Noise reducer for a rotor blade in a wind turbine

Abstract

A rotor blade assembly (100) for a wind turbine (10) comprising: a rotor blade (16) having surfaces defining a pressure side (22), a suction side (24), a leading edge (26), and a trailing edge (28), and extending between a tip (32) and a root (34), the rotor blade (16) further defining a blade pitch axis (40); and, a noise reducer (110) formed on a surface of the rotor blade (16), the noise reducer (110) comprising a plurality of teeth (112), each of the plurality of teeth (112) defining a centerline (128) and having a base (122) with a width (120), wherein the centerline (128) of each of the plurality of teeth (112) defines an individually adjusted angle that depends on a spanwise position, a local blade width (46), the width (120), a length (124), a bend angle (134), and / or a thickness (140) of each of the plurality of teeth (112), and that ranges between approximately 10 degrees from normal to the blade angle axis (40) and approximately perpendicular to the blade angle axis (40).

Description

[0001] The present disclosure generally relates to wind turbine rotor blades, and more particularly to noise reducers configured on the rotor blades. Furthermore, the present disclosure relates to a wind turbine, a method of manufacturing and / or assembling a rotor blade assembly, and a method of assembling a wind turbine.

[0002] Wind energy is considered one of the cleanest and most environmentally friendly energy sources currently available, and wind turbines have received increased attention in this regard. A modern wind turbine typically comprises a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades extract kinetic energy from the wind based on well-known airfoil principles. The rotor blades transfer the kinetic energy in the form of rotational energy by rotating a shaft that connects the rotor blades to a gearbox, or, if no gearbox is used, directly to the generator. The generator then converts the mechanical energy into electrical energy, which can be fed into a power grid.

[0003] In many cases, various components are attached to the rotor blades of wind turbines to perform different functions during operation. These components can often be mounted near the trailing edges of the rotor blades. For example, noise reducers can be mounted on the trailing edges of rotor blades to reduce noise and increase the efficiency associated with the rotor blade. Typical prior art noise reducers can have a variety of drawbacks and may not adequately reduce the noise associated with typical rotor blades. For example, currently known noise reducers may not take into account various characteristics of the wind flow across the rotor blades.

[0004] This error can complicate the noise reduction properties of the noise reducers. Furthermore, currently known noise reducers comprise a large number of teeth. The teeth of many currently known noise reducers may have similar sizes and shapes along the length of the noise reducer. Therefore, the noise reducers may not be able to individually account for changes in wind flow characteristics along the length of the rotor blade. This error can further complicate the noise reduction properties. US Pat. No. 5,088,665 A describes serrated trailing edges for improving the lift and drag characteristics of airfoils.

[0005] Therefore, an improved noise reducer for a rotor blade would be desirable. For example, a noise reducer with improved noise reduction features would be advantageous. In particular, a noise reducer that takes into account various characteristics of the wind flow across the rotor blades would be desirable.

[0006] The invention is defined by the appended claims.

[0007] Aspects and advantages of the invention will be set forth in part in the description which follows, or will be obvious from it, or may be learned by practice of the invention.

[0008] According to one aspect, a rotor blade assembly for a wind turbine is disclosed. The rotor blade assembly includes a rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a tip and a root. The rotor blade further includes a noise reducer formed on a surface of the rotor blade, the noise reducer comprising a plurality of teeth, each of the plurality of teeth defining a centerline. The centerline of each of the plurality of teeth defines a customized angle depending on the spanwise location, local blade width, pitch, length, bend angle, and / or thickness.

[0009] According to one aspect, a rotor blade assembly for a wind turbine is disclosed. The rotor blade assembly includes a rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a tip and a root. The rotor blade further defines a pitch axis. The rotor blade assembly further includes a noise reducer formed on a surface of the rotor blade, the noise reducer comprising a plurality of teeth, each of the plurality of teeth defining a centerline. The centerline of each of the plurality of teeth ranges between approximately 10 degrees from normal with respect to the pitch axis and approximately perpendicular to the pitch axis.

[0010] According to one aspect, a rotor blade assembly for a wind turbine is disclosed. The rotor blade assembly includes a rotor hub defining a center point and a rotor blade extending from the rotor hub, the rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a tip and a root. The rotor blade assembly further includes a noise reducer formed on a surface of the rotor blade, the noise reducer comprising a plurality of teeth, each of the plurality of teeth defining a centerline. A line is defined for each of the plurality of teeth between the centerline of each of the plurality of teeth and the center point of the rotor hub. The centerline of each of the plurality of teeth ranges between approximately 10 degrees from normal to the line and approximately perpendicular to the line.

[0011] According to further aspects, a wind turbine is disclosed. The wind turbine may, in particular, comprise at least one rotor blade or a rotor blade assembly as described herein.

[0012] Furthermore, a method for assembling, manually and / or industrially manufacturing a rotor blade assembly, a rotor blade and / or a wind turbine as described herein is disclosed.

[0013] The invention also relates to an apparatus for carrying out the disclosed methods and includes apparatus parts for carrying out each of the described method steps. The method steps can be carried out using hardware components, a computer programmed by appropriate software, a combination of the two, or in any other way. Furthermore, methods are disclosed by which the described apparatuses operate and / or by which the described elements are assembled. It includes method steps for carrying out each function of the apparatus.

[0014] These and other features, aspects, and advantages of the present invention will become more fully understood with reference to the following description and the appended claims. The accompanying drawings, which form a part of this specification, illustrate embodiments of the invention and, together with the description, are intended to explain the principles of the invention.

[0015] A complete and practical disclosure of the present invention, including the best mode for carrying it out, is presented in the description which refers to the attached figures, in which: Fig. 1 is a perspective view of an embodiment of a wind turbine according to the present disclosure; Fig. 2 is a perspective view of one embodiment of a rotor blade assembly of the present disclosure; Fig. 3 is a plan view of one embodiment of a noise reducer of the present disclosure; Fig. 4 is a cross-sectional view of one embodiment of a noise reducer of the present disclosure; Fig. 5 is a cross-sectional view of another embodiment of a noise reducer of the present disclosure; Fig. 6 is a cross-sectional view of another embodiment of a noise reducer of the present disclosure; Fig. 7 is a perspective view of another embodiment of a rotor blade assembly of the present disclosure; and, Fig. 8 is a plan view of another embodiment of a noise reducer of the present disclosure.

[0016] Reference will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the figures. Each example is provided to explain the invention, not to limit the invention. Indeed, it will be obvious to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment may be used in other embodiments to arrive at a further embodiment. The present invention is intended to cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0017] Fig. Figure 1 illustrates a conventional wind turbine 10. The wind turbine 10 comprises a tower 12 with a nacelle 14 mounted thereon. A plurality of rotor blades 16 are attached to the rotor hub 18, which in turn is connected to a main flange that rotates a main rotor shaft. The rotor hub 18 defines a center point 19 (see Figure 1). Fig. 7). The wind turbine power generation and control components are located within the nacelle 14. The view from Fig. Figure 1 is for illustrative purposes only, placing the invention within an exemplary field of use. It should be understood that the invention is not limited to any particular type of wind turbine configuration.

[0018] With reference to the Fig. 2 and Fig. 7, a rotor blade 16 according to the present disclosure may include surfaces defining a pressure side 22 and a suction side 24 (see Fig. 4 to 6) which extend between a leading edge 26 and a trailing edge 28, and which may extend from a blade tip 32 to a blade root 34.

[0019] In some embodiments, the rotor blade 16 may include a plurality of individual blade segments that are aligned contiguously from the blade tip 32 to the blade root 34. Each of the individual blade segments may be uniquely configured such that the plurality of blade segments define a complete rotor blade 16 having a designed aerodynamic profile, length, and other desired characteristics. For example, each of the blade segments may have an aerodynamic profile that corresponds to the aerodynamic profile of adjacent blade segments. Thus, the aerodynamic profiles of the blade segments may define a continuous aerodynamic profile of the rotor blade 16. Alternatively, the rotor blade 16 may be formed as a singular unitary blade having the designed aerodynamic profile, length, and other desired characteristics.

[0020] The rotor blade 16 may be curved in exemplary embodiments. Curving the rotor blade 16 may involve bending the rotor blade 16 in a generally flapwise direction and / or in a generally edgewise direction. The spoilerward direction may generally be interpreted as the direction (or the opposite direction) in which aerodynamic lift acts on the rotor blade 16. The edgeward direction is generally perpendicular to the spoilerward direction. A spoilerward bend of the rotor blade 16 is also known as a pre-bend, while the edgeward bend is also known as a sweep. Thus, a curved rotor blade 16 may be pre-bent and / or swept.The curving may enable the rotor blade 16 to better withstand spoiler-side and edge-side loads during operation of the wind turbine 10, and may further provide clearance for the rotor blade 16 from the tower 12 during operation of the wind turbine 10.

[0021] The rotor blade 16 may further define a blade angle axis 40, as shown in the Fig. 2 and Fig. 3. The pitch axis 40 may be generally fixed with respect to the rotor hub 18 of the wind turbine 10. For example, the pitch axis 40 may extend generally perpendicular to the rotor hub 18 and the blade root 34 through the center of the blade root 34. A pitch of the rotor blade 16, i.e., an angle that defines an orientation of the rotor blade 16 with respect to the airflow across the wind turbine 10, may be defined by the rotation of the rotor blade 16 about the pitch axis 40.

[0022] The rotor blade 16 may further define a blade width 42 and a span 44. As shown in the Fig. 2 and Fig. 7, the blade width 42 can vary across the span 44 of the rotor blade 16. Therefore, as discussed further below, a local blade width 46 can be specified at any point on the rotor blade 16 along the span 44.

[0023] As in the Fig. 2 to 8, the present disclosure may further be directed to a rotor blade assembly 100. The rotor blade assembly 100 may include a noise reducer 110 and a rotor blade 16. Generally, the noise reducer 110 may be configured on a surface of the rotor blade 16 and may reduce the aerodynamic noise emitted by the rotor blade 16 during operation of the wind turbine 10 and / or may increase the efficiency of the rotor blade 16. In an exemplary embodiment of the present disclosure, the noise reducer 110 may be configured on a surface of the rotor blade 16 proximate the trailing edge 28 of the rotor blade 16.Alternatively, the noise reducer 110 may be formed on a surface of the rotor blade 16 near the leading edge 26 of the rotor blade 16, or near the tip 32 or root 34 of the rotor blade 16, or at any other suitable location on the rotor blade 16.

[0024] In exemplary embodiments, as shown in the Fig. 2 to 5 and 7 to 8, the noise reducer 110 may be configured, for example, mounted, on the pressure side 22 of the rotor blade 16. In alternative embodiments, the noise reducer 110 may be configured, such as mounted, on the suction side 24. In yet other alternative embodiments, the noise reducer 110 may be configured on the rotor blade 16 between the pressure side 22 and the suction side 24.

[0025] As in Fig. 6, the noise reducer 110 may, for example, be configured on the trailing edge 28 between the pressure side 22 and the suction side 24. In this embodiment, the rotor blade 16 may be formed from one or more shell portions. For example, one shell portion may encompass the pressure side 22 and extend between the leading edge 26 and the trailing edge 28, while another shell portion may encompass the suction side 24 and extend between the leading edge 26 and the trailing edge 28. The noise reducer 110 may be mounted between these shell portions such that a portion of the noise reducer 110 is disposed inside the rotor blade 16, while another portion protrudes from the rotor blade 16. Alternatively, the noise reducer 110 may extend through a shell portion of the rotor blade 16 at a desired location, such as at the trailing edge 28.In further alternative embodiments, the noise reducer 110 may be attached directly to the exterior of the rotor blade between the pressure side 22 and the suction side 24 using, for example, a suitable adhesive or suitable mechanical fasteners. For example, in exemplary embodiments, the noise reducer 110 may be attached directly to the trailing edge 28.

[0026] The noise reducer 110 may include a plurality of teeth 112. In some embodiments, the teeth may extend from a base plate 114. In these embodiments, the base plate 114 may generally be the portion of the noise reducer 110 that is attached to the rotor blade 16 to form the noise reducer 110 on a surface of the rotor blade 16. Alternatively, the teeth 112 may be attached directly to the rotor blade 16 or may be an integral part of the rotor blade. For example, in embodiments where the noise reducer is formed on the trailing edge 28, the trailing edge 28 may simply include the plurality of teeth 112 extending therefrom, and the teeth 112 may be formed integrally with the trailing edge 28.

[0027] In some embodiments, the noise reducers 110 may be formed from a plurality of noise reducer sections. Each section may include one or more teeth 112, and each section may further include a base plate portion. Alternatively, the noise reducer 110 may be a single, unitary component.

[0028] As shown, adjacent teeth 112 may generally define notches 116 therebetween. While in exemplary embodiments, the teeth 112 are generally V-shaped, and thus define generally V-shaped notches 116, in alternative embodiments, the teeth 112 and notches 116 may be U-shaped, or may have any other shape or configuration suitable for reducing the noise emitted by the wind turbine 10 and / or increasing the efficiency of the rotor blade 16 during operation of the wind turbine 10. For example, in some embodiments, the teeth 112 and notches 116 may be generally sinusoidal or square sinusoidal.

[0029] As in the Fig. 3 and Fig. 8, each of the teeth 112 may have a width 120. The width 120 may be defined for each tooth 112 at a base 122 of each tooth. Furthermore, a tooth length 124 may be defined for each tooth 112. The length 124 may be measured between the base 122 and a tip 126 of the tooth 112, and may be defined generally perpendicular to the base 122. Furthermore, each of the teeth 112 may have a centerline 128. The centerline 128 may extend through the tip 126 of the tooth 112, such as through the center of the tip 126, and through the base 122 of the tooth, such as through the center of the base 122, and may generally divide the tooth 112 into two parts.

[0030] It should be understood that a tooth 112 according to the present disclosure may have any suitable characteristic, such as width 120, length 124, shape, or orientation, depending on the desired noise reduction characteristics for the noise reducer 110, while exemplary embodiments of the teeth are discussed below. Moreover, in exemplary embodiments, each individual tooth 112 may individually have characteristics as needed to achieve optimal noise reduction characteristics. However, in alternative embodiments, different groups of teeth 112 may have similar characteristics, or all of the teeth 112 may have similar characteristics, depending on the desired noise reduction characteristics for the noise reducer 110.

[0031] In some embodiments, as in the Fig. 2 and Fig. 3, the centerline 128 of a tooth 112 according to the present disclosure may be oriented with respect to the pitch axis 40 of the rotor blade 16. For example, in some embodiments, the centerline 128 may be in the range of approximately 10 degrees from normal to the pitch axis 40 and approximately perpendicular to the pitch axis 40. Alternatively, the centerline 128 may be in the range of approximately 5 degrees from normal to the pitch axis 40 and approximately perpendicular to the pitch axis 40. In other exemplary embodiments, the centerline 128 may be approximately perpendicular to the pitch axis 40. However, it should be understood that the present disclosure is not limited to teeth 112 having particular angles as discussed above, but that any suitable tooth 112 having any suitable angle is within the scope and spirit of the present disclosure.Advantageously, the above-discussed orientation of centerline 128 with respect to pitch axis 40 may improve the noise reduction characteristics of the noise reducer 110 of the present disclosure. For example, in many embodiments, the wind flow across the rotor blade assembly 100 may be generally perpendicular to pitch axis 40. The orientation of the teeth 112 with respect to pitch axis 40 allows the teeth 112 to better interact with the wind flow, thus improving the noise reduction characteristics of the present noise reducer 110.

[0032] In alternative embodiments, the centerline 128 of a tooth 112 according to the present disclosure may be oriented differently to enhance the noise reduction properties of the noise reducer 110 of the present disclosure. For example, as shown in Fig. 7 and Fig. 8, the centerline 128 of a tooth 112 may be oriented with respect to a line 129 from the base 122, such as the center of the base 122, to the center point 19 of the rotor hub of the wind turbine 10. As shown, the line 129 may be individually defined for each tooth 112 such that each tooth 112 has an individual orientation with respect to other teeth 112. In some embodiments, the centerline 128 may range between approximately 10 degrees from normal to line 129 and approximately perpendicular to line 129. Alternatively, the centerline 128 may range between approximately 5 degrees from normal to line 129 and approximately perpendicular to line 129. In further alternative exemplary embodiments, the centerline 128 may be approximately perpendicular to line 129.However, it should be understood that the present disclosure is not limited to teeth 112 having angles as discussed above, but that any suitable tooth 112 with any suitable angle is within the scope and spirit of the present disclosure. Advantageously, orienting the centerline 128 with respect to line 129, as discussed above, may enhance the noise reduction properties of the noise reducer 110 of the present disclosure. For example, in many embodiments, the wind flow across the rotor blade assembly 100 may be oriented with respect to line 129 for each individual tooth 112. Orienting the teeth 112 with respect to line 129 may allow the teeth 112 to better interact with the wind flow, thus enhancing the noise reduction properties of the present noise reducer 110.

[0033] As discussed above, in exemplary embodiments, each individual tooth 112 may have individual characteristics, such as width 120, length 124, shape, or orientation, as needed to achieve optimal noise reduction characteristics. Furthermore, in some embodiments, each individual tooth 112 may have a centerline 128 that defines a customized angle depending on a variety of factors. The angle may, in some embodiments, be customized relative to the blade pitch axis 40, line 129, or trailing edge 28. Tailoring the angle for each individual tooth may depend on factors such as (but not limited to) the position along the span 44, the local blade width 46, the width 120, the length 124, the bend angle (see below), and / or the thickness (see below).It should be understood that the factors for tailoring the angles of individual teeth are not limited to those disclosed above. Rather, any suitable factor discussed herein or elsewhere is within the scope and spirit of the present disclosure.

[0034] As discussed above, each tooth 112 may extend between a base 122 and a tip 126. In some embodiments, such as in embodiments where the teeth 112 are generally V-shaped, the tips 126 may generally be the pointed ends of the teeth 112. In these embodiments, the tips 126 have minimal or no radius. However, in other embodiments, the tips 126 may be rounded. In these embodiments, the rounded tips 126 may each have a radius. In some embodiments, the radius of a tip 126 may be less than or equal to about 2 millimeters. In other embodiments, the radius of a tip 126 may be less than or equal to about 1 millimeter.It should be understood, however, that the present disclosure is not limited to tips 126 having particular radii as discussed above, but that any suitable tip 126 having any suitable radius is within the scope and spirit of the present disclosure.

[0035] As discussed above, each of the teeth 112 may define a width 120 and a length 124. In some example embodiments, the width 120 and length 124 of each tooth 112 may be sized to optimize the noise reduction properties of the noise reducer 110. For example, in some example embodiments, a tooth 112 may have a length 124 to width 120 ratio ranging between about 0.5:1 and about 4:1. In other embodiments, a tooth 112 may have a length 124 to width 120 ratio ranging between about 1:1 and about 2:1. In still other embodiments, a tooth 112 may have a length 124 to width 120 ratio of about 2:1.It should be understood, however, that the present subject matter is not limited to teeth 112 having particular ratios as discussed above, but that any suitable tooth 112 having any suitable ratio is within the scope and spirit of the present disclosure.

[0036] As mentioned above, a local blade width 46 for the rotor blade 16 may be defined at any point on the rotor blade 16 relative to the span 44. Thus, for example, a local blade width 46 may be defined for each of the teeth 112. For example, the local blade width 46 may be measured along the span 44 at any point along the width 120 of the tooth 112, or may be calculated as an average of the blade widths across the width 120 of the tooth 112.

[0037] The teeth 112, in exemplary embodiments, may be optimized with respect to the local blade widths 46 for each tooth 112 to optimize the noise reduction properties of the noise reducer 110. For example, in some embodiments, the length 124 of a tooth 112 may range between approximately 5% of the local blade width 46 for the tooth 112 and approximately 15% of the local blade width 46 for the tooth 112. In other embodiments, the length 124 of a tooth 112 may be approximately 10% of the local blade width 46 for the tooth 112. However, it should be understood that the present disclosure is not limited to teeth 112 having particular lengths 124 as discussed above, but that any suitable tooth 112 having any suitable length 124 is within the scope and spirit of the present disclosure.

[0038] As in the Fig. 4 and Fig. 5, the rotor blade assembly 100 of the present disclosure may be subjected to wind flow during operation. The wind flow across the rotor blade assembly 100 may create flow streamlines. For example, the wind flow across the pressure side 22 may create a flow streamline, and the wind flow across the suction side 24 may also create a flow streamline. Furthermore, local flow streamlines for the rotor blade 16 may be defined at any point on the rotor blade 16 along the span 44. Thus, for example, a local flow streamline may be defined for each of the teeth 112. For example, the local flow streamline along the span 44 may be measured at any point along the width 120 of the tooth 112, or calculated as an average of the local flow streamlines across the width 120 of the tooth 112.Furthermore, in some embodiments, the local flow streamline for a tooth 112 may be a local pressure-side flow streamline 130 or a local suction-side flow streamline 132. Alternatively, the local flow streamline may be calculated based on the local pressure-side flow streamline 130 and the local suction-side flow streamline 132 and may be, for example, a local average flow streamline.

[0039] The teeth 112 may, in exemplary embodiments, be optimized with respect to a local flow streamline for each tooth 112 to optimize the noise reduction properties of the noise reducer 110. For example, the cross section of a tooth, as shown in the Fig. 4 and Fig. 5, be approximately parallel to the local flow streamline. For example, the Fig. 4 and Fig. 5 shows the cross-section of a tooth 112 that is approximately parallel to the local suction-side flow streamline 132. However, the cross-section of a tooth 112 may alternatively or additionally be approximately parallel, for example, to the local pressure-side flow streamline 130 or the local average flow streamline.

[0040] In addition or alternatively, a tooth 112, as in Fig. 4, specify a bend angle 134. The bend angle 134 may be specified with respect to the local blade width 46 for the tooth 112. In exemplary embodiments, the bend angle 134 may be calculated based on a local flow streamline to optimize noise reduction with respect to the local flow streamline and the individual tooth 112. For example, the bend angle 134 may be calculated such that the tooth 112 extending at a bend angle 134 conforms to the local flow streamline 112. In some embodiments, the bend angle 134 may be calculated based on a local flow streamline such that a cross-section of the tooth 112 extending at a bend angle 134 is approximately parallel to the local flow streamline.

[0041] In some embodiments, as in Fig. 4, the cross-section of tooth 112 may be generally linear. In exemplary embodiments, the linear cross-section may approximate a local flow streamline and / or be approximately parallel to the local flow streamline. In alternative embodiments, as shown in Fig. As shown in Figure 5, the cross-section of tooth 112 may be generally curvilinear. In exemplary embodiments, the curvilinear cross-section may conform to a local flow streamline and / or be approximately parallel to the local flow streamline.

[0042] Each tooth 112 may further define a thickness 140, as shown in Fig.4. The thickness of a tooth 112, in some embodiments, may range between approximately 0.1 millimeters and approximately 2.5 millimeters. In other embodiments, the thickness of a tooth 112 may range between approximately 1 millimeter and approximately 2 millimeters. However, it should be understood that the present subject matter is not limited to teeth 112 having a particular thickness 140 as discussed above, but that any suitable tooth 112 having any suitable thickness 140 is within the scope and spirit of the present disclosure. In some embodiments, the rotor blade may define a local flow streamline for each of the plurality of teeth, and wherein a cross-section of each of the plurality of teeth may be approximately parallel to the local flow streamline.

[0043] In some embodiments, a rotor blade assembly for a wind turbine may include a rotor hub defining a center point, a rotor blade extending from the rotor hub, the rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a tip and a root; and, a noise reducer formed on a surface of the rotor blade, the noise reducer having a plurality of teeth, each of the plurality of teeth defining a centerline, a line for each of the plurality of teeth being defined between the centerline of each of the plurality of teeth and the center point of the rotor hub, and the centerline of each of the plurality of teeth being in the range between approximately 10 degrees from normal to the line and approximately perpendicular to the line.

[0044] In some embodiments, the rotor blade may define a local flow streamline for each of the plurality of teeth, and wherein a cross-section of each of the plurality of teeth may be approximately parallel to the local flow streamline.

[0045] According to one aspect, a rotor blade assembly for a wind turbine is described, comprising a rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a tip and a root, and a noise reducer formed on a surface of the rotor blade, the noise reducer comprising a plurality of teeth, each of the plurality of teeth defining a centerline, the centerline of each of the plurality of teeth defining an individually adjusted angle dependent upon the spanwise position, local blade width, width, length, bend angle, and / or thickness.

[0046] In some embodiments, the rotor blade may further define a pitch axis, and wherein the centerline of each of the plurality of teeth may be in the range between approximately 10 degrees from normal to the pitch axis (40) and approximately perpendicular to the pitch axis (40).

[0047] In some embodiments, the rotor blade assembly may further comprise a rotor hub defining a center point, and wherein a line for each of the plurality of teeth is defined between the center line of each of the plurality of teeth and the center point of the rotor hub, and wherein the center line of each of the plurality of teeth is in the range of about 10 degrees from normal to the line and approximately perpendicular to the line.

[0048] This description uses examples, including the best mode contemplated, to disclose the invention and also to enable one skilled in the art to practice the invention, particularly to make and use devices or systems and to practice the contemplated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to one skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal representation in the claims or if they include equivalent structural elements with insubstantial differences from the literal representation in the claims. Reference symbol 10 wind turbines 12 Tower 14 gondolas 16 rotor blades 18 Rotor hub 19 Center 22 printed page 24 Suction side 26 leading edge 28 trailing edge 32 leaf tip 34 Leaf root 40 blade angle axis 42 sheet width 44 wingspan 46 Local leaf width 100 rotor blade arrangement 110 noise reducers 112 tooth 114 Base plate 116 incision 120 width 122 Base 124 length 126 lace 128 Center line 129 Line (tooth base to rotor hub) 130 Local pressure side flow streamline 132 Local suction side flow line 134 bending angles 140 thickness

Claims

[1] A rotor blade assembly (100) for a wind turbine (10) comprising: a rotor blade (16) having surfaces defining a pressure side (22), a suction side (24), a leading edge (26), and a trailing edge (28), and extending between a tip (32) and a root (34), the rotor blade (16) further defining a blade pitch axis (40); and, a noise reducer (110) formed on a surface of the rotor blade (16), the noise reducer (110) comprising a plurality of teeth (112), each of the plurality of teeth (112) defining a centerline (128) and having a base (122) with a width (120), wherein the centerline (128) of each of the plurality of teeth (112) defines an individually adjusted angle that depends on a spanwise position, a local blade width (46), the width (120), a length (124), a bend angle (134), and / or a thickness (140) of each of the plurality of teeth (112), and that ranges between approximately 10 degrees from normal to the blade angle axis (40) and approximately perpendicular to the blade angle axis (40). [2] The rotor blade assembly (100) of claim 1, wherein the rotor blade assembly (100) further comprises a rotor hub (18) defining a center point (19), and wherein a line (129) individually defined for each of the plurality of teeth (112) is defined between the base (122) of each of the plurality of teeth (112) and the center point (19), and wherein the center line (128) from each of the plurality of teeth (112) to the line (129) is within about 10 degrees of normal to the line (129) and is approximately perpendicular. [3] The rotor blade assembly (100) of any preceding claim, wherein each of the plurality of teeth (112) defines a width (120) and a length (124), and wherein each of the plurality of teeth (112) has a ratio of length (124) to width (120) in the range between approximately 0.5:1 and approximately 4:

1. [4] The rotor blade assembly (100) of any preceding claim, wherein the rotor blade (16) defines a local blade width (46) for each of the plurality of teeth (112), wherein each of the plurality of teeth (112) defines a length (124), and wherein the length (124) of each of the plurality of teeth (112) is in the range between approximately 5% of the local blade width (46) and approximately 15% of the local blade width (46). [5] The rotor blade assembly (100) of any preceding claim, wherein the rotor blade (16) defines a local flow streamline (130, 132) for each of the plurality of teeth (112), and wherein a cross-section of each of the plurality of teeth (112) is approximately parallel to the local flow streamline (130, 132). [6] The rotor blade assembly (100) of any preceding claim, wherein each of the teeth (112) defines a thickness (140), and wherein the thickness (140) of each of the plurality of teeth (112) is in the range between approximately 0.1 millimeters and approximately 2.5 millimeters, preferably wherein the thickness (140) of each of the plurality of teeth (112) is in the range between approximately 1 millimeter and approximately 2 millimeters. [7] The rotor blade assembly (100) according to any one of the preceding claims, wherein the noise reducer (110) is configured on the trailing edge (28) of the rotor blade (16). [8] A rotor blade assembly (100) for a wind turbine (10) comprising: a rotor hub (18) defining a center point (19); a rotor blade (16) extending from the rotor hub (18), the rotor blade (16) having surfaces defining a pressure side (22), a suction side (24), a leading edge (26), and a trailing edge (28) extending between a tip (32) and a root (34); and, a noise reducer (110) formed on a surface of the rotor blade (16), the noise reducer (110) having a plurality of teeth (112), each of the plurality of teeth (112) defining a centerline (128) and having a base (122) having a width (120), wherein a line (129) individually defined for each of the plurality of teeth (112) is defined between the base (122) of each of the plurality of teeth (112) and the center point (19), and wherein the center line (128) of each of the plurality of teeth (112) to the line (129) is in the range between approximately 10 degrees from vertical and approximately perpendicular to the line (129). [9] The rotor blade assembly (100) of claim 8, wherein the centerline (128) of each of the plurality of teeth (112) is approximately perpendicular to the line (129). [10] The rotor blade assembly (100) of claim 8 or 9, wherein the centerline (128) of each of the plurality of teeth (112) defines a customized angle that depends on a spanwise position, a local blade width (46), the width (120), a length (124), a bend angle (134), and / or a thickness (140) of each of the plurality of teeth (112), and that ranges between approximately 10 degrees from normal to the blade pitch axis (40) and approximately perpendicular to the blade pitch axis (40). [11] The rotor blade assembly (100) of any one of the preceding claims 8 to 10, wherein each of the plurality of teeth (112) defines a width (120) and a length (124), and wherein each of the plurality of teeth (112) has a ratio of length (124) to width (120) in the range between approximately 0.5:1 and approximately 4:

1. [12] The rotor blade assembly (100) of any one of the preceding claims 8 to 11, wherein the rotor blade (16) defines a local blade width (46) for each of the plurality of teeth (112), wherein each of the plurality of teeth (112) defines a length (124), and wherein the length (124) of each of the plurality of teeth (112) is in the range between approximately 5% of the local blade width (46) and approximately 15% of the local blade width (46). [13] The rotor blade assembly (100) of any one of the preceding claims 8 to 12, wherein the rotor blade (16) defines a local flow streamline (130, 132) for each of the plurality of teeth (112), and wherein a cross-section of each of the plurality of teeth (112) is approximately parallel to the local flow streamline (130, 132). [14] A wind turbine having at least one rotor blade arrangement according to any one of the preceding claims.

Images