WO2011053177A1 - Procedure and constructive solution for twin blades used in large diameter wind turbines - Google Patents

Procedure and constructive solution for twin blades used in large diameter wind turbines

Info

Publication number
WO2011053177A1
WO2011053177A1 PCT/RO2009/000025 RO2009000025W WO2011053177A1 WO 2011053177 A1 WO2011053177 A1 WO 2011053177A1 RO 2009000025 W RO2009000025 W RO 2009000025W WO 2011053177 A1 WO2011053177 A1 WO 2011053177A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
blade
blades
wind
twin
axial
Prior art date
Application number
PCT/RO2009/000025
Other languages
French (fr)
Inventor
Dan Andreescu
Original Assignee
Dan Andreescu
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

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING WEIGHT AND MISCELLANEOUS MOTORS; PRODUCING MECHANICAL POWER; OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03DWIND MOTORS
    • F03D1/00Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06Rotors
    • F03D1/065Rotors characterised by their construction, i.e. structural design details
    • F03D1/0658Fixing wind-engaging parts to rotor
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING WEIGHT AND MISCELLANEOUS MOTORS; PRODUCING MECHANICAL POWER; OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03DWIND MOTORS
    • F03D1/00Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06Rotors
    • F03D1/0608Rotors characterised by their form
    • F03D1/0633Rotors characterised by their form of the blades
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05BINDEXING SCHEME RELATING TO MACHINES OR ENGINES OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, TO WIND MOTORS, TO NON-POSITIVE DISPLACEMENT PUMPS, AND TO GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY
    • F05B2240/00Components
    • F05B2240/20Rotors
    • F05B2240/30Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/70Wind energy
    • Y02E10/72Wind turbines with rotation axis in wind direction
    • Y02E10/721Blades or rotors
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product
    • Y02P70/52Manufacturing of products or systems for producing renewable energy
    • Y02P70/523Wind turbines

Abstract

The patent "PROCEDURE AND CONSTRUCTIVE SOLUTION FOR TWIN BLADES USED IN LARGE DIAMETER WIND TURBINES" has applications in the power generation area. The scope of the patent is to allow manufacturing blades for horizontal axial wind turbines, having length (diameter) much larger than obtained with current technology. Current restrictions are primarily imposed by excessive increase of the bending moments at the base of the blade, due to aerodynamic forces and own blade weight that increase with the exterior diameter.

Description

PROCEDURE AND CONSTRUCTIVE SOLUTION FOR TWIN BLADES USED IN LARGE DIAMETER WIND TURBINES.

This patent deals with a procedure and a fabrication solution manufacturing large diameter blades for wind turbines with horizontal axis suitable for bigger power wind turbines, especially over 3.0 MW>.

The defining feature of this domain is the large exterior diameter of the wind turbines propeller, going up to one hundred meters, necessary to reach an unitary power over 5,0 MW and even more ,up to 150 m diameter for 10 MW and more. This leads to big constructive difficulties and huge weights of blades.

Due to the increasing of the length of blades the aerodynamic forces acting on the blade prevalent in axial direction and own weight ,in horizontal position .generate a really huge bending moment at the bottom of the blade (even more than 10**6 Nm ) which, in its turn, restricting the increase of the blade length and finally the wind turbines power and economically efficiency, As an example, for 6,0 MW turbine power, the necessary length of the blade is about 65 m and it weight is about 18 tones. The weight of blade increases with the length at the exponent 1,9...2,5. which leads to a big bend in horizontal position and limit the increasing the length of turbine blade,as an example the 100m length blade could reach 60t.

For this length it is computed that, with the existing constructive blade solution, the bottom bend produced by the own weight, in horizontal position, will overpass the bend produced by the aerodynamic forces and the total bend will really huge.

With the purpose to make wind turbines horizontal axis, with long blades (large diameters), an accepted procedure is to gradually augment chord and maximum thickness of the aerodynamic blade profile of the blade section from the tip to bottom and in same time to increase the wall blade thickness ,resulting the suitable increasing of the resistance modulus.

The disadvantage of this procedure is that on one hand, the increase of the enlarging blade section and wall thickness, as well its weight, while supplementary technical difficulties in production contribute to raising manufacturing costs; on the other hand, the increase in section is limited technologically and operationally, so that in practice propeller axial wind turbine diameters are limited to 125m-150m.

More increasing the length of blade, the fundamental and its harmonics value of vibrations are in the same range with the wind turbine rotation frequency .An unacceptable resonance process could issue. These are limiting factors in building larger, more efficient wind turbine units.

A known procedure used to make axial fans or wind turbines with long blades is in the Patent Request A/00241/2008 deposed in OSIM Romania and published in BOBI no.8/2008 in which is reinforced the blade with a supplementary structure near to the blade and fasten to the hub.

The disadvantage of this procedure is that being dedicated for axial fans with vertical axis not horizontal axis ,like this wind turbines does not solve the bend due to the own weight. To the purpose to make wind turbines , with horizontal axis, long blades an accepted constructive solution used to withstand very large bending moments at the bottom, is to made its like a plane propeller shape ,but with the profiles suitable to a turbine function, using aerodynamics profiles ,like Gottingen No. 622 or 623,the body blade being empty inside and built by light materials ,Iike FRP or carbon fibers, increasing the blade section toward the base ,toward the hub increasing the wall thickness and the profile maximum thickness, that can take the bending moment acting on the blade.

The disadvantage of this solution is that results a huge increasing of the blade section, from top to bottom and as well the weight of blade, the statistically data show that the blade weight is increasing with length at an exponent : 1,9-2,5. Like example, a 50 m long blade has about 10 1 and one with 60 m has about 15t, in spite the light materials which the blades are made. Moreover, its own fundamental frequency is low, less than 1,0 Hz , i.e. in the dangerous zone of blade resonance for longer blades, further impeding the increase of the turbine propeller exterior diameter. This makes impossible the further increasing the unitary turbine power the main way to reduce the unitary investment and operation costs at the level which makes the wind energy economically very efficient.

The disadvantage of this solution is that it also restricts the size increase of the blade section. Due to this big weight, the blades number in a propeller is now only three (the number should be odd),which is a big disadvantages for larger diameters, when the pitch becomes too larger and the blade chord ,at the top radius, issues from aerodynamic computation, becomes too big to be done from resistance reasons ,that reduces the <Power Coefficient ,means the efficiency of the wind turbine. Moreover, its own fundamental frequency is low, (1.5 to 3HZ for 20m), i.e. in the dangerous zone of blade resonance for longer blades, further impeding the increase of the turbine exterior diameter.

One known constructive solution used to build longer blades for axial fans or wind turbines needed to withstand a very large bending is in the Patent Request A/00241/2008 deposed in OSIM Romania and published in BOBI no.8/2008 in which is reinforced the blade with a supplementary structure ,which could be a blade also ,at a distance of 200-600mm near to the blade and fasten to the hub.

The disadvantage of this constructive solution is that being dedicated for axial fans with vertical axis not horizontal axis ,like this wind turbines does not solve the bend due to the own weight in the rotating plane ,when the blade is in horizontal position.

This patent solves this technical problem of increasing the resistance modulus of the blade, from tip to bottom, as well as is necessary to resist to the bend dues to the aerodynamic forces and blade weight in horizontal position, for larger blade lengths than currently available and without constructive or aerodynamic restrictions, thus allowing the manufacture of blades really much longer than currently available. That means to be possible to reach length of blades to 150m or even more and the wind turbine power to overpass 20 MW.

The procedure described in the patent eliminates the disadvantages described above by increasing the blade resistance modulus in the axial direction, by using a structure ,named twin blades,having in the axial direction, after the first blade one or more blades identically or not, with the first one like shape and length .materializing what in aerodynamic is called a blade cascade, connected between them with axial beams with aerodynamic shape and every twin blade ,if it is necessary, could be fortified in rotating plane by wires linked to laterally firm structures .

The constructive solution described in the patent eliminates the disadvantages described above by increasing the blade resistance modulus in the axial direction and in the rotation direction, using a blade structure ,named twin blades, having in the axial direction, after the every first blade one or more blades identically , or not , with the first one like shape and length , connected between them with axial beams with aerodynamic shape ,all this constructive structure being like a framework fixed on the same frame connected with the hub, the distance between blades , several meters range ,could be constant or variable ,from tip to bottom , and every twin blades ,if it is necessary, could be fortified in rotating plane by wires linking laterally firm structures and one of its axial beam .

Implementation of the invention/patent has the following advantages:

The twin blades assembly being like a framework could have a resistance modulus at least 10 times even 50 times bigger than the single blade,depending of the axial distance between the blades. This eliminates any fabrication and functional restriction in building a blade longer than the current practical length limit of a 70m-80m ,being possible to overpass 150m length.

Like result, the bottom solid area of the twin blades is much smaller ,means less material and weight than the single blade Reducing the blade weight will be possible to use more than three blades in a

propeller ,means 5 even seven, which is capital for reach good efficiency at big diameters

The very much increasing of the moment of inertia due to the framework structure of the twin blades, matched with the smaller bottom area increases the own frequency in a zone where there is no danger of resonance.

The twin blades have the solution to increase the module resistance in the rotating plane as is necessary to resist to the bending moment issued by its own weight in horizontal position.

Following are one implementation version of the invention in figures 1 & 2:

Fig.l Layout of the twin blades of the wind turbine with horizontal axis.

Fig. 2 Layout of the wind turbine propeller with twin blades.

The procedure described in this patent, indicates that the required increase of the blade 1 resistance modulus in the axial direction,blade 1 being hold by frame- base 2

on the horizontal wind turbine hub 3,by using a structure ,named twin blades 4,having in the axial direction, after the first blade 1 one or more blades 5 identically or not with the first one like shape and length materializing what in aerodynamic is called a blade cascade a, rigid connected between them with axial beams 6 with aerodynamic shape and every twin blade a ,especially for big blade 1 lengths, could be fortified in rotating plane by mean of the laterally firm structures 7 and wires 8,with the goal to resist in horizontal position to the bend due to the own weight. The constructive solution described in this patent consists in a structure ,named twin blades 4 having in the axial direction, after every first blade 1 one or more blades 5 identically or not with the blade 1 like shape and length , materializing what in aerodynamic is called a blade cascade a, the distance between blades 1,5 , several meters range ,could be constant or variable from tip to bottom ,every blades 1,5 having an aerodynamic profile in the section and a empty body blades 1,5 made by a thin cover 11 from light materials like FRP or aluminum ,but with some reinforcements 12 in side and the blades 1,5 rigid connected between them with axial beams 6 with aerodynamic shape ,all this constructive solution the twin blades 4 being like a rigid framework is hold on the same frame-base 2 connected with the horizontal axis wind turbine hub 3 and every twin blades 4 ,if it is necessary by resistance reasons, could be fortified in rotating plane by two laterally firm structures 7 built on the hub 3 and holding the twin blades 4 with the wires 8 having a dampfering and tension stress device 10 ,from articulation 10 fixed on one of the axial beam 6, which allows the twin blades 4 rotation related to the hub 3 .

Claims

1. Procedure for twin blades used in horizontal axis wind turbine and with big diameters consists in using a blade with a gradually increasing ,from tip to bottom, of the blade surface aerodynamic profile ,means the profile chord and maximum thickness and the blade wall thickness or a supplementary structure fastened to the hub which both leads to the increasing of the resistance modulus to the bottom, necessary to resist to the bend stress due to aerodynamic and own weight forces characterized by achieving the required increase of the blade (1) resistance modulus in the axial direction, blade (1) being hold by frame-base (2) on the horizontal wind turbine hub (3) by using a structure ,named twin blades (4),having in the axial direction, after the first blade (1) one or more blades (5) identically or not with the first one like shape and length materializing what in geodynamic is called a blade cascade (a) rigid connected between them with axial beams (6) with aerodynamic shape and every twin blade (a) .especially for big blade (1) lengths, could be fortified in rotating plane by mean of the laterally firm structures (7) and wires (8),with the goal to resist in horizontal position to the bend due to the own weight.
2. Constructive solution for horizontal axis wind turbine blades with big length which are made like a plane propeller and made from light and resistant materials like FRP or carbon fiber having in section an aerodynamic profile like Gottingen 622 :623 achieving the necessary bottom resistance modulus increasing the chord and the profile thickness or adding a supplementary structure fastened to the same hub characterized by the constructive solution described in the procedure 1 consisting in a structure ,named twin blades (4) having in the axial direction, after every first blade (1) one or more blades (5) identically or not with the blade (1) like shape and length , materializing what in aerodynamic is called a blade cascade (a), the distance between blades (1),(5) .several meters range ,could be constant or variable from tip to bottom, every blades (1),(5) having an aerodynamic profile in the section and the empty body blades (1),(5) is made by a thin cover (11) from light materials like FRP or aluminum ,but with some reinforcements (12) inside and the blades (1),(5) rigid connected between them with axial beams (6) with aerodynamic shape ,all this constructive solution the twin blades (4) being like a rigid framework is hold on the same frame-base (2) connected with the horizontal axis wind turbine hub (3) and every twin blades (4) ,if it is necessary by resistance reasons, could be fortified in rotating plane by two laterally firm structures (7) built on the hub (3) and holding the twin blades (4) with the wires (8) having a dampening and tension stress device (9) .from articulation 10 fixed on one of the axial beam (6), which allows the twin blades (4) rotation related to the hub (3) .
PCT/RO2009/000025 2009-10-28 2009-12-09 Procedure and constructive solution for twin blades used in large diameter wind turbines WO2011053177A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
RO200900874 2009-10-28
ROa200900874 2009-10-28

Publications (1)

Publication Number Publication Date
WO2011053177A1 true true WO2011053177A1 (en) 2011-05-05

Family

ID=43085951

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/RO2009/000025 WO2011053177A1 (en) 2009-10-28 2009-12-09 Procedure and constructive solution for twin blades used in large diameter wind turbines

Country Status (1)

Country Link
WO (1) WO2011053177A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013067916A1 (en) * 2011-11-11 2013-05-16 Zhang Xiangzeng New blade of composite material for horizontal-axis wind power generator
WO2014056507A1 (en) * 2012-10-12 2014-04-17 Aalborg Universitet Joined blade wind turbine rotor
WO2016048221A1 (en) * 2014-09-25 2016-03-31 Winfoor Ab Rotor blade for wind turbine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3239087A1 (en) * 1982-10-22 1984-04-26 Istvan Horvath Installation for harnessing wind energy
DE20206942U1 (en) * 2002-05-02 2002-08-08 Repower Systems Ag Rotor blade for wind turbines
EP2006537A2 (en) * 2007-06-21 2008-12-24 Martinez Manuel Torres Blade for a horizontal-axis wind generator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3239087A1 (en) * 1982-10-22 1984-04-26 Istvan Horvath Installation for harnessing wind energy
DE20206942U1 (en) * 2002-05-02 2002-08-08 Repower Systems Ag Rotor blade for wind turbines
EP2006537A2 (en) * 2007-06-21 2008-12-24 Martinez Manuel Torres Blade for a horizontal-axis wind generator

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013067916A1 (en) * 2011-11-11 2013-05-16 Zhang Xiangzeng New blade of composite material for horizontal-axis wind power generator
WO2014056507A1 (en) * 2012-10-12 2014-04-17 Aalborg Universitet Joined blade wind turbine rotor
EP2906819B1 (en) 2012-10-12 2017-05-03 Joint Blade Rotor A/S Joined blade wind turbine rotor
US9822760B2 (en) 2012-10-12 2017-11-21 Joint Blade Rotor A/S Joined blade wind turbine rotor
WO2016048221A1 (en) * 2014-09-25 2016-03-31 Winfoor Ab Rotor blade for wind turbine

Similar Documents

Publication Publication Date Title
Paraschivoiu et al. Double multiple streamtube model with recent improvements (for predicting aerodynamic loads and performance of Darrieus vertical axis wind turbines)
US5531567A (en) Vertical axis wind turbine with blade tensioner
Jackson et al. Innovative design approaches for large wind turbine blades
US7528497B2 (en) Wind-turbine with load-carrying skin
US6974307B2 (en) Self-guiding wind turbine
Riziotis et al. Aeroelastic stability of wind turbines: the problem, the methods and the issues
US7344360B2 (en) Wind turbine rotor blade with in-plane sweep and devices using same, and methods for making same
US7804186B2 (en) Modular array fluid flow energy conversion facility
US20080273974A1 (en) Wind turbine device
US6830436B2 (en) Wind turbine provided with nacelle
US20100150718A1 (en) Efficient systems and methods for construction and operation of accelerating machines
US4087202A (en) Vertical axis wind turbines
Eriksson et al. Evaluation of different turbine concepts for wind power
US20060133937A1 (en) System and method for passive load attenuation in a wind turbine
US20100296913A1 (en) Wind power generating system with vertical axis jet wheel turbine
US20090074585A1 (en) Wind turbine blades with trailing edge serrations
Veers et al. Aeroelastic tailoring in wind-turbine blade applications
US20060056972A1 (en) Wind turbine
US8164213B2 (en) Orbital track wind turbine
Tangler The evolution of rotor and blade design
US20090196755A1 (en) Modular Construction for Wind Turbine Blade
EP2107235A1 (en) A wind turbine blade with an auxiliary airfoil
US20110076149A1 (en) Systems and methods of assembling a rotor blade extension for use in a wind turbine
Menet et al. A comparative calculation of the wind turbines capacities on the basis of the L–σ criterion
Wilson Wind-turbine aerodynamics

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09821417

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase in:

Ref country code: DE

122 Ep: pct app. not ent. europ. phase

Ref document number: 09821417

Country of ref document: EP

Kind code of ref document: A1