: The windmill according to any one of claims 1 to 4; as well as A generator that generates electricity by rotating about the central axis of the windmill.

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