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
  • F03D1/0608—Rotors characterised by their aerodynamic shape
  • F03D1/0633—Rotors characterised by their aerodynamic shape of the blades
  • F03D1/0641—Rotors characterised by their aerodynamic shape of the blades of the section profile of the blades, i.e. aerofoil profile
• • 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
  • 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
  • F03D7/00—Controlling wind motors 
  • F03D7/02—Controlling wind motors  the wind motors having rotation axis substantially parallel to the air flow entering the rotor
  • F03D7/022—Adjusting aerodynamic properties of the blades
  • F03D7/0232—Adjusting aerodynamic properties of the blades with flaps or slats
• • 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
  • F03D80/00—Details, components or accessories not provided for in groups F03D1/00 - F03D17/00
  • F03D80/30—Lightning protection
• • 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
  • F05B2240/305—Flaps, slats or spoilers
  • F05B2240/3052—Flaps, slats or spoilers adjustable
• • 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
  • F05B2270/00—Control
  • F05B2270/60—Control system actuates through
  • F05B2270/605—Control system actuates through pneumatic actuators
• • 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 the field of rotor blades for wind turbine installations.
• it relates to wind turbine blades comprising devices for modifying the aerodynamic surface or shape of the blade, and for operating mechanisms for controlling the position and/or movement of such devices.
• the wind turbine can also be regulated to account for fast local variations in the wind velocity - the so-called wind gusts.
• the ability to regulate each of the wind turbine blades individually advan- tageously enables the loads to be balanced, reducing the yaw and tilt of the rotor.
• a well-known and effective method of regulating the loads on the rotor is by pitching the blades.
• pitching becomes a relatively slow regulation method incapable of changing the blade positions fast enough to account for e.g. wind gusts or other rela- tively fast load variations.
• Another way of regulating the blades is by changing their aerodynamic surfaces or shapes over parts or the entire length of the blade, thereby increasing or decreasing the blade lift or drag correspondingly.
• Different means of changing the airfoil shape are known such as different types of movable or adjustable flaps (e.g. trailing edge flaps, leading edge slats or Krueger flaps, Gurney flaps placed on the pressure side near the trailing edge, ailerons, or stall inducing flaps), vortex generators for controlling the boundary layer separation, adaptive elastic members incorporated in the blade surface, means for changing the surface roughness, adjustable openings or apertures, or movable tabs.
• aerodynamic devices or devices for modifying the aerodynamic surface or shape of the blade Such different means are here and in the following referred to in common as aerodynamic devices or devices for modifying the aerodynamic surface or shape of the blade.
• One important advantage of the relatively small aerodynamic devices is a potentially faster response due to less inertia than if the whole blade is being pitched.
• One drawback with the known different systems of various aerodynamic devices of the above mentioned types is how they are actuated and controlled. In order to reach the devices potential in the regulation of wind turbines, the aerodynamic surface modifying devices need to be able to operate quickly and repeatedly. Therefore the power consumption could be consid- erable.
• the aerodynamic devices are powered directly from the hub via a power link. An electrical cable is however undesirable due to the inevitable implications in relation to lightning. Further, known systems may exhibit problems with their operational speed. Moreover, known systems may exhibit poor mechanical stability.
• a wind turbine blade comprising a blade body and one or more devices for modifying the aerodynamic surface or shape of the blade, where the device(s) is movably connected to the blade body and where the wind turbine blade further comprises one or more operating mechanisms for controlling the position and/or movement of the device.
• the operating mechanism comprises at least one first compressible pressure chamber arranged in a region next to one or more lever elements connected to the blade body or the device such that a change of pressure in the pressure cham- ber causes its cross sectional diameter to change so as to thereby move the lever element and thereby modify the position and/or movement of the device relative to said blade body.
• a 'compressible' chamber is understood to cover a chamber of a material such as an elastic thermoplastic capable of attaining a different cross sectional diameter or width depending on the pressure inside the chamber relative to the surrounding pressure and/or forces applied to it.
• the wind turbine blade according to the above comprises at least two compressible pressure chambers and the pressure chambers are arranged on opposing sides of the lever element.
• a first pressure chamber may contribute to move the lever element and thereby the movable device in a first direction
• a second pressure chamber on the opposite side of the lever element may act to move the lever element in the opposite direction.
• the regulation ability of the operating system is increased considerably compared to a single pressure chamber system and the position of the movable device can be controlled and regulated much more precisely independent on the winds acting on the blade as such.
• the achievable regulation speed of the operating system can be increased by the use of several pressure chambers.
• the wind turbine blade comprises at least one elastic element such as. a spring or other resilient element which is arranged on an opposing side of the lever element(s) compared to the pressure chamber(s) and/or arranged on the same side of the lever element(s) as the pressure chamber(s).
• the elastic element(s) hereby acts to dampen any vibrations in the blade/device system.
• An elastic element used together with a pressure chamber may further render the use of a further pressure chamber acting to push the lever element in the opposite direction as the first pressure chamber superfluous.
• the one or more pressure chambers are connected to one or more pressure reservoirs via at least one first valve system and for providing pres- surization and/or depressurization of said pressure chambers.
• the one or more pressure reservoirs is at least partly constituted by one or more sections of beam walls of the wind turbine blade and/or is at least partly placed within an internal spar of the wind turbine blade.
• the pressure or optionally a vacuum reservoir
• the pressure chamber(s) is connected to an outer surface of the wind turbine blade via at least one second valve system.
• the pressure chamber may quickly and by simple means be depressurized to atmospheric pressure.
• the at least one first and/or second valve system described above is connected to a control unit via a power link providing the valve system with control signals for the operating of said device.
• the aerodynamic surface of the wind turbine blade may hereby be regulated quickly and effectively and modified continuously according to signals from a central control unit placed for instance in the nacelle of the wind turbine.
• the control signals may be electrical or light or other electromagnetic wave for instance.
• the power link may be replaced and the control signals may be pressure control signals.
• This may be achieved by a pressure tube connecting the control unit to the first and/or second valve system.
• the pressure tube may comprise a gas of a lower molecular weight than 28.9 kg/kmol, such as Helium He, Ammonia NH 3 , Hydrogen H 2 , Hydroxyl OH, Methane CH 4 , Natural Gas, Acetylene C 2 H 2 ,, or Neon Ne. Dry air has a molecular weight of 28.96 kg/kmol (as determined e.g. in Chemical Rubber Company, 1983. CRC Handbook of Chemistry and Physics. Weast, Robert C, editor. 63rd edition. CRC Press, Inc.
• Helium may be further advantageous due to being light in combination with its non-corrosive, non-toxic, and non explosive properties while at the same time being relative easy to acquire.
• the use of pressure control signals avoids electrical conductors being placed in the wind turbine blades and therefore, the potential risk of damage from lightning is reduced.
• the lever element in itself constitutes a part of the device for modifying the aerodynamic surface or shape of the blade hereby yielding a more compact, simple and robust constructional design with fewer mechanical parts.
• This may for instance be achieved by arranging a pressure chamber directly or indirectly next to an interior surface of a trailing edge aileron, whereby the aileron will be moved and its position affected directly by a change of pressure in the pressure chamber.
• the device for modifying the aerodynamic surface or shape of the blade comprises a movable trailing edge and/or an aileron.
• the one or more pressure chambers are positioned essentially in a longitudinal direction extending from a root portion to a tip portion of the blade which is especially advantageous for controlling and regulating aerodynamic devices such as flaps and ailerons as these are conventionally arranged along the length of the wind turbine blade and are rotated or moved in the chordwise plane of the blade transverse to the longi- tudinal direction.
• the device for modifying the aerodynamic surface or shape of the blade comprises a pressure skin and a suction skin, a first one of the pressure and suction skins being secured to or integral with the blade body, and a second one of the pressure and suction skins being slidably movable with respect to the blade body.
• a part of the second one of the pressure and suction skins which is slidably movable with respect to the blade body may in another embodiment comprise a radial surface arranged such that it is ratable about a hinge.
• the device for modifying the aerodynamic surface or shape of the blade is at least partly divided into a number of sections by interstices or connecting portions having higher elasticity than said sections.
• the construction of the aerodynamic device further results in the longitudinal bending modes of the blade and the device to decouple to a larger extent from the transverse bending modes. Furthermore, the modular nature of the construction allows a wider range and more efficient manufacturing methods for example thermoplastic moulding, and for easier maintenance where individual modules can be replaced or refurbished. Smaller modules may more readily be upgraded in a maintenance overhaul to later versions of the device.
• this then provides for individual or continuous adjustment of the different sections of the aerodynamic device by arranging one or more pressure chambers for each section or a number of sections and being regulated independently of the other pressure reservoirs used.
• the pressure chambers may however optionally be connected to the same pressure or vacuum reservoir.
• the interstices or connecting portions extend at least partly through a thickness of the device and from a trailing edge of said device and in an es- sentially chordwise direction, such that the overall longitudinal bending flexibility of the device is increased.
• the aerodynamic device may be assembled by the number of sections being premanufactured. The device can optionally be assembled during connection to or mounting on the wind turbine blade body.
• the pressure chamber(s) may comprise a pressure hose, or the pressure chamber(s) may comprise an inflatable bladder.
• the invention finally relates to a wind turbine comprising at least one wind turbine blade according to any of the embodiments described in the preceding. Advantages hereof are as described above for the wind turbine blade.
• Fig. 1 shows a wind turbine blade according to prior art and comprising movable aerodynamic devices in the shape of a movable trailing edge and an aileron,
• Figs. 2A, B, and C shows a wind turbine blade according to prior art in a cross sectional view with different types of movable aerodynamic devices
• Figs. 3-4 show an embodiment of an active trailing edge being controlled and operated by pressure according to an embodiment of the invention, and as seen in two different positions.
• Fig. 5 is a sketch of a wind turbine blade as subjected to edgewise gravity loads and comprising a movable trailing edge with a number of device segments according to the invention
• Fig. 6 shows a sketch of a wind turbine blade comprising an operating mechanism according to the invention
• Fig. 7 illustrates the connection of an operating mechanism according to the invention and connected to an inner pressure or vacuum chamber
• FIGS. 8-9 show different embodiments according to the invention of operating mechanisms for controlling and moving a movable trailing edge and as seen in cross sectional views, and
• Fig. 10 shows an embodiment of an aileron comprising an operating mechanism according to an embodiment the invention.
• Figure 1 shows a blade 100 for a wind turbine according to prior art and comprising some examples of so-called aerodynamic devices 101.
• the aerodynamic devices change or modify the aerodynamic surface or shape 105 of the wind turbine blade 100 thereby altering the lift and/or drag coefficients of the wind turbine blade during operation.
• the aerodynamic shape of the wind turbine blade 100 can be changed and regulated by changing the position of the movable trailing edge flap 102 placed along a part of the length or longitudinal direction 106 of the blade, or by the activation of a number of ailerons 103 also placed near and along the trailing edge 104 of the wind turbine blade on its suction side.
• the aerodynamic devices 101 may - as is the case with for instance the flaps or active trailing edges - be actuated or moved (rotated, translated, or combinations thereof) in a chord- wise plane 108 transverse to the length 106 of the blade.
• This is illustrated in the figures 2A, B, and C for different types of a slotted flap 109, an active trailing edge flap 102, and an aileron 103, respectively, which are all movably connected to the blade body 107.
• the chord- wise plane 108 here and throughout the description is used to describe a cross sectional plane transverse but not necessarily perpendicularly to the longitudinal direction 106 of the blade.
• FIG. 3 and 4 are shown an active trailing edge 101, 102 manipulated and controlled by an operating system according to an embodiment of the invention and in two different positions corresponding to its fully deactivated and fully activated state, respectively.
• two pressure hoses 401, 402 are provided which run along the length of the aerodynamic device 101.
• the pressure hoses 401, 402 are arranged next to and in this embodiment on opposing sides or surfaces 406 of a lever element 404 connected to or a part of the movable trailing edge 102.
• the movable trailing edge 102 is movably connected to the blade body 107 and can be rotated in relation to the blade body around the hinge 405.
• the lever element 404 extends in a direction directly from the hinge 405 whereby the forces applied to the lever elements from the pressure hoses are optimally transferred to a rotational movement of the trailing edge around the hinge.
• pressure hoses 401, 402 are shown as the actuating means for moving the active trailing edge.
• the pressure hoses 401, 402 are pressure chambers that change shape and cross section. In another embodiment, for example, they could be a local chamber such as an inflatable bladder that does not extend along the length of the aerodynamic device 101. It is only necessary that the pressure chamber changes shape to impart movement to the lever element 404.
• the lever element 404 is provided so that it moves in response to the force imparted from pressure hoses 401, 404. Therefore, the lever element 404 must have a sufficient surface area on which the pressure hoses 401, 404 can act so that the force can be transferred to the lever element.
• the pressure hoses are made of a compressible material such as for instance a thermoplast or elastomer which may be fibre reinforced allowing the hose to be compressed or squeezed thereby attaining a smaller cross sectional diameter or width 410 depending on the pressure inside the hose relative to the external pressure and forces applied to it.
• the first pressure hose 401 is depressurised (for instance by applying a vacuum to it or by venting it to atmospheric pressure), and the second pressure hose 402 has been pressurized whereby the first pressure hose 401 is compressed and squeezed to a certain extent resulting in the trailing edge flap 102 being held in its lowermost position.
• the first hose 401 is now pressurised and the second hose 402 is depressurised causing the lever element 404 between the two hoses to move which in turn causes the trailing edge flap 102 to move around the hinge 405.
• the two hoses 401, 402 may run along parts of or the entire length of the trailing edge flap 102 whereby the entire trailing edge flap can be controlled uniformly by only a single control system.
• a number of pressure hoses may be connected in series or parallel to different parts or sections of the aerodynamic device whereby the trailing edge flap may be controlled faster.
• Several systems of pressure hoses may also be applied on different parts of the trailing edge flap to allow the flap movement to be gradually increased from one end to the other, or to allow different parts of the device to be controlled and moved independently and individually.
• the compartment 408 comprising the two pressure hoses 401, 402 on each side of the lever element 405 is comprised in an intermediate attachment element 403 connecting the trailing edge to the blade body 107.
• This construction may be advantageous during assembly of the different blade parts allowing the trailing edge to be assembled with the attachment element prior to fastening to the main part of the blade.
• the compartment 408 for the pressure hoses may be comprised directly in the main blade body.
• the pressure hoses 401, 402 may be provided in the main blade body at a chordwise distance away from the trailing edge flap 102.
• the pres- sure hoses 401, 402 may be located adjacent to the main structural spar of the blade 100. Therefore, in contrast to the embodiment shown in figures 3 and 4, the lever element 404 will extend from the trailing edge flap 102, in a chordwise direction, to a position inside the blade body adjacent to the main spar.
• the trailing edge flap 102 is connected to the blade body 107 by means of flexible connection joint around which the flap 102 rotates.
• a radial surface 1200 with its center in the rotation hinge 405 may be provided to enable the flap 102 to move while maintaining the continuity of the blade surface when the flap is actuated.
• the flap 102 may be a de- formable trailing edge and may be connected to the blade body 107 by means of a flexible and/or elastic connection at both the suction skin and the pressure skin, so that the radial surface 1200 and the hinge 405 are not required.
• FIG 5 a wind turbine blade 100 mounted to a hub 301.
• the gravity loads imposes large edgewise loads on the blade resulting in large compression and tension strains along the leading 303 and trailing 104 edges as illustrated by the arrows 302.
• the sign of the strains naturally reverse during the rotational cycle of the blade.
• the longitudinal bending of the blade both in and out of operation due to the wind loads also result in large bending strains in the longitudinal direction 106 of the blade.
• the blade also flexes and twists to some extent down its length resulting in a varying complex three-dimensional stress and strain state.
• the operation ability of the different devices 101 for modifying the aerodynamic surface or shape of the blade 100 has been found to be highly improved by dividing the de- vices 101 into a number of sections or segments 303 in the longitudinal direction 106 of the device.
• This is illustrated in the figure 5 for an active trailing edge flap 102 which may be controlled and moved by an operating mechanism according to the invention for instance as described for the embodiment illustrated in the previous or preceding figures.
• the aerodynamic device 101 which may for instance comprise a movable trailing edge, a flap, and/or an aileron, comprises a number of sections 303 divided by interstices or connecting portions 304.
• the interstices 304 are open gaps of a certain width allowing for the sections to deform relative to each other with no or little contact between the sections.
• the interstices 304 or connecting portions may extend the whole way through the chordwise width 306 of the device or may alternatively extend only a certain portion such as e.g. 70- 90% through of the chordwise width 306 of the device from the device trailing edge 307 to- wards the blade body 107 and in the chordwise direction. Likewise, the interstices 304 or connecting portions may extend entirely or partly through the thickness of the device 101 (in and out of the paper).
• the interstices 304 may be placed at even distances in the longitudinal direction 106 of the blade or may be advantageously unevenly spaced, for instance at smaller intervals in regions of larger deformations.
• the two pressure hoses 401, 402 in the operation mechanism may as mentioned above run along parts of or the entire length of the trailing edge flap 102 and hereby control some or all of the sections of a sectioned trailing edge flap as sketched in figure 5. If the pressure hoses are connected to control each of the sections 303 of the aerodynamic device, all parts of the trailing edge flap may be controlled uniformly. Alternatively, several systems of pressure hoses may be applied on different parts or sections of the trailing edge flap allowing the flap movement to be gradually increased from one end to the other, or to allow different parts or sections of the device to be controlled and moved independently and individually.
• the operation mechanism comprising here a set of two pressure hoses 401, 402 may be pressurized by being coupled to a pressure reservoir 601 within the blade body 107.
• the pressure reservoir is conveniently placed in between the main beams or the spar 602 of the wind turbine blade 100 and is pressurized by a compressor 603 which may be placed in the root section of the blade or alternatively in the nacelle of the wind turbine.
• the spar 602 may in itself constitute a pressure reservoir for pressurizing the operating mechanism.
• the pressure reservoir is connected to the pressure hoses via a valve system 604 which based on control signals 609 from a controller 610 regulates the pressure in the different pressure hoses 401, 402 and hereby the position and movement of the aerodynamic device 101.
• a valve system 604 is shown in figure 7. For depressurizing the pressure hoses, this can be vented 611 by connection to for instance an outer surface of the blade or to some internal part of the blade of atmospheric pressure.
• the operating mechanism is illustrated for operating a movable trailing edge flap 102 which is segmented.
• the principles of the operating mechanism and its coupling to a pressure reservoir are the same for other aerodynamic devices for modifying the aerodynamic surface of the wind turbine blade such as ailerons, vortex generators etc.
• Sensors such as strain gauges or pressure sensors may monitor the loads experienced by the wind turbine blade 100 and the output from these sensors are provided to the controller 610 which will determine how the pressure hoses 401, 402 should be regulated in response to the loads acting on the wind turbine blade.
• the magnitude of the pressure and/or under pressure needed for controlling and regulating an aerodynamic device such as a movable trailing edge depend on different factors such as the dimensions (typically 15 -30% chord and 10-20% blade length) and weights of the de- vices to be moved and controlled, the regulation speed required, and the elastic properties of the pressure hoses.
• the regulation speed is typically of the order of 50-500 msec and the pressure required is typically 0.2-0.6 bar.
• one or more of the pressure hoses could equally well be connected to a vacuum reservoir which similarly could be placed within or even in part constituted by the internal spar or main beams of the wind turbine blade.
• Figure 8 illustrates an embodiment of the invention where the lever element 404 arranged in between the compressible pressure hoses 401, 402 is a part of the blade body 107, so that the pressure hoses are arranged within a compartment 408 comprised in the aerodynamic device 101 which in the illustrated example is a movable trailing edge 102.
• the operating mechanism according to the invention need not comprise exactly two compressible pressure hoses 401, 402, but can of course also function with one pressure hose alone where the reverse movement of the lever element up against the pressure hose may then optionally be regulated by the use of one or more elastic members such as springs. This is illustrated in figure 9, where a spring 901 is arranged opposite a pressure hose 401 on the other side of the lever element 404.
• the spring here acts to force the trailing edge back towards the pressure hose 401 if the pressure inside the pressure hose is lowered.
• the spring may naturally also be arranged next to the pressure hose connected to the lever element or on another side.
• Elastic members such as springs may also be used in combination with the previously illustrated embodiments of more than one pressure hoses.
• FIG 10 is illustrated an embodiment where the operating mechanism according to the invention is controlling and regulating the position and movement of a trailing edge aileron 103.
• the principle of the operating mechanism is similar to illustrated above for a movable trailing edge.

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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)

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• 2009
  • 2009-10-14 EP EP09740874A patent/EP2347125A2/de not_active Withdrawn
  • 2009-10-14 WO PCT/EP2009/063402 patent/WO2010043647A2/en active Application Filing

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