ROTOR BLADE OF A WIND POWER INSTALLATION

Abstract

The present disclosure relates to a rotor blade of a wind power installation, at least comprising a first rotor blade component having: a first end for arranging on the wind power installation, and a second end for connecting to a second rotor blade component; a second rotor blade component having: a first end for arranging on the first rotor blade component, and a second end wherein the first rotor blade component can be connected to the second rotor blade component at a separating point to the rotor blade, wherein the rotor blade has an aerodynamically open profile at the separating point.

Claims

1. A rotor blade of a wind power installation comprising: a first rotor blade component having: a first end for arranging on the wind power installation, and a second end for connecting to a second rotor blade component, and a second rotor blade component having: a first end for arranging on the first rotor blade component, and a second end, wherein the first rotor blade component is configured to be connected to the second rotor blade component at a separating point to the rotor blade, and wherein the rotor blade has an aerodynamically open profile at the separating point.

2. The rotor blade as claimed in claim 1, wherein the rotor blade has a progression with a plurality of different profiles in the rotor blade longitudinal direction, each profile having a leading edge, a trailing edge, and flow surfaces on the pressure side and the suction side connecting the leading edge and trailing edge, and wherein the trailing edge in at least one portion in the rotor blade longitudinal direction, in which the separating point lies, is designed as a thick trailing edge and forms the aerodynamically open profile.

3. The rotor blade as claimed in claim 2, wherein the thick trailing edge is formed by flow surfaces on the pressure side and the suction side spaced apart on the trailing edge, wherein a space between the flow surface on the pressure side and on the suction side on the trailing edge is considered a thickness of the trailing edge.

4. The rotor blade as claimed in claim 3, wherein a change in the thickness of the trailing edge has a local maximum, wherein the local maximum lies in a region about the separating point, and wherein the region about the separating point lies between 15 percent and 40 percent of the length of the rotor blade starting from a rotor blade root and/or the region is smaller than 10 percent of the length of the rotor blade.

5. The rotor blade as claimed in claim 4, wherein a thickness of the trailing edge has a monotonically decreasing progression in the rotor blade longitudinal direction.

6. The rotor blade as claimed in claim 2, wherein the pressure side has a concave progression at the separating point in a region of the trailing edge.

7. The rotor blade as claimed in claim 6, wherein a camber of the pressure side at the separating point in the region of the trailing edge is greater in terms of amount than the camber of the suction side at the separating point in the region of the trailing edge.

8. The rotor blade as claimed in claim 2, wherein: a direct connection between the leading edge and the trailing edge is a chord and a length thereof as a profile depth, a greater distance between a profile surface on the pressure side and the suction side perpendicularly to the profile depth is a profile thickness, a ratio of profile thickness to profile depth is referred to as the relative thickness, and a progression of the relative thickness over the rotor blade length is a thickness progression and a change in the thickness progression in a region of the separating point has a local maximum.

9. The rotor blade as claimed in claim 8, wherein the change in the thickness progression is defined as a deviation of the thickness progression following the rotor blade longitudinal direction.

10. The rotor blade as claimed in claim 8, wherein a camber of the thickness progression changes direction in the region of the separating point, wherein the camber is defined as the second deviation of the thickness profile following the rotor blade longitudinal direction and the direction changes when an algebraic sign changes.

11. The rotor blade as claimed in claim 1, wherein the relative thickness at the separating point is between 40% and 80%.

12. The rotor blade as claimed in claim 1, wherein a relative position of a maximum profile thickness, relative to the chord, is a thickness reserve, wherein the thickness reserve at the separating point is smaller than 30%.

13. The rotor blade as claimed in claim 1, wherein: a connection of incircles of the profile is a camber line, wherein a curvature is defined as the distance of the camber line from, and perpendicularly to, the chord, and a progression of the curvature along the profile depth displays a maximum in the rear 50%, measured from the leading edge.

14. The rotor blade as claimed in claim 13, wherein an algebraic sign of the curvature changes in a front 70% of the profile depth, measured from the leading edge, in a region between 40% and 70% of the profile depth.

15. The rotor blade as claimed in claim 13, wherein a value of the curvature at the separating point at each position in the profile depth direction is between plus and minus 10% relative to the profile depth at the separating point.

16. The rotor blade of a wind power installation as claimed in claim 1, wherein the rotor blade has a length of at least 70 meters.

17. The rotor blade as claimed in claim 16, wherein a maximum profile depth of the rotor blade is at most 6.5% of a length of the rotor blade.

18. The rotor blade of a wind power installation as claimed in claim 1, wherein the rotor blade has at least one component, the component being chosen from a vortex generator, a Gurney flap, a splitter plate, and a boundary layer fence.

19. The rotor blade of a wind power installation as claimed in claim 1, wherein the first rotor blade component has a first length and the second rotor blade component has a second length, wherein the first length of the first rotor blade component is shorter than the second length of the second rotor blade component such that the separating point is arranged in a region of the rotor blade of between 20 percent and 35 percent of a length of the rotor blade.

20. A wind power installation comprising a tower and a rotor blade as claimed in claim 1.

21. A wind park comprising a plurality of wind power installations as claimed in claim 20.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0076] The present disclosure is explained in greater detail below with the help of the accompanying figures, wherein the same reference signs are used for the same or similar assemblies.

[0077] FIG. 1 shows schematically and by way of example a perspective view of a wind power installation.

[0078] FIG. 2 shows schematically and by way of example a rotor blade of a wind power installation, in particular in three views.

[0079] FIG. 3 shows schematically and by way of example a profile of a rotor blade of a wind power installation at a separating point of the rotor blade, in particular in cross section.

[0080] FIG. 4 shows schematically and by way of example a progression of part of a profile of a rotor blade of a wind power installation along a length of the rotor blade.

[0081] FIG. 5 shows schematically and by way of example a progression of a thickness of the trailing edge and an associated trailing edge along a length of the rotor blade.

DETAILED DESCRIPTION

[0082] FIG. 1 shows schematically and by way of example a perspective view of a wind power installation 100. The wind power installation 100 is designed as a lift-based wind turbine with a horizontal axis and three rotor blades 200 on the windward side, in particular as a horizontal rotor. The wind power installation 100 has a tower 102 and a nacelle 104.

[0083] An aerodynamic rotor 106 with a hub 110 is arranged on the nacelle 104. Three rotor blades 200 are arranged on the hub 110, particularly symmetrically to the hub 110, preferably offset by 120°. The rotor blades 200 are preferably configured as described above and/or below.

[0084] FIG. 2 shows schematically and by way of example a rotor blade 200 of a wind power installation, as shown in FIG. 1, for example, in three views 200A, 200B, 200C.

[0085] The rotor blade 200 has a leading edge 202, a trailing edge 204, a suction side 206, a pressure side 208 and a length 1 r. In the first view 200A the rotor blade 200 in this case is shown from above, so with a view to the suction side 206.

[0086] In the second view 200B, the rotor blade 200 is shown from behind, so with a view to the trailing edge 204.

[0087] In the third view 200C, the rotor blade 200 is shown from below, so with a view to the pressure side 208.

[0088] The rotor blade 200 is designed as a two-part rotor blade 200, namely made up of a first rotor blade component 210 and a second rotor blade component 220, which can be assembled at a separating point 230 into the actual rotor blade 200. Functional or structural measures are needed for this purpose, for example, which extend from the separating point into the rotor blade components 210, 220, in particular in a region B.sub.230 about the separating point.

[0089] For transport reasons, the rotor blade 200 is typically divided into individual rotor blade components 210, 220, transported to the erection site of the wind power installation 100 and assembled on site. For this purpose, structural precautions have to be taken at the separating point 230, for example thicker material layers, in order to guarantee a reliable connection on site by bolts or by adhesive bonding, for example.

[0090] Consequently, it is usually unavoidable for a greater weight, and possibly even further unwanted, for example aerodynamic effects, such as disadvantageous induction factors or elasticities, for example, to occur in the region of the separating point 230, so in the region B.sub.230. The present disclosure acknowledges these disadvantages in the use of divided rotor blades and enables the most efficient rotor blade possible to be created under these marginal conditions which are taken as given.

[0091] The first rotor blade component 210 and the second rotor blade component 220 are connected to one another, particularly along the length, in other words so that the rotor blade 200 has a length 1 r which is substantially made up of the length l.sub.1 of the first rotor blade component 210 and the length l.sub.2 of the second rotor blade component 220.

[0092] The first rotor blade component 210 comprises a first end 212 for arranging on a blade connection of the wind power installation 100 and a second end 214 which is connected, in particular, to the first end 222 of the second rotor blade component 220. The first rotor blade component 210 may also be referred to as the rotor blade component close to the hub.

[0093] The second rotor blade component 220 comprises a first end 222 which is connected to the second end 214 of the first rotor blade component 214 and a second end 224 which can also be referred to as the rotor blade tip.

[0094] The second rotor blade component 220 is preferably substantially longer than the first rotor blade component 210, in particular such that the separating point lies in a region between 15 percent and 40 percent of the length l.sub.r of the rotor blade 200.

[0095] In addition, the rotor blade has optional serrations 240 on the trailing edge 206, in particular on the second rotor blade component 220, and also a Gurney flap 250 on the pressure side 208. The Gurney flap 250 extends particularly preferably both over part of the first rotor blade component 210 and over part of the second rotor blade component 220 and is therefore arranged in the region of the separating point 230, in particular.

[0096] The rotor blade 200 also has, in particular, an aerodynamically open profile (P) at the separating point 230, as shown in FIG. 3, for example.

[0097] FIG. 3 shows schematically and by way of example a profile P.sub.230 of a rotor blade, for example as shown in FIG. 2, at a separating point 230 of the rotor blade in a view 230′, in particular in cross section.

[0098] The profile P.sub.230 of the rotor blade 200 at the separating point 230 can therefore be seen from FIG. 3, in particular.

[0099] Particularly in the region of the separating point 230, the profile of the rotor blade 200 is not closed; in this example the rear edge has a finite thickness d.sub.HK. This means, in particular, that a flow-off point 270 on the suction side 206 and a flow-off point 272 on the pressure side 208 are spaced apart from one another at a distance of d.sub.HK on the trailing edge.

[0100] While a traditional “thick trailing edge” is shown in FIG. 3, in which the trailing edge is virtually perpendicular to the profile depth t and in which a sharp edge is provided to the respective flow-off points on the pressure side 208 and suction side 206, an aerodynamically open profile of the present invention is not limited to this.

[0101] The shape of the trailing edge may also be curved and is not limited to a straight line. The direction of the trailing edge may also deviate from a direction which is perpendicular to the profile depth. Finally, there is also no need for an acute transition between the trailing edge and the pressure side 208 or else the suction side 206. For example, a continuous or rounded transition may also be provided. The thickness of the trailing edge d.sub.HK is then determined as the space between the local camber maximums in each case on the pressure side 208 or the suction side 206, which then define the respective flow-off points 270, 272.

[0102] To provide a better understanding and, in particular, in order to illustrate the relationships described herein, the view 230′ is supplemented by a Cartesian coordinate system. In this case, the local profile depth t.sub.base is plotted as a percentage on the x-axis of the coordinate system. In addition, the local profile thickness dbase is plotted as a percentage on the y-axis of the coordinate system, particularly in relation to the profile depth.

[0103] Both the second end 214 of the first rotor blade component 210 and the first end 222 of the second rotor blade component 220 preferably exhibit the profile P.sub.230. This particularly enables a form fit of the two rotor blade components 210, 220 at the separating point 230 of the rotor blade 200.

[0104] The profile P.sub.230 is aerodynamically open, i.e., the upper side 206 and the lower side 208 of the rotor blade are spaced apart from one another at the trailing edge 204 by a thickness d.sub.HK, for example by 1.5 m or as shown in FIG. 4.

[0105] The profile P.sub.230 has a chord t which runs directly between the leading edge 202 and the trailing edge 204.

[0106] The profile P.sub.230 has, in addition, a profile thickness d, the local maximum d.sub.max of which lies at approx. 22 percent of the profile depth. This means, in particular, that the rotor blade has its maximum thickness at approx. 22 percent profile depth. The distance between the leading edge 202 and the point of the maximum thickness d.sub.max of the profile P.sub.230 is also referred to as the thickness reserve x.sub.d. The ratio of the thickness reserve x.sub.d to the profile depth t is, in addition, also referred to as the relative thickness reserve x.sub.d′.

[0107] At the separating point 230, or in the region B.sub.230 of the separating point 230, the rotor blade 200 has a material thickening M+, which can also be referred to as the preform thickening. The material thickening M+ is preferably more than 0.2 m and less than 1.0 m, preferably between 0.3 m and 0.7 m, in particular approx. 0.5 m. The material thickening M+ in this case should be understood as a structural thickening overall, which may extend both outwardly in a profile-enlarging manner, so as a contour thickening, but also to within the profile.

[0108] The rotor blade 200 also has only a slight camber at the separating point 230 or in the region B230 of the separating point 230. The slight camber is illustrated by the flat-running camber line s.

[0109] In addition, at the separating point 230, or in the region B230 of the separating point 230, the rotor blade 200 has a back swing, in other words a negative camber, which is illustrated by the negative progression of the camber line. The camber line s therefore has at least one change in algebraic sign, in particular in a region between 40 percent and 70 percent of the length l.sub.r of the rotor blade.

[0110] FIG. 4 shows schematically and by way of example a progression of the thickness d.sub.HK of the trailing edge 204 over the length 1 r of the rotor blade 200.

[0111] The trailing edge 204 of the rotor blade comes up to the region B.sub.230 of the separating point, for example up to 1.5 m, where it reaches its maximum, for example right at the separating point. The trailing edge then tapers to 0 m, for example with a 45 m blade length.

[0112] This means, in particular, that the profile P of the rotor blade is open up to a 45 m blade length and is then closed up to the blade tip at 100 m. The profile P of the rotor blade 200 is therefore only open in sections and, in particular, at the separating point 230.

[0113] FIG. 5 shows schematically and by way of example an alternative progression of the thickness d.sub.HK of the trailing edge 204 over the length l.sub.r of the rotor blade 200 and also the associated derivative d.sub.HK/d.sub.r. Unlike the progression in FIG. 4, the thickness d.sub.HK decreases monotonically, so that the maximum is already configured at, or in the environment of, the blade connection.

[0114] To begin with, there is a comparatively sharp decrease in the thickness of the trailing edge in a region 502, said trailing edge flattening out in a region 504 and then becoming thicker again in a region 506. In a region 508, the thickness of the trailing edge is zero, meaning that the aerodynamic profile is closed there.

[0115] The solution according to the invention can be seen particularly clearly in the lower or negative part of FIG. 5, in which the derivative d.sub.HK/d.sub.r is shown. The derivative or change in thickness of the trailing edge d.sub.HK/d.sub.r is negative over the entire rotor blade length, in other words, the thickness of the trailing edge decreases monotonically. The separating point 230 is configured in the region 512, in which the change in thickness of the trailing edge d.sub.HK/d.sub.r exhibits a local maximum.

[0116] Compared with this, the thickness of the trailing edge in the two surrounding regions 510 and 514 is greater, in other words the change in thickness of the trailing edge d.sub.HK/d.sub.r in the regions 510 and 514 is greater in terms of amount. Since the thickness of the trailing edge is zero in the region 508, the change in thickness of the trailing edge d.sub.HK/d.sub.r in the corresponding region 516 is likewise zero.

LIST OF REFERENCE SIGNS

[0117] 100 Wind power installation

[0118] 102 Tower

[0119] 104 Nacelle, in particular of the wind power installation

[0120] 106 Aerodynamic rotor, in particular of the wind power installation

[0121] 110 Nacelle, in particular of the wind power installation

[0122] 200 Rotor blade, in particular of the wind power installation

[0123] 200A Rotor blade, in particular in a first view

[0124] 200B Rotor blade, in particular in a second view

[0125] 200C Rotor blade, in particular in a third view

[0126] 202 Leading edge, in particular of the rotor blade

[0127] 204 Trailing edge, in particular of the rotor blade

[0128] 206 Upper side, in particular of the rotor blade

[0129] 208 Lower side, in particular of the rotor blade

[0130] 210 First rotor blade component

[0131] 212 First end, in particular of the first rotor blade component

[0132] 214 Second end, in particular of the first rotor blade component

[0133] 220 Second rotor blade component

[0134] 222 First end, in particular of the second rotor blade component

[0135] 224 Second end, in particular of the second rotor blade component

[0136] 230 Separating point of the rotor blade

[0137] 230′ View of the separating point

[0138] 240 Serration

[0139] 250 Gurney flap

[0140] 400 Progression of the thickness of the trailing edge over the length of the rotor blade

[0141] B230 Region of the separating point

[0142] d Profile thickness

[0143] d.sub.base Local profile thickness

[0144] d.sub.max Maximum local profile thickness

[0145] d.sub.HK Thickness of the trailing edge

[0146] l.sub.r Length of the rotor blade

[0147] l1 Length of the first rotor blade component

[0148] l2 Length of the second rotor blade component

[0149] M+ Material thickening, in particular at the separating point

[0150] P Profile of the rotor blade

[0151] P.sub.230 Profile of the rotor blade at the separating point

[0152] s Camber line

[0153] t Profile depth of the rotor blade

[0154] t.sub.base (Local) percentage profile depth

[0155] x.sub.d Thickness reserve

[0156] x.sub.d′ Relative thickness reserve

[0157] The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.