NL1031223C1 - Wind turbine blade, has brush at back edge of blade, where brush includes synthetic bristles that rest parallel to top or bottom of blade - Google Patents

Wind turbine blade, has brush at back edge of blade, where brush includes synthetic bristles that rest parallel to top or bottom of blade Download PDF

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Publication number
NL1031223C1
NL1031223C1 NL1031223A NL1031223A NL1031223C1 NL 1031223 C1 NL1031223 C1 NL 1031223C1 NL 1031223 A NL1031223 A NL 1031223A NL 1031223 A NL1031223 A NL 1031223A NL 1031223 C1 NL1031223 C1 NL 1031223C1
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NL
Netherlands
Prior art keywords
blade
brush
bristles
flow
noise
Prior art date
Application number
NL1031223A
Other languages
Dutch (nl)
Inventor
Stefan Oerlemans
Original Assignee
Stichting Nationaal Lucht En R
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 R filed Critical Stichting Nationaal Lucht En R
Priority to NL1031223A priority Critical patent/NL1031223C1/en
Priority to PCT/IB2007/001458 priority patent/WO2008035149A2/en
Application granted granted Critical
Publication of NL1031223C1 publication Critical patent/NL1031223C1/en

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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

Abstract

The blade has a brush at a back edge of the blade, where the brush includes synthetic bristles that rest parallel to top or bottom of the blade. The bristles are flexible such that the alignment of the brush does not affect the aerodynamic properties of the blade.

Description

1 Λ1 Λ

BeschrijvingDescription

Reductie van windturbinegeiuid door borstels op de achterrand van de bladenReduction of wind turbine noise by brushes on the trailing edge of the blades

Het komt regelmatig voor dat windturbines niet geplaatst mogen worden, of niet op 5 vol vermogen kunnen draaien, vanwege beperkende geluidsregels. Een belangrijke geluidsbron voor moderne windturbines is stromingsgeïnduceerd geluid van de bladen. Dit bladgeluid wordt hoofdzakelijk veroorzaakt door drukfluctuaties op het bladoppervlak die met de stroming over de achterrand van het blad bewegen, waar ze afstralen als geluid (achterrandgeluid). De drukfluctuaties worden veroorzaakt door de 10 turbulente grenslaag op het blad. Het geluidsreducerende effect van de borstels is gebaseerd op een vermindering van de discontinuïteit bij de achterrand van het blad. Door de eindige stromingsweerstand van de borstels worden de drukfluctuaties in de stromingsrichting geleidelijk vereffend, waardoor de achterrand minder effectief geluid afstraalt. Op basis van windtunnelmetingen aan vlakke platen, bladsecties, en 15 voorrandkleppen (van een vleugel) met borstels op de achterrand, kunnen geluidsreducties tot 10 dB worden verwacht in een breed frequentiegebied. De werkelijke geluidsreductie zal afhangen van de details van de borstels, de afmetingen van het blad, windsnelheid, toerental, etc.It often happens that wind turbines cannot be installed or cannot run at 5 full capacity due to restrictive noise regulations. An important sound source for modern wind turbines is flow-induced noise from the blades. This leaf noise is mainly caused by pressure fluctuations on the leaf surface that move with the flow over the trailing edge of the leaf, where they radiate as sound (trailing edge noise). The pressure fluctuations are caused by the turbulent boundary layer on the sheet. The noise-reducing effect of the brushes is based on a reduction of the discontinuity at the trailing edge of the blade. Due to the finite flow resistance of the brushes, the pressure fluctuations in the flow direction are gradually equalized, so that the rear edge radiates sound less effectively. Based on wind tunnel measurements on flat plates, blade sections, and front edge flaps (of a wing) with brushes on the rear edge, noise reductions of up to 10 dB can be expected in a wide frequency range. The actual noise reduction will depend on the details of the brushes, the dimensions of the blade, wind speed, speed, etc.

20 Figuur 1 toont als voorbeeld een bladsectie met een borstel op de achterrand. De borstel bestaat uit een enkele rij borstelharen die serieel op de achterrand van het blad zijn gemonteerd. Twee of meer rijen van borstelharen zijn in principe ook mogelijk. De borstelharen kunnen synthetisch of natuurlijk zijn. De doorsnede van de borstelharen kan rond zijn, maar kan ook een andere vorm hebben. De hoek tussen 25 een individuele haar (in rust) en de achterrand zal meestal rond de 90 graden liggen, maar andere hoeken zijn ook mogelijk, bijvoorbeeld als de stromingsrichting niet loodrecht op de achterrand staat door centrifugale krachten op het roterende blad (zie bovenaanzicht in Figuur 2). De borstelharen (in rust) kunnen evenwijdig aan de boven- of onderkant van het blad worden gemonteerd, maar andere oriëntaties zijn 30 ook mogelijk (zie zijaanzicht in Figuur 3). De borstelharen moeten flexibel zijn, zodat ze automatisch in de stromingsrichting gaan liggen, onder invloed van de aërodynamische krachten. Door deze automatische uitlijning met de stromingsrichting zijn de borstels effectief voor alle omstandigheden, bijvoorbeeld verschillende 1 0312 2 3 2 windsnelheden, toerentallen, of bladhoeken. Bovendien zorgt de automatische uitlijning ervoor dat de borstel geen invloed heeft op de aërodynamische eigenschappen van het blad. De lengte van de borstelharen kan constant zijn, maar kan ook variëren als functie van de radiale positie op het blad, bijvoorbeeld om de 5 verschillen in lokale grenslaagparameters te verdisconteren (zie bovenaanzicht in Figuur 4). De afstand tussen individuele borstelharen moet zodanig zijn dat de drukfluctuaties in de stromingsrichting geleidelijk worden vereffend, waarbij enige stroming door de borstel mogelijk is om drukvereffening mogelijk te maken (dus geen volledige afdichting). In principe kan de borstel worden toegepast op het gehele blad, 10 van de wortel tot de tip. In de praktijk zal het echter meestal afdoende zijn om alleen de buitenste 30% van het blad te behandelen, omdat daar vanwege de hogere snelheden het meeste geluid wordt geproduceerd. In plaats van de haren direct op het blad te bevestigen, kunnen borstelstrips van een bepaalde lengte worden geprepareerd. Het blad kan vervolgens worden behandeld door meerdere strips naast elkaar op het 1 s blad te bevestigen.Figure 1 shows as an example a leaf section with a brush on the trailing edge. The brush consists of a single row of bristles that are serially mounted on the trailing edge of the blade. Two or more rows of bristles are also possible in principle. The bristles can be synthetic or natural. The cross section of the bristles may be round, but may also have a different shape. The angle between an individual hair (at rest) and the trailing edge will usually be around 90 degrees, but other angles are also possible, for example if the direction of flow is not perpendicular to the trailing edge due to centrifugal forces on the rotating blade (see top view in Figure 2). The bristles (at rest) can be mounted parallel to the top or bottom of the blade, but other orientations are also possible (see side view in Figure 3). The bristles must be flexible so that they automatically lie in the direction of flow under the influence of the aerodynamic forces. Because of this automatic alignment with the flow direction, the brushes are effective for all conditions, for example different wind speeds, speeds, or blade angles. In addition, the automatic alignment ensures that the brush has no influence on the aerodynamic properties of the blade. The length of the bristles can be constant, but can also vary as a function of the radial position on the blade, for example to take into account the differences in local boundary layer parameters (see top view in Figure 4). The distance between individual bristles must be such that the pressure fluctuations in the flow direction are gradually equalized, whereby some flow through the brush is possible to allow pressure equalization (thus not a complete seal). In principle, the brush can be applied to the entire leaf, from the root to the tip. In practice, however, it will usually be sufficient to treat only the outer 30% of the blade, because the higher speed produces the most noise there. Instead of fixing the hairs directly on the blade, brush strips of a certain length can be prepared. The sheet can then be treated by attaching several strips next to each other on the 1 s sheet.

1 031 2231 031 223

Claims (8)

1. Een belangrijke geluidsbron voor moderne windturbines is stromingsgeïnduceerd geluid van de bladen.1. An important sound source for modern wind turbines is flow induced noise from the blades. 2. Op basis van windtunnelmetingen kunnen aanzienlijke geluidsreducties worden verwacht door toepassing van borstels op de achterrand van de bladen.2. Considerable noise reductions can be expected on the basis of wind tunnel measurements by applying brushes to the trailing edges of the blades. 3. De borstel bestaat uit een of meerdere rijen borstelharen die serieel op de achterrand van het blad zijn gemonteerd.3. The brush consists of one or more rows of bristles that are serially mounted on the trailing edge of the blade. 4. De optimale eigenschappen van de borstelharen (bijvoorbeeld materiaal, lengte, 10 doorsnede, oriëntatie, onderlinge afstand) hangen af van de stromingscondities op het blad ter plaatse van de borstel.4. The optimum properties of the bristles (for example material, length, cross-section, orientation, mutual distance) depend on the flow conditions on the blade at the location of the brush. 5. De borstelharen moeten flexibel zijn, zodat ze automatisch in de stromingsrichting gaan liggen. Hierdoor zijn de borstels effectief voor alle omstandigheden. Bovendien zorgt de automatische uitlijning ervoor dat de borstel 15 geen invloed heeft op de aërodynamische eigenschappen van het blad.5. The bristles must be flexible so that they automatically lie in the direction of flow. This makes the brushes effective for all conditions. Moreover, the automatic alignment ensures that the brush 15 has no influence on the aerodynamic properties of the blade. 6. De afstand tussen individuele borstelharen moet zodanig zijn dat de drukfluctuaties in de stromingsrichting geleidelijk worden vereffend, waarbij enige stroming door de borstel mogelijk is om drukvereffening mogelijk te maken (dus geen volledige afdichting).6. The distance between individual bristles must be such that the pressure fluctuations in the flow direction are gradually equalized, whereby some flow through the brush is possible to allow pressure equalization (thus not a complete seal). 7. In principe kan de borstel worden toegepast op het gehele blad. In de praktijk zal het echter meestal afdoende zijn om alleen de buitenste 30% van het blad te behandelen, omdat daar het meeste geluid wordt geproduceerd.7. In principle, the brush can be applied to the entire blade. In practice, however, it will usually be sufficient to treat only the outer 30% of the blade, since it produces the most noise. 8. In plaats van de haren direct op het blad te bevestigen, kunnen borstelstrips van een bepaalde lengte worden geprepareerd. Het blad kan vervolgens worden 25 behandeld door meerdere strips naast elkaar op het blad te bevestigen. 1031223 -.···>*·8. Instead of fixing the hair directly on the blade, brush strips of a certain length can be prepared. The sheet can then be treated by attaching several strips next to each other on the sheet. 1031223 -. ···> * ·
NL1031223A 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 NL1031223C1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
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
PCT/IB2007/001458 WO2008035149A2 (en) 2006-02-23 2007-02-26 Rotor blade for a wind turbine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
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
NL1031223 2006-02-23

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NL1031223C1 true NL1031223C1 (en) 2007-08-24

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WO (1) WO2008035149A2 (en)

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US7976276B2 (en) 2010-11-04 2011-07-12 General Electric Company Noise reducer for rotor blade in wind turbine
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
US8414261B2 (en) 2011-05-31 2013-04-09 General Electric Company Noise reducer for rotor blade in wind turbine
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EP2570656B1 (en) * 2011-09-19 2016-05-04 Nordex Energy GmbH Wind energy assembly rotor blade with a thick profile trailing edge
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US9506452B2 (en) 2013-08-28 2016-11-29 General Electric Company Method for installing a shear web insert within a segmented rotor blade assembly
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US9494134B2 (en) 2013-11-20 2016-11-15 General Electric Company Noise reducing extension plate for rotor blade in wind turbine
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US10465652B2 (en) 2017-01-26 2019-11-05 General Electric Company Vortex generators for wind turbine rotor blades having noise-reducing features
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WO2008035149A2 (en) 2008-03-27
WO2008035149A3 (en) 2009-02-19

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Effective date: 20100901