ADAPTABLE SPOILER FOR A WIND TURBINE ROTOR BLADE

Abstract

Provided is a spoiler, in particular adaptable spoiler, for a wind turbine blade including: a main body including an airfoil shaped surface to be exposed to air flow; at least one stiffening element distinct from the main body and supporting the airfoil surface, wherein the stiffening element is in particular configured to enforce the shape of the airfoil surface during loading by wind during operation of the wind turbine.

Claims

1. A spoiler for a wind turbine blade, comprising: a main body comprising an airfoil shaped surface to be exposed to air flow at least one stiffening element distinct from the main body and supporting the airfoil shaped surface, wherein the stiffening element is configured to enforce the shape of the airfoil surface.

2. The spoiler according to claim 1, wherein the stiffening element is not exposed to an air flow the rotor blade is subjected to, wherein the stiffening element has decreasing thickness from upstream to downstream in an air flow direction.

3. The spoiler according to claim 1, wherein the stiffening element is elastic and/or prebent and/or has a shape of a plane or a curved shape different from a plane.

4. The spoiler according to claim 1, wherein the stiffening element is installed in the main body below the airfoil shaped surface, and/or the stiffening element is installed buried in the main body.

5. The spoiler according to claim 1, wherein the main body comprises a single piece or several pieces comprising plastic and/or thermoplastic material and/or thermoset material.

6. The spoiler according claim 1, wherein the main body comprises plural stiffening element contact portions contacting and/or holding the stiffening element by force-fit and/or form-fit.

7. The spoiler according to claim 1, wherein the contact portions comprise a first, a second and a third contact portion, the third contact portion separated from the first and second contact portion to be downstream in an air flow direction, wherein the contact portions are along a longitudinal direction of the spoiler.

8. The spoiler according to claim 1, wherein the first and the second contact portion fixedly clamp an upstream portion of the stiffening element, wherein a downstream contact portion of the stiffening element presses to the third contact portion in a direction against a force exerted on the airfoil shaped surface by an expandable device.

9. The spoiler according to claim 1, wherein the first and second contact portions are each part of a respective slit in the main body into which a respective upstream end edge of the stiffening element is at least partially inserted, thereby holding the stiffening element partly by form-fit, and/or wherein the third contact portion is arranged to allow sliding of the downstream contact portion of the stiffening element relative to the third contact portion of the main body upon inflating or deflating the expandable device.

10. The spoiler according to claim 1, wherein the stiffening element is located: in a central region of the airfoil surface away from the rear end and the front end of the spoiler, or in at least a half or a rear end portion of the spoiler.

11. The spoiler according to claim 1, wherein the stiffening element comprises a composite and/or laminate comprising: a fibre material and thermoplastic and/or thermosetting material.

12. The spoiler according to claim 1, further comprising an expandable device, inflatable with air and arranged to change shape and/or tilt of the spoiler airfoil surface, thereby providing an adaptable spoiler.

13. The spoiler according to claim 1, further comprising: a further stiffening element arranged to change position and/or orientation and/or tilt when hose or bag is inflated or deflated.

14. A rotor blade of a wind turbine comprising: a blade airfoil surface; and at least one adaptable spoiler according to claim 1 installed at the blade airfoil surface, wherein the spoiler sections are installed along the longitudinal direction of the blade airfoil surface.

15. The rotor blade according to claim 1, further comprising: a flow regulating device, installed at the blade airfoil surface downstream the spoiler, wherein depending on a state of the adaptable spoiler, the effect of the flow regulating device on the air flow is changed.

Description

BRIEF DESCRIPTION

[0044] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0045] FIG. 1 schematically illustrates, a side sectional view, (a portions of) a rotor blade according to different embodiments of the present invention including an adaptable spoiler according to different embodiments of the present invention;

[0046] FIG. 2 shows a main body having an airfoil shaped surface;

[0047] FIG. 3 illustrates a (portion of a) wind turbine blade according to a further embodiment of the present invention including an adaptable spoiler;

[0048] FIG. 4 schematically illustrates a (portion of a) rotor blade according to a further embodiment of the present invention comprising an adaptable spoiler according to a still further embodiment of the present invention;

[0049] FIG. 5 shows a spoiler of the wind turbine blade illustrated in a schematic manner, comprises the stiffening element 559 which is supported also at three contact regions;

[0050] FIG. 6 illustrates a single plastic piece with rotational support on both ends, but with freedom for sliding between the stiffening element and the plastic piece;

[0051] FIG. 7 illustrate a wind turbine blade including an adaptable spoiler in a first state corresponding to different activation state;

[0052] FIG. 8 illustrate a wind turbine blade including an adaptable spoiler in another state corresponding to different activation state;

[0053] FIG. 9 illustrate a wind turbine blade including an adaptable spoiler in another state corresponding to different activation state; and

[0054] FIG. 10 illustrate a wind turbine blade including an adaptable spoiler in another state corresponding to different activation state.

DETAILED DESCRIPTION

[0055] Elements similar in structure and/or function are labelled with reference signs differing only in the first digit.

[0056] The rotor blade 100 schematically (and partially) illustrated in FIG. 1 in a side sectional view looking along the longitudinal axis 101 of the rotor blade 100 (corresponding to the longitudinal direction of the spoiler 150) comprises a blade airfoil surface 103, in particular on a suction surface which is exposed to air flow during operation of the rotor blade 100. The rotor blade 100 further comprises an adaptable spoiler 150 which is installed at the blade airfoil surface 103, in particular in a front portion of a suction surface of the rotor blade 100. The adaptable spoiler may e.g., arranged in locations between 25% and 60%, or between 30% and 45% of the front portion of the blade. The rotor blade 100 comprises a main body 102 having the airfoil shaped surface 103.

[0057] In FIGS. 1 to 10, only a front portion of the respective rotor blade is illustrated, where the respective spoiler is installed. The rotor blade may extend further downstream to comprise for example a rear trailing edge portion at which for example a vortex generator is installed. Adaptation of the spoilers illustrated in FIGS. 1 to 10 allow to change the effect of the vortex generator, which may by installed downstream the respective spoiler, for example at a trailing edge or close to a trailing edge of the rotor blade.

[0058] In FIG. 1, the spoiler 150 is illustrated in two different states, namely in a retracted (or inactivated) state and an extended (or activated) state. The retracted or inactive state is labeled with reference signs ending with the letter “a” and the extended or active state is labeled with reference signs ending with the letter “b”.

[0059] The spoiler 150 comprises a main body 153 which comprises an airfoil shaped surface 155 (illustrated are the configurations of the airfoil shaped surface in the retracted state 155a and the extended or active state labeled with reference sign 155b. For enabling different states of the adaptable spoiler 150, the adaptable spoiler 150 comprises a hose 157, which can be in a deflated state 157a, to achieve the inactive or retracted state of the airfoil surface 155a. Furthermore, the bag 157 can be inflated (for example by a hydraulic or pneumatic apparatus) to adopt an inflated state 157b causing the tilting up of the airfoil shaped surface to adopt the configuration labeled with reference sign 155b.

[0060] The adaptable spoiler 150 further comprises at least one stiffening element 159 (in configuration 159a, 159b), which is distinct from the main body 153 and which is supporting the airfoil surface 155 in the configuration 155a as well as in the configuration 155b. When in the retracted state, an air flow 161a is established close or near the airfoil surface 155a, when in the extended state an air flow 161b is established.

[0061] As can be taken from FIG. 1, the stiffening element 159a, 159b is not exposed to the air flow 161a or 161b in the different states of the adaptable spoiler 150. When changing from the retracted state to the extended state of the spoiler 150, the stiffening element bends to change the configuration 159a to the configuration 159b having a slightly curved shape, while in the configuration 159a the stiffening element has a shape of a plane or is bent (curved) to better follow (or support) the airfoil geometry.

[0062] As can also be taken from FIG. 1, the stiffening element 159 (in particular in the configurations 159a, 159b) is installed in the main body 153 below the airfoil surface 155a, 155b in the different configurations.

[0063] The main body 153 may comprise one or more plastic pieces. In the embodiment 150 illustrated in FIG. 1, the main body 153 comprises an attachment point 163 having a larger thickness than the airfoil shaped surface portion 155. The stiffening element connects a front portion 165 of the spoiler 150 with the attachment point 163 thereby enforcing or stiffening the entire spoiler 150.

[0064] All spoilers according to embodiments of the present invention, which are illustrated in FIGS. 1 to 10, may be configured as adaptable spoilers in which all may comprise a hose or a bag which may be inflated for changing the state of the spoiler similar to the embodiment as illustrated in FIG. 1.

[0065] FIG. 1 illustrates plastic pieces interconnected with a stiffening element.

[0066] The rotor blade 200 illustrated in FIG. 2 comprises a main body 202 having an airfoil shaped surface 203. The main body 253 of the spoiler 250 is integrally formed for example from plastic. The airfoil shaped surface 255 guides an air flow 261 during operation of the wind turbine close to the surface of the spoiler 250.

[0067] The main body 253 of the spoiler 250 illustrated in FIG. 2 comprises plural stiffening element contact portions 267a, 267b, 267c, 267d which all contact and/or hold the stiffening element 259 by force-fit or form-fit. In particular, the contact portions 267a and 267c form a slit 269a between them in which an edge 271a of the stiffening element 259 is inserted. Furthermore, the contact portions 267b and 267d form between them another slit 269b in which another end edge 271b of the stiffening element 259 is inserted, thereby, the stiffening element 259 is in particular hold at least partly by form-fit. In particular the slits may be angled in such a way, that the stiffening element has to be inserted with a “pre-bending” into the slits, such that when the spoiler is in its inactive position, there is a residual force pressing the spoiler against the blade, such that it does not lift off from the surface.

[0068] FIG. 2 illustrates a single plastic piece with integrated pre-bent stiffening element.

[0069] FIG. 3 schematically illustrates a (portion of a) wind turbine blade 300 according to a further embodiment of the present invention including an adaptable spoiler 350 according to another embodiment of the present invention, wherein in FIG. 3 the spoiler 350 is illustrated in an extended state in which the bag 357 is in a filled or pressurized state. The stiffening element 359 is supported by a contact region 367a close to an edge of the stiffening element from one side. Further, the stiffening element 359 is hold by a contact portion 367b from another side of the stiffening element and from a still further contact portion 367c from the side at which also the contact portion 367a contacts the stiffening element 359. Thus, the three contact portions 367a,b,c of the main body 353 of the spoiler 350 are separated from each other and clamp the stiffening element 359 from two different sides.

[0070] The (elastic) stiffening element 359 exerts, below the surface 355, a force in a direction 373 away from the airfoil surface 355 to the two contact portions 367a and 367c and exerts a force in a direction 375 towards the airfoil surface 355 to the contact portions 367b which is arranged between the two contact portions 367a, 367c.

[0071] In the embodiment illustrated in FIG. 3, the stiffening element 359 is located in a central region 377 of the spoiler 350 away from the rear end 379 and away from the front end 381 of the spoiler.

[0072] FIG. 3 illustrates a single plastic piece, three-point support for an integrated stiffening element.

[0073] FIG. 4 schematically illustrates a (portion of a) rotor blade 400 according to a further embodiment of the present invention comprising an adaptable spoiler 450 according to a still further embodiment of the present invention. Again, the stiffening element 459 is hold or supported at the main body 453 by three contact regions of the main body, namely the contact regions 467a, 467b, 467c. Different from the embodiment of the spoiler 350 illustrated in FIG. 3, the spoiler 450 illustrated in FIG. 4 includes a rear end extension 483 extending the spoiler 450 at a rear end 479.

[0074] FIG. 4 illustrates a single plastic piece, threepoint support for an integrated stiffening element, including a rear end extension to increase the deflection of the flow.

[0075] The contact portions 367a, 367b, 367c of the embodiment 350 of the spoiler and the contact portions 467a, 467b and 467c of the embodiment 450 of the spoiler comprise protruding structures.

[0076] The spoiler 550 of the wind turbine blade 500 illustrated in a schematic manner in FIG. 5, comprises the stiffening element 559 which is supported also at three contact regions 567a, 567b and 567c. The first and second contact portions 567a, 567b form a slit clamping an upstream edge or portion of the stiffening element 559. The third contact portion 567c comprises a nose onto which a downstream edge or portion of the stiffening element 559 presses, in particular against a force exerted by the hose 567 located below the nose 567c. The downstream edge or portion of the stiffening element 559 can slide relative to the third contact portion 567c upon inflating or deflating the hose 557.

[0077] FIG. 5 illustrates a single plastic piece acting as a cover and fully supporting the stiffening element.

[0078] The embodiment of the spoiler 650 installed at the wind turbine blade 600 illustrated in FIG. 6, comprises two contact portions 667a, 667b close to each other in a front portion of the spoiler contacting the stiffening element 659 from opposite sides and further comprises a contact portion 667c established on a backside of the airfoil shaped surface 655. The bag or hose 657 is arranged downstream the contact portion 667c. The stiffening element 659 may have a thickness decreasing in the direction of the air flow 661 (corresponding to chord-wise direction).

[0079] FIG. 6 illustrates a single plastic piece with rotational support on both ends, but with freedom for sliding between the stiffening element and the plastic piece. FIG. 6 shows an embodiment.

[0080] FIGS. 7 to 9 schematically illustrate a wind turbine blade 700 including an adaptable spoiler 750 in different states 750a, 750b, 750c corresponding to different activation states. Thereby, the FIG. 9 illustrates the deactivated state 750c. The spoiler 750 comprises a stiffening element 759 and a further stiffening element 785 with surface 786 which is exposed to the air flow 761. In particular, the further stiffening element 785 is in different position and/or orientation or tilt when the hose or bag 757 is in different inflation states as indicated with reference signs 757a, 757b, 757c. Furthermore, the spoiler 750 comprises a stiffening plate 759 in a front portion of the spoiler being installed within the main body 753 of the spoiler.

[0081] FIGS. 7 to 9 illustrate two stiffening elements and no plastic element.

[0082] The rotor blade 1000 schematically illustrated in FIG. 10 comprises a stiffening element 1059 buried within a main body 1053 of a spoiler 1050. FIG. 10 illustrates one stiffening element bent to create a profile. The blade has an “indentation”, the spoiler is made out of a single stiffening element which is bent into the required configuration.

[0083] Embodiments of the present invention may provide several benefits: [0084] High lifetime of spoiler for a high number of activation cycles, [0085] reduction of lift coefficient level when desired, [0086] increase of drag level when desired, [0087] fast power control, [0088] additional degree of freedom for control of aerodynamic forces on blades.

[0089] Embodiments may be applied to at least one of the following: [0090] Selective reduction of loading at different positions along the spanwise direction at different wind speeds, [0091] increase of aerodynamic damping at high wind speeds, or when else required, [0092] reduction of aerodynamic loading during over-speed situations, [0093] reduction of aerodynamic loading during idling, [0094] reduction of aerodynamic loading during manual, emergency, or normal shutdown events, [0095] reducing pitch activity by combination of pitching and activation of the flow-regulating device, [0096] activation of spoiler in combination with individual pitch control.

[0097] There are a number of possible activations: [0098] Activation depending on the rotor speed of the turbine, [0099] Slow activation (for example depending only on wind speed), [0100] Fast activation (for example 1P or 3P for a combination with IPC) [0101] on/off activation (for example for over-speed, shutdown events, events with extreme high turbulence), [0102] persistent activation (for example for idling), [0103] independent activation of different spoiler sections on the blade [0104] Independent activation of different spoiler sections on the blade to maintain the rotor speed at the nominal level.

[0105] Possible pressure supply system characteristics include the following: [0106] activation by a pressurized fluid, in particular pressurized air, pressurized dry air, or any other gas such as inert gases (e.g. nitrogen or helium) [0107] low required volume of air (achieved for example by controlling a change of shape in the pressurized chamber, rather than an expansion of the chamber), [0108] pressurized reservoirs close to the points of activation (for rapid response and reduction of power requirements for the supply system). This can be done for example by placement of tubes of larger diameter internally in the blade close to the pressure supply points, [0109] simultaneous connection to pressure and vacuum chambers to increase response speed, [0110] constant flow through a purge valve to avoid accumulation of humidity/dirt/compression oil, etc. [0111] use of pre-heated air in case icing could be an issue, [0112] independent activation of different radial segments, [0113] use of control valves at particular stations to avoid/permit flow of pressurized air from one radial position to a further radial position, [0114] use of pneumatically activated pneumatic valves (to avoid electrical signals), [0115] use of stagnation pressure at some radial station as input to pneumatic control valves, [0116] use pitch position as input to pneumatic control valves (for example high pitch position file open valves and thus activate the spoiler), [0117] Use the rotor speed as input to pneumatic control valves (for example high rotor speed may lead to opening of valves and thus activation of the spoiler), [0118] Use of turbulence level as input to pneumatic control valves.

[0119] In the flow spoiler there may be no need for an electrical or mechanical component.

[0120] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0121] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.