WO2008035149A2 - Rotor blade for a wind turbine - Google Patents

Rotor blade for a wind turbine Download PDF

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Publication number
WO2008035149A2
WO2008035149A2 PCT/IB2007/001458 IB2007001458W WO2008035149A2 WO 2008035149 A2 WO2008035149 A2 WO 2008035149A2 IB 2007001458 W IB2007001458 W IB 2007001458W WO 2008035149 A2 WO2008035149 A2 WO 2008035149A2
Authority
WO
WIPO (PCT)
Prior art keywords
rotor blade
brush hairs
blade according
trailing edge
previous
Prior art date
Application number
PCT/IB2007/001458
Other languages
French (fr)
Other versions
WO2008035149A3 (en
Inventor
Stefan Oerlemans
Original Assignee
Stichting Nationaal Lucht- En Ruimtevaart Laboratorium
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Stichting Nationaal Lucht- En Ruimtevaart Laboratorium filed Critical Stichting Nationaal Lucht- En Ruimtevaart Laboratorium
Publication of WO2008035149A2 publication Critical patent/WO2008035149A2/en
Publication of WO2008035149A3 publication Critical patent/WO2008035149A3/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06—Rotors
    • F03D1/065—Rotors characterised by their construction elements
    • F03D1/0675—Rotors characterised by their construction elements of the blades
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00—Components
    • F05B2240/20—Rotors
    • F05B2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2250/00—Geometry
    • F05B2250/30—Arrangement of components
    • F05B2250/31—Arrangement of components according to the direction of their main axis or their axis of rotation
    • F05B2250/314—Arrangement of components according to the direction of their main axis or their axis of rotation the axes being inclined in relation to each other
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2260/00—Function
    • F05B2260/96—Preventing, counteracting or reducing vibration or noise
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction

Definitions

  • the invention firstly relates to a rotor blade for a wind turbine, comprising a leading edge, a trailing edge, an upper low pressure surface and a lower high pressure surface, and having an inner root end for connection to a hub and a free outer tip end defining therebetween a rotor blade span.
  • wind turbines play an increasingly important role. However, it often occurs that wind turbines are prevented from being erected or are not allowed to operate at full power because of restrictive requirements with respect to the production of noise.
  • An important source of noise in modern wind turbines is noise of the rotor blades induced by the air flow.
  • Such rotor blade noise basically is caused by pressure fluc- tuations on the rotor blade lower and upper surfaces, which pressure fluctuations move along with the air flow over the trailing edge of the rotor blade, at which locations they radiate as noise (trailing edge ,noise) .
  • Such pressure fluctuations mainly are caused by the turbulent boundary layer on the rotor blade.
  • a rotor blade for a wind turbine of the present type is characterised by brush hairs positioned at, or in the immediate vicinity of, the trailing edge of the rotor blade.
  • brush hairs positioned at, or in the immediate vicinity of, the trailing edge of the rotor blade substantially reduce the trailing edge noise of rotor blades .
  • This noise reduction primarily is based on a diminishing of the discontinuity at the trailing edge of the rotor blade. Due to the finite flow resistance of the brush hairs pressure fluctuations are gradually equalised in the flow direction, as a result of which the trailing edge less effectively radiates noise.
  • noise reductions up to 10 dB are expected in a wide frequency range.
  • the actual noise reduction will depend on a number of parameters, such as properties of the brush hairs, shape and dimensions of the rotor blade, number of revolutions of the rotor blade, etcetera.
  • the brush hairs are serially arranged along the trailing edge.
  • “serially” means that the brush hairs substantially are arranged along a line. This line does not necessarily have to be a straight line (for example, when the rotor blade is twisted the trailing edge generally will not define a straight line, but a curved line) .
  • the brush hair are arranged in a single series, it is also possible that the brush hairs are arranged in multiple series extending substantially in parallel to each other. Applying multiple se ⁇ ries means, that at least one of said series cannot be positioned exactly at the trailing edge of the rotor blade, but will have to be positioned in the immediate vicinity thereof. However, it also might be possible that all series are positioned in the immediate vicinity without anyone be- ing positioned exactly at the trailing edge of the rotor blade .
  • the brush hairs are arranged in a number of separate bundles.
  • Each bundle comprises a defined amount of brush hairs. It is not necessary that each bundle comprises the same amount of brush hairs .
  • the bundles themselves again may be arranged serially along the trailing edge as defined above .
  • the brush hairs are provided along substantially the entire extension of the trailing edge. This means, that brush hairs are provided along substantially the entire rotor blade span.
  • the brush hairs are provided only over part of the rotor blade span, for example only over substantially the outer 30% of the rotor blade span.
  • the brush hairs may extend substantially perpendicularly to the trailing edge.
  • the brush hairs extend inclined relative to the trailing edge.
  • the brush hairs may be inclined somewhat towards the outer tip end of the rotor blade to cope with a flow direction which is not perpendicularly to the trailing edge (e.g. due to centrifugal forces acting on the rotating rotor blade) .
  • the brush hairs extend in parallel to one of the upper and lower surfaces of the rotor blade. Again, this applies with respect to the local extension of the upper and lower surfaces of the rotor blade (which may vary span-wise when the rotor blade is twisted) .
  • the brush hairs are inclined relative to both the upper and lower surfaces of the rotor blade.
  • all brush hairs substantially are of equal length
  • the length of the brush hairs varies between the inner root end and the free outer tip end of the rotor blade.
  • the length of the brush hairs increases from the inner root end towards the free outer tip end. Such an increase may be linearly, but also may occur in any other desired manner (to cope with the local flow characteristics at different span-wise positions along the rotor blade) .
  • the brush hairs are sufficient flexible to adopt, during use of the rotor blade, a shape in correspondence with local air flow conditions. Generally this means, that the brush hair will have differ- ent positions in a rest position (rotor blade not active) and a working position (rotor blade active, that means rotating) .
  • Yet another feature for influencing the noise- reducing effect of the brush hairs constitutes the choice of the cross-section of the brush hairs, which for example may be circular or non-circular.
  • the distance between individual brush hairs should be such, that pressure fluctuations in the flow direction are gradually equalised, but a certain flow through the brush hairs is allowed for making possible such a pressure equalisation.
  • the brush hairs should not constitute a complete seal.
  • the brush hairs may be attached directly to the rotor blade.
  • the production and maintenance of rotor blades in accordance with the present invention may be optimized when the brush hairs are attached to at least one strip member which, on its turn, is attached to the rotor blade.
  • strip members may be prepared separately and may then be attached to the rotor blade. The preparation of such strip members then may occur at a different location than the location where the rotor blade is used (the location where the wind turbine is erected) .
  • such a strip member is releasably at- tachable to the rotor blade, allowing an easy disconnection for maintenance or replacement .
  • the brush hairs may be of a synthetic or natural nature .
  • the invention further relates to a strip member provided with brush hairs for application on a rotor blade according to the present invention.
  • Figure 1 shows in a frontal view a rotor blade of a wind turbine ;
  • figure 2 shows, on a larger scale, and perspec- tively, a cross-section according to II-II in figure 1;
  • figure 3 shows a top plan view of an embodiment;
  • figure 4 shows a top plan view of another embodiment;
  • figure 5 shows a cross-section according to figure 2 of an embodiment;
  • figure 6 shows a cross-section according to figure 2 of another embodiment;
  • figure 7 shows a top plan view of yet another embodiment, and
  • figure 8 shows, on a still larger scale, a frontal view of the trailing edge section of yet another embodiment of a rotor blade.
  • a rotor blade 1 for a wind turbine comprising (with respect to the direction of rotation) a leading edge 2, a trailing edge 3, an inner root end 4 for connection to a hub 5 of the wind turbine and a free outer tip end 6. Between the inner root end 4 and free outer tip end 6 a rotor blade span S is defined. Further, referring to figure 2, the rotor blade 1 comprises an upper low pressure surface 7 and a lower high pressure surface 8. Specifically referring to figure 2 the rotor blade
  • FIG 1 comprises brush hairs 9 positioned at, or in the immediate vicinity of, the trailing edge 3 of the rotor blade (these brush hairs are not illustrated in figure 1) .
  • said brush hairs 9 are serially arranged along the training edge 3.
  • only one series of brush hairs 9 has been illustrated in figure 2, there also may be multiple series extending substantially in parallel to each other .
  • Figures 3 and 4 substantially show a top plan view in accordance with III in figure 2; in figure 3 an embodiment of a rotor blade 1 is illustrated in which all brush hairs 9 substantially are of equal length and extend substantially perpendicularly to the trailing edge 3.
  • the brush hairs 9 extend inclined relative to the trailing edge 9.
  • the inclination is such, that the free ends of the brush hairs 9 are somewhat directed towards the free outer tip end 6 of the rotor blade 1 (which would be located at the top of figure 4, then) .
  • Figure 5 which basically corresponds with the cross-section according to figure 2, illustrates that the brush hairs substantially extend in parallel to the lower surface 8 of the rotor blade 1. Consequently, the brush hairs 9 are inclined relative to the upper surface 7.
  • the brush hairs 9 are inclined relative to both the upper and lower surfaces 7 and 8, respectively, of the rotor blade 1.
  • Figure 7 shows an embodiment of the rotor blade 1 in which the length of the brush hairs 9 varies between the inner root end and free outer tip end of the rotor blade 1.
  • the length of the brush hairs 9 may increase from the inner root end 4 (bottom) towards the free outer tip end 6 (top) .
  • the brush hairs 9 basically are provided along substantially the entire extension (span S) of the trailing edge (thus basically ranging from the inner root end 4 towards the free outer tip end 6) . It is possible, however, that the brush hairs 9 are provided only over part of the rotor blade span S, for example only the outer 30% thereof as indicated by the hatched section in figure 1.
  • FIG. 8 shows, on a much larger scale, a frontal view of the trailing edge section 3 which is provided with brush hairs 9 arranged in a number of separate bundles .
  • each bundle comprises three brush hairs 9.
  • the brush hairs 9 are sufficiently flexible to adopt, during use of the rotor blade, a shape in correspondence with local air flow conditions.
  • the brush hairs may have different cross sections, for example a circular cross section or a non-circular cross section.
  • the brush hairs 9 are attached directly to the rotor blade
  • the brush hairs 9 also may be attached to at least one strip member 10 (indicated in dotted lines in figure 2) which, on its turn, is attached to the rotor blade 1, for example releasably attached.
  • strip member 10 indicated in dotted lines in figure 2

Abstract

A connector holder has a U-shaped frame and supports an internal connector-receiving part within the U-shaped frame. Guide pieces are provided that grip the ends of a connector and the cable to which the connector is attached. The connector-receiving part thereby floats inside of the U-shaped frame so as to be positioned accurately for mounting to an opposing connector.

Description

Rotor blade for a wind turbine
The invention firstly relates to a rotor blade for a wind turbine, comprising a leading edge, a trailing edge, an upper low pressure surface and a lower high pressure surface, and having an inner root end for connection to a hub and a free outer tip end defining therebetween a rotor blade span.
In the production of environment-friendly energy wind turbines play an increasingly important role. However, it often occurs that wind turbines are prevented from being erected or are not allowed to operate at full power because of restrictive requirements with respect to the production of noise. An important source of noise in modern wind turbines is noise of the rotor blades induced by the air flow. Such rotor blade noise basically is caused by pressure fluc- tuations on the rotor blade lower and upper surfaces, which pressure fluctuations move along with the air flow over the trailing edge of the rotor blade, at which locations they radiate as noise (trailing edge ,noise) . Such pressure fluctuations mainly are caused by the turbulent boundary layer on the rotor blade.
It is an object of the present invention to provide an improved rotor blade for a wind turbine of the type referred to above .
Thus, in accordance with the present invention, a rotor blade for a wind turbine of the present type is characterised by brush hairs positioned at, or in the immediate vicinity of, the trailing edge of the rotor blade.
It appears, that brush hairs positioned at, or in the immediate vicinity of, the trailing edge of the rotor blade substantially reduce the trailing edge noise of rotor blades . This noise reduction primarily is based on a diminishing of the discontinuity at the trailing edge of the rotor blade. Due to the finite flow resistance of the brush hairs pressure fluctuations are gradually equalised in the flow direction, as a result of which the trailing edge less effectively radiates noise.
Based on wind tunnel measurements noise reductions up to 10 dB are expected in a wide frequency range. Of course, the actual noise reduction will depend on a number of parameters, such as properties of the brush hairs, shape and dimensions of the rotor blade, number of revolutions of the rotor blade, etcetera.
In a first preferred embodiment the brush hairs are serially arranged along the trailing edge. In this aspect, "serially" means that the brush hairs substantially are arranged along a line. This line does not necessarily have to be a straight line (for example, when the rotor blade is twisted the trailing edge generally will not define a straight line, but a curved line) .
Although it is possible, that the brush hair are arranged in a single series, it is also possible that the brush hairs are arranged in multiple series extending substantially in parallel to each other. Applying multiple se~ ries means, that at least one of said series cannot be positioned exactly at the trailing edge of the rotor blade, but will have to be positioned in the immediate vicinity thereof. However, it also might be possible that all series are positioned in the immediate vicinity without anyone be- ing positioned exactly at the trailing edge of the rotor blade .
According to another embodiment of the rotor blade, the brush hairs are arranged in a number of separate bundles. Each bundle comprises a defined amount of brush hairs. It is not necessary that each bundle comprises the same amount of brush hairs . The bundles themselves again may be arranged serially along the trailing edge as defined above .
In a basic embodiment of the rotor blade according to the present invention the brush hairs are provided along substantially the entire extension of the trailing edge. This means, that brush hairs are provided along substantially the entire rotor blade span.
However, in accordance with another embodiment, the brush hairs are provided only over part of the rotor blade span, for example only over substantially the outer 30% of the rotor blade span.
From experiments it appeared that such outer 30% of the rotor blade span contributes the larger part of the noise generated by the rotor blade, and that providing the brush hairs only there already eliminates a major part of such noise.
With respect to the positioning of the brush hairs a number of parameters may be varied for obtaining an opti- mal result. For example, the brush hairs may extend substantially perpendicularly to the trailing edge.
It should be noted, that "perpendicularly to the trailing edge" should be considered at the respective local span-wise position of the rotor blade. However, it is possible too that the brush hairs extend inclined relative to the trailing edge. For example the brush hairs may be inclined somewhat towards the outer tip end of the rotor blade to cope with a flow direction which is not perpendicularly to the trailing edge (e.g. due to centrifugal forces acting on the rotating rotor blade) . Further it is possible, that the brush hairs extend in parallel to one of the upper and lower surfaces of the rotor blade. Again, this applies with respect to the local extension of the upper and lower surfaces of the rotor blade (which may vary span-wise when the rotor blade is twisted) .
In an alternative embodiment, however, the brush hairs are inclined relative to both the upper and lower surfaces of the rotor blade. Whereas in a simple embodiment all brush hairs substantially are of equal length, it is also possible that the length of the brush hairs varies between the inner root end and the free outer tip end of the rotor blade. For exam- pie one may adopt an embodiment in which the length of the brush hairs increases from the inner root end towards the free outer tip end. Such an increase may be linearly, but also may occur in any other desired manner (to cope with the local flow characteristics at different span-wise positions along the rotor blade) .
Further it is preferred that the brush hairs are sufficient flexible to adopt, during use of the rotor blade, a shape in correspondence with local air flow conditions. Generally this means, that the brush hair will have differ- ent positions in a rest position (rotor blade not active) and a working position (rotor blade active, that means rotating) .
Yet another feature for influencing the noise- reducing effect of the brush hairs constitutes the choice of the cross-section of the brush hairs, which for example may be circular or non-circular.
It should be noted, that the distance between individual brush hairs should be such, that pressure fluctuations in the flow direction are gradually equalised, but a certain flow through the brush hairs is allowed for making possible such a pressure equalisation. Thus, the brush hairs should not constitute a complete seal.
For the construction of the rotor blade the brush hairs may be attached directly to the rotor blade. However, the production and maintenance of rotor blades in accordance with the present invention may be optimized when the brush hairs are attached to at least one strip member which, on its turn, is attached to the rotor blade. Such strip members may be prepared separately and may then be attached to the rotor blade. The preparation of such strip members then may occur at a different location than the location where the rotor blade is used (the location where the wind turbine is erected) .
Preferably, such a strip member is releasably at- tachable to the rotor blade, allowing an easy disconnection for maintenance or replacement .
The brush hairs may be of a synthetic or natural nature .
The invention further relates to a strip member provided with brush hairs for application on a rotor blade according to the present invention.
Hereinafter the invention will be elucidated while referring to the drawing, in which embodiments thereof are illustrated. Figure 1 shows in a frontal view a rotor blade of a wind turbine ; figure 2 shows, on a larger scale, and perspec- tively, a cross-section according to II-II in figure 1; figure 3 shows a top plan view of an embodiment; figure 4 shows a top plan view of another embodiment; figure 5 shows a cross-section according to figure 2 of an embodiment; figure 6 shows a cross-section according to figure 2 of another embodiment; figure 7 shows a top plan view of yet another embodiment, and figure 8 shows, on a still larger scale, a frontal view of the trailing edge section of yet another embodiment of a rotor blade.
Firstly referring to figure 1 a rotor blade 1 for a wind turbine is illustrated, comprising (with respect to the direction of rotation) a leading edge 2, a trailing edge 3, an inner root end 4 for connection to a hub 5 of the wind turbine and a free outer tip end 6. Between the inner root end 4 and free outer tip end 6 a rotor blade span S is defined. Further, referring to figure 2, the rotor blade 1 comprises an upper low pressure surface 7 and a lower high pressure surface 8. Specifically referring to figure 2 the rotor blade
1 comprises brush hairs 9 positioned at, or in the immediate vicinity of, the trailing edge 3 of the rotor blade (these brush hairs are not illustrated in figure 1) . In the embodiment of figure 2, said brush hairs 9 are serially arranged along the training edge 3. Although only one series of brush hairs 9 has been illustrated in figure 2, there also may be multiple series extending substantially in parallel to each other .
Figures 3 and 4 substantially show a top plan view in accordance with III in figure 2; in figure 3 an embodiment of a rotor blade 1 is illustrated in which all brush hairs 9 substantially are of equal length and extend substantially perpendicularly to the trailing edge 3. In the embodiment according to figure 4, however, the brush hairs 9 extend inclined relative to the trailing edge 9. Preferably. the inclination is such, that the free ends of the brush hairs 9 are somewhat directed towards the free outer tip end 6 of the rotor blade 1 (which would be located at the top of figure 4, then) . Figure 5, which basically corresponds with the cross-section according to figure 2, illustrates that the brush hairs substantially extend in parallel to the lower surface 8 of the rotor blade 1. Consequently, the brush hairs 9 are inclined relative to the upper surface 7. In the embodiment according to figure 6 the brush hairs 9 are inclined relative to both the upper and lower surfaces 7 and 8, respectively, of the rotor blade 1.
Figure 7 shows an embodiment of the rotor blade 1 in which the length of the brush hairs 9 varies between the inner root end and free outer tip end of the rotor blade 1. For example, the length of the brush hairs 9 may increase from the inner root end 4 (bottom) towards the free outer tip end 6 (top) .
In the embodiments illustrated the brush hairs 9 basically are provided along substantially the entire extension (span S) of the trailing edge (thus basically ranging from the inner root end 4 towards the free outer tip end 6) . It is possible, however, that the brush hairs 9 are provided only over part of the rotor blade span S, for example only the outer 30% thereof as indicated by the hatched section in figure 1.
Figure 8 shows, on a much larger scale, a frontal view of the trailing edge section 3 which is provided with brush hairs 9 arranged in a number of separate bundles . In this schematic illustration each bundle comprises three brush hairs 9.
The provision of the brush hairs 9 at, or in the immediate vicinity of, the trailing edge 3 of the rotor blade 1 is helpful in reducing trailing edge noise. For ob- taining such a function, it may be advisable that the brush hairs 9 are sufficiently flexible to adopt, during use of the rotor blade, a shape in correspondence with local air flow conditions.
It has not been shown in detail that the brush hairs may have different cross sections, for example a circular cross section or a non-circular cross section.
Whereas, in a very simple emebodiment, the brush hairs 9 are attached directly to the rotor blade, the brush hairs 9 also may be attached to at least one strip member 10 (indicated in dotted lines in figure 2) which, on its turn, is attached to the rotor blade 1, for example releasably attached. There may be only one such strip member 10 or a number of such strip members .
The specific choice of positioning of brush hairs and shapes and dimensions of such brush hairs depend from many parameters, such as, for example, expected wind velocities, number of revolutions and angle of incidence of the rotor blade. The choice should be such, that the brush hairs 9 do not have influence on the aerodynamic characterics of the rotor blades .
The invention is not limited to the embodiments described before, which may be varied widely within the scope of the invention as defined by the appending claims .

Claims

1. Rotor blade for a wind turbine, comprising a leading edge, a trailing edge, an upper low pressure surface and a lower high pressure surface, and having an inner root end for connection to a hub and a free outer tip end defin- ing there between a rotor blade span, characterized by brush hairs positioned at, or in the immediate vicinity of, the trailing edge of the rotor blade.
2. Rotor blade according to claim 1, wherein the brush hairs are serially arranged along the trailing edge.
3. Rotor blade according to claim 2, wherein the brush hairs are arranged in a single series.
4. Rotor blade according to claim 2 , wherein the brush hairs are arranged in multiple series extending substantially in parallel to each other.
5. Rotor blade according to claim 1, wherein the brush hairs are arranged in a number of separate bundles .
6. Rotor blade according to any of the previous claims, wherein the brush hairs are provided along substantially the entire extension of the trailing edge.
7. Rotor blade according to any of the claims 1-5, wherein the brush hairs are provided only over part of the rotor blade span.
8. Rotor blade according to claim 7, wherein the brush hairs are provided only over substantially the outer 30% of the rotor blade span.
9. Rotor blade according to any of the previous claims, wherein the brush hairs extend substantially perpendicularly to the trailing edge.
10. Rotor blade according to any of the claims 1- 8, wherein the brush hairs extend inclined relative to the trailing edge.
11. Rotor blade according to any of the previous claims, wherein the brush hairs extend in parallel to one of the upper and lower surfaces of the rotor blade .
12. Rotor blade according to any of the claims 1- 10, wherein the brush hairs are inclined relative to both the upper and lower surfaces of the rotor blade.
13. Rotor blade according to any of the previous claims, wherein all brush hairs substantially are of equal length.
14. Rotor blade according to any of the claims 1-
12, wherein the length of the brush hairs varies between the inner root end and the free outer tip end of the rotor blade .
15. Rotor blade according to claim 14, wherein the length of the brush hairs increases from the inner root end towards the free outer tip end.
16. Rotor blade according to any of the previous claims, wherein the brush hairs are sufficiently flexible to adopt, during use of the rotor blade, a shape in correspon- dence with local air flow conditions.
17. Rotor blade according to any of the previous claims, wherein the brush hairs have a circular cross section.
18. Rotor blade according to any of the claims 1- 16, wherein the brush hairs have a non-circular cross section.
19. Rotor blade according to any of the previous claims, wherein the brush hairs are attached directly to the rotor blade.
20. Rotor blade according to any of the claims 1-
18, wherein the brush hairs are attached to at least one strip member which, on its turn, is attached to the rotor blade .
21. Rotor blade according to claim 20, wherein the strip member is releasably attachable to the rotor blade.
22. Strip member provided with brush hairs, for application on a rotor blade according to claim 20 or 21.
23. Wind turbine provided with at least two rotor blades according to any of the claims 1-21.
PCT/IB2007/001458 2006-02-23 2007-02-26 Rotor blade for a wind turbine WO2008035149A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL1031223 2006-02-23
NL1031223A NL1031223C1 (en) 2006-02-23 2006-02-23 Wind turbine blade, has brush at back edge of blade, where brush includes synthetic bristles that rest parallel to top or bottom of blade

Publications (2)

Publication Number Publication Date
WO2008035149A2 true WO2008035149A2 (en) 2008-03-27
WO2008035149A3 WO2008035149A3 (en) 2009-02-19

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NL (1) NL1031223C1 (en)
WO (1) WO2008035149A2 (en)

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US7976283B2 (en) 2010-11-10 2011-07-12 General Electric Company Noise reducer for rotor blade in wind turbine
US7976276B2 (en) 2010-11-04 2011-07-12 General Electric Company Noise reducer for rotor blade in wind turbine
US8083488B2 (en) 2010-08-23 2011-12-27 General Electric Company Blade extension for rotor blade in wind turbine
US8267657B2 (en) 2010-12-16 2012-09-18 General Electric Company Noise reducer for rotor blade in wind turbine
EP2570656A1 (en) * 2011-09-19 2013-03-20 Nordex Energy GmbH Wind energy assembly rotor blade with a thick profile trailing edge
US8414261B2 (en) 2011-05-31 2013-04-09 General Electric Company Noise reducer for rotor blade in wind turbine
US8430638B2 (en) 2011-12-19 2013-04-30 General Electric Company Noise reducer for rotor blade in wind turbine
US8523515B2 (en) 2010-11-15 2013-09-03 General Electric Company Noise reducer for rotor blade in wind turbine
WO2014048581A1 (en) * 2012-09-25 2014-04-03 Siemens Aktiengesellschaft A wind turbine blade with a noise reducing device
US8834127B2 (en) 2011-09-09 2014-09-16 General Electric Company Extension for rotor blade in wind turbine
US8834117B2 (en) 2011-09-09 2014-09-16 General Electric Company Integrated lightning receptor system and trailing edge noise reducer for a wind turbine rotor blade
DK178050B1 (en) * 2011-10-19 2015-04-13 Gen Electric WINDOW ROTOR REMOVALS WITH REAR EDGE EXTENSION AND PROCEDURE
US9297357B2 (en) 2013-04-04 2016-03-29 General Electric Company Blade insert for a wind turbine rotor blade
US9494134B2 (en) 2013-11-20 2016-11-15 General Electric Company Noise reducing extension plate for rotor blade in wind turbine
US9506452B2 (en) 2013-08-28 2016-11-29 General Electric Company Method for installing a shear web insert within a segmented rotor blade assembly
US9638164B2 (en) 2013-10-31 2017-05-02 General Electric Company Chord extenders for a wind turbine rotor blade assembly
US10180125B2 (en) 2015-04-20 2019-01-15 General Electric Company Airflow configuration for a wind turbine rotor blade
US10465652B2 (en) 2017-01-26 2019-11-05 General Electric Company Vortex generators for wind turbine rotor blades having noise-reducing features
US10746157B2 (en) 2018-08-31 2020-08-18 General Electric Company Noise reducer for a wind turbine rotor blade having a cambered serration
US10767623B2 (en) 2018-04-13 2020-09-08 General Electric Company Serrated noise reducer for a wind turbine rotor blade
EP3747764A1 (en) * 2015-12-18 2020-12-09 Amazon Technologies, Inc. Propeller blade treatments for sound control

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US8083488B2 (en) 2010-08-23 2011-12-27 General Electric Company Blade extension for rotor blade in wind turbine
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US7976283B2 (en) 2010-11-10 2011-07-12 General Electric Company Noise reducer for rotor blade in wind turbine
US8523515B2 (en) 2010-11-15 2013-09-03 General Electric Company Noise reducer for rotor blade in wind turbine
US8267657B2 (en) 2010-12-16 2012-09-18 General Electric Company Noise reducer for rotor blade in wind turbine
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US8414261B2 (en) 2011-05-31 2013-04-09 General Electric Company Noise reducer for rotor blade in wind turbine
US8834127B2 (en) 2011-09-09 2014-09-16 General Electric Company Extension for rotor blade in wind turbine
US8834117B2 (en) 2011-09-09 2014-09-16 General Electric Company Integrated lightning receptor system and trailing edge noise reducer for a wind turbine rotor blade
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US20130071253A1 (en) * 2011-09-19 2013-03-21 Gunter Fischer Wind Turbine Rotor Blade having a Thick Profile Trailing Edge
US9347427B2 (en) * 2011-09-19 2016-05-24 Nordex Energy Gmbh Wind turbine rotor blade having a thick profile trailing edge
DK178050B1 (en) * 2011-10-19 2015-04-13 Gen Electric WINDOW ROTOR REMOVALS WITH REAR EDGE EXTENSION AND PROCEDURE
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US9297357B2 (en) 2013-04-04 2016-03-29 General Electric Company Blade insert for a wind turbine rotor blade
US9506452B2 (en) 2013-08-28 2016-11-29 General Electric Company Method for installing a shear web insert within a segmented rotor blade assembly
US9638164B2 (en) 2013-10-31 2017-05-02 General Electric Company Chord extenders for a wind turbine rotor blade assembly
US9494134B2 (en) 2013-11-20 2016-11-15 General Electric Company Noise reducing extension plate for rotor blade in wind turbine
US10180125B2 (en) 2015-04-20 2019-01-15 General Electric Company Airflow configuration for a wind turbine rotor blade
EP3747764A1 (en) * 2015-12-18 2020-12-09 Amazon Technologies, Inc. Propeller blade treatments for sound control
US10465652B2 (en) 2017-01-26 2019-11-05 General Electric Company Vortex generators for wind turbine rotor blades having noise-reducing features
US10767623B2 (en) 2018-04-13 2020-09-08 General Electric Company Serrated noise reducer for a wind turbine rotor blade
US10746157B2 (en) 2018-08-31 2020-08-18 General Electric Company Noise reducer for a wind turbine rotor blade having a cambered serration

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