DK179472B1 - Blade with pre-deflection for downwind type wind turbine - Google Patents

Blade with pre-deflection for downwind type wind turbine Download PDF

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Publication number
DK179472B1
DK179472B1 DKPA201770364A DKPA201770364A DK179472B1 DK 179472 B1 DK179472 B1 DK 179472B1 DK PA201770364 A DKPA201770364 A DK PA201770364A DK PA201770364 A DKPA201770364 A DK PA201770364A DK 179472 B1 DK179472 B1 DK 179472B1
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DK
Denmark
Prior art keywords
end portion
blade
radial
curvature
distal end
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DKPA201770364A
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Danish (da)
Inventor
Hjort Søren
Original Assignee
Envision Energy (Denmark) Aps
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Priority to DKPA201770364A priority Critical patent/DK179472B1/en
Priority to PCT/DK2018/050111 priority patent/WO2018215037A1/en
Publication of DK201770364A1 publication Critical patent/DK201770364A1/en
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    • 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
    • F03D1/0633—Rotors characterised by their aerodynamic shape of the blades
    • 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
    • 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
    • F05B2240/21—Rotors for wind turbines
    • F05B2240/221—Rotors for wind turbines with horizontal axis
    • F05B2240/2213—Rotors for wind turbines with horizontal axis and with the rotor downwind from the yaw pivot axis
    • 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

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Wind Motors (AREA)

Abstract

Blade with pre-deflection for downwind type wind turbine, where the blade has a radial proximal end portion, a radial distal end portion, and an intermediate portion which extends between the radial proximal end portion and the radial distal end portion, and where at least part of the intermediate portion of the blade is pre-deflected such that in an unloaded state, at least part of the blade is curved away from an imaginary pitch axis, connecting the radial proximal end portion and the radial distal end portion, where the pre-deflection shift curvature sign, from a first curvature to a second curvature, at an inflection point at the intermediate portion, whereby it is achieved that the pre-deflection radial distribution on a downwind turbine blade ensures sufficient tip-tower clearance and that the deflected blade is perpendicular to the wind passing through the rotor under loaded, power-producing conditions.

Description

(19) DANMARK (10)
Figure DK179472B1_D0001
(12)
PATENTSKRIFT
Patent- og Varemærkestyrelsen
Int.CI.: F03D 1/06 (2006.01)
Ansøgningsnummer: PA 2017 70364
Indleveringsdato: 2017-05-22
Løbedag:2017-05-22
Aim. tilgængelig: 2018-11-23
Patentets meddelelse bkg. og publiceret den: 2018-11-27
Patenthaver:
ENVISION ENERGY (DENMARK) ApS, Randersvej 2A, 8600 Silkeborg, Danmark
Opfinder:
Søren Hjort, Buske lundtoften 77, 8600 Silkeborg, Danmark
Fuldmægtig:
Patrade A/S, Ceresbyen 75, 8000 Århus C, Danmark
Titel: Blade with pre-deflection for downwind type wind turbine
Fremdragne publikationer:
EP 2990643 A1
WO 2015/081962 A1
US 2014/234108 A1
US 2013/315746 A1 US 2011/223034 A1
Sammendrag:
Blade with pre-deflection for downwind type wind turbine, where the blade has a radial proximal end portion, a radial distal end portion, and an intermediate portion which extends between the radial proximal end portion and the radial distal end portion, and where at least part of the intermediate portion of the blade is pre-deflected such that in an unloaded state, at least part of the blade is curved away from an imaginary pitch axis, connecting the radial proximal end portion and the radial distal end portion, where the predeflection shift curvature sign, from a first curvature to a second curvature, at an inflection point at the intermediate portion, whereby it is achieved that the pre-deflection radial distribution on a downwind turbine blade ensures sufficient tip-tower clearance and that the deflected blade is perpendicular to the wind passing through the rotor under loaded, power-producing conditions.
Fortsættes...
Figure DK179472B1_D0002
i
Blade with pre-deflection for downwind type wind turbine
Field of the Invention
The present invention relates to a blade with pre-deflection for downwind type wind turbine, where the blade has a radial proximal end portion being the root of the blade configured to be fixed to a hub, a radial distal end portion being the tip of the blade, and an intermediate portion which extends between the radial proximal end portion and the radial distal end portion, and where at least part of the intermediate portion of the blade is pre-deflected such that in an unloaded state, at least part of the blade is curved away from an imaginary pitch axis, connecting the radial proximal end portion and the radial distal end portion.
The invention further relates to the use of a blade with pre-deflection.
Background of the Invention
During the last 5 decades, wind turbines have experienced a tremendous continuous growth, both in size and product volume. For reasons of aesthetics and low noise emission, the all dominating rotor configuration type has been upwind - not downwind, meaning that the rotor is upwind of the wind turbine tower during normal operation.
The upscale of wind turbines have enabled a steady reduction of Cost-of-Energy (CoE), and the largest wind turbine blades are now approaching lengths of 100m. This poses many practical challenges. One of these challenges is the problem of the blades becoming so long and flexible that the dynamic blade deflections during wind turbine operation jeopardize the clearance between the blade tip and the turbine tower.
For many years, preventive design steps have been quite successful:
1. Increasing the overhang between the nacelle hub and the tower.
2. Increasing the cone angle between the rotor plane and the pitch axis.
3. Increasing the blade upstream pre-deflection.
4. Increasing blade stiffness by using thicker aerodynamic profiles.
5. Increasing blade stiffness by adding extra structural material with the sole purpose of reducing tip deflection.
6. Change to a stiffer Fibre-Reinforced-Plastic (FRP) material, e.g. from glassfibre to carbon-fibre.
Common for the above preventive steps are that they either induce higher mechanical loads (1., 2., 4. and 5.), higher material cost (4., 5.), or impose manufacturing and transport related challenges (3.).
During the last decade, and due to the continued upscaling, the use of these preventive steps to secure sufficient tip-tower clearance is not always enough, especially if the use of carbon-fibre (6.) is not favoured for reasons of cost and/or manufacturing complexity. Consequently, some wind turbine manufacturers have been forced to use the tip- tower preventive steps 1.-5. excessively to the point where the aerodynamic efficiency is clearly compromised and the blade cost of material is clearly increased, both having an unfavourable impact on CoE.
From EP 2447523 Al a wind power generator is known where the blade geometry only works in combination with coning, since the applied pre-deflection is uniform with same side curvature from root to tip.
Object of the Invention
With the continuing upscale wind turbine size, there is a need for a technology change that somehow alleviates the need for excessive use of the preventive steps 1.-6. and associated adverse impact on CoE. One example of such a technology change is the use of downwind configured wind turbines, i.e. with the rotor being downwind of the wind turbine tower during normal operation. An object of the invention is the advantage of a downwind turbine, which is the significantly reduced design constraint of securing sufficient tip-tower clearance, since the aerodynamic forces tend to push the rotating blade away from the tower - not towards it.
A blade designed for downwind configuration - i.e. a downwind blade - should be differently shaped than a traditional upwind blade. The difference concerns the socalled pre-deflection shape of the blade. The pre-deflection is the radial distribution of the non-pitched blade’s out-of-plane distance to the pitch axis. Pre-deflection was not necessary on old small wind turbine blades. On modern conventional upwind turbines, the pre-deflection radial distribution is always upstream away from the tower. Modern downwind turbines are not common, so no preferred method for applying pre- deflection has been established. Another object of the invention is the pre-deflection radial distribution on a modern downwind turbine blade that should be designed with the following requirements in mind:
a. The pre-deflection must help ensure sufficient tip-tower clearance.
b. The pre-deflection must be such that the deflected blade is perpendicular to the wind passing through the rotor under loaded, power-producing conditions.
These requirements are the same as for a conventional upwind turbine, but will for a downwind turbine lead to a different, unique optimal shape of the pre-deflection radial distribution.
On a traditional upwind turbine, requirements a. and b. are both satisfied by applying the blade pre-deflection such that the radial distribution span from root to tip of said pre-deflection curves uniformly upstream, i.e. away from the tower.
If this type of pre-deflection, with uniform upstream curvature, is used on a downwind turbine, then requirement b. is satisfied, but certainly not requirement a. If the opposite type of pre-deflection, with uniform downstream curvature, was used on a downwind turbine, then requirement a. would be satisfied, but not requirement b.
Therefore, pre-deflection curvature on a downwind turbine should not be monotone,
i.e. with same sign curvature from root to tip, but should change curvature direction, i.e. sign of curvature, at a certain radial location between root and tip. Geometrically, according to definition, a point on a curve, where the curvature shifts sign, is an inflection point.
A wind turbine blade pre-deflection curve, seen from root to tip, which curves downstream, i.e. away from the tower, on the inner part of the blade, and then flips sign of curvature at a radial position, say at the 50% between root and tip, and then curves upstream towards the tower on the remaining outer section of the blade, will be able to satisfy both requirement a. and requirement b.
The key to obtaining both requirement a. and b. on a downwind turbine is to abstain from the uniform curvature pre-deflection, and introduce an inflectional point where the pre-deflection curvature shifts sign from downwind curvature to upwind curvature.
Description of the Invention
According to a first aspect of the invention, the above object is achieved with a blade with pre-deflection for downwind type wind turbine of the type mentioned in the introduction, where the blade has a radial proximal end portion being the root of the blade configured to be fixed to a hub, a radial distal end portion being the tip of the blade, and an intermediate portion which extends between the radial proximal end portion and the radial distal end portion, and where at least part of the intermediate portion of the blade is pre-deflected such that in an unloaded state, at least part of the blade is curved away from an imaginary pitch axis, connecting the radial proximal end portion and the radial distal end portion, and where the pre-deflection shift curvature sign, from a first curvature closest to the proximal end to a second curvature closest to the distal end, at an inflection point at the intermediate portion between the proximal end portion and the radial distal end portion.
This makes it possible to fulfil the overall objects of the invention, where the advantage is the significantly reduced design constraint of securing sufficient tip- tower clearance, since the aerodynamic forces tend to push the rotating blade away from the tower - not towards it.
A curvature in this aspect means any geometrical shape, from a straight line/shape via a curvature with a constant radius to a curvature with change- able radii. The cylindrical section span adjacent to the root is normally straight, i.e. with zero curvature. In that case the monitoring of curvature, inflection point, and opposite-signed curvature starts at the radial point where the straight section adjacent to the root ends.
In a second aspect, the present invention also relates to a blade with pre-deflection, where the inflection point is positioned between the proximal end portion and the radial distal end portion, where the first curvature makes up 20-70 %, preferably 35-60 % and even further preferably 50 % of the intermediate portion.
This makes it possible to vary the percentage depending on the requirements for the specific blade for a specific wind turbine setup, i.e.:
Tip-tower clearance constraint.
Blade flexibility.
In a third aspect, the present invention also relates to a blade with pre-deflection, where the first curvature pre-deflection shape and the second oppositely signed curvature pre-deflection shape are different.
This makes it possible to further vary the form and shape of the blade, where the blade does not have similar curves or monotone curves, but curves with different shape/form/radii, etc.
In a fourth aspect, the present invention also relates to a blade with pre-deflection, where the first curvature is configured to curve upstream towards a tower when fixed to a hub at a wind turbine, and the second curvature is configured to curve downstream away from a tower when fixed to a hub at a wind turbine.
In a fifth aspect, the present invention also relates to a blade with pre-deflection, where the first curvature is configured to curve downstream away from a tower when fixed to a hub at a wind turbine, and the second curvature is configured to curve upstream towards a tower when fixed to a hub at a wind turbine.
With the fourth and fifth aspect it becomes possible to construct, produce and conduct a blade with an S-shape or mirror image S-shape, when looking at the blade from the leading edge or the trailing edge along the chord line. Thus, it becomes possible to define a first curvature which is in one direction, and hence a second curvature which is then in the opposite direction.
In a sixth aspect, the present invention also relates to a blade with pre-deflection, where the radial distal end portion being the tip of the blade is positioned upstream in relation to the imaginary pitch axis, when the radial proximal end portion, being the root of the blade, is fixed to a hub.
In a seventh aspect, the present invention also relates to a blade with pre-deflection, where the radial distal end portion, being the tip of the blade, is positioned at the imaginary pitch axis, when the radial proximal end portion being the root of the blade is fixed to a hub.
In an eight aspect, the present invention also relates to a blade with pre-deflection, where the radial distal end portion, being the tip of the blade, is positioned downstream in relation to the imaginary pitch axis, when the radial proximal end portion, being the root of the blade, is fixed to a hub.
With the sixth, seventh and eighth aspects it is possible to construct, produce and conduct a blade with pre-deflection suitable for any purpose, need and situation, where the impact, according to the influence of aerodynamics, is taken into account.
In a ninth aspect, the present invention also relates to a use of a blade with pre- deflection, for downwind type wind turbine.
Description of the Drawing
The invention will be described in further detail below by means of non-limiting embodiments with reference to the drawing, in which:
Fig. 1 shows an upwind type wind turbine.
Fig. 2 shows a downwind type wind turbine.
Fig. 3 shows a schematic view of a blade with pre-deflection for a downwind type wind turbine according to the invention.
Fig. 4 shows a schematic view of a blade with an S-shape pre-deflection for a downwind type wind turbine according to the invention.
Fig. 5 shows a schematic view of a blade with a mirror image S-shape pre- deflection for a downwind type wind turbine according to the invention.
Fig. 6-9 shows examples of downwind type wind turbines with blades with predeflections according to the invention.
In the drawings, the following reference numerals have been used for the designations used in the detailed part of the description:
1. Wind turbine
2. Tower
3. Foundation
4. Nacelle
5. Hub
6. Wind turbine blade
7. Radial proximal end portion/the root of the blade
8. Radial distal end portion / the tip of the blade
9. Blade with pre-deflection
10. Intermediate portion
11. Pre-deflection
12. Imaginary pitch axis
13. First curvature
14. Second curvature
15. Inflection point
16. Wind direction
17. Third curvature
Detailed Description of the Invention
In figure 1 a typical upwind type wind turbine 1 is seen comprising a tower 2 installed at a foundation 3. At the top of the tower 2, a nacelle 4 comprising e.g. a gearbox, a generator and other components is seen, where the mentioned components are covered by a nacelle cover. At the nacelle 4, there is also installed a shaft for carrying a rotor comprising a hub 5 and two wind turbine rotor blades 6. The rotor blades 6 are arranged at the hub 5 at a radial proximal end portion 7 called the root of the blade 6. The second end 8 of the rotor blades 6 constitutes a tip end. The wind direction 16 is shown and indicated at the figure with a number of arrows.
In figure 2 a downwind type wind turbine 1 is seen comprising a tower 2 installed at a foundation 3. At the top of the tower 2, a nacelle 4 comprising e.g. a gearbox, a generator and other components is seen, where the mentioned components are covered by a nacelle cover. At the nacelle 4, there is also installed a shaft for carrying a rotor comprising a hub 5 and two wind turbine rotor blades 6. The rotor blades 6 are arranged at the hub 5 at a radial proximal end portion 7 called the root of the blade 6. The second end 8 of the rotor blades 6 constitutes a tip end. The wind direction 16 is shown and indicated at the figure with a number of arrows.
In figure 3 a blade with pre-deflection 9 for a downwind type wind turbine is seen, where the blade 6 has a radial proximal end portion 7 being the root of the blade configured to be fixed to a hub 5, a radial distal end portion 8 being the tip of the blade 6, and an intermediate portion 10 which extends between the radial proximal end portion 7 and the radial distal end portion 8, and where at least part of the intermediate portion 10 of the blade 6 is pre-deflected such that in an unloaded state, at least part of the blade 6 is curved away from an imaginary pitch axis 12, connecting the radial proximal end portion 7 and the radial distal end portion 8 where the pre-deflection 11 shift curvature sign, from a first curvature 13 closest to the radial proximal end 7, to a second curvature 14 closest to the radial distal end 8, at an inflection point 15 at the intermediate portion 10 between the radial proximal end portion 7 and the radial distal end portion 8.
The figure also shows that the radial distal end portion 8, being the tip of the blade 6, are positioned: upstream (dotted line) in relation to the imaginary pitch axis 12; at the imaginary pitch axis 12 and downstream (dotted line) in relation to the imaginary pitch axis 12, when the radial proximal end portion 7, being the root of the blade 6, is fixed to a hub 5.
Figure 3 also shows that the inflection point 15 is positioned between the proximal end portion 7 and the radial distal end portion 8, where the first curvature 13 makes up a smaller part of the blade 6 than the second curvature 14.
Figure 4 and figure 5 shows that the inflection point 15 is positioned right between the proximal end portion 7 and the radial distal end portion 8, where the first curvature 13 makes up approximately the same part of the blade 6 as the second curvature 14. However, the figures are examples and the first curvature 13 could in fact make up 2070 %, preferably 35-60 % and even further preferably 50 % of the intermediate portion 10.
In fig. 4 a blade with a S-shape pre-deflection for a downwind type wind turbine according to the invention and in fig. 5 a blade with a mirror image S-shape pre- deflection for a downwind type wind turbine according to the invention.
The figures thus shows, that the first curvature 13 pre-deflection shape and the second oppositely signed curvature 14 pre-deflection shape are different.
Where figure 4 shows that the first curvature 13 is configured to curve upstream towards a tower 2 when fixed to a hub 5 at a wind turbine 1 and the second curvature 14 is configured to curve downstream away from a tower 2 when fixed to a hub 5 at a wind turbine 1, figure 5 shows that the first curvature 13 is configured to curve downstream away from a tower when fixed to a hub at a wind turbine, and the second curvature is configured to curve upstream towards a tower when fixed to a hub at a wind turbine.
Figures 6 to 9 shows different examples of downwind type wind turbines 1 with blades 6 with pre-deflections 11 according to the invention. All figures basically show a downwind type wind turbine 1 as shown in figure 2 with blade with pre-deflection 9 as shown in figure 3.
Hence, the figures show a downwind type wind turbine 1 comprising a tower 2 installed at a foundation 3. At the top of the tower 2, a nacelle 4 comprising e.g. a gearbox, a generator and other components is seen, where the mentioned components are covered by a nacelle cover. At the nacelle 4, there is also installed a shaft for carrying a rotor comprising a hub 5 and two wind turbine rotor blades 6. The rotor blades 6 are arranged at the hub 5 at a radial proximal end portion 7 called the root of the blade 6. The second end 8 of the rotor blades 6 constitutes a tip end. The wind direction 16 is shown and indicated at the figure with a number of arrows.
The figures likewise shows rotor blades 6 with pre-deflection 9, where the blades 6 has a radial proximal end portion 7 being the root of the blade configured to be fixed to a hub 5, a radial distal end portion 8 being the tip of the blade 6, and an intermediate portion 10 which extends between the radial proximal end portion 7 and the radial distal end portion 8, and where at least part of the intermediate portion 10 of the blade 6 is pre-deflected such that in an unloaded state, at least part of the blade 6 is curved away from an imaginary pitch axis 12, connecting the radial proximal end portion 7 and the radial distal end portion 8 where the pre-deflection 11 shift curvature sign, from a first curvature 13 closest to the radial proximal end 7, to a second curvature 14 closest to the radial distal end 8, at an inflection point 15 at the intermediate portion 10 between the radial proximal end portion 7 and the radial distal end portion 8.
Figure 6 shows that the radial distal end portion 8, being the tip of the blade 6, is positioned upstream in relation to the imaginary pitch axis 12; figure 7 shows that the radial distal end portion 8, being the tip of the blade 6, is positioned at the imaginary pitch axis 12 and figure 8 shows that the radial distal end portion 8, being the tip of the blade 6, are positioned downstream in relation to the imaginary pitch axis 12, where the radial proximal end portion 7, being the root of the blade 6, is fixed to a hub 5. The figures also shows that the inflection point 15 is positioned between the proximal end portion 7 and the radial distal end portion 8, where the first curvature 13 makes up a smaller part of the blade 6 than the second curvature 14.
Figure 9 shows an example of a downwind type wind turbine 1 with blades 6 with predeflections 11 according to the invention. The figure basically shows a downwind type wind turbine 1 as shown at figure 2 with blades with pre-deflection 9 as shown in figure 3, but where the figure shows one inflection point 15 positioned between the proximal end portion 7 and the radial distal end portion 8, where the first curvature 13 makes up a smaller part of the blade 6 than the second curvature 14 and an inflection point 15 also positioned between the proximal end portion 7 and the radial distal end portion 8, but at a point where a third curvature 17 makes up a smaller part of the blade 6 than the second curvature 14.
π

Claims (9)

PATENTKRAV 1. Forudbøjet vinge (6) til vindturbine (1) af nedstrømstypen, hvor vingen (6) har et radielt proksimalt endeparti (7), som er vingeroden og konfigureret til at fastgøres på et nav (5), et radielt distalt endeparti (8), som er vingespidsen, og et mellemliggende parti (10), som strækker sig mellem det radielle proksimale endeparti (7) og det radielle distale endeparti (8), og hvor mindst en del af det mellemliggende parti (10) af vingen (6) er forud bøjet, sådan at mindst en del af vingen i en ubelastet tilstand krummer væk fra en imaginær pitch akse (12), der forbinder det radielle proksimale endeparti (7) og det radielle distale endeparti (8), kendetegnet ved, at forudbøjningen skifter krumningsfortegn fra en første krumning (13) nærmest den proksimale ende til en anden krumning (14) nærmest den distale ende ved et vendepunkt (15) på det mellemliggende parti (10) mellem det proksimale endeparti (7) og det radielle distale endeparti (8).A pre-bent vane (6) for a downstream type wind turbine (1), the vane (6) having a radially proximal end portion (7) which is the wing root and configured to be attached to a hub (5), a radial distal end portion (8) ), which is the wing tip, and an intermediate portion (10) extending between the radial proximal end portion (7) and the radial distal end portion (8), and wherein at least a portion of the intermediate portion (10) of the wing (6) ) is pre-bent such that at least a portion of the wing in an unloaded condition curves away from an imaginary pitch axis (12) connecting the radial proximal end portion (7) and the radial distal end portion (8), characterized in that the pre-bend changes sign of curvature from a first curvature (13) closest to the proximal end to a second curvature (14) closest to the distal end at a turning point (15) of the intermediate portion (10) between the proximal end portion (7) and the radial distal end portion ( 8). 2. Forudbøjet vinge ifølge krav 1, kendetegnet ved, at vendepunktet (15) er placeret mellem det proksimale endeparti (7) og det radielle distale endeparti (8), hvor den første krumning (13) udgør 20-70%, fortrinsvis 35-60% og endda yderligere foretrukket 50% af det mellemliggende parti (10).Pre-bent wing according to claim 1, characterized in that the turning point (15) is located between the proximal end portion (7) and the radial distal end portion (8), the first curvature (13) constituting 20-70%, preferably 35- 60% and even more preferably 50% of the intermediate portion (10). 3. Forudbøjet vinge ifølge krav 1 eller 2, kendetegnet ved, at den første forudbøjede krumningsform og den anden forudbøjede krumningsform med modsat fortegn er forskellige.Pre-bent wing according to claim 1 or 2, characterized in that the first pre-bent shape of curvature and the second pre-bent shape of curvature with opposite signs are different. 4. Forudbøjet vinge ifølge ethvert af krav 1 til 3, kendetegnet ved, at den første krumning (13) er udformet til at krumme opstrøms mod et tårn (2) ved fastgørelse til et nav (5) på en vindturbine (1), og den anden krumning (14) er udformet til at krumme nedstrøms væk fra et tårn (2) ved fastgørelse til et nav (5) på en vindturbine (1).Pre-bent wing according to any one of claims 1 to 3, characterized in that the first curvature (13) is designed to curve upstream against a tower (2) by attachment to a hub (5) on a wind turbine (1), and the second curvature (14) is designed to curve downstream away from a tower (2) by attachment to a hub (5) on a wind turbine (1). 5. Forudbøjet vinge ifølge ethvert af krav 1 til 3, kendetegnet ved, at den første krumning (13) er udformet til at krumme nedstrøms væk fra et tårn (2) ved fastgørelse til et nav (5) på en vindturbine (1) , og den anden krumning (14) er udformet til at krumme opstrøms mod et tårn (2) ved fastgørelse til et nav (5) på en vindturbine (1).Pre-bent blade according to any one of claims 1 to 3, characterized in that the first curvature (13) is designed to curve downstream away from a tower (2) by attachment to a hub (5) of a wind turbine (1), and the second curvature (14) is designed to curve upstream against a tower (2) by attachment to a hub (5) on a wind turbine (1). 6. Forudbøjet vinge ifølge ethvert af krav 1 til 5, kendetegnet ved, at det radielle distale endeparti (8), som er vingespidsen, er placeret opstrøms i forhold til den imaginære pitch akse (12), når det radielle proksimale endeparti (7), som er vingeroden, er fastgjort til et nav (5).A pre-bent wing according to any one of claims 1 to 5, characterized in that the radial distal end portion (8), which is the wing tip, is located upstream of the imaginary pitch axis (12) when the radial proximal end portion (7) , which is the wing root, is attached to a hub (5). 7. Forudbøjet vinge ifølge ethvert af krav 1 til 5, kendetegnet ved, at det radielle distale endeparti (8), som er vingespidsen, er placeret ved den imaginære pitch akse (12), når det radielle proksimale endeparti (7), som er vingeroden, er fastgjort til et nav (5).Pre-bent wing according to any one of claims 1 to 5, characterized in that the radial distal end portion (8), which is the wing tip, is located at the imaginary pitch axis (12) when the radial proximal end portion (7), which is the wing root, is attached to a hub (5). 10 8. Forudbøjet vinge ifølge ethvert af krav 1 til 5, kendetegnet ved, at det radielle distale endeparti (8), som er vingespidsen, er placeret nedstrøms i forhold til den imaginære pitch akse (12), når det radielle proksimale endeparti (7), som er vingeroden, er fastgjort til et nav (5).Pre-bent wing according to any one of claims 1 to 5, characterized in that the radial distal end portion (8), which is the wing tip, is located downstream of the imaginary pitch axis (12) when the radial proximal end portion (7) ), which is the wing root, is attached to a hub (5). 15 9. Anvendelse af en forudbøjet vinge (6) ifølge ethvert af krav 1 til 8 til en vindturbine (1) af nedstrømstypen.Use of a pre-bent vane (6) according to any one of claims 1 to 8 for a wind turbine (1) of the downstream type. 1/81/8
Figure DK179472B1_C0001
Figure DK179472B1_C0001
DKPA201770364A 2017-05-22 2017-05-22 Blade with pre-deflection for downwind type wind turbine DK179472B1 (en)

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