JP2018150898A - Vertical shaft windmill, its blade, and wind power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical shaft windmill improved in rotational energy conversion efficiency by suppressing separation of air current on rotary inner peripheral faces of blades.SOLUTION: A vertical shaft wind mill includes a vertical main shaft rotatably disposed, a support body disposed on the vertical main shaft, and blades 9 connected to the vertical main shaft through the support body and rotated by receiving wind. In a cross-sectional shape of the blades 9, radial outer faces or inner faces to a rotation center of the blades 9 are gradually expanded to a radial outer side or inner side from front and back both ends in a rotation advancing direction, and an expansion amount is maximum at a part near a front end in the rotation advancing direction. Serration 15 in which crest portions 16 projecting to a rear side in the rotation advancing direction and retreated trough portions 17 are alternately arranged, is formed on rear edges in the rotation advancing direction of the blades 9.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a vertical axis wind turbine having a vertical main shaft, its blades, and a wind turbine generator including the vertical axis wind turbine.

  The wind turbines used in the wind turbine generator include a horizontal axis wind turbine in which horizontal blades around the axis of the main shaft provided horizontally rotate, and a vertical axis wind turbine in which vertical blades rotate around the axis of the main shaft provided vertically. (For example, Patent Document 1). In both types, in the case of a system in which a blade is rotated by lift, the cross-sectional shape of the blade is an airfoil as shown in FIG. When the wing 9 receives wind, a difference occurs between the flow velocity of the wind flowing along the bulging surface 22 and the flow velocity of the wind flowing along the opposite surface 23, and the difference between the flow velocity becomes a pressure difference and lift is generated. To do.

  However, it is known that in the streamlined wing, the air flow is separated on the opposite surface 23 side, and a vortex is generated. This vortex is called a separation vortex and causes a stall. In the horizontal axis wind turbine, for the purpose of preventing the generation of the separation vortex, it has been proposed to form a serration in which a peak and a valley are arranged at the trailing edge of the blade (for example, Patent Document 2).

JP 2004-204801 A JP 2003-336572 A

  Vertical axis wind turbines are being developed as relatively small wind turbines because rotational force can be obtained regardless of the wind direction and control over the wind direction is unnecessary. However, the vertical axis wind turbine has the following problems to be solved.

In general, in the case of a horizontal axis wind turbine, if the wind speed and direction are constant and the blade rotation speed is constant, the wind inflow angle and the relative inflow speed of the blade do not change during one rotation of the blade. For this reason, there is no change in the airflow flowing along the wing, and the rotational energy conversion efficiency is not affected.
On the other hand, in the vertical axis wind turbine, even if the wind speed and direction are constant and the rotation speed of the blade is constant, the wind inflow angle and the relative inflow speed of the blade greatly change during one rotation of the blade. For this reason, the airflow flowing along the blades peels and adheres during one rotation. In other words, the separation of the air current adversely affects the rotational energy conversion efficiency for converting the wind energy into the rotational energy of the blades. In particular, the airflow tends to peel off at the trailing edge of the blade at a low wind speed with a slow relative inflow speed, at a low rotation speed, or at startup. For this reason, even if the wind blows, it takes time until the rotational speed reaches a predetermined rotational speed for generating torque, resulting in poor rotational energy conversion efficiency.

An object of the present invention is to provide a vertical axis windmill with good rotational energy conversion efficiency by suppressing separation of airflow on the rotating inner peripheral surface of a blade in order to solve the above-mentioned problems peculiar to the vertical axis windmill. That is.
Another object of the present invention is to provide a blade of a vertical axis wind turbine that improves the rotational energy conversion efficiency when used in a vertical axis wind turbine by suppressing the occurrence of air flow separation.
Still another object of the present invention is to provide a wind power generator having good power generation efficiency.

A vertical axis wind turbine according to the present invention includes a vertical main shaft that is rotatably provided, a support provided on the vertical main shaft, and an axial center of the vertical main shaft that is connected to the vertical main shaft via the support and receives wind. And wings rotating around
The cross-sectional shape of the wing is such that the radially outer surface or inner surface with respect to the rotation center of the wing gradually bulges from the front and rear ends in the direction of rotation of the wing toward the outer or inner side in the radial direction. It is the largest shape near the front end in the direction of travel,
A serration is formed on the trailing edge of the wing in the rotational direction in which the ridges protruding from the rear side in the rotational direction and the valleys receding are alternately arranged.

  According to this configuration, since the wing has the above-described cross-sectional shape, lift is generated when the wing receives wind, and the wing rotates around the axis of the vertical main shaft by this lift. In the case of a vertical axis windmill, one of the causes of the stalling of rotation is separation of the airflow from the blade surface. In this configuration, since the serration is formed at the trailing edge of the blade rotation direction, the radial airflow is faster than the inner surface along the outer surface at the rear end of the blade in the radial direction with respect to the rotation center of the blade. The flow of the airflow along the inner surface is attracted, and the separation of the airflow along the inner surface is suppressed. Thereby, the section where the rotation of the blade is stalled is shortened, and the rotational energy conversion efficiency in one rotation is improved.

  Also, at low rotation speeds or low wind speeds where the relative speed is low and the air flow is easy to peel off, the air flow is likely to adhere to the blade wall due to the serration shape. Increases the rotation speed of the wing. Furthermore, even if the wind weakens, the wings are difficult to stop rotating. As a result, the torque generation region during one rotation of the blade is expanded, and the rotational energy conversion efficiency is further improved.

In the present invention, the serration may be formed in a wave shape in which the top side of the peak portion is narrowed when viewed from the radial direction with respect to the rotation center of the blade.
The wave shape that narrows the top side of the mountain portion increases the width in the direction along the axis of the vertical main axis of the valley portion as it goes backward, so the action of attracting airflow along the inner surface in the radial direction is strong Become.

Further, the serration may have a curved shape with a convex curve at the peak as viewed from a radial direction with respect to the rotation center of the blade.
If the ridge has a convex curved shape, the rear end of the ridge has a roundness, so that it is difficult to be damaged, and the effect of the airflow on the outer surface is more easily exhibited.

The peak portion of the serration may increase in width along the axis of the vertical main shaft as it goes from the outside in the radial direction with respect to the rotation center of the blade to the inside.
In this case, the side surface of the mountain portion becomes an R surface inclined so that the width of the valley portion becomes narrower as it goes inward. Thereby, the airflow along the outer surface in the radial direction is smoothly guided to the trough.

In the present invention, when the wing has a main wing portion extending in parallel with the vertical main shaft and a winglet extending obliquely from both ends of the main wing portion toward the vertical main shaft, the rotation progress in the main wing portion. The serration may be formed at the rear end in the direction.
Further, serrations may be formed only on the main wing part.

The blade of the vertical axis wind turbine of the present invention is for a vertical axis wind turbine having a vertical main axis,
The cross-sectional shape is such that the radially outer surface or inner surface with respect to the center of rotation gradually bulges from the front and rear ends in the rotational direction toward the outer side or the inner side in the radial direction, and the amount of bulge is most at the location near the front end in the rotational direction. It has a large wing shape,
A serration is formed at the rear edge of the rotation traveling direction, in which crests protruding from the rear side in the rotation traveling direction and troughs receding are alternately arranged.

  As described above, when the cross-sectional shape is the cross-sectional shape, air flow separation on the inner surface in the radial direction is suppressed when wind is received. For this reason, when this blade is used for a vertical axis wind turbine, the stalled section due to separation is shortened, so that the rotational energy conversion efficiency of the vertical axis wind turbine is improved.

The wind power generator of the present invention includes the vertical axis wind turbine and a generator that generates electric power by the rotation of the vertical main shaft of the vertical axis wind turbine.
As described above, the vertical axis windmill used in this wind power generator has good rotational energy conversion efficiency. For this reason, this wind power generator has good power generation efficiency.

  A vertical axis wind turbine according to the present invention includes a vertical main shaft that is rotatably provided, a support provided on the vertical main shaft, and an axial center of the vertical main shaft that is connected to the vertical main shaft via the support and receives wind. And the blade has a transverse cross-sectional shape such that the radially outer surface or inner surface of the blade with respect to the rotation center of the blade gradually increases from the front and rear ends in the direction of rotation of the blade. A ridge that bulges inward and has a bulge amount that is the largest shape near the front end in the direction of rotation, and protrudes toward the rear side in the direction of rotation of the wing at the trailing edge of the direction of rotation. Since the serrations in which the retreating troughs are alternately arranged are formed, the separation of the airflow on the rotating inner peripheral surface of the blade is suppressed, and the rotational energy conversion efficiency is good.

  The blade of the vertical axis wind turbine according to the present invention is for a vertical axis wind turbine having a vertical main shaft, and has a cross-sectional shape in which the radial outer surface or inner surface with respect to the center of rotation gradually increases from the front and rear ends in the rotational traveling direction. Bulges outward or inward, and the amount of the bulge is the largest at the position near the front end in the rotational direction, and the peak part projects from the rear side in the rotational direction at the rear edge of the rotational direction. And serrated troughs are formed alternately, so that the separation of the airflow is suppressed, and the rotational energy conversion efficiency is improved when used in a vertical axis wind turbine.

  Since the vertical axis windmill of this invention is equipped with the said vertical axis windmill and the generator which produces electric power by rotation of the said vertical main axis | shaft of this vertical axis windmill, electric power generation efficiency is good.

It is a front view of the wind power generator provided with the vertical axis windmill concerning one embodiment of this invention. It is a top view of the wind power generator. (A) is the front view of the blade | wing of the same vertical axis windmill, (B) is the side view. It is IV-IV sectional drawing of FIG. 3 (B). It is a perspective view of a part of the wing. (A) is a partial plan view of an example of the wing, and (B) is a side view thereof. (A) is a partial plan view of a different example of the wing, and (B) is a side view thereof. (A) is a partial plan view of still another example of the wing, (B) is a side view thereof, and (C) is a cross-sectional view of VIIIC-VIIIC. (A) is a partial plan view of a further different example of the wing, and (B) is a side view thereof. (A) is a partial plan view of a further different example of the wing, and (B) is a side view thereof. (A) is a partial plan view of a further different example of the wing, and (B) is a side view thereof. It is explanatory drawing which shows the relationship between the rotation position of a wing | blade, and the direction and speed of the wind which flow into a wing | blade. (A), (B) is a figure which respectively shows the torque generation area | region and stall area | region during 1 rotation of a blade | wing. It is a graph which shows the relationship between the rotational speed of a wing | blade and the output which a wing | blade generate | occur | produces. It is the perspective view which represented a part of conventional wing | blade in the cross section.

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of a wind turbine generator having a vertical axis wind turbine according to an embodiment of the present invention, and FIG. 2 is a plan view thereof. A steel tower 2 is constructed on a foundation 1 built on the ground, and a wind power generator 3 is installed on the steel tower 2. The wind power generator 3 includes a vertical axis windmill 4, a generator 6 that generates electric power by rotation of the vertical main shaft 5 of the vertical axis windmill 4, and other devices for power distribution and control. The vertical main shaft 5 extends in the vertical direction, is rotatably supported by a bearing, and the lower portion is connected to the generator 6. The vertical main shaft 5, the generator 6, and other equipment are covered with a cover 7.

  In the vertical axis wind turbine 4, a plurality of blades 9 are attached to the vertical main shaft 5 via a support 8. In the example shown in the figure, the number of blades 9 is two, and each blade 9 is provided at a position with a 180 ° phase difference around the vertical main axis 5. The number of wings 9 may be three or more. The support 8 has one horizontal arm 8a that is horizontally fixed to the upper end of the vertical main shaft 5, and an upward oblique direction and a downward oblique direction from the vicinity of the central portion of the horizontal arm 8a toward the left and right sides of the figure. It consists of a total of four diagonal arms 8b. The left wing 9 is coupled to the left end of the horizontal arm 8a and the left two oblique arms 8b, and the right wing 9 is coupled to the right end of the horizontal arm 8a and the two oblique arms 8b on the right side. Yes. When the vertical axis wind turbine 4 receives wind, the vertical axis wind turbine 4 rotates around the axis O of the vertical main shaft 5 in the direction of the arrow in FIG.

  3A and 3B are a front view and a side view of the wing 9. The wings 9 are parallel to the vertical main shaft 5 (see FIG. 1), that is, a main wing portion 10 extending in the vertical direction, and upper and lower portions extending obliquely from the upper and lower end portions of the main wing portion 10 to the vertical main shaft 5 side. It consists of a winglet 11. The winglet 11 may extend linearly or may extend curvedly. In the case of a curved shape, the curved line may be an arc shape or a combination of a plurality of arcs having different curvatures. The upper and lower winglets 11 are formed in the same shape that is line-symmetric with respect to the center line CL of the intermediate portion in the longitudinal direction of the main wing portion 10.

  In the following description, the axial center direction of the vertical main shaft 5 is referred to as “vertical direction”. Further, the outer diameter side in the radial direction around the axis O of the vertical main shaft 5 is defined as “outer side”, and the inner diameter side is defined as “inner side”. Further, when the vertical axis wind turbine 4 rotates in the direction of the arrow in FIG. 2, the side on which the blades 9 advance is referred to as “front side”, and the opposite side is referred to as “rear side”.

  As shown in FIG. 3A, the thickness of the main wing portion 10 is constant over the entire upper and lower parts, and the winglet 11 is thinner in the radial direction toward the tip side. However, the radial thickness of each of the main wing part 10 and the winglet 11 differs depending on the position in the rotational traveling direction. The thicknesses of the main wing portion 10 and the winglet 11 described above are about the thickness of the maximum thickness portion in the rotation traveling direction.

  As shown in FIG. 3B, the width of the main wing portion 10 is constant in the direction of rotation, and the width of the winglet 11 is gradually reduced gradually toward the tip side. The apex position P which is the most advanced position in the up-down direction of the winglet 11 is closer to the front than the center in the direction of rotation.

  4 is a cross-sectional view taken along the line IV-IV in FIG. As shown in the figure, the cross-sectional shape of the main wing part 10 is such that the rotation inner peripheral surface, that is, the outer side surface 12 or inner side surface 13 in the radial direction gradually bulges outward or inward in the radial direction from both front and rear ends in the direction of rotation. The amount of bulge is the largest shape at a location near the front end in the direction of rotation. In this example, the inner side surface 13 in the radial direction has a curved shape in which the front end portion is smoothly connected to the outer side surface 12, and the rear portion is flatter than the front end portion. The inner side surface 13 may have a shape that swells inward in the radial direction from the front end to the rear end, or may have a shape in which a central portion in the rotation traveling direction is recessed. Although illustration is omitted, the cross-sectional shape of the winglet 11 is the same as that of the main wing part 10 although the dimensions of the wing part 10 are different from those of the main wing part 10 in the radial direction and the rotational direction. In FIG. 4, the wings 9 are shown as solid. However, in some cases, the wings 9 may be formed in a hollow shape with a fiber reinforced resin or the like in order to reduce the weight.

  As shown in FIGS. 3B, 4, and 5, a serration 15 is provided at the rear edge of the main wing portion 10 in the rotational traveling direction. In the serrations 15, the peak portions 16 projecting toward the rear side in the rotation traveling direction and the valley portions 17 receding are alternately arranged. As a method of forming the serration 15, a portion that becomes the valley portion 17 at the rear end portion of the main wing portion 10 may be cut out, or another member or serration 15 that becomes the peak portion 16 is formed at the rear end edge of the main wing portion 10. Another formed member may be attached.

6 to 11 show various forms of serrations. Of these figures, (B) is drawn with a larger ratio of dimensions in the blade thickness direction.
In the serration 15A shown in FIG. 6, when viewed from the radial direction, a series of peak portions 16 has a triangular waveform. The top part of the peak part 16 and the bottom part of the valley part 17 have an acute angle when viewed from the radial direction.
In the serration 15B shown in FIG. 7, a series of peak portions 16 has a trapezoidal waveform when viewed from the radial direction. The top of the peak 16 and the bottom of the trough 17 may be rounded by a curve.

  In the serration 15C shown in FIG. 8, when viewed from the radial direction, a series of peak portions 16 has a peak convex waveform. The peak convex curve waveform means that each peak 16 has a curved shape convex backward. If the peak portion 16 has a convex curved shape, the rear end of the peak portion 16 has a rounded shape and is not easily damaged.

  In the example of FIG. 8, as shown in the cross-sectional view of FIG. 8C, the peak portion 16 becomes wider in the vertical direction as it goes from the outside to the inside. In other words, the side surface 16a of the peak portion 16 is a tapered surface or an R surface inclined so that the width of the valley portion 17 becomes narrower as it goes inward. Thereby, the airflow along the outer surface 12 in the radial direction is smoothly guided to the valley portion 17. The triangular waveform and trapezoidal waveform serrations 15A and 15B and the rectangular waveform serration 15D described later may be tapered or rounded.

  Each of the serrations 15A, 15B, and 15C has a wave shape that narrows the top side of the peak portion 16 when viewed from the radial direction. With this wave shape, the width in the vertical direction of the valley portion 17 becomes wider toward the rear, so that the action of inducing the flow of airflow along the inner surface 13 in the radial direction becomes stronger.

  Like serration 15D shown in FIG. 9, it does not need to be the wave shape which the top part side of the peak part 16 narrows. In this serration 15D, a series of peaks 16 has a rectangular waveform.

  The serration 15E shown in FIG. 10 is formed in another member 18 attached to the rear edge of the main wing part 10. In this example, the waveform of the peak portion 16 is similar to that of the serration 15A of FIG. 6, but the other serrations 15B, 15C, and 15D may be formed as separate members.

  The serration 15F shown in FIG. 11 is formed by attaching another member that becomes the peak 16 to the rear edge of the main wing part 19. In this example, as in the serration 15C of FIG. 8, the series of peaks 16 is a peak convex curve waveform, but the serrations of other waveforms also have peaks 16 at the trailing edge of the main wing 19. A separate member can be attached to form a serration.

The operation of the vertical axis wind turbine 4 having this configuration will be described.
If the blade 9 has the cross-sectional shape shown in FIG. 4, when the blade 9 receives the wind W, the airflow A2 is accelerated by the shape of the inner surface of the front edge of the blade 9, and lift is generated in the forward direction of the blade. It becomes a driving force. With this lift, the vertical axis wind turbine 4 rotates about the axis O of the vertical main shaft 5 in the direction of the arrow in FIG. Providing the winglets 11 at both ends of the blade 9 suppresses the generation of vortices near the blade tip and suppresses the generation of noise.

  FIG. 12 is an explanatory diagram showing the relationship between the rotational position of the blade 9 and the direction and speed of the wind flowing into the blade 9. It is assumed that the wind at the wind speed V0 is blowing from the left to the right in the right diagram of FIG. The arrows in the figure indicate the relative direction and inflow speed of the wind received by the blade 9. The left figure of FIG. 12 represents the state of the wing | blade 9 when the wing | blade 9 exists in each rotation position.

  When the wing 9 is at the position of the circled number 1, the wing 9 receives the wind at the inflow speed V1 obtained by adding the wind speed V0 and the traveling speed S of the wing 9 from the front in the rotational traveling direction. In this state, as shown in the left diagram of FIG. 12, the airflow A1 outside the blade 9 and the airflow A2 inside the wing 9 are attached flows along the outer surface 12 and the inner surface 13, respectively.

  When the blade 9 is in the position of the circled number 2, the blade 9 receives the wind of the inflow velocity V2 that is a vector value of the wind velocity V0 and the traveling velocity S from the oblique outer diameter side in the rotational traveling direction. In this state, as shown in the left diagram of FIG. 12, the airflow A <b> 1 outside the wing 9 is an attached flow along the outer surface 12, but the inner airflow A <b> 2 becomes peeled from the inner surface 13. However, if the serration 15 (FIG. 4) is formed at the trailing edge of the blade 9 in the rotational traveling direction, the flow of the airflow A2 inside the blade 9 is attracted by the fast airflow A1 along the outer surface 12. . Thereby, peeling of the airflow A2 on the inner side surface 13 is suppressed.

  When the blade 9 is at the position of the circled numeral 3, the blade 9 receives the wind of the inflow velocity V3 that is a vector value of the wind velocity V0 and the traveling velocity S from the oblique outer diameter side. In this state, as shown in the left diagram of FIG. 12, the inner airflow A2 is completely separated from the inner side surface 13 at the blade rear end.

  As described above, since the serrations 15 are formed at the trailing edge of the rotation direction of the blade 9, the flow of the airflow along the inner surface 13 in the radial direction is caused by the fast airflow along the outer surface 12 in the radial direction. The airflow along the inner surface 13 is suppressed by being attracted. For example, when there is no serration 15, there is a possibility that separation of the air current 2 occurs when the blade 9 is at the position of the circled number 2, but when there is the serration 15, the separation of the air current 2 at the same point is eliminated. be able to. Thereby, the section where the rotation of the blade 9 is stalled is shortened, and the rotational energy conversion efficiency in one rotation is improved.

FIGS. 13A and 13B are diagrams showing the relationship between the torque generation region and the stall region during one rotation of the blade. As an example, (A) in a vertical axis wind turbine having a rotor diameter of 2 m shows a case where the rotational speed is 90 min ⁻¹ , and (B) shows a case where the rotational speed is 50 min ⁻¹ . Comparing the two, it can be seen that the torque generation region is narrow when the rotational speed is low. This is because, particularly at low wind speeds where the relative inflow speed is low or during low rotation, the relative speed of the airflow is small, so the airflow flowing through the blade wall surface stalls, and the timing of separation at the rear end of the blade wall surface is accelerated.

  However, if serrations 15 are formed on the blades 9, air flow separation is suppressed even at low wind speeds and low rotations. Therefore, as shown by the white arrows in FIG. Can do. For example, as in FIG. 13A, the torque generation region can be expanded to the position of the circled number 3.

  In addition, since the separation of the airflow is suppressed, when the wind blows in a low rotation state or in a rotation stop state, the output of the blade increases, so the blade speed can be reduced to a predetermined rotational speed that generates efficient torque in a short time. 9 speed increases. Furthermore, even if the wind weakens, the wing 9 is difficult to stop rotating. As a result, the torque generation region during one rotation of the blade is expanded, and the rotational energy conversion efficiency is further improved.

  As described above, it is effective to form the serrations 15 on the blades 9 in a situation peculiar to the vertical axis wind turbine in which the wind inflow angle to the blades greatly changes during one rotation of the blades. With and without serrations, the output generated by the blades 9 by wind was calculated by fluid analysis. The result is shown in FIG. As a result, it can be seen that at any rotation speed, a larger output is generated than when there is no serration. It can also be seen that the effect is particularly great at low speeds.

  As described above, the vertical axis wind turbine 4 using the blades 9 in which the serrations 15 are formed has high rotational energy conversion efficiency. For this reason, the wind power generator 3 provided with this vertical axis windmill 4 has good power generation efficiency.

  As mentioned above, although the form for implementing this invention based on the Example was demonstrated, embodiment disclosed here is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 3 ... Wind power generator 4 ... Vertical axis windmill 5 ... Vertical main shaft 6 ... Generator 8 ... Support body 9 ... Wing 10 ... Main wing part 11 ... Winglet 12 ... Outer side surface 13 ... Inner side surface 15, 15A, 15B, 15C, 15D, 15E, 15F ... serration 16 ... mountain part 17 ... valley part O ... axis

Claims (7)

A vertical main shaft provided rotatably, a support provided on the vertical main shaft, and a wing connected to the vertical main shaft via the support and receiving wind to rotate around the axis of the vertical main shaft. A vertical axis windmill with
The cross-sectional shape of the wing is such that the radially outer surface or inner surface with respect to the rotation center of the wing gradually bulges from the front and rear ends in the direction of rotation of the wing toward the outer or inner side in the radial direction. It is the largest shape near the front end in the direction of travel,
A vertical axis wind turbine characterized in that a serration is formed on the trailing edge of the blade in the rotational direction in which the ridges projecting toward the rear side in the rotational direction and the valleys receding are alternately arranged. .   2. The vertical axis wind turbine according to claim 1, wherein the serration is formed in a wave shape in which a top side of the peak portion is narrowed when viewed from a radial direction with respect to a rotation center of the blade. 3.   3. The vertical axis wind turbine according to claim 1, wherein the serration is a curved shape having a convex curve at the peak portion when viewed from a radial direction with respect to a rotation center of the blade. 4.   The vertical axis wind turbine according to any one of claims 1 to 3, wherein the peak portion of the serration is an axial center of the vertical main shaft as it goes from the outside in the radial direction with respect to the rotation center of the blade. A vertical axis windmill with a wider width along the axis.   5. The vertical axis wind turbine according to claim 1, wherein the blade includes a main wing portion extending in parallel to the vertical main shaft, and obliquely from both ends of the main wing portion toward the vertical main shaft. A vertical axis wind turbine having a winglet that bends and extends, and the serration is formed at a rear end of the main wing portion in the rotational traveling direction. A blade of a vertical axis wind turbine having a vertical main axis,
The cross-sectional shape is such that the radially outer surface or inner surface with respect to the center of rotation gradually bulges from the front and rear ends in the rotational direction toward the outer side or the inner side in the radial direction, and the amount of bulge is most at the location near the front end in the rotational direction. Large shape,
A blade of a vertical axis wind turbine, wherein a serration is formed at the trailing edge of the rotational direction in which ridges protruding from the rear side of the rotational direction and troughs retreating are alternately arranged.   A wind turbine generator comprising: the vertical axis wind turbine according to any one of claims 1 to 5; and a generator that generates electric power by rotation of the vertical main shaft of the vertical axis wind turbine.

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