US20130195670A1 - Rotor for a wind turbine - Google Patents

Rotor for a wind turbine Download PDF

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Publication number
US20130195670A1
US20130195670A1 US13/643,471 US201113643471A US2013195670A1 US 20130195670 A1 US20130195670 A1 US 20130195670A1 US 201113643471 A US201113643471 A US 201113643471A US 2013195670 A1 US2013195670 A1 US 2013195670A1
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US
United States
Prior art keywords
blade
rotor
radius
sol
blades
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Legal status (The legal status 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 status listed.)
Abandoned
Application number
US13/643,471
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English (en)
Inventor
Thomas Bjertrup Nielsen
Erik Sloth
Alejandro Gomez Gonzalez
Rasmus Jensen
Mads Reck
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SE BLADES Tech BV
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SE BLADES Tech BV
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Application filed by SE BLADES Tech BV filed Critical SE BLADES Tech BV
Assigned to SE BLADES TECHNOLOGY B.V. reassignment SE BLADES TECHNOLOGY B.V. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: JENSEN, RASMUS, RECK, MADS, BJERTRUP NIELSEN, THOMAS, SLOTH, ERIK, GONZALEZ, ALEJANDRO GOMEZ
Publication of US20130195670A1 publication Critical patent/US20130195670A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/02—Blade-carrying members, e.g. rotors
    • 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
    • F03D1/0608—Rotors characterised by their aerodynamic shape
    • 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
    • F05B2250/70—Shape
    • 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
    • F05B2250/70—Shape
    • F05B2250/71—Shape curved
    • 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 present invention relates to a rotor for a wind turbine, where the wind turbine comprises at least a tower, a nacelle on top of said tower and a rotor, said rotor having a diameter of 50 metres or more, and being connected to a substantially horizontal main shaft, said main shaft being rotatably mounted in said nacelle, said wind turbine being of the type where the rotor is facing up-wind, where said rotor comprises at least one blade, but preferably three blades and a hub, said blades having an elongated shape with a root end and a tip end, where said blades at the root end are connected to said hub and where the interface between said hub and said blades comprises a pitch mechanism, further said rotor has a rotor plane, described by the area swept by the blades, said rotor plane being with a cone shape, i.e. the rotor plane is with an angle towards the up-wind direction, where the cone shape—at least partly—originates from the shape of the hub, and
  • chord is the length of the chord of the blade at the specific radius and R is the maximum diameter of the rotor.
  • a wind turbine of the “Danish Type” is also known as a front runner, with a substantial horizontal main shaft, and with a rotor having three blades and facing upwind.
  • a number of engineering challenges occurs. One of these challenges is to secure a sufficient clearance between the tip of the rotating blades and the tower, under the different working conditions for the wind turbine.
  • a blade of said rotor comprises at least two blade sections in the lengthwise direction of said blade, where at least one blade section has a curvature along the blade and relative to a second blade section, where said curvature results in the tip end of said blade being offset (x) relative to the axis of the blade root in the flap wise direction of the blade and in the up-wind direction, where the ratio (x/L) of the offset (x) relative to a distance (L) from the tip end of the blade to the blade root, said distance (L) being measured perpendicular to the plane of the root end of the blade and said offset (x) being measured as the perpendicular offset from the axis of the blade root, is between 0 and 0.1, and that said rotor is with a cone angle ⁇ between 0 and 10 degrees, said cone angle ⁇ being measured between the axis of the blade root and perpendic
  • slender blade profile and at the same time having a relatively small ratio (x/L) also called “pre-bending” of the blade together with a cone shaped rotor plane, has a number of advantages.
  • First of all the slender blade profiles have the advantage that the load from the wind is minimized as the blade area exposed to the wind is smaller and therefore less stresses and loads are transferred from the blades to the rest of the wind turbine structure.
  • the blades are pre-bend and thus giving the possibility to be deflected even more by the wind and still maintaining a sufficient clearance between the tip of the blades and the tower. Pre-bending does, however, give some trouble during fabrication and transportation if the ratio (x/L) is too big.
  • the hub of the rotor manufactured with the interface for the blades with an angle.
  • the rotor-plane will have the shape of a cone.
  • This cone together with the pre-bended and slender blades will create a sufficient tip to tower clearance and at the same time the blades can be transported by vehicle without extraordinary trouble.
  • a blade of said rotor can have a combined radius specific solidity Sol r at:
  • a blade of said rotor can have a combined radius specific solidity Sol r at:
  • the blades can be made of a uniform type of fibres, e.g. glass fibres and with a suitably resin such as a polyester or epoxy resin.
  • a further advantage of the slender blade is that it becomes possible to have rotor blades with less thickness and thus it becomes possible to use high performance airfoils which are more efficient.
  • the ratio (x/L) of the offset (x) relative to a distance (L) is between 0.022 and 0.087, or even more preferred between 0.033 and 0.054, as the pre-bend ratio (x/L) then will have a size making transportation of long blades of up to 50 metres or more possible by vehicle and at the same time securing the necessary tip to tower clearance.
  • Yet another preferred embodiment of a rotor for a wind turbine according to the invention can have a rotor with a cone angle ⁇ between 1 and 6 degrees or even more preferred between 2 and 5 degrees, said cone angle ⁇ being measured between the axis of the blade root and perpendicular to the axis of the main shaft.
  • a cone angle ⁇ as described will together with the previous mentioned construction details fulfil the wish of a wind turbine with slender and pre-bended blades installed on a hub where the interface is with an angle.
  • the reduced weight together with the slender profile will also have a positive effect on the complete structure, as the aerodynamic will decrease and thereby allowing for further optimization of structural strength of the different parts of the construction.
  • the main shaft is tilted with an angle between ⁇ 2 and +4 degrees, or between ⁇ 2 and +2 degrees, or even between 0 and +2 degrees, said angle being measured at the hub and between horizontal and the centre line of said main shaft.
  • Noise emission from wind turbines has a modulating character i.e. the emitted noise level is varied over time. At close distances a major part of this variation originates from the difference in distance from the observer position to the blade. At longer distances, this variation in observer distance vanishes, but modulation of the noise level is still seen from longer distances. The cause of this is primarily that the blades emit varying noise as a function of the position in the rotation. When the main shaft has a tilt angle a and the wind shear is vertical or close to vertical, the blades will experience variances in the inflow speed of the wind. This will cause variations in the aerodynamic angle of attack. These variations will result in the described variation in noise emission and will be minimized by having only a small tilt angle ⁇ e.g. between 0 and +2 degrees to horizontal.
  • the invention further comprises an embodiment where a blade for a rotor according to the invention is assembled from two or more blade sections, and where the two or more sections comprises co acting means for assembling said blade sections into one functionally complete blade for a rotor.
  • the advantages of the slender blades i.e. the low radius specific solidity.
  • the advantages of the slenderness is that the annual yield per load ratio is higher resulting in lower wind turbine costs per kWh produced over 20 years.
  • the annual yield increases as the rotor diameter can be increased with the slender blades for the same load level compared to a traditional blade with wider chord distribution.
  • fatigue loads the same coefficient of lift—Cl as a function of the angle of attack, will reduce the load variations over time due to turbulence with a reduced chord according to the invention.
  • a further advantage of having a small tilt is the reduction in unsteady loads.
  • Unsteady loads may be of a purely mechanical character (for example the own weight of the blades), as well as of an aerodynamic nature (interaction with the wind).
  • a low rotor tilt has an influence on the aerodynamic loads, causing a reduction in the unsteadiness of these.
  • the angle between the incident wind and the blades oscillates in time, causing fatigue loads which are detrimental for the structure. Not only the fatigue loads are lower, but also the aerodynamic performance of the whole rotor is higher due to a more optimal incidence on the blade elements.
  • FIG. 1 shows a part of a wind turbine with normal blades.
  • FIG. 2 shows a part of a wind turbine with slender blades.
  • FIG. 3 shows a rotor with a hub with a cone angle ⁇ and with a pre-bended blade.
  • FIG. 4 shows a rotor with a hub with a cone angle ⁇ and with a pre-bended blade.
  • FIG. 5 shows a rotor with a hub with a cone angle ⁇ and with a pre-bended blade.
  • FIG. 1 a part of the top of a wind turbine 1 is seen.
  • the wind turbine 1 consists of a tower 2 , a nacelle 3 , and a rotor 4 , said rotor 4 consisting of a hub 5 and three blades 6 .
  • an area 7 is swept by the blades 6 .
  • the ratio between this area 7 and the area of the three blades 6 which are facing towards the wind, is an expression for the rotors solidity.
  • a new ratio Sol r is used to be able to use a solidity ratio as a function of the radius.
  • This ratio Sol r is called the combined radius specific solidity and is the ratio between the added length of the chord 8 on all the blades and the circumference of the circle 15 described by the maximum radius on the rotor 4 .
  • chord is the length of the chord of the blade at the specific radius and R is the maximum diameter of the rotor.
  • FIG. 2 another rotor is seen where the combined radius specific solidity clearly is less than in FIG. 1 .
  • a blade as shown in FIG. 1 is depicted with a dashed line, just to illustrate the difference in the ratio Sol r .
  • FIG. 3 the top of a wind turbine 1 is shown as seen from the side, where the tower 2 has a centre line 10 , the nacelle 3 has a line 11 indicating the direction of the main shaft. Further, a rotor 4 with a hub 5 and with a blade 6 is shown. The hub 5 is with an angled interface for the blades 6 . The direction of the interface is indicated with a line 12 parallel to the interface and the root end of the blade 6 . Another line 13 indicates the centre line 13 of a blade 6 and yet another line 14 is indicating where the distance x is measured. Further, the distance L is the distance between the interface line 12 and where the line 14 is intersecting the line 13 .
  • the ratio x/L is used as geometrical expression for the pre-bend of the blades 6 , and the start of the pre-bend is illustrated with a line 16 , and in this embodiment approximately 1 ⁇ 2 of the blade is with a straight pre-bend.
  • the angle between the line 11 and horizontal is describing the tilt angle ⁇ .
  • the tilt angle ⁇ is zero.
  • the angle between the line 11 and the line 12 is describing the cone angle ⁇ .
  • FIGS. 4 and 5 other ways of shaping the pre-bended blades 6 is shown.
  • the blade 6 has a straight portion from the hub 5 and approximately 1 ⁇ 3 of the length of the blade 6 , where the outer 2 ⁇ 3 of the blade has a forward curved shape, illustrated with the line 16 , resulting in the same ratio x/L as seen in FIG. 3 .
  • the blade has a straight portion of approximately 2 ⁇ 3 of the length of the blade 6 , and the outer 1 ⁇ 3 is with a curved shape, once again illustrated by the line 16 and still with the same ratio x/L as in FIGS. 3 and 4 .

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Wind Motors (AREA)
US13/643,471 2010-04-26 2011-04-15 Rotor for a wind turbine Abandoned US20130195670A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DKPA201070170 2010-04-26
DKPA201070170 2010-04-26
PCT/EP2011/056065 WO2011134810A1 (en) 2010-04-26 2011-04-15 Rotor for a wind turbine

Publications (1)

Publication Number Publication Date
US20130195670A1 true US20130195670A1 (en) 2013-08-01

Family

ID=44259798

Family Applications (1)

Application Number Title Priority Date Filing Date
US13/643,471 Abandoned US20130195670A1 (en) 2010-04-26 2011-04-15 Rotor for a wind turbine

Country Status (6)

Country Link
US (1) US20130195670A1 (zh)
EP (1) EP2564057B1 (zh)
CN (1) CN102985684B (zh)
AU (1) AU2011246663B2 (zh)
WO (1) WO2011134810A1 (zh)
ZA (1) ZA201208870B (zh)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140234108A1 (en) * 2011-05-31 2014-08-21 Dewind Europe Gmbh Rotor with a curved rotor blade for a wind power plant
WO2022002334A1 (en) * 2020-06-29 2022-01-06 Vestas Wind Systems A/S A wind turbine
US20230235721A1 (en) * 2020-06-29 2023-07-27 Vestas Wind Systems A/S A wind turbine

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9175668B2 (en) * 2012-04-19 2015-11-03 General Electric Company Hub for wind turbine rotor
US9074581B2 (en) 2012-06-12 2015-07-07 General Electric Company Cone angle insert for wind turbine rotor
US9109578B2 (en) 2012-06-12 2015-08-18 General Electric Company Root extender for a wind turbine rotor blade
CN106762409B (zh) * 2016-11-23 2019-04-02 沈阳大学 一种基于β锥角的风力机叶素动量修正方法
DE102018005965A1 (de) * 2018-07-30 2020-01-30 Senvion Gmbh Rotorblatt für eine windenergieanlage, windenergieanlage; verfahren zum verlängern eines rotorblatts sowie verfahren zum herstellen eines rotorblatts

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080206055A1 (en) * 2005-02-22 2008-08-28 Kristian Balschmidt Godsk Wind Turbine Blade

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DE29612720U1 (de) 1996-07-23 1996-10-02 Aerodyn Gmbh Windkraftanlage
AU745240B2 (en) * 1997-09-04 2002-03-14 Lm Wind Power International Technology Ii Aps Windmill rotor and wind blades therefor
DE102004023774A1 (de) 2004-05-11 2005-12-22 Repower Systems Ag Windenergieanlage
ES2297998B1 (es) * 2005-10-28 2009-07-20 GAMESA INNOVATION & TECHNOLOGY, S.L. Pala partida para aerogeneradores.
DE202006013519U1 (de) 2006-08-29 2006-12-21 Euros Entwicklungsgesellschaft für Windkraftanlagen mbH Windenergieanlage mit konusförmig angeordneten Rotorblättern
DE102006053712A1 (de) 2006-11-15 2008-05-21 Nordex Energy Gmbh Rotorblatt und Windkraftanlage
MX2009006076A (es) 2006-12-22 2009-08-13 Vestas Wind Sys As Turbina eolica con aspas para rotor equipada con aletillas y aspas para el rotor.
US20100104444A1 (en) 2007-02-28 2010-04-29 Garcia Andujar Juan Carlos Blade for wind turbines
EP2129908B1 (en) 2007-03-20 2010-12-01 Vestas Wind Systems A/S Wind turbine blades with vortex generators
WO2008113349A2 (en) 2007-03-20 2008-09-25 Vestas Wind Systems A/S Slow rotating wind turbine rotor with slender blades
US8714928B2 (en) * 2008-06-06 2014-05-06 General Electric Company Rotor assembly for a wind turbine and method of assembling the same

Patent Citations (1)

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Publication number Priority date Publication date Assignee Title
US20080206055A1 (en) * 2005-02-22 2008-08-28 Kristian Balschmidt Godsk Wind Turbine Blade

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140234108A1 (en) * 2011-05-31 2014-08-21 Dewind Europe Gmbh Rotor with a curved rotor blade for a wind power plant
WO2022002334A1 (en) * 2020-06-29 2022-01-06 Vestas Wind Systems A/S A wind turbine
US20230235721A1 (en) * 2020-06-29 2023-07-27 Vestas Wind Systems A/S A wind turbine
US11852118B2 (en) 2020-06-29 2023-12-26 Vestas Wind Systems A/S Wind turbine

Also Published As

Publication number Publication date
ZA201208870B (en) 2014-10-29
AU2011246663B2 (en) 2015-03-12
CN102985684A (zh) 2013-03-20
CN102985684B (zh) 2015-11-25
EP2564057A1 (en) 2013-03-06
EP2564057B1 (en) 2015-08-26
WO2011134810A1 (en) 2011-11-03
AU2011246663A1 (en) 2012-11-29

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AS Assignment

Owner name: SE BLADES TECHNOLOGY B.V., NETHERLANDS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BJERTRUP NIELSEN, THOMAS;SLOTH, ERIK;GONZALEZ, ALEJANDRO GOMEZ;AND OTHERS;SIGNING DATES FROM 20130114 TO 20130322;REEL/FRAME:030220/0389

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION