JPS6090992A - Spiral blade type vertical shaft windmill - Google Patents

Abstract

PURPOSE:To reduce torque fluctuation and drag fluctuation by forming rotor blades integrally with and spiral about the rotary shaft of the windmill. CONSTITUTION:The spiral rotor blades 11, 12 are arranged about the rotary shaft of the windmill, which connects the rotary shafts 16, 17, so as to be symmetrical to the shaft and so as to have the angles of twist of 180 deg.. The spiral rotor blades 11, 12 are fixed to respective end plates 13, 15 at the uppermost and lowermost section thereof. The ratio of areas of dynamic blade, receiving torque in a direction to rotate the windmill, and brake blade, receiving torque into the direction of braking, becomes constant independently from a rotating angle theta, therefore, there is little torque fluctuation. The area of projection of the windmill is also constant independently from the rotary angle theta and, therefore, the drag force, effecting on the whole of the windmill, will never be fluctuated substantially.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a vertical axis wind turbine, and more particularly to a vertical axis wind turbine suitable for use in small wind turbine generators, wind pumps, and the like.

[Background of the invention]

A typical example of a conventional vertical axis wind turbine is a Saponius wind turbine with two or three rotor excitations.

Saponius wind turbines have advantages such as a simple structure, good startup performance, and little influence from changes in wind direction, but the degree of wind action on the rotor stem differs depending on the rotation angle θ of the wind turbine. For this reason, the rotational torque varies depending on the rotation angle θ of the windmill, and the drag force of the wind acting on the entire windmill also varies, so the windmill has to be photographed extensively, making stable operation difficult. As a conventional method aimed at alleviating this drawback, the Savonius windmill shown in Fig.
September 3rd]. As shown in FIG. 1, this wind turbine has two upper and lower Saponius wind turbines stacked one on top of the other, and the upper rotor R1 and the lower rotor blades are arranged 90 degrees apart in the gold rotation angle θ direction. In addition, 3, 4 and 5 in FIG. 1 are end plates, and 6 and 7 are rotating shafts. FIG. 2 shows the quiet torque distribution taken in the radial direction of the quiet torque coefficient Cmk with respect to the rotation angle θ of the wind turbine shown in FIG. As shown in the figure, the maximum and minimum of the static torque coefficient Cs occur at four locations even when two layers of Savonius-style single metal are stacked,
and the maximum value C6n and minimum value C of static torque coefficient 1'l Cs
The ratio Cgn/C[IL of st, is as large as 2 or more, and the variation in rotational torque is not sufficiently small. In order to sufficiently reduce this variation in rotational torque, it is necessary to
It is conceivable to stack them in 0 or more stages, but the structure shown in FIG. 1 has the following drawbacks when multi-staged. (
1) An intermediate end plate 4 is required to connect each stage,
As the weight of the wind turbine increases, it becomes a resistance during rotation, increasing costs and reducing the efficiency of the wind turbine. (2) When connecting each stage, the center of rotation between each stage is likely to be twisted, causing vibration. (3) The end plate 4 in the middle of each stage connection part prevents air flow between each stage, reducing wind turbine efficiency.

[Object of the Invention] An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to create a vertical axis wind turbine. It is an object of the present invention to provide a vertical axis wind turbine that has small torque fluctuations and drag fluctuations without having to be constructed in multiple stages, and has high wind turbine efficiency.

[Summary of the invention]

In order to achieve all of the above objects, the present invention employs a rotor field in which the rotor blades are integrally molded in a spiral shape around the rotation axis of the wind turbine. At this time, the twist angle α of this spiral rotor blade is when the number of wind turbine rotor blades is N.

However, n is a positive integer. This means that regardless of the rotation angle θ of the wind turbine,
The rotational torque acting on the N helical rotor blades and the drag force acting on the entire wind turbine are constant, allowing stable operation with less vibration. In addition, the wind after entering the spiral rotor is
A part of it flows along the helical rotor and acts in a direction that helps the rotation of the windmill, thereby increasing the efficiency of the windmill.

[Embodiments of the invention]

The present invention will be explained in detail below with reference to all embodiments. FIG. 3 is a structural diagram showing an embodiment of the spiral blade type vertical axis wind turbine of the present invention. Moreover, FIG. 4 is an AA cross section, a B-B cross section, a C-C cross section, and a D-D cross section of FIG.

FIG. In Figure 3,
Reference numerals 11 and 12 indicate a pair of helical rotors, 13° and 15 indicate upper and lower end plates, respectively, and 16 and 17 indicate a rotating shaft. 2
The spiral rotor blades 11 and 12 are connected to a rotating shaft 16. They each have a twist angle α of 180° around the wind turbine rotation axis, and are arranged axially symmetrically to the wind turbine rotation axis.

The two helical rotor blades 11 and 12 are fixed to end plates 13 and 15 at the upper and lower parts, respectively. Rotating shaft 16
17 are fixed to the end plates 13 and 15, respectively.

As shown in FIG. 4, the cross section at each point in the axial direction of the wind turbine in FIG. 1 is such that the top A-A cross section is rotated 1800 times to become the bottom E-E cross section.

The material of the spiral rotor blades is ERP, which is lightweight and has high strength.
'fr: Although used, aluminum alloy etc. can also be used.

The operating characteristics of the helical blade vertical axis wind turbine of the present invention will be explained below. FIG. 5 shows measured values of the static torque distribution taken in the radial direction of the quiet torque coefficient C111 with respect to the rotation angle θ of the wind turbine in FIG. Here, the static torque coefficient Cs is expressed by the following equation.

However, Os = Static torque coefficient TB = Static torque ρ = Air density U = Wind speed As = Wind turbine projected area (if As changes depending on the rotation angle θ, take its maximum value) R = Wind turbine rotation radius , the static torque coefficient C- is 1 regardless of the rotation angle θ.
1 is constant. This means that the proportion of the area of the brake vane 22 (Fig. 5), which receives torque in the direction of braking, as opposed to the power tool 21 (Fig. 5), which receives torque in the direction of rotating the wind turbine due to the wind, is In the spiral blade type vertical axis wind turbine, the torque is constant regardless of the rotation angle θ, and stable operation with almost no torque fluctuation is possible. In addition, in this windmill, the projected area of the windmill is also constant regardless of the jQ1 rotation angle θ, and if the wind speed is approximately constant, the drag force acting on the entire windmill hardly changes and stable operation is possible. Furthermore, since the quiet torque does not depend on the rotation angle θ, the wind turbine can be started quickly even if the wind blows from any direction when the wind turbine is stopped.

Normally, natural wind constantly changes its direction. When the wind direction fluctuates, in the conventional wind turbine shown in FIG. 1, the rotation angle relative to the wind direction fluctuates, causing torque and drag to fluctuate, and the wind direction fluctuation also causes vibration. On the other hand, in the wind turbine of the present invention shown in FIG. 3, even if the wind direction changes, the torque and drag force
: Since it does not fluctuate, it can operate stably even when the wind direction fluctuates.

Figure 6 shows the output characteristics of the wind turbine shown in Figure 3 of the present invention.
This is a comparison with the conventional wind turbine shown in the figure. In Fig. 6, the vertical axis is the wind turbine output coefficient CP.

The horizontal axis is the peripheral speed ratio φ. Here, the wind turbine output coefficient Cp and the circumferential speed ratio φ are quantities defined by the following equation.

However, Cp'' Wind turbine output coefficient P = Wind turbine output ρ = Air density U = Wind speed AR - Wind turbine projected area φ = Circumferential speed ratio R = Wind turbine rotation radius W = Wind turbine rotation angular speed In Fig. 6, 31 indicated by a black circle is The output characteristics of the conventional wind turbine in Figure 1 and 32 indicated by white circles are representative examples of the output characteristics of the wind turbine of the present invention in Figure 3.The output characteristics 31 of the wind turbine of the present invention in Figure 6 Compared to the output characteristic 32 of the wind turbine shown in Fig. 1, the maximum output coefficient Cp is larger by more than 10%, and the circumferential speed ratio range in which the output coefficient CP is large is also wider. This is due to the difference in the shape of the rotor blades of the wind turbine of the present invention shown in FIG.
The rotor blades 1 and 2 of the conventional wind turbine shown in the figure are straight in the length direction, and the upper rotor blade 1 and the lower rotor blade 2 have an end plate 4.
It is separated by Therefore, a part of the wind that enters the abdomen of the power blade, for example, the rotor blade 2, passes through the trailing edge of the rotor blade 2 and passes through the abdomen of the control blade (another rotor blade paired with the rotor blade 2). Some of the other wind escapes from the leading edge of the power blade, but in the vertical direction, the rotor blade is vertical, the end plate 4, etc. causes a negative flow to the brake blade. Acts to add full torque. Therefore, the output coefficient of the wind turbine decreases.

On the other hand, in the wind turbine of the present invention, as shown in FIG. 3, the rotor blades 11 and 12 are configured in a smooth spiral shape. Therefore, in the present invention, one rotor blade has a part that works as a power blade and a part that works as a brake blade, and although it is difficult to clearly distinguish between the power blade and the brake blade, it is difficult to clearly distinguish between the power blade and the brake blade. For example, when the rotor blade 11 works as a power blade, the other rotor blade 12 works as a brake blade.

Therefore, the wind incident on the power blade portion of the wind turbine of the present invention is
As in conventional wind turbines, some of the wind escapes through the trailing edge of the power vane to the brake blade membrane, and some of the wind escapes through the leading edge of the power vane. Furthermore, in the wind turbine of the present invention, since the rotor blades are configured in a smooth spiral shape, a portion of the wind that is incident on the power blade portion escapes along the spiral rotor blade. Wind also acts in a direction that provides rotational torque to the windmill.

Furthermore, the wind at the back of the brake blade also escapes along the spiral of the rotor blade, enters the abdomen of the power blade, and acts in the direction of giving rotational torque to the wind turbine. It becomes more compared to .

Due to these effects, the output coefficient Cse of the wind turbine of the present invention can be increased.

FIG. 7 shows another embodiment of the present invention, which differs from FIG. 3 in that only one helical rotor excitation 41 is used. At this time, the twist angle α of the spiral is 360°. In this embodiment, the rotational torque is small due to the small number of rotor blades, but the rotor can rotate at high speed.
It has the effect of being suitable for uses such as power generation.

FIG. 8 shows another embodiment of the present invention, which differs from FIG.
That's a given. In FIG. 8, 51 and 52 are spiral rotor blades.
The twist angle α is 1800. This pair of rotor blades 5
1, 52 are 54, 55, 56, 57, 58 on the rotating shaft 53
It is fixed by support rods of 59, 60 and 61 degrees.

FIG. 9 shows a cross section taken along line FF in FIG. 8. Rotor blades 51,5
The cross-sectional shape of No. 2 is airfoil-shaped as shown in Fig. 9.
A suitable airfoil shape is NACAOO12 type.

Gyromill type windmills rotate by aerodynamic forces that are different from the Saponius windmills described previously. In other words, the Savonius wind turbine rotates by obtaining a torque due to the difference in wind drag acting on the power vane and brake vane of the rotor blade. On the other hand, a gyro mill type wind turbine rotates by obtaining torque from the lift force acting on the rotor, which has an airfoil-shaped cross section. but,
Even in a gyro mill type wind turbine, the magnitude and direction of lift acting on the rotor blades change depending on the rotation angle θ of the wind turbine, and torque fluctuations cannot be avoided. In FIG. 9, the rotor blade receives minimum lift when the rotation angle θ=90° and 270°, and receives maximum lift when θ=0° and 180°. However, as in this embodiment shown in FIG. 8, the rotor J! l! !
By making the wind turbine spiral, the positions of torque fluctuations acting on the rotor blades are dispersed, thereby making it possible to reduce torque fluctuations acting on the entire wind turbine, allowing stable operation with less vibration.

In the embodiment described above, the twist angle α of the helical rotor blade is α=360° when the number of rotor blades is one.
, when the number of rotor blades is two, α = 180°, but
Generally, when the number of rotor members ff is N and a positive integer fn, the same effect can be obtained by setting the twist angle α to be expressed by a linear equation.

Further, the direction of the spiral may be a right-handed thread direction or a left-handed thread direction.

〔Effect of the invention〕

As explained above, according to the present invention, by configuring the rotor of a wind turbine in a spiral around the excited rotation axis, torque fluctuations and drag fluctuations are almost eliminated, and stable operation with less vibration is possible. At the same time, the efficiency of the wind turbine can be increased.

[Brief explanation of drawings]

Fig. 1 is a structural diagram of a conventional two-stage Sponius wind turbine, Fig. 2 is an explanatory diagram showing the static torque characteristics of the wind turbine in Fig. 1, and Fig. 3 is a structural diagram showing an embodiment of the wind turbine of the present invention. , FIG. 4 is a cross-sectional view showing the shape of the rotor blade at each axial position of the wind turbine shown in FIG. 3, FIG. The figures are an explanatory diagram showing the output characteristics of the wind turbine in Fig. 1 and the wind turbine in Fig. 3, Fig. 7 is a structural diagram showing a modification of the wind turbine of the present invention, and Fig. 8 is another modification of the wind turbine of the invention. FIG. 9 is a cross-sectional view taken along F-15 of the wind turbine shown in FIG. 8. 1... Upper rotor blade, 2... Lower rotor blade, 3, 4
゜5... End plate, 6, 7... Rotating shaft, 11.12...
・Spiral rotor blade, 13.15... End plate, 16.17
... Rotating shaft, 41 ... Spiral rotor blade % 42.4
3... End plate, 44.45... Rotating axis %5'l, 52
...Spiral rotor R153...Rotating axis% 54,5
5,56,57゜58.59,60.61...Support rod, α...O-helix angle of spiral rotor blade, θ...Rotation angle of wind turbine 408...Silent torque coefficient, Cp... Wind turbine output coefficient, N... Rotor blade 270゜p (,!Ty-) Chi7 Haze

Claims (1)

[Claims] 1. A vertical axis wind turbine comprising a vertically arranged rotating shaft and one or more unscrewed rotor blades on the rotating shaft,
A spiral gear type vertical axis wind turbine characterized in that the rotor JK is a spiral rotor blade twisted spirally around the rotating shaft. 2. A spiral tool according to claim 1, characterized in that the helical rotor blade has a twist angle α of 360°, where N1 is a positive integer representing the number of rotor blades. vertical axis windmill.