Systems and methods of assembling a rotor blade for use in a wind turbine

A method of assembling a rotor blade for use with a wind turbine. The method includes coupling a first sparcap to at least one first panel wall to form a first blade section, wherein the first sparcap has a first chordwise width. A second sparcap is coupled to at least one second panel wall to form a second blade section. The second sparcap has a second chordwise width that is larger than the first chordwise width. The first blade section is coupled to the second blade section to form the rotor blade.

BACKGROUND OF THE INVENTION

The embodiments described herein relate generally to a wind turbine rotor blade and, more particularly, to a sparcap system for a wind turbine rotor blade.

At least some known wind turbine rotor blades include two blade shell portions of fiber reinforced polymer. The blade shell portions are molded and then coupled together along cooperating edges using a suitable adhesive material. The blade shell portions typically include panel walls that are made using suitable, evenly distributed fibers, fiber bundles, or mats of fibers layered in a mold part. However, the panel walls are relatively light and have only low rigidity. Therefore, a stiffness and a rigidity, as well as a buckling strength, of the panel walls may not withstand the loads and forces exerted on the rotor blade during operation. To increase the strength of the rotor blade, the blade shell portions are reinforced by sparcaps laminated to the inner surface of the blade shell portions. Typically, the sparcaps extend substantially along a longitudinal length of the rotor blade. At least some known rotor blades include sparcaps with symmetrical cross-section widths and approximately equal cross-section areas. At least some known sparcaps are fabricated from suitable glass material.

Flapwise loads, which cause the rotor blade tip to deflect towards the wind turbine tower, are transferred along the rotor blade predominantly through the sparcaps. Further, with a continuously increasing length of wind turbine rotor blades in recent years, meeting stiffness requirements is a major concern in the structural design of the rotor blade. As such, conventional blade designs are either over-strengthened resulting in a heavier design or over-stiffened resulting in a costly design. In addition, conventional rotor blade designs include thicker panel walls and/or larger panel wall lengths so that panel walls are comparatively more expensive than sparcaps. At least some known wind turbine rotor blades include panel walls that are fabricated from suitable balsa material, which is relatively more expensive than sparcap material.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, a method of assembling a rotor blade for use with a wind turbine is provided. The method includes coupling a first sparcap to at least one first panel wall to form a first blade section, wherein the first sparcap has a first chordwise width. A second sparcap is coupled to at least one second panel wall to form a second blade section. The second sparcap has a second chordwise width that is larger than the first chordwise width. The first blade section is coupled to the second blade section to form the rotor blade.

In another aspect, a rotor blade for use with a wind turbine is provided. The rotor blade includes a first blade section that includes at least one first panel wall. A second blade section includes at least one second panel wall, and is coupled to the first blade section to form the rotor blade. A first sparcap is coupled to the first blade section and has a first chordwise width. A second sparcap coupled to the second blade section and has a second chordwise width that is greater than the first chordwise width.

In yet another aspect, a wind turbine is provided. The wind turbine includes a tower, a nacelle coupled to the tower, a hub rotatably coupled to the nacelle, and at least one rotor blade coupled to the hub. The rotor blade includes a first blade section that includes at least one first panel wall. A second blade section includes at least one second panel wall, and is coupled to the first blade section to form the rotor blade. A first sparcap is coupled to the first blade section and has a first chordwise width. A second sparcap coupled to the second blade section and has a second chordwise width that is greater than the first chordwise width.

The embodiments described herein facilitate assembling a rotor blade that meets rotor blade stiffness and deflection requirements with a reduced length of a panel wall. More specifically, the rotor blade described herein includes sparcaps that include asymmetric cross-section widths with approximately equal cross-section areas that provide a sufficient blade stiffness that enables the rotor blade to have a suitable tip deflection similar to conventional rotor blades. In addition, by providing sparcaps with asymmetric widths, a reduced amount of more expensive panel material is required to be included in a blade section, thereby reducing the overall costs of manufacturing the rotor blade.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments described herein include a wind turbine that includes at least one rotor blade that includes a panel wall having a length shorter than a length of panel wall of a conventional rotor blade. More specifically, in one embodiment, the rotor blade described herein includes sparcaps having asymmetrical cross-section widths with approximately equal cross-section areas that enable the rotor blade to have a stiffness and tip deflection similar to conventional rotor blades that include a panel wall having a greater length, and include sparcaps with symmetric cross-section widths.

FIG. 1is a perspective view of an exemplary wind turbine10. In the exemplary embodiment, wind turbine10is a horizontal-axis wind turbine. Alternatively, wind turbine10may be a vertical-axis wind turbine. In the exemplary embodiment, wind turbine10includes a tower12that extends from a supporting surface14, a nacelle16mounted on tower12, and a rotor18that is coupled to nacelle16. Rotor18includes a rotatable hub20and at least one rotor blade22coupled to and extending outward from hub20. In the exemplary embodiment, rotor18has three rotor blades22. In an alternative embodiment, rotor18includes more or less than three rotor blades22. In the exemplary embodiment, tower12is fabricated from tubular steel such that a cavity (not shown inFIG. 1) is defined between supporting surface14and nacelle16. In an alternative embodiment, tower12is any suitable type of tower having any suitable height.

Rotor blades22are spaced about hub20to facilitate rotating rotor18. Rotor blades22include a blade root portion24and a blade tip portion26, and are mated to hub20by coupling blade root portion24to hub20at a plurality of load transfer regions27. Load transfer regions27have a hub load transfer region and a blade load transfer region (both not shown inFIG. 1). Loads induced to rotor blades22are transferred to hub20by load transfer regions27.

In the exemplary embodiment, rotor blades22have a length L1that extends from blade root portion24to blade tip portion26. In one embodiment, length L1has a range from about 15 meters (m) to about 91 m. Alternatively, rotor blades22may have any suitable length that enables wind turbine10to function as described herein. For example, other non-limiting examples of blade lengths include 10 m or less, 20 m, and 37 m, or a length that is greater than 91 m. As wind strikes rotor blades22from a direction28, rotor18is rotated about an axis of rotation30. As rotor blades22are rotated and subjected to centrifugal forces, rotor blades22are also subjected to various forces and moments. As such, rotor blades22may deflect and/or rotate from a neutral, or non-deflected, position to a deflected position. A pitch adjustment system32rotates rotor blades22about a pitch axis34for adjusting an orientation of rotor blades22with respect to direction28of the wind. A speed of rotation of rotor18may be controlled by adjusting the orientation of at least one rotor blade22relative to wind vectors. In the exemplary embodiment, a pitch of each rotor blade22is controlled individually by a control system36. Alternatively, the blade pitch for all rotor blades22may be controlled simultaneously by control system36. Further, in the exemplary embodiment, as direction28changes, a yaw direction of nacelle16may be controlled about a yaw axis38to position rotor blades22with respect to direction28.

FIG. 2is a sectional view of an exemplary rotor blade100suitable for use with wind turbine10.FIG. 3is a cross-sectional view of exemplary rotor blade100along chordwise sectional line3-3inFIG. 2. Identical components illustrated inFIG. 3are labeled with the same reference numbers used inFIG. 2. Rotor blade100includes a first or root end102configured to facilitate mounting rotor blade100to hub20and a second or tip end104opposing root end102. A body106of rotor blade100extends between root end102and tip end104and along a longitudinal axis107. In one embodiment, rotor blade100includes a first blade section108, such as a suction side blade section, and an opposing second blade section110(shown inFIG. 3), such as a pressure side blade section, coupled to first blade section108to form rotor blade100. A spar114is coupled to and extends between first blade section108and second blade section110. In the exemplary embodiment, spar114extends almost the full longitudinal length of rotor blade100. Alternatively, spar114extends at least partly along the longitudinal length of rotor blade100. As used herein, the term “longitudinal length” refers to a length of body106along the longitudinal axis107of rotor blade100.

Referring toFIG. 3, in the exemplary embodiment, rotor blade100includes a first or suction sidewall120and a cooperating second or pressure sidewall122. Pressure sidewall122is coupled to suction sidewall120along a leading edge124and along an opposing trailing edge126. Suction sidewall120and pressure sidewall122are coupled together to define a cavity128between suction sidewall120and pressure sidewall122. Specifically, cavity128is bordered at least in part by an inner surface130of suction sidewall120and an inner surface132of pressure sidewall122. A blade skin134is coupled to a pressure sidewall outer surface136and to a suction sidewall outer surface138to form rotor blade100defining a contour of rotor blade100as shown in the cross-section views. Spar114is positioned within cavity128and extends between pressure sidewall122and suction sidewall120. Spar114includes a first or suction side sparcap142, a second or pressure side sparcap144, and at least one shearweb146that extends between suction side sparcap142and pressure side sparcap144. A nose bonding cap148is coupled to suction sidewall120and pressure sidewall122to form leading edge124. A trailing edge bonding cap150is coupled to suction sidewall120and pressure sidewall122to form trailing edge126.

In the exemplary embodiment, suction sidewall120includes a suction side trailing edge panel152coupled to suction side sparcap142, and a suction side leading edge panel154coupled to suction side sparcap142. Suction side trailing edge panel152is coupled to trailing edge bonding cap150and extends between trailing edge bonding cap150and suction side sparcap142. Suction side leading edge panel154is coupled to nose bonding cap148and extends between nose bonding cap148and suction side sparcap142.

Pressure sidewall122includes a pressure side trailing edge panel156and a pressure side leading edge panel158. Pressure side trailing edge panel156is coupled to pressure side sparcap144and extends between pressure side sparcap144and trailing edge bonding cap150. Pressure side leading edge panel158is coupled to pressure side sparcap144and extends between pressure side sparcap144and nose bonding cap148.

Suction side sparcap142and pressure side sparcap144each includes a cross-section area equal to a product of a chordwise thickness and a chordwise width as measured along a neutral axis160that extends from leading edge124to trailing edge126. In the exemplary embodiment, suction side sparcap142has a first cross-section area162. Pressure side sparcap144has a second cross-section area164that is approximately equal to first cross-section area162. Suction side sparcap142further has a first chordwise width166and a first maximum chordwise thickness168. Pressure side sparcap144has a second chordwise width170that is longer than first chordwise width166, and a second maximum chordwise thickness172that is less than first maximum chordwise thickness168.

In the exemplary embodiment, suction side sparcap142has an inner surface174that is positioned at a first distance d1from rotor blade neutral axis160. Pressure side sparcap144has an inner surface176that is positioned at a second distance d2from neutral axis160that is greater than first distance d1. The greater second distance d2enables pressure side sparcap144to compensate for a reduced stiffness as a result of a shorter maximum chordwise thickness172as compared to suction side sparcap142maximum chordwise thickness168.

One or more suction side core fillets178are coupled to suction side sparcap142, suction side trailing edge panel152, and/or to suction side leading edge panel154to provide a smooth surface-transition between suction side sparcap inner surface174and an inner surface180of suction side leading edge panel154, and between inner surface174and an inner surface182of suction side trailing edge panel152. One or more pressure side core fillets184are coupled to pressure side sparcap144, to pressure side leading edge panel158, and/or to pressure side trailing edge panel156for providing a smooth surface-transition between inner surface176of pressure side sparcap144and an inner surface186of pressure side leading edge panel158, and between inner surface176and an inner surface188of pressure side trailing edge panel156. In the exemplary embodiment, suction side core fillets178have a third maximum chordwise thickness190. Pressure side core fillets184have a fourth maximum chordwise thickness192that is less than third maximum chordwise thickness190.

FIGS. 4-6are cross-sectional views of alternative embodiments of rotor blade100. Identical components illustrated inFIGS. 4-6are labeled with the same reference numbers used inFIG. 3. Referring toFIG. 4, in an alternative embodiment, suction side sparcap cross-section area162is approximately equal to pressure side sparcap cross-section area164. Suction side sparcap142has a chordwise width194and pressure side sparcap144has a chordwise width196. Suction side sparcap142has a maximum chordwise thickness198and pressure side sparcap144has a maximum chordwise thickness200. In this alternative embodiment, suction side sparcap chordwise width194is greater than pressure side sparcap chordwise width196, and suction side sparcap maximum chordwise thickness198is less than pressure side sparcap maximum chordwise thickness200. Additionally, suction side core fillets178have a thickness202that is less than a thickness204of pressure side core fillets184.

Referring toFIG. 5, in a further alternative embodiment, suction side sparcap142is substantially symmetrical to pressure side sparcap144. Each of suction side sparcap142and pressure side sparcap144includes a width206and maximum chordwise thickness208that are approximately equal to each other. In this alternative embodiment, a third sparcap210is coupled to pressure sidewall122at pressure side trailing edge panel156. The addition of third sparcap210during rotor blade100assembly allows a length of pressure side trailing edge panel156to be shortened as compared to conventional rotor blades that include a panel wall having a greater length and sparcaps with symmetric cross-section widths. Alternatively, third sparcap210is coupled to suction sidewall120at suction side trailing edge panel152.

Referring toFIG. 6, in a further alternative embodiment, suction side sparcap142is substantially symmetrical to pressure side sparcap144. In this embodiment, third sparcap210is coupled to pressure sidewall122at pressure side leading edge panel158. The addition of third sparcap210during rotor blade100assembly allows a length of pressure side leading edge panel158to be shortened as compared to conventional rotor blades. Alternatively, third sparcap210is coupled to suction sidewall120at suction side leading edge panel154, which allows a length of suction side leading edge panel154to be reduced.

FIG. 7is a sectional view of an alternative rotor blade300.FIG. 8is a cross-sectional view of rotor blade300along chordwise sectional line8-8inFIG. 7. Identical components illustrated inFIG. 8are labeled with the same reference numbers used inFIG. 7. In this alternative embodiment, rotor blade300includes a spar302that extends from a root end304towards a tip end306, extending substantially along the full longitudinal length of rotor blade300. Spar302includes a suction side sparcap308and a pressure side sparcap310. Each of suction side sparcap308and pressure side sparcap310includes a first or root portion312positioned at or near rotor blade root end304, and a second or tip portion314positioned at or near rotor blade tip end306. Root portion312has a first chordwise width318. Tip portion314has a second chordwise width320that is less than first chordwise width318. In this embodiment, spar302includes a stepped width extending from rotor blade root end304to rotor blade tip end306along the longitudinal length of rotor blade300. Alternatively, spar302includes a tapered width extending from rotor blade root end304to rotor blade tip end306along the longitudinal length of rotor blade300.

FIG. 9is a flowchart of an exemplary method400for assembling wind turbine rotor blade100. In the exemplary embodiment, method400includes coupling402a first sparcap142to one or more panel walls to form a first blade section120. Second sparcap144is coupled404to one or more panel walls to form second blade section122. First blade section120is coupled406to second blade section122to form rotor blade100. Third sparcap210is optionally coupled408to one or more panel walls while forming first blade section or second blade section122.

The above-described systems and methods facilitate assembling a rotor blade that meets conventional rotor blade stiffness and deflection requirements with a reduced length of the panel wall. Panel walls are typically more expensive to manufacture than sparcaps and include a more expensive material. More specifically, the rotor blade described herein includes sparcaps that have asymmetric cross-section widths with approximately equal cross-section areas that provide a sufficient blade stiffness that enables the rotor blade to have a suitable tip deflection similar to conventional rotor blades and to satisfy strength, bending stiffness, and buckling stiffness requirements of known wind turbine rotor blades. In addition, by providing sparcaps with asymmetric cross-section widths, a reduced amount of more expensive panel material is required to be included in a blade section, thereby reducing the overall costs of manufacturing the rotor blade. As such, the cost of assembling a wind turbine is significantly reduced.

Exemplary embodiments of systems and methods for assembling a rotor blade for use in a wind turbine are described above in detail. The systems and methods are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the methods may also be used in combination with other rotor blade improvement systems and methods, and are not limited to practice with only the wind turbine systems as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many other rotor blade applications.