WO2015107061A1

WO2015107061A1 - Wind turbine or hydroelectric power plant

Info

Publication number: WO2015107061A1
Application number: PCT/EP2015/050550
Authority: WO
Inventors: Franz Brunner; Ulrich Papenburg
Original assignee: Erka Technik Gmbh
Priority date: 2014-01-14
Filing date: 2015-01-14
Publication date: 2015-07-23
Also published as: DE102014100382A1

Abstract

The aim of the invention is to provide a rotor which is simple, efficient, and suitable for use in small wind turbines or hydroelectric power plants. This is achieved by a rotor which comprises the following: - an axis of rotation; - a first curved main blade with a first concave front surface; and - a second main blade with a second concave front surface, said second main blade being identical to the first main blade in particular and being held and aligned axially symmetrical to the first main blade with respect to the axis of rotation. The invention is characterized by a first front blade on the face facing the concave surface of the first main blade; and a second front blade, which is identical to the first front blade in particular, on the face facing the concave surface of the second main blade.

Description

Rotor for a wind or hydroelectric plant

description

The invention relates to a rotor for a small wind turbine and a

Wind turbine comprising a corresponding rotor.

The wind power is already being used as regenerative energy source to a large extent for the production of electrical energy. Some of the plants are large wind turbines, which are often concentrated in wind farms with up to more than one hundred wind turbines and capacities of up to several hundred MW.

In addition, there are also small wind turbines for the small and medium power range of a few KW, which are particularly suitable for self-supply. This makes them particularly interesting for consumers and small and medium-sized enterprises. Small wind turbines are attractive electricity suppliers, for example for farmers, wastewater treatment plant operators, for companies with constant power consumption, for owners of electric vehicles, but also for ecologically motivated people

Private individuals. They allow a self-sufficient energy supply, for example, from remote farms, cottages and mountain huts, where there are no

Network connection exists, or even on ships and sailing yachts.

Rotors for wind turbines can be carried out in various ways. It can be distinguished between rotors with vertical and horizontal axis of rotation. So far, mainly small wind turbines in

used horizontal construction.

Vertical runners are quiet, storm-proof, easy to assemble and almost maintenance-free. They are independent of the wind direction. However, they usually have a high weight and thus a relatively low efficiency. Horizontal-running wind turbines usually have a slightly better efficiency, but are technically more complex, generate noise and are maintenance-intensive. In contrast to vertical runners, they must be tracked with the wind direction. Among the vertical runners, there are essentially two principles on which the shape of the rotor can be based. Darrieus rotors use the aerodynamic lift of the profile of the rotor blades. Savonius rotors are resistance rotors that use the flow resistance of the rotor blades to drive.

A Savonius rotor usually consists of two mounted on a vertical rotor axis horizontal circular disks, between which two or more semicircular curved wings are mounted vertically. The wings are offset from each other so that a part of the wind is diverted from the blade side that is just open to the flow and can act on the back of the concave blade there. The mode of action is based on both dynamic buoyancy and resistance-induced propulsion. Unbraked, the maximum speed is around 1.6. Therefore, the Savonius is also considered storm-proof. The biggest performance factor is for the Savonius

usually at a speed of about 0.6 to 0.8 and maximum efficiency is currently estimated at 28%. In its most widespread

The Savonius rotor is used as the drive for fans on vehicles and chimneys.

The advantages of Savonius rotors are their low starting torque and high output even at low wind speeds. Already from one

Wind speed of 1.5 m / s energy can be gained. The rotors are robust, low maintenance and easy to install. Due to their low speed, they do not have to be stopped even during storms. In contrast to systems with horizontal axes, there is no shadow cast.

Savonius rotors are therefore well suited for power generation in small wind turbines. In this case, it is possible either to feed the generated electricity into the public grid or to operate a stand-alone system without connection to the public grid. Possible applications are the power supply of homes, farms or small businesses, battery charging stations for electric vehicles, the self-sufficient operation of street lighting or

Mobile masts and the like. Also conceivable is the energy supply of sailing ships and trucks. In addition, the rotor type is also suitable as a water turbine, for example for power generation on small streams. The object of the present invention is to provide an efficient rotor for small wind turbines.

This object is achieved by the rotor according to claim 1 and by

Wind turbine solved according to claim 14.

In particular, this object is achieved by a rotor comprising:

a rotation axis;

a first curved main wing having a first concave front surface; and

- A, in particular to the first main wing identical, second main wing having a second concave front surface which is supported and aligned with respect to the axis of rotation axially symmetrical to the first main wing;

- A first slat on the concave surface of the first main wing side facing; and

- One, in particular to the first slat identical, second slat on the concave surface of the second main wing side facing.

The problem is solved by a rotor based on the principle of

Savonius rotor is based and has additional slats.

By attaching two slats on the rotor according to the invention, the torque exerted on the rotor by a fluid flowing through the rotor, in particular water or air, can be increased. With the help of such a rotor, the efficiency of power generation in a wind or hydroelectric power plant can be increased.

The presence of the slats may be suitable for effecting a spatially and temporally more uniform torque on the rotor. As a result, a burden on the design can be reduced and a quieter rotation of the rotor can be effected.

The cross section of the slats may be asymmetrical in order to create a (predominantly) dynamic buoyancy. In this case, the asymmetrically shaped slat can be flowed around by a fluid so that there is a pressure on one side and a suction on the other side. According to the invention, the slat can be designed so that the resulting force on the Wing causes a rotationally oriented torque on the rotor. The advantage is that the resistance-induced drive of the rotor is reinforced by the main wing to the dynamic buoyancy resulting drive through the slats. The slats can be shaped, for example, at least in cross-section similar or identical to an aircraft wing.

In another embodiment, the cross section of at least one slat is formed symmetrically. Regardless of the symmetrical and the

Asymmetrical design of the cross-section of the slats, this cross section viewed in the longitudinal direction preferably has a first portion with a first maximum diameter and a second portion with a second

Maximum diameter, wherein the first maximum diameter of the second maximum diameter significantly different. For example, the second maximum diameter may be less than 70 or 50 or 30% of the first

Maximum diameter be. In one embodiment, the length of the second portion is at least 10%, more preferably at least 20% of the length of the first portion and / or the area (in cross section) of the second portion is at least 10% or 20% or 30% of the total area of the cross section ,

In one embodiment, the cross-section of at least one slat is teardrop-shaped.

In one embodiment, the distance between an outer

Radius of rotation of one of the slats and an inner radius of rotation of one of the slats smaller, in particular by 40% - 80%, as an outer radius of rotation of one of the main wing. The radius of rotation can be understood as the radius of a circle which a point in a cross-sectional area of the rotor describes during the rotation about the axis of rotation. The outer radius of rotation of one of the main wings or one of the slats can be the radius of a circle which describes the point of the main wing or slat farthest from the axis of rotation. The inner radius of rotation can be correspondingly defined by a circle which describes a point of a wing closest to the axis of rotation. The slats can therefore be made smaller than the main wing. By the resulting

Size ratio of the slats to the main wings, the slats best suited to amplify the torque generated by the main blades and acting on the rotor.

In another embodiment, the outer radius of rotation of one of the slats is smaller than the outer radius of rotation of one of the main wings. The

Slats can therefore be offset in relation to the main wings inwards.

The slats can be at a certain angle to the main wings

be arranged. In this case, the outer chord of the first slat can be rotated relative to the outer chord of the first main wing by an angle of 70 ° to 100 °. Accordingly, the outer chord of the second slat can also be rotated relative to the outer chord of the second main wing by an angle of 70 ° to 100 °. Under an outer chord, the longest possible connecting line between two points of the concave portion of a wing in one

Cross-sectional area are understood. The orientation of the main and vane should strengthen the resistance-driven propulsion through the main wing optimally by dynamic buoyancy on the slats.

In one embodiment, the outer chords of the first and second main wings extend parallel to each other or lie on a straight line.

The outer chords of the main wing can take the positions 0 and 180 with respect to a rotation axis. The corresponding positions can vary. In one embodiment, these positions (0 and 180 degrees) vary by max. 30 degrees, especially around max. 15 degrees. Ie. for example, with respect to the outer chord of the first main wing that it may be inclined relative to the 0 degree position (with respect to the axis of rotation). This does not mean that the outer chord of a correspondingly inclined main wing must necessarily pass through the axis of rotation.

In one embodiment, the inner surface of the main wing is curved, preferably at an outer radius of rotation of 70 cm have a radius between 20 and 60, in particular between 40 and 50 cm. The slats may also have a corresponding curvature, for example, at an outer radius of rotation of 70 cm with a radius of 10 to 50 cm, in particular 20 to 40 cm. The rotor or parts of the rotor, in particular the main wings and / or the slats, can be made at least partially from a fiber composite material, in particular GRP, CFRP or aramid fiber. The use

State-of-the-art fiber composite materials enable an ultra-light weight

Construction with maximum strength, UV resistance and weather resistance. A rotor made of ultralight materials can have a higher efficiency than a rotor made of conventional materials. In addition, a rotor made of fiber composites is characterized by low weight and ease of transportability.

The rotor can be made up of individual modules that run along the

Rotation axis are positively connected. The individual modules are preferably identical. A modular design results in a high degree of flexibility, since existing systems can be retrofitted to increase performance and individual components can be replaced in the event of damage. The modular design also facilitates the transport of the rotor.

A positive connection should in particular also exist if the surfaces of the main wing and slats do not extend parallel to the axis of rotation but are twisted spirally around them. For this purpose, the individual modules themselves may have a part of the rotation. Positive locking can in particular mean that the main wing and the secondary wing to the

Interfaces between two modules have no edges.

The rotor and / or a single rotor module may have on at least one side a plate or webs perpendicular to the axis of rotation, which is connected to the main wings, the slats and / or the axis of rotation. This plate may be provided to define the position of the main wings and slats relative to one another and to the axis of rotation. The plate may be a circular disk. Also, a circular plate with area-wise recesses is conceivable. In this way, material and weight can be saved. The plate is suitable for suppressing flow components in the longitudinal direction (Z-axis). These forces can benefit the torque.

In one embodiment, the main wings and / or slats are spirally twisted along the axis of rotation. With such a helix structure offer the concave front surfaces of the main wing a fluid flowing from any direction at each angle of rotation an attack surface. This results in the advantage that the rotor experiences a driving torque at every point of the rotation. In addition, there is no disruptive change from strong and weak load of the rotor construction during rotation.

The helical rotation of the main wing and / or the slat can be designed so that the rotation over the entire length of the axis of rotation corresponds to a half or full turn. This results in the advantage that the concave front surface of the main wing, which offers a specific direction of flow, is the same at every angle of rotation. The position of the slat then offers the same buoyancy effect at each rotation angle. This results in constant flow over the entire rotation uniform torque.

One way to implement the slats provides a maximum wall thickness of one of the slats, which is at least twice the average wall thickness of one of the main wings. The wall thickness can be understood as the shortest distance between a certain point of the concave front surface and the convex back surface of a main wing or a slat. The wall thickness of the flow resistance generating main wing can for

Saving of material and weight are kept low. To create a dynamic buoyancy, however, the slats may have a profile that includes a thicker wall thickness.

Another possibility for the execution of slats provides a rounding of the outer edge of a slat whose radius of curvature is at least 10% of the maximum wall thickness of the slat. The outer edge may be the side of the slat farthest from the axis of rotation. A rounded outer edge of the slat may aerodynamic

Improve properties of the rotor.

Furthermore, the above object can be achieved by a wind turbine comprising one of the previously described rotors and a generator, wherein the rotor is mechanically, in particular via a transmission, connected to the generator. In one embodiment, the axis of rotation of the rotor is vertically aligned. This results in the advantage that the rotor can be driven from any horizontal wind directions.

The generator or parts of the generator can be integrated in the rotor, in particular in the axis of rotation. This allows a particularly simple transmission of the movement from the rotor to the generator, for which a gear is not needed in principle. This saves material and space.

Further advantageous embodiments will be apparent from the

Dependent claims.

The invention will now be described by means of several embodiments

described in more detail with reference to figures. Hereby show:

Fig. 1 is a sectional surface of a rotor;

Fig. 2 shows a sectional area of a rotor and circles of different

Rotational radii;

3 shows a sectional surface of a rotor and outer chords of a main and a slat;

4 shows a sectional surface of a slat;

Fig. 5 is a rotor; and

Fig. 6 is a plan view of a section through a rotor module.

In the following descriptions, the same reference numbers are used for the same and like parts.

1 shows a sectional area of a rotor with a first curved main wing 12 and an axially symmetrical with respect to a rotation axis 10 arranged second curved main wing 13. The two main wings 12,13 are in particular identical. On the sides of the concave front surfaces of the main wings 12,13 a first 15 and a second 16 slats are supported. The Concave front sides of the main wings act as a resistance to an incoming fluid and generate a rotation of the rotor. The slats generate a dynamic buoyancy when flowing through a fluid. Both effects lead to a clockwise rotation for the rotor shown, regardless of the wind direction.

The arrangement of the main wings 12,13 and slats 15,16 shown in Fig. 1 can be described so that the orientation of the first main wing 12 is referred to as 0 °. By orientation, for example, the connecting line between the two end points of the first main wing can be understood. The angle is to be measured from the axis of rotation 10 from. The second main wing 13 is mounted at 180 °. The possible shown in Fig. 1

Arrangement of the first slat 15 is then approximately at 50 ° and the arrangement of the second slat 16 corresponding to 230 °.

FIG. 2 shows a sectional surface of a rotor as in FIG. 1 and in addition

Rotation radii 21,22,23. Shown are an inner radius of rotation 21 of a slat 15, 16, an outer radius of rotation 22 of a slat 15,16 and an outer radius of rotation 23 of a main wing 12,13. The radius of rotation

21, 22, 23 is the radius of a circle which a point describes during a rotation about the axis of rotation 10. The outer radius of rotation 22,23 a wing 12,13,15,16 refers to the farthest from the axis of rotation 10 point of the wing 12,13, 15,16 and the inner radius of rotation 21 corresponding to the axis of rotation 10 closest point one

Slat 15, 16. In the embodiment of FIG. 2, the distance between the outer 22 and the inner 21 rotation radius of a slat 15,16 about 60% smaller than the outer radius of rotation 23 of a main wing 12,13. In addition, the slats 15,16 are offset from the main wings 12,13 inside. This is reflected in the fact that the outer radius of rotation 22 of the slats 15,16 is smaller than the outer radius of rotation 23 of the main wing 12,13.

FIG. 3 shows a sectional area of a rotor with outer chords 25, 26 of the first slat 15 and of the first main wing 12. The longest possible connecting line between two points of the concave becomes

Section of a sectional surface of the wings 12,13,15,16 referred to as outer chord 25,26. In the embodiment in Fig. 3, the angle α between the outer chord 25 of the first slat 15 and the outer chord 26 of the first Main wing 12 about 90 °. A corresponding arrangement applies to the second slat 16 and second main wing 13, since they are arranged in Fig. 3 axially symmetrical to the first slat 15 and the first main wing 12 with respect to the axis of rotation 10.

4 shows a section through a first slat 15. To produce a dynamic lift, the slat 15 is shaped in the manner of a support surface. Shown are a maximum wall thickness 27 and an outer edge 29 of the slat 15. A wall thickness refers to the shortest distance between a point of the concave front surface and the convex back surface of the slat. The maximum wall thickness 27 is thus achieved, as shown in Fig. 4, at the widest point of the section through the wing. The outer edge 29 is the farthest from the axis of rotation 10 side of the slat 15. In Fig. 4, the outer edge 29 has a rounding according to the invention, which has a radius of curvature of not less than 10% of the maximum wall thickness 27.

5, an embodiment of a rotor is shown. The main wings 12, 13 and the slats 15, 16 are spirally twisted about the axis of rotation 10. The rotation axis 10 is oriented vertically. The orientation of the concave front surface of the first main wing 12 changes over the entire length of the rotation axis 10 by 180 °. In Fig. 5 shows the concave

Front surface of the first main wing 12 at the upper end of the rotor, or the axis of rotation 10, from the viewer to the rear, at the lower end of the

Rotation axis 10 forward. The surfaces of the second main wing 13 and the first 15 and second 16 slats are carried out in a corresponding manner.

FIG. 6 shows a plan view of a module of a rotor. The module is bounded at the bottom by a circular plate 18. The belonging to the rotor module parts of the main wing 12,13 and the slats 15,16 are connected to the plate 18 and protrude from the plane of the plate 18 out. In order to produce a structure of a helically rotated rotor of identical modules form-fitting, the parts of the wings 12,13,15, 16 are tilted in the module and perform a part of the rotation about the rotation axis 10 from. When joining several such modules, the continuous shape of the main wings 12, 13 and slat 15, 16 shown in FIG. 5 results. LIST OF REFERENCE NUMBERS

10 rotation axis

12 First main wing

13 Second main wing

15 First slat

16 second slat

18 plate

21 inner radius of rotation of a slat

22 outer radius of rotation of a slat

23 outer radius of rotation of a main wing

25 outer tendon of the first slat

26 outer tendon of the first main wing

27 Maximum wall thickness of the first slat

29 outer edge of the first slat

α angle between the outer chord of the first slat and the outer chord of the first main wing

Claims

claims

A rotor comprising:

- a rotation axis (10);

- A first curved main wing (12) having a first concave front surface; and

- A, in particular to the first main wing (12) identical, second main wing (13) having a second concave front surface which is axially symmetrical with respect to the axis of rotation (10) to the first main wing (12) supported and aligned,

marked by:

- A first slat (15) on the concave surface of the first main wing (12) facing side; and

- A, in particular to the first slat (15) identical, second slat (16) on the concave surface of the second main wing (13) facing side.

2. Rotor according to claim 1,

d a d u rc h e ke n ze i c h n et that

a cross-section of the first (15) and / or second (16) slat for generating a dynamic buoyancy is formed asymmetrically.

3. Rotor according to one of claims 1 or 2,

d a d u rc h e ke n ze i c h n et that

a distance between an outer radius of rotation (22) of the first (15) and / or second (16) slat and an inner radius of rotation (21) of the first (15) and / or second (16) slat smaller, in particular by 40% -80 %, as an outer radius of rotation (23) of the first (12) and / or second (13) main wing.

4. Rotor according to one of the preceding claims,

d a d u rc h e ke n ze i c h n et that

an outer radius of rotation (22) of the first (15) and / or second (16) slat is less than the outer radius of rotation (23) of the first (12) and / or second (13) main wing.

5. Rotor according to one of the preceding claims,

d a d u r c h e n c i n e c e n s that

the first slat (15) is arranged such that an outer chord (25) of the first slat (15) is rotated relative to an outer chord (26) of the first main wing (12) by an angle (oc) of 70 ° to 100 °.

6. Rotor according to one of the preceding claims,

d a d u r c h e n c i n e c e n s that

the main wing (12,13) and / or the slats (15,16) at least partially made of a fiber composite material, in particular GRP, CFRP or

Aramid fiber, are made.

7. Rotor according to one of the preceding claims,

d a d u r c h e n c i n e c e n s that

the rotor consists of individual, preferably identical, modules which are positively connected along the axis of rotation (10).

8. Rotor according to one of the preceding claims,

d a d u r c h e n c i n e c e n s that

the rotor and / or a single rotor module, on at least one side of a perpendicular to the axis of rotation (10) plate (18) with the main wings (12,13), the slats (15) and / or the

Rotation axis (10) is connected.

9. Rotor according to one of the preceding claims,

d a d u r c h e n c i n e c e n s that

the first (12) and / or second (13) main wing and / or the first (15) and / or second (16) slat along the axis of rotation (10)

are twisted spirally.

10. Rotor according to one of the preceding claims,

d a d u r c h e n c i n e c e n s that

a helical rotation of the first (12) and / or second (13) main wing and / or the first (15) and / or second (16) slat along the axis of rotation (10) over an entire length of

Rotation axis (10) corresponds to a half or full turn.

11. Rotor according to one of the preceding claims,

d a d u rc h e ke n ze i c h n et that

the rotor consists of individual, preferably identical, modules which each have a twist and are positively connected along the axis of rotation (10) such that the first (12) and / or second (13) main wing and / or the first (15) and / or second (16) slats are spirally twisted.

12. Rotor according to one of the preceding claims,

d a d u rc h e ke n ze i c h n et that

the maximum wall thickness (27) of the first (15) and / or second (16) slat is at least twice the average wall thickness of the first (12) and / or second (13) main wing.

13. Rotor according to one of the preceding claims,

d a d u rc h e ke n ze i c h n et that

a rounding (29) is formed on an outer edge of the first (15) and / or second (16) slat with a radius of curvature of at least 10% of the maximum wall thickness (27) of the first (15) and / or second (16) slat.

14. Wind turbine, comprising

a rotor according to one of the preceding claims and a

Generator,

wherein the rotor is mechanically, in particular via a transmission, connected to the generator.

15. Wind power plant according to claim 14,

d a d u rc h e ke n ze i c h n et that

the axis of rotation of the rotor is vertically aligned.

16. Wind power plant according to one of claims 14 or 15,

d a d u rc h e ke n ze i c h n et that

the generator or parts of the generator are integrated in the rotor, in particular in the axis of rotation (10).