Wind turbine blade and wind turbine

Abstract

A wind turbine blade (3) comprising sensor means (8) for detecting a characteristic of flow-induced noise (10) generated by the blade (3) and actuator means (9) for emitting an anti-noise signal (23) in order to at least partially counteract the flow-induced noise (10), in which the sensor means (8) are arranged to detect a characteristic of the flow-induced noise (10) generated by the blade (3), and the actuator means (9) are arranged to emit an anti-noise signal (23) in order to at least partially counteract the flow-induced noise (10). The actuator device (9) comprises an aerodynamically shaped housing (24) attached to an outer surface (25) of the blade (3). The aerodynamically shaped housing of the actuator device reduces a reduction in the aerodynamic efficiency of the blade. In addition, turbulent flow is prevented from being generated at the sharp edge of the shell.

Description

Technical Field

[0001] The present invention relates to a wind turbine blade and a wind turbine. Background Art

[0002] Wind turbine blades are known to generate noise due to the flow of air along their outer surfaces. This noise primarily occurs at the blade edges, such as the trailing edge (so-called trailing-edge noise). The intensity and frequency of this noise depend on blade characteristics, such as the shape of the blade edge and the characteristics of the airflow.

[0003] The noise generated by the rotating rotor blades of onshore wind turbines is considered a nuisance by people living near the wind turbines. Furthermore, various legal regulations and restrictions exist regarding the permissible noise levels for wind turbines. Known methods for reducing flow-induced edge noise in wind turbine blades include improved designs of the blade's airfoil, and in particular, of the blade's trailing edge. For example, aerodynamic attachments, such as serrated panels mounted to the pressure or suction side of the blade near its trailing edge, can be arranged on the blade. Furthermore, active noise cancellation of flow-induced trailing edge noise is proposed in EP 3 249 216 A1. Summary of the Invention

[0004] It is an object of the present invention to provide an improved wind turbine blade.

[0005] Therefore, a wind turbine blade is provided. The wind turbine blade includes a sensor arrangement for detecting characteristics of flow-induced noise generated by the blade and an actuator arrangement for emitting an anti-noise signal to at least partially cancel the flow-induced noise. Furthermore, the actuator arrangement includes an aerodynamically shaped housing attached to an outer surface of the blade.

[0006] Using this sensor device and actuator device, blade-generated noise, such as flow-induced trailing edge noise, can be actively suppressed. For example, the sensor device is configured to detect unsteady flow characteristics associated with the flow-induced noise generated by the blades. Furthermore, an anti-noise signal is generated by the actuator device, for example, based on the characteristics of the flow-induced noise detected by the sensor device (e.g., unsteady flow characteristics), such that the anti-noise signal destructively interferes with the emitted noise. In this way, the noise generated by the blades can be at least partially canceled. Consequently, noise emissions from the wind turbine can be reduced.

[0007] Furthermore, the actuator device, ie the housing of the actuator device, is advantageously attached to the outer surface of the blade.Thus, in contrast to an arrangement of the actuator device inside the blade, holes in the blade outer shell can be avoided.

[0008] Furthermore, due to the aerodynamic shape of the actuator device housing, the aerodynamic impact of the actuator device on the blade is minimized. In particular, the impact of the housing on the aerodynamic efficiency of the blade, and therefore on the energy production of the wind turbine, is reduced. Furthermore, due to the aerodynamic design of the housing, which avoids sharp edges, the generation of vortices, aerodynamic drag, and noise at the edges of the housing is significantly reduced.

[0009] Wind turbine blades are part of the wind turbine's rotor. A wind turbine is a device that converts the kinetic energy of wind into electrical energy. For example, a wind turbine includes a rotor with one or more blades, each connected to a hub; a nacelle containing a generator; and a tower that holds the nacelle at its top. The wind turbine's tower may be connected to the wind turbine's foundation, such as a monopile or concrete foundation in the seabed, via a transition piece. For example, a wind turbine is an onshore wind turbine. However, a wind turbine may also be an offshore wind turbine.

[0010] A wind turbine blade (e.g., its root section) is configured for fixed or rotatable connection to a hub. Aside from the (cylindrical) root section, the wind turbine blade is aerodynamically designed. Specifically, the wind turbine blade comprises a pressure side and a suction side. These sides are connected at a leading edge and a trailing edge. Viewed in cross section, these sides, along with the leading and trailing edges, define the airfoil of the wind turbine blade (the blade airfoil).

[0011] For example, a wind turbine blade includes a shell made of a fiber-reinforced laminate. The shell defines the outer shape of the blade. For example, the shell includes a suction side shell and a pressure side shell arranged at the suction side and pressure side of the blade, respectively.

[0012] For example, the housing of the actuator arrangement is attached to the suction side of the blade (eg suction side shell).However, for example, the housing of the actuator arrangement may also be attached to the pressure side of the blade (eg pressure side shell).

[0013] For example, the housing of the actuator device is attached to the outer surface of the blade using adhesive. Using adhesive for attachment avoids any intrusion into the blade structure. However, the housing of the actuator device can also be attached using bolts and corresponding threaded holes in the blade structure. Alternatively, the housing can be mounted to the blade structure by being directly incorporated into an outer layer of the blade structure material (e.g., a fiber-reinforced laminate).

[0014] For example, a sensor device configured to detect characteristics of flow-induced noise generated by the blade is also attached to the outer surface of the blade (e.g., to the suction side and / or pressure side of the blade). For example, the sensor device is configured to detect flow characteristics of a fluid (e.g., air) flowing around the blade. For example, the sensor device is configured to characterize turbulence in the aerodynamic boundary layer.

[0015] For example, a sensor device may include one or more sensor cells capable of detecting flow characteristics of a fluid passing through the corresponding sensor cell. For example, the sensor device and / or each of the one or more sensor cells may include a diaphragm (e.g., a membrane) and / or a microphone. In its simplest form, the sensor device and / or the corresponding sensor cell may simply include a small opening in its surface for sensing the fluctuating surface pressure caused by the fluid passing through the opening.

[0016] This actuator arrangement reduces or eliminates flow-induced noise (e.g., flow-induced edge noise) from the rotor blades. This is achieved through the use of anti-noise. Flow-induced edge noise is typically a broadband noise source caused by turbulence. Therefore, edge noise is irregular, i.e., random. Furthermore, the associated acoustic pressure fluctuations are non-deterministic. Therefore, even when the statistical characteristics are known, the acoustic pressure fluctuations cannot be predicted temporally based on the current or previous acoustic signals.

[0017] However, it turns out that the unsteady surface pressure patterns that generate noise (e.g., sound at the edge) can be approximately assumed to be invariantly convective with the flow along the suction or pressure side of the blade (i.e., along the chord). This assumption is known in the literature as the "frozen turbulence" assumption. In the present invention, this fact is exploited to detect unsteady surface pressure patterns upstream of the edge, allowing the construction and emission of a noise-canceling anti-noise signal to produce at least partial noise cancellation of the trailing edge noise at at least one observer position or along at least one observer direction.

[0018] For example, the actuator device includes one or more actuator units for generating the anti-noise signal. For example, the actuator device includes two, three or four actuator units. However, the actuator device may also include more than four actuator units. The actuator device and / or the one or more actuator units are capable of converting electrical signals into mechanical movements. For example, the actuator device and / or the one or more actuator units include at least one diaphragm and / or a loudspeaker and / or a deformable surface for generating the anti-noise signal. For example, the surface of the diaphragm of the actuator device is exposed to the housing to emit the anti-noise signal. For example, the actuator device and / or the one or more actuator units also include a device for moving the corresponding diaphragm.

[0019] For example, the anti-noise signal generated and emitted by the actuator device is an acoustic signal that is superimposed on the noise signal generated by the blade so that destructive interference occurs. By this destructive interference, the noise generated by the blade is reduced.

[0020] Furthermore, for example, the actuator device is connected (wired or wirelessly) to the sensor device for data transmission (for example, for transmitting a detected noise signal from the sensor device to the actuator device).

[0021] For example, a wind turbine blade may include a control unit for generating a control signal to control an actuator device to emit an anti-noise signal. For example, the control unit is configured to generate the control signal based on a noise signal detected by a sensor device. For example, the control unit is configured to receive the detected noise signal from the sensor device. Furthermore, for example, both the actuator device and the sensor device may be connected (wired or wirelessly) to the control unit for data transmission. For example, the actuator device may be connected to the sensor device via the control unit for data transmission.

[0022] Using a control unit to generate the anti-noise signal has the advantage of producing a more optimized and customized anti-noise signal, potentially achieving a greater degree of flow-induced noise cancellation. For example, rather than being located on the outer surface of the blade, such a control unit could be located within the nacelle, tower, tower base, and / or rotor blade. This has the advantage of not disrupting the fluid flow through the rotor blade and protecting it from environmental conditions such as weather.

[0023] Further details on the properties of the detection of flow-induced noise by the sensor arrangement and the generation of the anti-noise signal by the actuator arrangement can be found in EP 3 249 216 A1, the content of which is incorporated herein by reference.

[0024] In an embodiment, the actuator arrangement comprises at least one gas chamber accommodated within the housing for improving radiation efficiency.

[0025] According to one embodiment, the actuator arrangement comprises: at least one diaphragm exposed at an outer surface of the housing for converting kinetic energy into acoustic energy to generate an anti-noise signal, and At least one gas chamber is accommodated within the housing such that the at least one diaphragm forms part of an enclosure of the at least one gas chamber.

[0026] The provision of a gas chamber improves the acoustic radiation efficiency of the actuator assembly. In particular, the gas chamber can reduce or prevent radiation efficiency losses. For example, radiation efficiency losses at low frequencies (e.g., 500 Hz or less, 400 Hz or less, 300 Hz or less, 200 Hz or less, and / or 100 Hz or less) can be reduced or prevented. Generating an anti-noise signal in this low-frequency range is particularly important for efficient noise reduction in blades. Therefore, the provision of a gas chamber can generate a stronger anti-noise signal.

[0027] Due to the aerodynamic shape of the housing of the actuator device, the gas chamber can be accommodated in the housing with no or only insignificant degradation of the aerodynamic performance of the blade.

[0028] For example, the gas chamber is a closed gas chamber. The chamber may also include vents or alternatively a passive (non-driven) diaphragm (called a passive radiator) for improving low frequency radiation.

[0029] The actuator device may also comprise more than one (eg closed) gas chamber.In particular, the housing of the actuator device may house more than one (eg closed) gas chamber.

[0030] For example, the at least one diaphragm comprises a first surface and a second surface at opposite sides thereof.Furthermore, for example, the first surface is exposed at the housing, and the second surface forms a part of the enclosure of the at least one gas chamber.

[0031] According to another embodiment, the total volume of the at least one gas chamber is 0.03 liters or more, 0.05 liters or more, 0.1 liters or more, 0.13 liters or more, 0.15 liters or more, 0.2 liters or more and / or 0.3 liters or more.

[0032] The aerodynamically shaped housing of the actuator arrangement allows for accommodating a gas chamber having a large volume without any or only a slight reduction in the aerodynamic performance of the blade. Furthermore, the large volume of the gas chamber provides improved sound radiation efficiency.

[0033] If the actuator device includes multiple gas chambers, the total volume (i.e., "the total volume of the at least one gas chamber") is the total volume of the multiple gas chambers. In other words, if the actuator device has multiple gas chambers, the total volume is the sum of the volumes of the individual gas chambers.

[0034] In an embodiment, the actuator device comprises a plurality of gas chambers, and the volume of each of the plurality of gas chambers is 0.03 liters or more, 0.05 liters or more, 0.1 liters or more, 0.13 liters or more, 0.15 liters or more, 0.2 liters or more and / or 0.3 liters or more.

[0035] According to another embodiment, the aerodynamically shaped shell has an aerodynamically shaped cross-section and / or airfoil with a first side and a second side connected to each other at a leading edge and a trailing edge.

[0036] For example, a fluid flow impacts an aerodynamically shaped shell at a leading edge of the shell. The fluid flow is then split at the leading edge of the shell so that a portion of the flow is directed along a first side of the shell to the trailing edge of the shell, and another portion of the flow is directed along a second side of the shell to the trailing edge of the shell.

[0037] For example, the airfoil of the aerodynamically shaped shell is a symmetrical airfoil. In particular, for example, the first side and the second side of the shell airfoil are symmetrical to each other about a line connecting a leading edge and a trailing edge of the shell airfoil.

[0038] According to another embodiment, a blade having an aerodynamically shaped shell is configured such that a fluid flow approaching the shell from a leading edge of the blade flows from the leading edge to a trailing edge of the shell.

[0039] The fluid flow (eg air flow) approaching the shell from the leading edge of the blade is particularly guided from the leading edge of the blade along the blade surface to the leading edge of the shell. Therefore, the fluid flow meets the shell at the leading edge of the shell.

[0040] Depending on whether the attachment position of the housing on the blade is on the suction side or the pressure side of the blade, the fluid flow is directed towards the housing along the suction side or the pressure side of the blade respectively: For example, when the shell is attached to the suction side of the blade, a fluid flow approaching the shell from the leading edge of the blade is directed from the leading edge of the blade along the suction side of the blade to the leading edge of the shell.

[0041] For example, when the shell is attached to the pressure side of the blade, a fluid flow approaching the shell from the leading edge of the blade is directed from the leading edge of the blade along the pressure side of the blade to the leading edge of the shell.

[0042] For example, as used herein, the phrase "a blade having an aerodynamically shaped shell is configured such that..." means "the outer shape of the shell is configured and the shell is arranged (eg, in a certain orientation) on the outer surface of the blade such that..."

[0043] According to another embodiment, the shell is arranged on one of the suction side and the pressure side of the blade. Furthermore, the blade with the shell is configured so that the fluid flow approaching the shell from the leading edge of the blade is split at the leading edge of the shell, so that: a portion of the fluid flow flows from the leading edge of the shell along said one of the suction side and the pressure side of the blade and along the first side of the shell to the trailing edge of the shell, and Another portion of the fluid flow flows from the leading edge of the shell, along the one of the suction side and the pressure side of the blade and along the second side of the shell to the trailing edge of the shell.

[0044] According to another embodiment, The housing is arranged on one of the suction side and the pressure side of the blade, and The leading edge of the shell is disposed upstream and the trailing edge of the shell is disposed downstream, both relative to fluid flow along said one of the suction side and the pressure side of the blade.

[0045] For example, when the shell is arranged on the suction side of the blade, the leading edge of the shell is arranged upstream and the trailing edge of the shell is arranged downstream, both relative to the fluid flow along the suction side of the blade. Corresponding considerations also apply to the attachment of the shell on the pressure side of the blade.

[0046] According to another embodiment, the shell is attached to the attachment surface of the blade and the shell has an aerodynamically shaped cross section in a plane arranged parallel to the attachment surface of the blade and / or parallel to a tangent to the attachment surface of the blade.

[0047] For example, the dimensions of the attachment surface of the blade correspond to and / or are equal to the dimensions of the footprint of the housing.The footprint of the housing is in particular the dimensions of the area on the blade surface which is covered by the housing.

[0048] For example, the attachment surface is substantially flat.In this case, the shell has an aerodynamically shaped cross section in a plane arranged parallel to the attachment surface of the blade.

[0049] For example, the attachment surface may also have a curvature and / or a non-flat structure. In this case, the shell has an aerodynamically shaped cross section in a plane arranged parallel to a tangent line (eg a tangent plane) to the curved attachment surface of the blade.

[0050] According to another embodiment, the housing has rounded edges at its outer surface.

[0051] For example, the rounded edge is a convex edge.

[0052] For example, the housing may have a rounded (eg convex) edge (eg only) at its surface facing away from the blade and / or at an outer surface of said attachment surface.

[0053] According to another embodiment, the housing tapers towards a leading edge of the blade and / or towards a trailing edge of the blade, viewed in a section taken parallel to the airfoil of the blade.

[0054] Here, “towards the leading edge of the blade and / or towards the trailing edge of the blade” is to be understood as “towards the leading edge of the blade and / or towards the trailing edge of the blade relative to the flow direction” and / or “along the surface of the blade towards the leading edge of the blade and / or along the surface of the blade towards the trailing edge of the blade”.

[0055] For example, the shell may taper towards the leading edge of the blade and / or towards the trailing edge of the blade in one or more tapered regions of the shell so that the shell has a concave portion in the tapered region. For example, the outer surface of the shell may converge smoothly towards the surface of the blade.

[0056] According to another embodiment, the housing of the actuator arrangement is attached at one of the suction side and the pressure side of the blade such that a distance between the housing and the trailing edge of the blade is shorter than a distance between the housing and the leading edge of the blade.

[0057] Trailing-edge noise radiation from a blade (e.g., its airfoil) is concentrated toward the trailing edge of the blade / airfoil (the source location). Therefore, by positioning the actuator housing near the noise source the device is designed to cancel, the trailing-edge noise and the anti-noise signal propagate toward the observer via more similar paths. This approach allows the noise and anti-noise signals to remain more correlated at this distance, improving noise cancellation performance.

[0058] According to another embodiment, the actuator arrangement comprises one or more actuator units for generating the anti-noise signal, each actuator unit comprising a diaphragm for converting kinetic energy into acoustic energy, and the one or more actuator units being at least partially accommodated within a housing.

[0059] For example, the actuator arrangement comprises two, three or four actuator units for generating the anti-noise signal.

[0060] According to another embodiment, the actuator arrangement comprises a plurality of actuator units and a plurality of gas chambers, each gas chamber being associated with a respective actuator unit such that a diaphragm of the respective actuator unit forms part of an enclosure of the respective associated gas chamber.

[0061] In the case of multiple actuator units, the control unit can generate and send different signals to different actuator units to achieve optimal noise cancellation at one or more observer positions. Furthermore, by having each actuator unit have its own gas chamber, crosstalk between actuator units can be reduced. Specifically, since loudspeakers radiate both forward and backward, if two actuator units (loudspeakers) share the same gas chamber, crosstalk between the actuator units will occur. For example, the first actuator unit (loudspeaker) will also radiate through the gas chamber of the second actuator unit (loudspeaker).

[0062] According to a further embodiment, the actuator arrangement comprises a plurality of actuator units which are arranged chordwise with respect to a chord line of the blade airfoil and / or with respect to a chord line of the casing airfoil.

[0063] A chordwise arrangement relative to a chord line of the blade airfoil means in particular an arrangement of the plurality of actuator units parallel to a direction pointing from the leading edge of the blade to the trailing edge of the blade relative to the flow direction (along the surface of the blade).

[0064] According to another aspect, a wind turbine is provided, comprising one or more wind turbine blades as described above.

[0065] Other possible embodiments or alternatives of the present invention also encompass combinations of features not explicitly mentioned herein that are described above or below with respect to the embodiments. A person skilled in the art may also add individual or isolated aspects and features to the most basic form of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Other embodiments, features and advantages of the present invention will become apparent from the following description and the dependent claims taken in conjunction with the accompanying drawings, in which: Figure 1 A wind turbine according to an embodiment is shown; Figure 2 It shows the embodiment according to Figure 1 a partial perspective view of a blade of a wind turbine; Figure 3 Along Figure 2 The cross-sectional view along line III-III in FIG. Figure 2 a blade and a housing of an actuator device attached to a surface of the blade; Figure 4 Shown along Figure 3 A cross-sectional view of the housing taken along line IV-IV; Figure 5 A view showing a portion of the surface of a blade and a housing according to another embodiment; Figure 6 Shown with Figure 3 a similar view illustrating the distances of the housing from the leading and trailing edges of the blades; Figure 7 Shown Figure 3 An enlarged view of a housing of an actuator device, wherein the actuator device includes an actuator unit and a gas chamber; Figure 8 Shown with Figure 7 A similar view, but for another embodiment of the actuator arrangement, wherein the actuator arrangement comprises three actuator units and three gas chambers; Figure 9 Shown with Figure 7 A similar view, but for another embodiment of the actuator arrangement, wherein the actuator arrangement comprises three actuator units and a gas chamber; and Figure 10 Pictured Figure 7 The volume of the gas chamber.

[0067] In the drawings, like reference numbers indicate identical or functionally equivalent elements unless otherwise indicated. DETAILED DESCRIPTION

[0068] Figure 1 A wind turbine 1 according to an embodiment is shown. The wind turbine 1 includes a rotor 2 having one or more blades 3 connected to a hub 4. The hub 4 is connected to a generator (not shown) disposed within a nacelle 5. During operation of the wind turbine 1, the blades 3 are driven to rotate by the wind, and the kinetic energy of the wind is converted into electrical energy by the generator in the nacelle 5. The nacelle 5 is disposed at the upper end of a tower 6 of the wind turbine 1. The tower 6 stands on a foundation 7, such as a monopile or a concrete foundation. The foundation 7 is connected to and / or driven into the ground or seabed.

[0069] Figure 2 It shows the embodiment according to Figure 1 A partial perspective view of a blade 3 of a wind turbine 1 is shown.

[0070] The blade 3 comprises sensor means 8 and actuator means 9 for active noise cancellation of flow induced noise 10 generated by the blade 3. The main noise source of the blade 3 is the so called trailing edge noise 10 generated at the trailing edge 14 of the blade 3.

[0071] like Figure 2 As shown in FIG, the blade 3 includes an aerodynamically shaped cross-sectional profile (blade airfoil 12). The blade airfoil 12 includes a leading edge 13 and a trailing edge 14. In addition, the blade airfoil 12 also includes a suction side 15 and a pressure side 16, which are connected to each other via the leading edge 13 and the trailing edge 14. A chord line 17 of the blade airfoil 12 connects the leading edge 13 to the trailing edge 14.

[0072] Furthermore, the blade 3 comprises a shell 18. The shell 18 is made of fiber-reinforced resin, for example.

[0073] The outer shell 18 includes a suction side outer shell 19 and a pressure side outer shell 20. The suction side outer shell 19 and the pressure side outer shell 20 surround an inner cavity 21 of the blade 3.

[0074] The sensor device 8 is configured to detect characteristics (eg, features) of the flow-induced noise 10 generated by the blade 3. For example, the sensor device 8 includes several sensor units 22 for detecting the characteristics of the flow-induced noise 10. As an example, Figure 2 , three sensor units 22 are shown. However, the sensor device 8 may also include more or fewer than three sensor units 22.

[0075] For example, the sensor device 8 and / or each sensor unit 22 comprises a microphone for detecting characteristics of the noise 10. However, the sensor device 8 and / or each sensor unit 22 may also comprise other means for detecting characteristics of the noise 10.

[0076] The actuator arrangement 9 is configured for emitting an anti-noise signal 23. The anti-noise signal 23 is generated by the actuator arrangement 9 for at least partially cancelling the flow-induced noise 10.

[0077] For example, the actuator arrangement 9 comprises one or more speakers or other devices for generating the anti-noise signal 23 .

[0078] The actuator device 9 has an aerodynamically shaped housing 24 attached to the outer surface 25 of the blade 3. Figure 2 In the example shown, the housing 24 of the actuator device 9 is attached to the outer surface 25 of the suction side shell 19 of the blade 3. Although not shown in the drawings, in other examples, the housing 24 of the actuator device 9 may also be attached to the outer surface 26 of the pressure side shell 20 of the blade 3 ( Figure 3 ).

[0079] Figure 3 The cross-sectional view shows Figure 2 The blade 3, wherein the cross section along Figure 2 Intercepted along line III-III.

[0080] exist Figure 3 , a fluid flow 27 (e.g., air flow 27) is illustrated along surfaces 25, 26 of a blade 3. The fluid flow 27 is split into two parts 28, 29 at the leading edge 13 of the blade. A first part 28 of the fluid flow 27 is directed along the suction side 15 of the blade 3 to the trailing edge 14 of the blade 3. A second part 29 of the fluid flow 27 is directed along the pressure side 16 of the blade 3 to the trailing edge 14 of the blade 3.

[0081] Figure 3 Furthermore, a cross-sectional view of the housing 24 of the actuator device 9 is shown. The housing 24 has a rounded edge 30 ( Figure 7 ). In addition, the housing 24 has a tapered portion 31 ( Figure 7 ), which tapers in a direction towards the leading edge 13 of the blade 3 and in a direction towards the trailing edge 14 of the blade 3 (said directions being relative to the direction of the flow path of the flow 28 along the surface 25 of the blade 3 ).

[0082] Figure 4A cross section of the aerodynamically shaped housing 24 of the actuator device 9 is shown. Figure 3 The line IV-IV in the interception. Figure 4 As can be seen in FIG, the shell 24 has an airfoil 32 (e.g., a symmetrical airfoil 32) having a leading edge 33 and a trailing edge 34. The shell airfoil 32 also includes a first side 35 and a second side 36 connected to each other at the leading edge 33 and the trailing edge 34 of the shell 24. A chord line 37 connects the leading edge 33 and the trailing edge 34 to each other.

[0083] With respect to the suction side 15 ( Figure 3 ) of the fluid flow 28, the leading edge 33 of the shell 24 is arranged upstream, and the trailing edge 34 of the shell 24 is arranged downstream.

[0084] Due to the described construction of the housing 24 and the arrangement of the housing 24 on the blade 3, the flow 28 ( Figure 3 ) approaches the shell 24 from the leading edge 13 of the blade 3. Furthermore, the fluid flow 28 encounters the shell 24 at the leading edge 33 of the shell 24. At the leading edge 33 of the shell 24, the fluid flow 28 is divided into two parts 38 and 39. The first part 38 of the approaching flow 28 is directed along a first side 35 of the shell 24 to the trailing edge 34 of the shell 24. The second part 39 of the approaching flow 28 is directed along a second side 36 of the shell 24 to the trailing edge 34 of the shell 24.

[0085] In particular, the housing 24 is in plane E ( Figure 7 ) with an aerodynamically shaped section (airfoil 32, Figure 4 ), the plane E is arranged to coincide with the attachment surface 40 ( Figure 3 ) are parallel. The attachment surface 40 of the blade 3 is, in particular, the surface to which the shell 24 of the blade 3 is attached. In the example shown, the attachment surface 40 is part of the suction side surface 25 of the blade 3 (in other examples, it may also be part of the pressure side surface 26 of the blade 3). The dimension S of the attachment surface 40 is, in particular, equal to the footprint F of the shell 24.

[0086] On the non-flat attachment surface 40' of the blade 3' ( Figure 5 ), the shell 24 ′ may have an aerodynamically shaped cross-section in plane E (airfoil 32, Figure 4 ), the plane E is arranged parallel to a tangent plane T of the attachment surface 40 ' of the blade 3 '. The tangent plane T is based in particular on a tangent line T of the attachment surface 40 ' at point P, as Figure 5 As seen in the cross-sectional view.

[0087] like Figure 6As shown in , the housing 24 of the actuator device 9 can be attached at the suction side 15 (suction side shell 19) of the blade 3 so that the distance D1 between the housing 24 and the trailing edge 14 of the blade 3 is shorter than the distance D2 between the housing 24 and the leading edge 13 of the blade 3. The distances D1, D2 are distances relative to the flow path of the corresponding fluid flow 28 (or 29).

[0088] Figure 7 Shows Figure 3 1 is an enlarged view of the housing 24 of the actuator device 9. As shown, the actuator device 9 includes one or more actuator units 41 for generating the anti-noise signal 23 ( Figure 2 The actuator units 41 are at least partially housed within the housing 24 . Each actuator unit 41 includes a diaphragm 42 for converting kinetic energy into acoustic energy. The diaphragm 42 is exposed at an outer surface 44 of the housing 24 .

[0089] Furthermore, each actuator unit 41 includes a driving unit 43 for driving the movement of the diaphragm 41 , so that sound waves and / or pressure waves can be generated by moving the diaphragm 42 .

[0090] In addition, if Figure 7 As shown in , the actuator device 9 may further comprise at least one (eg closed) gas chamber 45 housed within the housing 24 . In particular, the diaphragm 42 forms part of an enclosure 46 of the gas chamber 45 .

[0091] exist Figure 7 In FIG, an example of an actuator device 9 is shown having one actuator unit 41 and one gas chamber 45. However, the actuator device 9 ′, 9 ″ may also comprise more than one actuator unit 41 and / or more than one gas chamber 45, such as Figure 8 and Figure 9 As shown in .

[0092] Figure 8 An example of an actuator device 9' is shown having three actuator units 41' and three gas chambers 45'. Each actuator unit 41' comprises a diaphragm 42' and a drive unit 43'. Furthermore, each gas chamber 45' is associated with a (single) corresponding actuator unit 41', such that the diaphragm 42' of the respective actuator unit 41' forms part of the enclosure 46' of the respective associated gas chamber 45'.

[0093] Figure 9An example of an actuator device 9 ″ is shown having three actuator units 41 ″ and one gas chamber 45 ″. Each actuator unit 41 ″ comprises a diaphragm 42 ″ and a drive unit 43 ″. For illustration purposes, the diaphragm 42 ″ and the drive unit 43 ″ are provided with reference numerals for only one of the three actuator units 41 ″. Furthermore, one large gas chamber 45 ″ is associated with all three actuator units 41 ″, so that the diaphragms 42 ″ of the actuator units 41 ″ form part of the enclosure 46 ″ of the one gas chamber 45 ″.

[0094] In the embodiment where the actuator arrangement 9 ′, 9 ″ comprises a plurality of actuator units 41 ′, 41 ″, the plurality of actuator units 41 ′, 41 ″ may be arranged relative to the chord line 17 ( Figure 3 ) and / or arranged chordwise relative to the chord line 37 of the shell airfoil 32.

[0095] The aerodynamic shape of the housing 24, 24', 24" with the actuator device 9, 9', 9" allows to accommodate a relatively large total volume V in the housing 24, 24', 24". tot One or more gas chambers 45, 45', 45" without significantly reducing the aerodynamic performance of the blade 3, 3', 3". The total volume V of the gas chamber 45, 45', 45" tot In large cases, the sound radiation loss can be reduced and the sound radiation efficiency can be improved.

[0096] For example, the gas chamber 45 ( Figure 7 ) is given by the product of its width B, height H and depth T, as Figure 10 In addition, Figure 8 The volume V1', V2, V3 of each of the three gas chambers 45' and Figure 9 The volume V1" of the gas chamber 45" can also be as follows Figure 10 Given as shown in .

[0097] The gas chambers 45, 45', 45" may have a rectangular block shape (cuboid shape), such as Figure 10 Furthermore, although not shown in the drawings, any of the gas chambers 45, 45', 45" may also have a shape different from a rectangular block shape.

[0098] For example, the total volume V of the gas chamber 45 is tot = V1( Figure 7 ), the total volume V of the gas chamber 45' tot ' = V1' + V2 + V3 ( Figure 8 ) and / or the total volume V of the gas chamber 45″ tot" = V1" ( Figure 9 ) has a value of 0.1 liter or more to provide sufficient acoustic efficiency of the respective actuator device 9, 9', 9".

[0099] For example, in order to generate the anti-noise signal 23, the wind turbine blade 3 comprises a control unit 48 ( Figure 2 ), for generating a control signal A based on the sensor signal B of the sensor device 8. The sensor signal B of the sensor device 8 corresponds in particular to the noise 10 of the blade 3. The control unit 48 is configured to control the actuator device 9 by means of the control signal A so that the actuator device 9 emits the anti-noise signal 23. For example, the control unit 48 is configured to generate the control signal A so that the superposition of the noise 10 and the anti-noise signal 23 results in destructive interference.

[0100] For example, the actuator device 9 is connected (wired 49 or wirelessly) to the sensor device 22 for data transmission via a control unit 48. For example, the control unit 48 is arranged inside the blade 3 (ie in the inner cavity 21 of the blade 3).

[0101] Thus, the described active noise cancellation system (i.e. the sensor device 8 and the actuator device 9 and, for example, the control unit 48) allows a significant reduction in the noise emissions of the blade 3. This noise reduction is achieved by means of the aerodynamically shaped shell 24 without significantly degrading the aerodynamic characteristics of the blade 3.

[0102] Although the invention has been described in terms of preferred embodiments, it will be apparent to those skilled in the art that modifications are possible in all embodiments.

Claims

1. A wind turbine blade (3) comprising a sensor device (8) for detecting a characteristic of flow-induced noise (10) generated by the blade (3) and an actuator device (9) for emitting an anti-noise signal (23) in order to at least partially cancel the flow-induced noise (10), wherein: The actuator device (9) comprises an aerodynamically shaped housing (24) attached to the outer surface (25) of the blade (3).

2. The wind turbine blade according to claim 1, wherein The actuator device (9) comprises: at least one diaphragm (42) exposed at an outer surface (44) of the housing (24) for converting kinetic energy into acoustic energy to generate the anti-noise signal (23), and At least one gas chamber (45) is accommodated within the housing (24) such that the at least one diaphragm (42) forms part of an enclosure (46) of the at least one gas chamber (45).

3. The wind turbine blade according to claim 2, wherein: The total volume (V tot ) is 0.03 liters or more, 0.05 liters or more, 0.1 liters or more, 0.13 liters or more, 0.15 liters or more, 0.2 liters or more and / or 0.3 liters or more.

4. The wind turbine blade according to any one of claims 1 to 3, wherein: The aerodynamically shaped shell (24) has an aerodynamically shaped cross section (32) and / or airfoil (32) having a first side (35) and a second side (36) connected to each other at a leading edge (33) and a trailing edge (34).

5. The wind turbine blade according to claim 4, wherein: The blade (3) having an aerodynamically shaped shell (24) is configured such that a fluid flow (28) approaching the shell (24) from a leading edge (13) of the blade (3) flows from a leading edge (33) of the shell (24) to a trailing edge (34) of the shell (24).

6. The wind turbine blade of claim 5, wherein: The housing (24) is arranged on one of the suction side (15) and the pressure side (16) of the blade (3), and The blade (3) with the shell (24) is configured such that a fluid flow (28) approaching the shell (24) from the leading edge (13) of the blade (3) is split at the leading edge (33) of the shell (24) such that: A portion (38) of the fluid flow (28) flows from the leading edge (33) of the shell (24) along said one of the suction side (15) and the pressure side (16) of the blade (3) and along the first side (35) of the shell (24) to the trailing edge (34) of the shell (24), and Another portion (39) of the fluid flow (28) flows from the leading edge (33) of the shell (24) along the one of the suction side (15) and the pressure side (16) of the blade (3) and along the second side (36) of the shell (24) to the trailing edge (34) of the shell (24).

7. A wind turbine blade according to any one of claims 4 to 6, wherein: The housing (24) is arranged on one of the suction side (15) and the pressure side (16) of the blade (3), and The leading edge (33) of the shell (24) is arranged upstream, and the trailing edge (34) of the shell (24) is arranged downstream, both relative to the fluid flow (28) along the one of the suction side (15) and the pressure side (16) of the blade (3).

8. A wind turbine blade according to any one of claims 1 to 7, wherein: The shell (24) is attached to the attachment surface (40) of the blade (3) and the shell (24) has an aerodynamically shaped cross-section (32) and / or airfoil (32) in a plane (E), the plane (E) being arranged parallel to the attachment surface (40) of the blade (3) and / or parallel to a tangent (T) to the attachment surface (40') of the blade (3).

9. A wind turbine blade according to any one of claims 1 to 8, wherein: The housing (24) has a rounded edge (30) at its outer surface (44).

10. A wind turbine blade according to any one of claims 1 to 9, wherein: When viewed in a section parallel to the airfoil (12) of the blade (3), the shell (24) tapers (31) toward the leading edge (13) of the blade (3) and / or toward the trailing edge (14) of the blade (3).

11. A wind turbine blade according to any one of claims 1 to 10, wherein: The housing (24) of the actuator device (9) is attached at one of the suction side (15) and the pressure side (16) of the blade (3) such that a distance (D1) between the housing (24) and the trailing edge (14) of the blade (3) is shorter than a distance (D2) between the housing (24) and the leading edge (13) of the blade (3).

12. A wind turbine blade according to any one of claims 1 to 11, wherein: The actuator device (9) comprises one or more actuator units (41) for generating the anti-noise signal (23), each actuator unit (41) comprising a diaphragm (42) for converting kinetic energy into acoustic energy, and the one or more actuator units (41) are at least partially accommodated in the housing (24).

13. A wind turbine blade according to any one of claims 1 to 12, wherein: The actuator device (9') comprises a plurality of actuator units (41') and a plurality of gas chambers (45'), each gas chamber (45') being associated with a respective actuator unit (41') such that the diaphragm (42') of the respective actuator unit (41') forms part of an enclosure (46') of the respective associated gas chamber (45').

14. A wind turbine blade according to any one of claims 1 to 13, wherein: The actuator arrangement (9') comprises a plurality of actuator units (41') which are arranged chordwise relative to a chord line (17) of the blade airfoil (12) and / or relative to a chord line (37) of the shell airfoil (32).

15. A wind turbine (1) comprising one or more wind turbine blades (3) according to any one of claims 1-14.

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