KR101655955B1

KR101655955B1 - Vertical Axis Turbine with inclined blades for Wind Power Generation

Info

Publication number: KR101655955B1
Application number: KR1020150039980A
Authority: KR
Inventors: 이준상; 나지성; 선상규
Original assignee: 연세대학교 산학협력단; 선상규
Priority date: 2015-03-23
Filing date: 2015-03-23
Publication date: 2016-09-08

Abstract

One aspect of the present invention relates to a vertical axis wind turbine having an inclined blade, and more particularly, to a vertical axis wind turbine provided with an inclined blade so as to disperse a pressure generated on a wind contact surface of the blade, .
According to an embodiment of the present invention, it is possible to provide a wind turbine having an increased efficiency by suppressing a vortex generated inside the wind turbine by maintaining the blade inclined at a predetermined angle, thereby maintaining the wind speed of the wind passing through the turbine at a predetermined level or more have.

Description

&Lt; Desc / Clms Page number 1 > Vertical Axis Turbine with inclined blades for Wind Power Generation &

One aspect of the present invention relates to a vertical axis wind turbine having an inclined blade, and more particularly, to a vertical axis wind turbine provided with an inclined blade so as to disperse a pressure generated on a wind contact surface of the blade, .

The contents described in this section merely provide background information on the embodiment of the present invention and do not constitute the prior art.

Generally, wind power generators are developed by converting natural wind energy into mechanical energy.

That is, the wind turbine generator is installed in a windy place so as to not only inflow the wind but also generate power and electricity by rotating the wind turbine with the force of the wind.

In such a wind turbine, a wind turbine has a horizontal rotary shaft system in which a rotary shaft is installed parallel to the ground along the direction of the rotary shaft, and a vertical rotary shaft system in which the rotary shaft is perpendicular to the ground.

Here, the horizontal axis wind turbine has a propeller blade and uses the lift force of the wind. The rotation speed of the rotary blade is high, so that the generation efficiency is high. However, the direction of the rotary blade must be changed according to the wind direction, Since the angle of the blade must be changed, a complicated device is required.

On the other hand, the vertical axis wind turbine is applied to small wind power generation system because it has a low power generation efficiency but can obtain a large turning force even at low wind speed and does not depend on the wind direction.

Vertical-axis wind turbines are often distinguished by the Dariyasu blade method and the Sabonius blade method. The darius blade system uses the lift force of the wind and does not start up by itself and needs an auxiliary power unit.

On the other hand, the SABONIUS blade system uses a drag force of the wind, so it can obtain a large turning force at low wind speed and has its own maneuvering power, so it is mainly used in a small wind turbine generator.

The vertical axis type wind turbine having such a sandwich blade generally has a structure in which a blade formed by bending a rectangular plate material into a predetermined shape is coupled between a flat plate type upper plate coupled to the vertical axis and a lower plate.

However, in such a wind turbine, there is a problem that efficiency and performance are greatly deteriorated due to vortex or irregular pressure generated in the turbine when the turbine is changed in air flow.

In addition, in the region where the wind direction varies from time to time and the wind speed is slow, the turbine does not rotate properly, which makes it difficult to continuously and stably produce electric power.

Accordingly, an aspect of the present invention has been proposed in order to solve the above-mentioned problems, and an object of the present invention is to provide a wind turbine with improved efficiency by suppressing vortex generated inside a blade.

The technical object of the present invention is not limited to the above-mentioned technical objects and other technical objects which are not mentioned can be clearly understood by those skilled in the art from the following description will be.

In order to accomplish the above-mentioned object, one aspect of the present invention is to provide a windscreen comprising a first guiding surface and a second guiding surface for guiding wind, a second guiding surface formed between the first guiding surface and the second guiding surface, A wind guide having an inlet passage through which wind is introduced by the second guide surface; And

A first support and a second support arranged to be rotatable inside the wind guide and arranged to face each other and a plurality of blades connecting the first support and the second support, The first support and the second support are spaced apart from each other along the circumferential direction and each of the plurality of blades is formed so as to be inclined with respect to the center line of the rotation so as to be inclined to the wind introduced through the inflow passage And a rotating body having a contact surface, the contact surface being formed into a curved surface so as to surround the introduced wind.

The contact surface of the blade may be twisted outward from one end connected to the first support to the other end connected to the second support.

The contact surface of the blade may be inclined toward the circumferential direction of the first and second supports.

One end of the contact surface that is connected to the first support may be connected to the other end of the contact surface in the circumferential direction of the first support in advance of the other end connected to the second support, .

The wind guide includes an upper plate and a lower plate facing each other, and a plurality of side walls connecting the upper plate and the lower plate, and a rotating body mounting portion into which the rotating body is inserted may be formed at the center portion.

In accordance with another aspect of the present invention, there is provided an air bag comprising a first guiding surface and a second guiding surface for guiding wind, a second guiding surface formed between the first guiding surface and the second guiding surface, A wind guide having an inlet through which wind is introduced by the second guide surface; And

A first support and a second support arranged to be rotatable inside the wind guide and arranged to face each other and a plurality of blades connecting the first support and the second support, The first support and the second support being spaced from one another along the circumferential direction, each of the plurality of blades having a contact surface contacting the wind introduced through the inlet, And a rotating body that is curved outwardly at one end connected to the second support and connected to the second support, and the contact surface is formed into a curved surface so as to cover the introduced wind.

According to another aspect of the present invention, there is provided a wind turbine comprising: a wind guide having a top plate and a bottom plate facing each other, a plurality of side walls connecting the top plate and the bottom plate,

A rotating body rotatably installed in the rotating body mounting part, the rotating body having an upper supporting part and a lower supporting part, and a plurality of blades installed between the upper supporting part and the lower supporting part so as to be inclined with respect to the center line of rotation;

A shaft connected to the lower support and rotated together with the lower support;

A generator connected to the shaft to perform power generation; And

And a housing surrounding the shaft and the generator.

The blade may be twisted from one end connected to the upper support to the other end connected to the lower support.

The wind guide may be rotatably installed on the upper portion of the housing.

According to an embodiment of the present invention, a fin may be formed on the upper surface of the wind guide to rotate the wind guide according to the wind direction.

As described above, according to the embodiment of the present invention, the blades are inclined or twisted at a predetermined angle, thereby suppressing the vortex generated inside the wind turbine, thereby maintaining the wind speed of the wind passing through the turbine at a certain level or more, An increased wind turbine can be provided.

In addition, the effects of the present invention have various effects such as excellent durability according to the embodiments, and such effects can be clearly confirmed in the description of the embodiments described later.

1 shows a rotating body of a wind turbine according to an embodiment of the present invention.
Fig. 2 shows a wind guide of a wind turbine according to an embodiment of the present invention.
3 schematically shows a wind turbine generator according to an embodiment of the present invention.
Figure 4 shows the simulation domain and blade information of a blade of a wind turbine according to an embodiment of the present invention.
5 shows the velocity and the magnitude contour of the blade circumferential direction for analyzing the efficiency and the flow characteristics according to the blade inclination angle change.
6 shows the distribution and the change of the pressure according to the change of the blade tilt angle.
FIG. 7 is a graph showing changes in twist angle and observation of flow characteristics and pressure distribution when the inclination angle of the blade is 20 °.

Hereinafter, an embodiment of the present invention will be described in detail with reference to exemplary drawings.

It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In addition, the size and shape of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, terms specifically defined in consideration of the constitution and operation of the present invention are only for explaining the embodiments of the present invention, and do not limit the scope of the present invention.

1 shows a rotating body of a wind turbine according to an embodiment of the present invention.

Fig. 2 shows a wind guide of a wind turbine according to an embodiment of the present invention.

3 schematically shows a wind turbine generator according to an embodiment of the present invention.

1 also shows a state in which the inclination angle and the twist angle of the blade 130 of the rotating body 100 are changed. 1 (a) shows a case where both the inclination angle and the twist angle of the blade 130 are 0 °, FIG. 1 (b) shows the case where the inclination angle and the twist angle are 10 ° and 0 °, (D) are 20 ° and 10 °, respectively, and Fig. 1 (e) shows the case of 20 ° and 20 °, respectively.

Referring to FIGS. 1 and 2, the wind turbine according to the present embodiment may include a wind guide 200 and a rotating body 100.

Here, the wind guide 200 guides the wind and drives it in a specific direction to transmit the wind direction to the rotating body 100. The configuration of the wind guide 200 is formed between a first guiding surface and a second guiding surface for guiding wind, a second guiding surface formed between the first guiding surface and the second guiding surface, And may include an inlet through which the induced wind flows.

The wind guide 200 includes upper and lower plates 250 and 260 facing each other and a plurality of side walls 210, 220, 230 and 240 connecting the upper plate 250 and the lower plate 260, A rotating body mounting portion 270 into which the rotating body 100 is inserted may be formed. The upper plate 250 and the lower plate 260 may be formed so that their rims include an arc shape. The rotating body mounting portion 270 may be formed at the center of the upper plate 250 and the lower plate 260 so that the rotating body 100 may be inserted and installed.

Some of the plurality of sidewalls 210, 220, 230, and 240 collect wind and induce wind, while the rest of the sidewalls 210, 220, 230, and 240 can prevent vortices from occurring around the wind guide 200. The plurality of side walls 210, 220, 230, 240 may be four, depending on the embodiment. Two of which may form the first guiding surface and the second guiding surface described above. All or a part of the plurality of side walls 210, 220, 230 and 240 may be formed to be bent at a predetermined angle. Such a structure in which the side wall is bent can suppress the vortex generated around the wind guide 200 and allow the wind to flow smoothly into the rotating body 100.

The rotating body 100 may be installed in the rotating body mounting portion 270 of the wind guide 200 so as to be rotatable inside the wind guide 200. The structure of the rotating body 100 includes a first support 110 and a second support 120 disposed to face each other and a plurality of blades 130 connecting the first support 110 and the second support 120 .

Here, the plurality of blades 130 may be disposed at the rims of the first support 110 and the second support 120 at intervals along the circumferential direction.

Each of the plurality of blades 130 may be formed to be inclined with respect to the center line of rotation of the rotating body 100 described above and may have a contact surface that slopes in contact with the wind introduced through the inlet of the wind guide 200. Here, the contact surface may be formed as a curved surface so as to surround the introduced wind. Here, the contact surface may be formed to be inclined at a predetermined inclination angle.

The contact surface may be inclined toward the circumferential direction of the first support 110 and the second support 120 according to the embodiment. The inclination direction of the contact surface may include a radial component as well as a circumferential component of the first support 110 and the second support 120.

The first support part 110 may be positioned on the second support part 120. In this case, one end 131 of the contact surface, which is connected to the first support part 110, May be connected ahead of the other end 132 connected to the first support 110 by a predetermined distance in the circumferential direction.

That is, the contact surface may be formed so that the portion connected to the first support 110 located at the upper portion is connected to the portion connected to the second support 120 located at the lower portion at a position ahead of the circumferential direction. Through this structure, the upper end of the contact surface of the blade 130 can be first contacted with the wind introduced through the inlet of the wind guide 200, and the wind contact with the lower end of the contact surface can be contacted most later.

The contact surface of the blade 130 may be outwardly twisted from one end 131 connected to the first support 110 to the other end 132 connected to the second support 120 according to the embodiment. Here, the contact surface can be formed to twist at a set twist angle. Since the contact surface of the blade 130 is formed outwardly twisted, the influence of the wind (A) induced by the first guiding surface and the wind (B) guided by the second guiding surface, .

According to another embodiment, the contact surface may be formed so as to be inclined at a predetermined inclination angle and at the same time twisted to a predetermined twist angle.

The efficiency and characteristics of the blade 130 according to the inclination angle and the twist angle of the contact surface of the blade 130 of the wind turbine according to an embodiment of the present invention will be described below.

Figure 4 shows the simulation domain and blade information of a blade of a wind turbine according to an embodiment of the present invention.

In the present simulation, the blade 130 is used for a 1 kw class wind turbine and the specification of the blade 130 is such that the radius r of the semicircle of the blade 130 r = 0.07 m, the position D of the blade 130 = 0.6 m, = 1.4 m, and the rotation speed is 15.7 rad / s. In addition, before the flow enters the blade 130, the influence of the wind guide 200 which biases the wind in one direction is considered. Considering the influence of the wind guide 200, in the present specification, the area of the wind guide 200 where the wind is concentrated rather than the swept area of the blade 130 is used as an index in calculating the energy density. The domain for the analysis of the blade 130 flow is 8.4mx 5.6mx 2.8m, and the inlet boundary condition of the domain is 12m / s of the Dirhiclet boundary condition and the outlet boundary condition is the constant pressure condition (p = atmospheric pressure) . The peripheral wall of the domain was set so as not to affect the flow around the blade 130 under the free-shear condition. Detailed specifications and domain information are shown in Fig.

The unsteady incompressible 3-D Reynolds-Averaged Navier-Stokes (RANS) is considered as the governing equation to solve the flow around the blade 130, and the k-w model is applied to the turbulence simulation to overcome the Reynolds stress. The governing equations (1) and (2) below represent the continuity equation of fluid and the momentum conservation equation.

[Mathematical expression (1)]

[Mathematical expression (2)]

Where v is the kinematic viscosity and overbar is the time average.

The k-w model is a method suitable for calculating the velocity reduction and vortex around the blade 130 by calculating the turbulent viscosity by considering the turbulent kinetic energy and the vortex equation. The governing equations are discretized by the finite volume method. In order to simulate the rotational motion of the blade 130, the blade 130 is implemented by the Immersed Boundary Method and rotated by a constant angular velocity.

In this specification, optimization is performed by adjusting the inclination angle at which the blade 130 tilts forward and the twist angle at an angle difference between the upper and lower ends in order to optimize the efficiency of the sawtooth type blade 130. After tilting angle was tested independently, twist angle was changed at the tilting angle with the best efficiency and flow characteristics.

FIG. 5 shows the velocity and the magnitude contour of the blade circumferential direction for analyzing the efficiency and flow characteristics according to the inclination angle of the blade. 5 (a) shows a case (Case 1) where the inclination angle of the blade 130 is 0 (Case 1), FIG. 5 (b) shows a case 10 (Case 2) . The left side of FIG. 5 shows the phenomenon of the velocity reduction, and the right side shows the influence of the vortex. FIG. 5 shows a case where the twist angle is 0 °.

Referring to FIG. 5, as the angle of the blade 130 further tilts forward, it is observed that the speed reduction phenomenon in the inside and the outside of the blade 130 and the wake decrease. The speed reduction of the wind guide 200 and the rear of the blade 130 can be seen to be remarkably reduced and the speed reduction due to the tip vortices occurring in the blade tip is also reduced. This can be considered to be caused by an increase in the inclination angle of the blade 130 by reducing the tip vortices and the internal rotor vortices by reducing the relative contact area between the wind and the blade 130. [

6 shows the distribution and the change of the pressure according to the change of the inclination angle of the blade. FIG. 6 shows the pressure distribution based on the atmospheric pressure 101325.

6, positive pressure is applied to the front surface of the rotating blade 130, negative pressure is applied to the back surface, and negative pressure is applied to the opposite blade 130 due to the characteristic of the sawtooth blade 130 vortex and separation. In Case 1, the pressure is distributed evenly in the up and down directions. On the other hand, when the inclination angle of the blade 130 is increased, it is observed that the pressure is concentrated at both ends 131 and 132 and the pressure is decreased at the center 133. It can be seen that the efficiency is improved due to the increase in the torque due to the increase in the pressure at both ends 131 and 132 and the decrease in the vortex and separation at the center 133. The efficiency is calculated by the following equation (3) to be 26.3% and 27.8% , And 28.9%, respectively, showing an increase in efficiency of about 2.6% by increasing the inclination angle of the blade 130.

(3)

FIG. 7 is a graph showing changes in twist angle and observation of flow characteristics and pressure distribution when the inclination angle of the blade is 20 °. Fig. 7 (a) shows a case (Case_4) where the twist angle is 10 degrees, and Fig. 7 (b) shows a case (Case_5) when the twist angle is 20 degrees.

FIG. 7 shows a sensitivity test of the twist angle based on the inclination angle of the optimized blade 130 (Case_3) and the flow characteristics and pressure distribution of the twist angle cases Case4 and Case5.

Referring to FIG. 7, similarly to the inclination angle of the blade 130, the change of the twist angle also affected the reduction of the speed and the formation of the vortex, but the torque tended to be rather reduced when the twist angle was more than 20 degrees. In case of Case_4, the direction of the wind changed due to the wind derivative (200) and the twist angle were increased while the torque increased, whereas the case_5 decreased. From the viewpoint of the reduction of velocity and the distribution of pressure, Case_4 can be observed to have suitable flow characteristics and pressure distribution for good efficiency.

The tip speed ratio (TSR) of 15.7 rad / s set in the simulation is 0.78, which is the best efficiency in the case of the optimized blade (Case_4) within the TSR range. In order to obtain the efficiency within the TSR range, the simulation was performed by adjusting the RPM. As a result, it can be observed that the case (Case_4) of the optimization blade has higher efficiency in all the TSR sections than the case (Case_1) of the conventional blade. In particular, it can be seen that the efficiency is improved by about 18% at about TSR = 0.8.

3, the wind turbine generator 300 according to another embodiment of the present invention includes an upper plate 250 and a lower plate 260 facing each other, and a lower plate 260 connected to the upper plate 250 and the lower plate 260 A wind guide 200 including a plurality of sidewalls 210, 220, 230 and 240 and having a rotor installation part 270 formed at a center thereof; And is rotatably installed in the rotating body mounting part 270 and is installed between the upper support part 110 and the lower support part 120 with an upper support part 110 and a lower support part 120, A rotating body (100) having a plurality of blades (130) installed to be inclined; A shaft 310 connected to the lower support 120 and rotating together with the lower support 120; A generator 320 connected to the shaft 310 to produce electricity; And

And a housing (330) surrounding the shaft (310) and the generator (320).

The blade 130 may be twisted outward from one end 131 connected to the upper supporter 110 to the other end 132 connected to the lower supporter 120.

The wind guide 200 may be installed to be rotatable on the upper portion of the housing 330. The wind guide 200 may be provided on the upper surface of the wind guide 200 with a pin (Fin, Fin) may be formed. The structure of the pin 280 makes it possible to efficiently collect the wind by directing the inlet of the wind guide 200 to the wind direction in an area where the wind speed is low and the direction of the wind changes frequently.

Meanwhile, the wind power generation apparatus according to another embodiment of the present invention is a wind power generation apparatus that can include the wind turbine of the above-described embodiment. Any wind turbine generator capable of applying the wind turbine of the above-described embodiment may be used. Since such a wind power generator itself is well known in the art, a detailed description thereof will be omitted.

The above description is only illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention.

The embodiments disclosed in the present invention are not intended to limit the scope of the present invention and are not intended to limit the scope of the present invention.

The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: rotating body
110: first support
120: second support
130: blade
131: A pair of blades
132: the other end of the blade
133: central portion of the blade
200: wind induction
210, 220, 230, 240: a plurality of side walls
250: top plate
260: Lower plate
270: Rotor mounting part
280: pin
300: Wind generator
310: shaft
320: generator
330: Housing

Claims

A first induction surface and a second induction surface for inducing the wind, an inlet formed between the first induction surface and the second induction surface and through which the wind induced by the first induction surface and the second induction surface flows, Branch wind derivatives; And
A first support and a second support arranged to be rotatable inside the wind guide and arranged to face each other and a plurality of blades connecting the first support and the second support, Wherein the plurality of blades are formed so as to be inclined with respect to the center line of rotation of the blades so as to be in contact with the wind coming in through the inlet, Wherein the contact surface is formed as a curved surface so as to surround the introduced wind;
Lt; / RTI >
The wind guide includes an upper plate and a lower plate facing each other, a plurality of side walls connecting the upper plate and the lower plate, a rotating body mounting portion into which the rotating body is inserted,
Wherein a portion of the plurality of sidewalls forms the first guiding surface and the second guiding surface so as to induce wind collecting and the remainder is formed by bending at a predetermined angle so as to suppress generation of a vortex around the wind derivation, .

The method according to claim 1,
Wherein the contact surface of the blade is twisted outward from one end connected to the first support to the other end connected to the second support.

The method according to claim 1,
Wherein the contact surfaces of the blades are inclined toward the circumferential direction of the first and second support rods.

The method according to claim 1,
One end of the contact surface, which is connected to the first support, is connected ahead of the other end connected to the second support by a predetermined distance in the circumferential direction of the first support, and the first support is located on the upper part of the second support. Wind turbine.

delete

A first induction surface and a second induction surface for inducing the wind, an inlet formed between the first induction surface and the second induction surface and through which the wind induced by the first induction surface and the second induction surface flows, Branch wind derivatives; And
A first support and a second support arranged to be rotatable inside the wind guide and arranged to face each other and a plurality of blades connecting the first support and the second support, The first support and the second support being spaced from one another along the circumferential direction, each of the plurality of blades having a contact surface contacting the wind introduced through the inlet, Wherein the contact surface is formed as a curved surface so as to surround the introduced wind;
Lt; / RTI >
The wind guide includes an upper plate and a lower plate facing each other, a plurality of side walls connecting the upper plate and the lower plate, a rotating body mounting portion into which the rotating body is inserted,
Wherein a portion of the plurality of sidewalls forms the first guiding surface and the second guiding surface so as to induce wind collecting and the remainder is formed by bending at a predetermined angle so as to suppress generation of a vortex around the wind derivation, .

A wind guide including a top plate and a bottom plate facing each other, a plurality of side walls connecting the top plate and the bottom plate,
A rotating body rotatably installed in the rotary body mounting part, the rotating body having an upper support and a lower support, and a plurality of blades installed between the upper support and the lower support and inclined with respect to a center line of the rotation;
A shaft connected to the lower support and rotated together with the lower support;
A generator connected to the shaft to produce electricity; And
A housing surrounding the shaft and the generator;
/ RTI >
A plurality of sidewalls forming a first wind inducing surface and a second wind inducing surface so as to induce wind collecting, and the remainder being formed by bending at a predetermined angle so as to suppress generation of a vortex around the wind induction, Device.

8. The method of claim 7,
Wherein the blade is twisted outward from the one end connected to the upper support to the other end connected to the lower support.

8. The method of claim 7,
And the wind guide is rotatably installed on the upper portion of the housing.

10. The method of claim 9,
And a fin for rotating the wind guide is formed on an upper surface of the wind guide.