Joined wind turbine blades with noise reduction strips

Abstract

A joined wind turbine rotor blade (28) includes a first blade segment (30) and a second blade segment (32) extending in opposite directions from a chord-wise joint line (34). Each of the blade segments (30, 32) includes a pressure side shell member (31) and a suction side shell member (33). A sealing band (100) is applied over the shell members (31, 33) so as to bridge across the chord-wise joint line (34). The sealing band (100) includes a side edge (102) that is aligned parallel to an airflow (104) over the shell members (31, 33) at the chord-wise joint line (34) at defined load and operating conditions on the joined wind turbine blade (28).

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Serial No.: 16 / 139,197, filed on September 24, 2018, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present subject matter relates generally to wind turbine rotor blades, and more particularly to sealing band configurations between joined blade segments designed to reduce noise and vibration generated at the joint profile. Background Art

[0004] Wind power is considered one of the cleanest, most environmentally friendly energy sources currently available, and wind turbines are gaining increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from the wind using the known airfoil principle and transfer the kinetic energy through rotational energy to rotate a shaft that couples the rotor blades to a gearbox, or directly to the generator if a gearbox is not used. The generator then converts the mechanical energy into electrical energy that can be deployed to a utility grid.

[0005] Wind turbine rotor blades generally include a body shell formed from two shell halves of a composite laminate material. The shell halves are generally manufactured using a molding process and then coupled together along corresponding ends of the rotor blade. Generally, the body shell is relatively lightweight and has structural properties (e.g., stiffness, bending resistance, and strength) that are not configured to withstand bending moments and other loads imposed on the rotor blade during operation.

[0006] In recent years, wind turbines used for wind power generation have increased in size to achieve improved power generation efficiency and increase the amount of power generated. Along with the increase in the size of wind turbines used for wind power generation, wind turbine rotor blades have also increased significantly in size (e.g., up to 55 meters in length), resulting in difficulties in integrated manufacturing and delivery and transportation of the blades to the site.

[0007] In this regard, the industry is developing segmented wind turbine rotor blades in which individual blade segments are manufactured and transported to the site for assembly into complete blades ("joined" blades). In certain configurations, the blade segments are joined together by a beam structure that extends spanwise from one blade segment into a receiving segment of another blade segment. For example, reference is made to U.S. Patent Publication No. 2015 / 0369211, which describes a first blade segment having a longitudinally extending beam structure that is structurally connected to a second blade segment at a receiving segment. The beam structure forms part of an internal support structure for the blade and includes a shear web connected to a suction side spar cap and a pressure side spar cap. A plurality of bolted joints are used to connect the beam structure to a receiving segment in a second blade segment, including spanwise bolts on an end face of the beam and at least one chordwise bolt passing through the beam structure that is spaced from a joint line between the blade segments.

[0008] Similarly, U.S. Patent Publication No. 2011 / 0091326 describes a joined blade in which a first blade portion and a second blade portion extend from a joint in opposite directions. Each blade portion includes a spar section that forms a structural component of the blade and is longitudinally extended, wherein the first blade portion and the second blade portion are structurally connected by a spar bridge that connects the spar sections. The spar bridge may be an extension of one of the spar sections that is received in a receiving spar section of the other blade portion. The construction also uses threaded bolts extending from the end faces of the spar to connect and tension the spar in the receiving spar section.

[0009] However, it has been found that the linked blade configuration is susceptible to increased vibration and noise generation caused by the joint. The associated deflection between the root end blade segment and the tip end blade segment results in a flapping direction offset between the shell components at the joint line. This situation is particularly present in linked blade designs that employ chord-wise bolts or pins spaced (spanwise) from the joint line to transfer loads from the chord-wise bolts to the blade shell. This span-wise spacing (combined with the differences in stiffness and orientation between the blade segments and the linked internal support structure) results in a flapping direction offset between the shell components.

[0010] In addition to the induced flapping direction deviation, torsional forces are also generated at the attachment structure, which generates a torsional deviation between the shell components, particularly at the trailing edge of the blade.

[0011] When air flows over the shell surface under loading conditions of the wind turbine, flapping direction deviation and / or twisting direction deviation at the joint line leads to the generation of turbulent vortices, which can significantly increase the vibration and noise generated at the joint line.

[0012] Therefore, an improved joint structure between blade segments joining blades that addresses the noted problems would be a beneficial advancement in the art. Summary of the invention

[0013] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0014] In one aspect, the present disclosure relates to a method for reducing noise and vibration in a joint structure between a first blade segment and a second blade segment connecting a wind turbine rotor blade. Each of the first blade segment and the second blade segment includes a shell member having a pressure side shell member and a suction side shell member. The method includes determining an actual deflection induced at a chord-wise joint line between the shell members of the first blade segment and the second blade segment at a load condition (under defined operating conditions) on the connecting wind turbine rotor blade, wherein the actual deflection is any one or a combination of a flap-wise deflection generated by a flap-wise force, a torsional deflection generated by a torsional force, or a yaw-wise deflection generated by a yaw-wise force. Based on these induced deflections, a modified structure of the joint structure is defined at an unloaded condition on the wind turbine rotor blade, which at least partially compensates for one or more of the actual deflection components at the load condition. The first blade segment and the second blade segment are then connected or connected with a modified structure of the joint structure, wherein at the load condition, the modified structure of the joint structure reduces one or both of the flap-wise deflection and the torsional deflection between the shell members of the first blade segment and the second blade segment.

[0015] The method is not limited to a specific joint structure between blade segments. However, in a specific embodiment, the joint structure includes a beam structure extending from a first blade segment in the span direction and a receiving section formed in a second blade segment for receiving the beam structure, wherein a modified configuration of the joint structure includes a change in the connection between the beam structure and the receiving section. For example, the first blade segment may be a tip end blade segment, and the second blade segment is a root end blade segment. The joint structure may include a chord-wise pin extending through the beam structure and the receiving section at a location spaced from the joint line in the span direction. The modified configuration of the joint structure may include an alternative location for the chord-wise pin that compensates for one or more of a flap-wise offset, a torsion-wise offset, or a yaw-wise offset at a loaded condition. The alternative location may be selected to produce one or more of an antagonistic flap-wise offset, an antagonistic torsion-wise offset, or an antagonistic yaw-wise offset at an unloaded condition.

[0016] In yet another embodiment of the method, the step of determining a modified configuration of the joint structure includes determining a combination of materials in the joint structure that may also contribute to reducing one or more of the flap-directed excursion, the torsion-directed excursion, or the yaw-directed excursion at the loaded condition. The combination of materials may be an independent modification to the joint structure, or may be combined with a change in the location of the chord-directed pin or other alterations to the joint structure. The change in material may include, for example, adding or removing material from the joint structure to achieve stiffness or torsion resistance that reduces one or more of the flap-directed excursion, the torsion-directed excursion, or the yaw-directed excursion at the loaded condition.

[0017] In a particular embodiment, the load / operating condition is a variable at a speed close to the rated output speed of the wind turbine on which the linked wind turbine rotor blade is used, and the flap direction offset, twist direction offset, or yaw direction offset at the load condition is based on an average of the corresponding offsets at the rated output speed over a range of wind speeds. This determination may be from actual measurements of an operating wind turbine, or may be made via computer modeling of the linked wind turbine blades at the load condition.

[0018] The present invention also includes a connected wind turbine rotor blade having a joint structure having the characteristics discussed above. Specifically, such a blade includes a first blade segment and a second blade segment extending in opposite directions from a chord-wise joint line, each of the blade segments having a pressure side shell component and a suction side shell component. The joint structure is disposed between the first blade segment and the second blade segment, wherein the joint structure includes a resisting offset at an unloaded condition on the rotor blade, the resisting offset compensating for one or more of a flap direction offset, a torsion direction offset, or a yaw direction offset at a loaded condition. With this construction, the joint structure reduces the noise and vibration generated by the connected wind turbine rotor blades at a loaded condition.

[0019] In a particular blade embodiment, the joint structure comprises a beam structure extending from a first blade segment in a spanwise direction and a receiving section formed in a second blade segment for receiving the beam structure. The first blade segment may be a tip end blade segment and the second blade segment is a root end blade segment. The joint structure may comprise a chord-wise pin extending through the beam structure and the receiving section at a location spaced from the joint line in a spanwise direction, wherein the chord-wise pin is located at a location that at least partially generates the deflection of the opposition at an unloaded condition.

[0020] In certain embodiments of the rotor blade, the joint structure includes a combination of materials that can also help reduce one or more of flap-directed excursions, torsion-directed excursions, or yaw-directed excursions at loaded conditions. The combination of materials can be a standalone modification to the joint structure, or can be combined with a change in the location of the chord-wise pin. The change in material can include, for example, adding or removing material from the joint structure to achieve stiffness or torsion resistance that reduces one or both of flap-directed excursions and torsion-directed excursions at loaded conditions.

[0021] The present invention also includes a connected wind turbine rotor blade having a sealing band structure that reduces blade vibration and noise at operating conditions of the wind turbine. The connected wind turbine rotor blade includes a first blade segment and a second blade segment extending in opposite directions from a chord-wise joint line, wherein each of the blade segments has a pressure side shell member and a suction side shell member. The sealing band is applied to the pressure side shell member and the suction side shell member along the chord-wise joint line. The sealing band has a side edge that is aligned parallel to the airflow over the pressure side shell member and the suction side member at the chord-wise joint line at a defined load / operating condition on the connected wind turbine blade. The edge of the band and the cross-sectional shape of the band define a raised profile relative to the surface of the shell member. By aligning the edge of the band parallel to the airflow over the blade, noise and blade vibration that would otherwise be caused by the presence of the band are minimized.

[0022] The sealing band may have a constant cross-sectional profile along its entire longitudinal length, wherein such a profile may include a relatively thick central section that tapers about opposite side edges of the band. In a particular embodiment, the sealing band may include a deformable intermediate spacer designed to protrude or fit between the first blade segment and the second blade segment along the chord-wise joint line. As discussed above, the spacer may be used to attenuate any one or combination of flap-, torsion-, or yaw-directed forces acting on the replacement blade tip segment.

[0023] In certain embodiments, the chord-wise joint line is also oriented parallel to the airflow over the pressure side shell member and the suction side shell member at load conditions. However, this embodiment may increase the complexity, time, and expense of the joint structure between the blade segments. Therefore, in another embodiment, the length of the chord-wise joint line is minimized and oriented substantially perpendicular to the leading edge of the connecting wind turbine blades. With this arrangement, the side edges of the sealing band are not parallel to the chord-wise joint line, but are maintained parallel to the airflow over the blade surface. With respect to this embodiment, the sealing band may include a deformable spacer, wherein the spacer is defined on the lower side of the sealing band in a non-parallel orientation relative to the side edges of the sealing band.

[0024] With respect to the above embodiment, the sealing band may be continuous and have a length so as to wrap around the pressure side shell member and the suction side shell member, wherein the opposite ends of the sealing band meet at the trailing edge of the wind turbine blade. In this embodiment, the spacers extend from the midpoint of the sealing band at opposite and equal angles.

[0025] In another embodiment, the sealing tape comprises a first tape segment applied to the pressure side shell component and a second tape segment applied to the suction side shell component, wherein the first tape segment and the second tape segment are joined at a first seam joining a leading edge of a wind turbine blade and a second seam joining a trailing edge of the wind turbine blade.

[0026] The sealing tape may be made of any suitable pliable material that can conform to the shape of the blade shell component, such as a natural or synthetic fiber mesh material, a vinyl or plastic material, a composite material, etc. The sealing tape may be applied to the blade shell component using any suitable adhesive. In a particular embodiment, the sealing tape includes a pre-applied adhesive on its underside for attachment to the pressure side shell component and the suction side shell component.

[0027] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] A complete and open disclosure of the present invention including its best mode for one skilled in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0029] Figure 1 showing a perspective view of a wind turbine that may utilize joined wind turbine blades according to the present disclosure;

[0030] Figure 2 A rotor blade having a first blade segment and a second blade segment and a joint structure connecting the blade segments is shown.

[0031] Figure 3 is a perspective view of an embodiment of a first blade segment having a joint structure;

[0032] Figure 4 is a perspective view of an embodiment of a second blade segment having a joint structure;

[0033] Figure 5 A perspective view of coupled wind turbine blades depicting flapping and torsional forces acting on the blades;

[0034] Figure 6A partial perspective view of a joint line between blade segments to illustrate the flapping direction induced offset between blade segments at the joint line;

[0035] Figure 7 A partial perspective view of a joint line between blade segments to illustrate the offset caused by the flapping direction and the twisting direction between the blade segments at the joint line;

[0036] Figures 8a to 8d is a sequential diagrammatic view of an embodiment for modifying a joint structure in a joined wind turbine blade to compensate for flap-direction induced deflection at a loading condition on the blade;

[0037] Figures 9a to 9d is a sequential diagrammatic view of an embodiment for modifying a joint structure in a joined wind turbine blade to compensate for deflections caused by a torsional orientation at a loading condition on the blade;

[0038] Fig.10 is a view of an embodiment of a joined wind turbine blade having a sealing strip according to additional aspects of the present invention;

[0039] Fig.11 is a view of an alternative embodiment of joined wind turbine blades having a sealing strip;

[0040] Fig.12 is a perspective view of an embodiment of a sealing tape;

[0041] Fig.13 is a perspective view of an alternative embodiment of a sealing tape;

[0042] Fig.14 is a lower side view of an embodiment of a sealing tape incorporated into a spacer structure;

[0043] Fig.15 A lower side view of a sealing tape configuration utilizing separate tape strips; and

[0044] Fig.16 is a partial perspective view of airflow over joined wind turbine blades having a sealing band in accordance with aspects of the present invention. DETAILED DESCRIPTION

[0045] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are shown in the accompanying drawings. Each example is provided by way of illustration of the present invention, without limiting the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature shown or described as part of an embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, it is intended that the present invention covers such modifications and variations within the scope of the appended claims and their equivalents.

[0046] In general, the present subject matter relates to joined wind turbine rotor blades having a modified joint structural configuration for compensating for or counteracting one or both of flapwise and torsional directional offsets between blade segments under loading conditions on the rotor blades. Using the present unique methods and rotor blade configurations, noise and vibration generated at the joint line between blade segments are reduced.

[0047] Now referring to the accompanying drawings, Figure 1 1 is a side view of an exemplary wind turbine 10 that can use linked wind turbine rotor blades according to an embodiment of the present invention. In this embodiment, the wind turbine 10 is a horizontal axis wind turbine. Alternatively, the wind turbine 10 can be a vertical axis wind turbine. In this embodiment, the wind turbine 10 includes a tower 12 extending from a support surface 14, a nacelle 16 mounted on the tower 12, a generator 18 positioned within the nacelle 16, a gearbox 20 coupled to the generator 18, and a rotor 22 rotationally coupled to the gearbox 20 using a rotor shaft 24. The rotor 22 includes a rotatable hub 26 and at least one rotor blade 28, at least one rotor blade 28 is coupled to the rotatable hub 26 and extends outwardly from the rotatable hub 26. As shown, the rotor blade 28 includes a blade tip 17 about a blade root 19.

[0048] Reference Figure 2 and Figure 3 , depicts a joined rotor blade 28 having a first blade segment 30 and a second blade segment 32 according to aspects of the present technology. The first blade segment 30 and the second blade segment 32 extend in opposite directions from a chord-wise joint line 34. Each of the blade segments 30, 32 includes a pressure side shell member 31 and a suction side shell member 33. The first blade segment 30 and the second blade segment 32 are connected by an internal support structure 36 extending into both blade segments 30, 32 to facilitate joining of the blade segments 30, 32. Arrow 38 shows that the segmented rotor blade 28 in the illustrated example includes two blade segments 30, 32, and these blade segments 30, 32 are joined by inserting the internal support structure 36 into the second blade segment 32.

[0049] In the depicted embodiment, the first blade segment includes a beam structure 40 that forms part of the internal support structure 36 and extends longitudinally (e.g., spanwise) for structural connection with the internal support structure 36 in the second blade segment 32. The beam structure 40 may be integrally formed with the first blade segment 30 as an extension protruding from a spar section 42, thereby forming an extended spar section. The beam structure 40 includes at least one interconnecting web 44 (e.g., a shear web) connected to a suction side spar cap 46 and a pressure side spar cap 48. In the illustrated embodiment, the beam structure 40 is formed as a box-type structure with opposing interconnecting webs 44.

[0050] The first blade segment 30 may include one or more first bolt joints (also referred to as "pins") toward a first end 54 of the beam structure 40. For example, the bolt 52 may be located on the end 54 of the beam structure 40 and oriented in the spanwise direction. The first blade segment 30 may also include a bolt joint slot 50, which is located on the beam structure 40 proximal to the chord-wise joint 34 and oriented in the chord-wise direction. There may be a bushing within the bolt joint slot 50, which is arranged to have a tight interference fit with a bolt tube or pin 53, which is used to connect the second blade segment 32 to the first blade segment 30. It should be appreciated that for the purpose of connecting the first blade segment 30 and the second blade segment 32 to each other, any combination of bolt tubes 52, 53 and bolt slots 50 may be constructed between the beam structure 40 and the receiving section 60 ( Figure 4 )between.

[0051] exist Figure 4 In the second blade segment 32, the internal support structure 36 includes a receiving section 60, which extends longitudinally (spanwise) within the second blade segment 32 for receiving the beam structure 40 of the first blade segment 30. The receiving section 60 includes a plurality of spar structural members 66, which extend longitudinally for connecting to the beam structure 40 of the first blade segment 30 along the length of the receiving section 60. Although in Figure 4 It is not depicted, but it is easy to understand that the receiving section 60 includes any combination of bolt slots 50 or bolts 52, 53 for interconnecting with corresponding bolts or slots of the beam structure 40. For example, a bolt slot is configured in the distal end (away from the chord-wise joint 34) of the receiving section 60 for receiving a bolt 52 provided on the end 54 of the beam structure 40.

[0052] Figure 5 1 and 2. The concept of describing a flap-directed force 71, a torsion-directed force 73, and a yaw-directed force 75 acting on a coupled wind turbine blade, wherein such forces may generate a flap-directed offset 70 ( 71 ) between shell members of a first blade segment 30 and a second blade segment 32, respectively, at a chord-wise joint 34. Figure 6), torsional direction offset 72( Figure 7 ), and the yaw direction offset 77( Figure 6 ). These deflection components 70, 72 and 77 may combine to cause an actual deflection 68 between the shell members. The flap direction force 71 tends to act uniformly across the chord-wise aspect of the first blade segment 30, causing the first blade segment 30 to substantially "bend" toward the second blade segment 32, and causing the shell member 31 to shift in a vertical direction 70 along the chord-wise joint 34. The twist direction force 73 tends to generate a twist of the first blade segment 30 relative to the second blade segment 32 along the span-wise axis of the blade, causing the shell member 31 to shift 72 in the twist direction of the chord-wise joint 34. The yaw direction force 75 tends to generate a lateral movement of the first blade segment 30 relative to the second blade segment 32 transverse to the span-wise axis of the blade, causing the shell member 31 to shift 77 in the yaw direction of the chord-wise joint 34. As explained above, at operational loads on the wind turbine (the loads on the turbine blades 28 when the wind turbine 10 is operating within the rated power output range of the power curve), these induced excursions 70 , 72 , 77 may generate excessive vibrations and noise in the blades 28 .

[0053] Figure 6 The actual offset 68 is depicted as a combination of the flap direction offset 70 and the yaw offset 77 . Figure 7 The actual offset 68 is depicted as a combination of a flap direction offset 70, a twist direction offset 72, and a yaw direction offset 77. It should be appreciated that the actual offset 68 may be caused by any one or a combination of the offset components 70, 72, and 77.

[0054] In addition, refer to Figure 5 , the blade 28 may be designed with an unloaded medium sweep inboard (closer to the blade root) relative to the blade pitch axis P, while the outboard section (closer to the blade tip) may sweep up to 10 degrees aft relative to the pitch axis P ( Figure 5 The angle θ in the figure).

[0055] In Figure 8A to Figure 8d , the determination and compensation of the flapping direction deviation 70 induced in the blade 28 under load is depicted according to aspects of the present disclosure. Similarly, in Figures 9a to 9d , the determination and compensation of a twist direction deflection 72 induced in the blade 28 under load is depicted. It should be appreciated that a similar approach may be employed for determining and compensating for a yaw direction deflection.

[0056] Reference Figure 8a and Figure 9a , depicts the joined blades 28 at the chord-wise joint 34 in an initial unloaded condition, wherein an initially negligible flap-wise or twist-wise deflection is induced in the blade at the joint 34 . Figure 8bThe same joined blade 28 is depicted at an initial loading condition (e.g., under load at rated power of the wind turbine), wherein a flapwise offset 70 between shell members of the first blade segment 30 and the second blade segment 32 at the chord-wise joint 34 is depicted. Similarly, Figure 9b A joined blade 28 is depicted under an initial loading condition (e.g., under a load near or at the rated power of the wind turbine), wherein a torsional directional offset 72 between shell components of a first blade segment 30 and a second blade segment 32 at a chord-wise joint 34 is depicted. The method includes determining the magnitude of one or both of the flap-wise offset 70 and the torsional directional offset 72. This determination may be accomplished by measuring the actual offset at the chord-wise joint 34 using a sensor, camera, etc. when the blade 28 (or similar blades) is under a load at a defined operating condition. Alternatively, the actual offset may be determined via a suitable modeling program. As mentioned, it is recognized that the actual offset 68 at the chord-wise joint 34 may be a combination of the flap-wise offset 70, the torsional directional offset 72, and the yaw directional offset 77. Furthermore, any one of these offsets may be negligible, with the actual offset being primarily due to one or a combination of the other offsets under the load on the blade 28.

[0057] Reference Figure 8c Based on the actual deflection induced at the joint 34 when the blade 28 is under load, a modified configuration of the joint structure 36 is defined on the blade 28 at the unloaded condition that will compensate for the induced deflection. The modified configuration may compensate for only one of the flap direction deflection 70 or the torsion direction deflection 72, but preferably compensates for both types of deflections 70, 72.

[0058] It should be appreciated that the present method encompasses scenarios where an actual offset 68 is determined empirically or via computer modeling for a particular type of blade at a defined location and under defined operating conditions, and that offset 68 is then used to define a modified configuration for a subsequent number of blades 28. It is not necessary to determine the actual offset and modified configuration on an individual basis for each blade 28.

[0059] As mentioned, the modified configuration of the joint structure 36 may include determining a combination of materials in the joint structure 36 that reduces one or both of the flapping direction excursion 70 and the torsional direction excursion 72 at the loaded condition. This combination of materials may be a separate modification to the joint structure, or may be combined with a change in the location of the components of the joint structure 36, as described below. The change in material may include, for example, adding or removing material from the joint structure 36 to achieve a stiffness or torsional resistance that reduces one or both of the flapping direction excursion 70 and the torsional direction excursion 72 at the loaded condition.

[0060] Figure 8c An embodiment is depicted in which the joint structure 36 is structurally modified in the unloaded state of the blade 26 to compensate for the induced flapping direction offset 70 ( Figure 8b ). In this embodiment, the joint structure 36 includes a beam structure 40 extending from the first blade segment 30 (the tip end segment) in the spanwise direction, and a receiving section 60 formed in the second blade segment 32 (the root end segment) for receiving the beam structure 40. The modified construction of the joint structure 36 includes a change in the connection between the beam structure 40 and the receiving section 60. The joint structure 36 includes a chord-wise pin 53 extending through the beam structure 40 and the receiving section 60 at a location spaced from the joint line 34 in the spanwise direction. An alternative location for the chord-wise pin 53 is determined that compensates for a flapping direction offset 70 at a loaded condition, wherein the alternative location is selected to produce an opposing flapping direction offset on the blade 28 at an unloaded condition. For example, as enlarged in FIG. 8C for illustrative purposes, the chord-wise pin 53 may be relative to Figure 8a The initial position depicted in FIG. 1 is lowered or raised toward the pressure side or suction side of the blade 28 to produce opposing flapping direction deviations.

[0061] Similarly, Fig.9c An embodiment is depicted in which the joint structure 36 is structurally modified in the unloaded state of the blade 26 to compensate for the induced torsional direction offset 72 ( Figure 9b ). The modified configuration of the joint structure 36 includes a change in the connection between the beam structure 40 and the receiving section 60. The joint structure 36 includes a chord-wise pin 53 extending through the beam structure 40 and the receiving section 60 at a location spaced from the joint line 34 in the spanwise direction. An alternate location for the chord-wise pin 53 is determined that compensates for the torsional deflection 72 at the loaded condition, wherein the alternate location is selected to produce an opposing torsional deflection on the blade 28 at the unloaded condition. For example, as exaggerated in FIG. 9C for illustrative purposes, the chord-wise pin 53 may be located from Figure 9a The initial orientation depicted in is rotated to Fig.9c The modified position in order to produce an opposing torsional direction offset.

[0062] Once modifications to the joint structure 36 are determined, the link blades 28 are assembled according to such modifications. Figure 8c The modified assembled link blade 28 is depicted in an unloaded state, while Figure 8d The blade 28 is depicted under load, wherein Figure 8b There is a flapping direction offset of 70 through Figure 8c Likewise, Fig.9c The modified assembled link blade 28 is depicted in an unloaded state, while Figure 9d The blade 28 is depicted under load, wherein Figure 9b The torsional direction offset 72 exists in Fig.9c Compensation for the modifications depicted in .

[0063] The present invention also includes joined wind turbine rotor blades 28 with a joint structure 36 having the properties discussed above.

[0064] Reference Figures 10 to 16 , the present invention also includes a joined wind turbine rotor blade 28 having a sealing strip 100 configuration that reduces blade vibration and noise at operating conditions of the wind turbine. The joined wind turbine rotor blade 28 includes a first blade segment 30 and a second blade segment 32 extending in opposite directions from a chord-wise joint line 34, wherein each of the blade segments 30, 32 has a pressure side shell member 31 and a suction side shell member 33. It should be appreciated that the sealing strip 100 configuration may be incorporated with respect to a joined wind turbine blade 28 having the above-described configuration with respect to Figure 2 9, and in this regard, Figure 2 The discussion up to Figure 9 is about Figures 10 to 16 As an alternative, the sealing tape 100 configuration may be used as a Figure 2 The modified joint structure of FIG. 9 joins separate components on a wind turbine blade.

[0065] The sealing band 100 is applied over the pressure side shell member 31 and the suction side shell member 33 so as to bridge across the chord-wise joint line 34. The sealing band 100 has a side edge 102 that projects to extend at least somewhat from the shell members 31, 33. The sealing band is oriented on the shell members 31, 33 so that at defined load conditions on the attached wind turbine blades 28, such as load conditions at the rated output speed of the wind turbine on which the attached wind turbine rotor blades 28 are used, the side edge 102 is aligned parallel to the airflow 104 over the shell members 31, 33 at the chord-wise joint line 34. The band edge 102 and the cross-sectional shape of the band 100 define a convex profile relative to the surface of the shell members 31, 33. By aligning the edge 102 of the band 100 parallel to the airflow 104 over the blade, noise and blade vibration that would otherwise be caused by the presence of the band 100 are minimized.

[0066] like Fig.12 and Fig.13 As depicted in FIG. 1 , the sealing strip 100 may have a constant cross-sectional profile 106 along its entire longitudinal length, wherein such a profile may include a relatively thicker central section 107 that tapers with respect to the opposite side edges 102 of the strip. In certain embodiments, the sealing strip 100 may include a deformable intermediate spacer 108 ( Fig.12 ) or wedge 109( Fig.13 ), which is formed on or attached to the underside 122 of the band 100 and is designed to protrude or fit between the first blade segment 31 and the second blade segment 32 along the chord-wise joint line 34, as shown by Fig.16 . The spacer 108 or wedge 109 is preferably formed of the same material as the band 100, or may be a separate component secured to the underside 122 of the band 100. The spacer 108 or wedge 109 is compressible (when forces acting on the blade tip segment 30 cause the above-discussed deflection between the blade tip segment 30 and the segment 32), and thus serves to attenuate any one or combination of flap-, torsion-, or yaw-directed forces acting on the replacement blade tip segment 30.

[0067] It should be appreciated that "load conditions" as used herein may also refer to defined operating conditions and circumstances determined or anticipated for a wind turbine that may affect the flow over the blades and therefore may require consideration of more than just the load at a point on the wind turbine power curve.

[0068] Reference Fig.10 In some embodiments, the chord-wise joint line 34 is also oriented parallel to the airflow 104 over the shell members 31, 33 at the loaded condition. However, this embodiment may increase the complexity, time, and expense of forming the joint structure between the blade segments 30, 32. Fig.11 In another embodiment depicted in FIG. 1 , the length of the chord-wise joint line 34 is minimized and oriented substantially perpendicular to the leading edge 74 of the joining wind turbine blade 28. With this arrangement, the side edge 102 of the sealing band 100 is not parallel to the chord-wise joint line 34, but is maintained parallel to the airflow 104 over the blade surface, as in FIG. Fig.11 With respect to this embodiment, the sealing strip 100 may include a deformable spacer 108 or wedge 109 , wherein the spacer 108 or wedge 109 is defined on the underside 122 of the sealing strip 100 in a non-parallel orientation relative to the side edge 102 of the sealing strip 100 .

[0069] Reference Fig.14 With respect to the above embodiments, the sealing tape 100 may be continuous and have a length so as to wrap around the pressure side shell member 31 and the suction side shell member 33, wherein the opposite ends of the sealing tape 100 are connected at the seam 126 ( Fig.10 In this embodiment, the spacers 108 or wedges 109 extend at opposite and equal angles from a midpoint 124 of the sealing band 100, the midpoint 124 corresponding to the relative location of the leading edge 74 when the band 100 is applied to the blade 28.

[0070] Reference Fig.11and Fig.15 In another embodiment, the sealing tape 100 includes a first tape segment 110 applied to the pressure side shell component 31 and a second tape segment 112 applied to the suction side shell component 33, wherein the first tape segment 110 and the second tape segment 112 are joined at a first seam 128 at the leading edge 74 of the wind turbine blade 28 and at a second seam 126 at the trailing edge 76 of the wind turbine blade 28.

[0071] The sealing tape 100 may be made of any suitable pliable material that can conform to the shape of the blade shell components 31, 33, such as natural or synthetic fiber web materials, vinyl or plastic materials, composite materials, etc. The sealing tape may be applied to the blade shell components using any suitable adhesive. In a particular embodiment, the sealing tape 100 includes a pre-applied adhesive layer 114 ( Fig.13 and Fig.16 ) for attachment to the pressure side shell member 31 and the suction side shell member 3.

[0072] This written description uses examples to disclose the invention (including the best mode) and also to enable those skilled in the art to practice the invention (including making and using any devices or systems and performing any incorporated methods). The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. If these other examples include structural elements that do not differ from the literal language of the claims, or if these other examples include equivalent structural elements that are not significantly different from the literal language of the claims, then these other examples are intended to be within the scope of the claims.

Claims

1. A connected wind turbine rotor blade (28), comprising: a first blade segment (30) and a second blade segment (32) extending in opposite directions from a chord-wise joint line (34), each of the blade segments having a pressure side shell member (31) and a suction side shell member (33); a sealing tape (100) applied to the pressure side shell member (31) and the suction side shell member (33) along the chord-wise joint line (34); and The sealing band (100) includes side edges (102) aligned parallel to the airflow (104) over the pressure side shell member (31) and the suction side shell member (33) at the chord-wise joint line (34) at defined load and operating conditions on the joined wind turbine rotor blade (28); Wherein the chord-wise joint line (34) is also oriented parallel to the airflow (104) over the pressure side shell member (31) and the suction side shell member (33) at the defined load and operating conditions.

2. The joined wind turbine rotor blade (28) according to claim 1, characterized in that The sealing strip (100) includes a constant cross-sectional profile (106) along its entire longitudinal length.

3. The joined wind turbine rotor blade (28) according to claim 2, characterized in that The sealing band (100) further includes a deformable spacer (108) protruding between the first blade segment (30) and the second blade segment (32) along the chord-wise joint line (34).

4. The joined wind turbine rotor blade (28) of claim 1, wherein: The chord-wise joint line (34) is oriented perpendicular to the leading edge (74) of the joined wind turbine blades such that the side edge (102) of the sealing band (100) is non-parallel to the chord-wise joint line (34).

5. The joined wind turbine rotor blade (28) according to claim 4, characterized in that The sealing band (100) further comprises a deformable spacer (108) which protrudes between the first blade segment (30) and the second blade segment (32) along the chord-wise joint line (34), the spacer being defined on the lower side (122) of the sealing band in a non-parallel orientation relative to the side edge (102) of the sealing band.

6. The joined wind turbine rotor blade (28) according to claim 5, characterized in that The sealing band (100) is continuous and includes a length so as to wrap around the pressure side shell member (31) and the suction side shell member (33), wherein opposite ends (103) of the sealing band meet at the trailing edge (76) of the attached wind turbine blade (28), and the spacers (108) extend at opposite and equal angles from a midpoint (124) of the sealing band (100).

7. The joined wind turbine rotor blade (28) of claim 5, wherein: The sealing tape (100) comprises a first tape segment (110) applied to the pressure side shell component (31) and a second tape segment (112) applied to the suction side shell component (33), the first tape segment and the second tape segment being joined at a first seam (126) at the leading edge (74) of the joined wind turbine blade and a second seam (128) at the trailing edge (76) of the joined wind turbine blade.

8. The joined wind turbine rotor blade (28) of claim 1, wherein: The sealing tape (100) includes a pre-applied adhesive (114) on its underside (122) for attachment to the pressure side shell component (31) and the suction side shell component (33).

9. The joined wind turbine rotor blade (28) of claim 1, wherein: The sealing strip (100) includes a constant cross-sectional profile (106) along its entire longitudinal length, the constant cross-sectional profile (106) having a tapered, convex middle portion (116) with respect to opposite side edges (102).

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