ROTOR BLADE AND WIND TURBINE

Abstract

A rotor blade of a wind turbine that has a Gurney flap, to an associated wind turbine, and to an associated method. A rotor blade for a wind turbine, having a rotor blade length, having a rotor blade depth which extends over the rotor blade length, having a rotor blade thickness which extends over the rotor blade length, and having a thickness of a trailing edge of the rotor blade, which thickness extends over the rotor blade length, said rotor blade comprising a Gurney flap, which has a height which extends over the rotor blade length, wherein the height of the Gurney flap is dimensioned according to the thickness of the trailing edge in such a way that a ratio of the height of the Gurney flap and the thickness of the trailing edge is between greater than 0% and 25%, in particular between 5% and 25%.

Claims

1. A rotor blade for a wind turbine comprising: a rotor blade rotor blade body having a rotor blade length, a rotor blade depth that extends over the rotor blade length, and a rotor blade thickness that extends over the rotor blade length, the rotor blade body having a thickness of a trailing edge, wherein the thickness extends over the rotor blade length a Gurney flap, having a height that extends over the rotor blade length, wherein the height of the Gurney flap is dimensioned according to the thickness of the trailing edge in such a way that a ratio of the height of the Gurney flap and the thickness of the trailing edge is between 0% and 25%.

2. The rotor blade as claimed in claim 1, comprising a rotor blade flange, wherein from the rotor blade flange, the ratio of the height of the Gurney flap and the thickness of the trailing edge increases to a maximum value.

3. The rotor blade as claimed in claim 1, wherein the maximum value of the ratio of the height of the Gurney flap and the thickness of the trailing edge is between 5% and 15% of a relative blade length.

4. The rotor blade as claimed in claim 1, wherein the Gurney flap is arranged on the rotor blade body between 3% and 35% of the relative blade length.

5. The rotor blade as claimed in claim 1, wherein the Gurney flap is arranged on a pressure side of the rotor blade.

6. The rotor blade as claimed in claim 1, wherein an angle between the height of the Gurney flap and a profile chord of the rotor blade is between 90° and 170°.

7. The rotor blade as claimed in claim 1, wherein, at a position of the rotor blade length, a ratio of the height of the Gurney flap and the rotor blade depth is greater than 1%.

8. The rotor blade as claimed in claim 1, wherein the ratio of the height of the Gurney flap and the thickness of the trailing edge is between 4% and 25%, in a range between 0% and 5% of the relative blade length, and/or 4% and 25%, in a range between 5% and 10% of the relative blade length; and/or 0% and 25% in a range between 10% and 15% of the relative blade length; and/or 0% and 23% in a range between 15% and 20% of the relative blade length; and/or 0% and 20% in a range between 20% and 25% of the relative blade length; and/or 0% and 15% in a range between 25% and 30% of the relative blade length; and/or 0% and 10% in a range between 30% and 35% of the relative blade length.

9. The rotor blade as claimed in claim 1 comprising a flat back profile with or without rounded edge regions, and the thickness of the trailing edge is defined as a distance between a profile contour of the pressure side and a profile contour of a suction side orthogonal to the profile chord.

10. The rotor blade as claimed in claim 1 comprising a closed profile, and wherein the thickness of the trailing edge is defined as the distance between a profile contour of the pressure side and a profile contour of the suction side orthogonal to the profile chord at that point of the rotor blade depth at which a free pressure-side flow prevails during operation.

11. The rotor blade as claimed in claim 1, comprising a transition region, wherein the transition region comprises a section with a flat back profile and a section with a circular-cylindrical profile, wherein the section with the circular-cylindrical profile faces the rotor blade flange, and wherein the Gurney flap is arranged in the transition region.

12. The rotor blade as claimed in claim 1, wherein the Gurney flap extends in a direction of the height from a root point to a tip point, and/or the Gurney flap has, orthogonal to a direction of the height, a thickness oriented substantially parallel to the profile chord of the rotor blade, wherein the Gurney flap extends in a longitudinal direction orthogonally to the direction of the height and orthogonally to the thickness, and an areal extent is formed by the extent in the longitudinal direction and the height.

13. The rotor blade as claimed in claim 1, comprising at least one of a blade adapter or a blade extension, wherein the at least one of the blade adapter or the blade extension has the rotor blade flange.

14. A wind turbine comprising a nacelle and a rotor blade as claimed in claim 1.

15. A wind farm comprising at least two wind turbines as claimed in claim 14.

16. A method for forming a rotor blade of a wind turbine, the method comprising: forming a rotor blade body having a rotor blade length, a rotor blade depth that extends over the rotor blade length, a rotor blade thickness that extends over the rotor blade length, and a thickness of a trailing edge of the rotor blade, wherein the thickness extends over the rotor blade length, wherein the forming comprises providing a Gurney flap having a height that extends over the rotor blade length, wherein the height of the Gurney flap is dimensioned according to the thickness of the trailing edge in such a way that a ratio of the height of the Gurney flap and the thickness of the trailing edge is between greater than 0% and 25%.

17. The method as claimed in claim 16 wherein the ratio is between 5% and 25%.

18. The rotor blade as claimed in claim 2 the is between 5% and 25%.

19. The rotor blade as claimed in claim 3 wherein the maximum value of the ratio of the height of the Gurney flap and the thickness of the trailing edge is between 6% and 12% of the relative blade length.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0055] Preferred exemplary embodiments will be discussed by way of example on the basis of the appended figures. In the figures:

[0056] FIG. 1 shows a schematic three-dimensional view of a wind turbine;

[0057] FIG. 2 shows a schematic three-dimensional view of an embodiment of a rotor blade;

[0058] FIGS. 3-5 show plan views of the rotor blade shown in FIG. 2;

[0059] FIG. 6 shows a schematic two-dimensional view of a further embodiment of a rotor blade with a flat back profile;

[0060] FIG. 7 shows a schematic two-dimensional view of a rotor blade with a flat back profile with rounded corners;

[0061] FIG. 8 shows a schematic two-dimensional view of a rotor blade with a closed profile; and

[0062] FIG. 9 shows a schematic view of a design region for the ratio of the height of the Gurney flap and the thickness of the trailing edge.

[0063] In the figures, identical or substantially functionally identical or similar elements are denoted by the same reference signs.

DETAILED DESCRIPTION

[0064] FIG. 1 shows a schematic three-dimensional view of a wind turbine 100. The wind turbine 100 has a tower 102 and a nacelle 104 on the tower 102. An aerodynamic rotor 106 having three rotor blades 108, which each have a rotor blade length R, and having a spinner 110 is provided on the nacelle 104. During the operation of the wind turbine 100, the aerodynamic rotor 106 is set in rotational motion by the wind and thereby also rotates an electrodynamic rotor or runner of a generator, which is coupled directly or indirectly to the aerodynamic rotor 106. The electric generator is arranged in the nacelle 104 and generates electrical energy.

[0065] The pitch angles of the rotor blades 108 can be varied by way of pitch motors at the rotor blade roots of the respective rotor blades 108. The rotor blades 108 have a thickness of a trailing edge, which thickness extends over the rotor blade length R. The rotor blades 108 furthermore have Gurney flaps (not visible here), which have a height which extends over the rotor blade length R. The height of the Gurney flaps is dimensioned according to the thickness of the trailing edges, specifically in such a way that a ratio of the height of the Gurney flaps and the thickness of the trailing edge is between greater than 0% and 25%, in particular between 5% and 25%.

[0066] FIGS. 2 to 5 show schematic three-dimensional views of a further embodiment of a rotor blade 200. The rotor blade 200 extends in a longitudinal direction L from a rotor blade flange 204 to a rotor blade tip (not shown). The rotor blade extends with a rotor blade depth T orthogonally to the longitudinal direction L and with a rotor blade thickness D orthogonally to the rotor blade length L and orthogonally to the rotor blade depth T.

[0067] In a region adjoining the rotor blade flange 204, the rotor blade 200 has a circular-cylindrical profile 210. On a side of the circular-cylindrical profile 210 that faces away from the rotor blade flange 204, the rotor blade 200 has a flat back profile 212. In a transition region consisting of a section with the circular-cylindrical profile 210 and of a section with the flat back profile 212, the rotor blade 200 has a Gurney flap 214. The Gurney flap 214 is arranged on the pressure side 206 of the rotor blade 200. In particular, the Gurney flap 214 is arranged in a manner adjoining a trailing edge 202 of the rotor blade 200.

[0068] FIG. 6 shows a schematic two-dimensional view of a further embodiment of a rotor blade 300 with a flat back profile. The rotor blade 300 extends in a rotor blade depth T from a leading edge 302 to a trailing edge 304. The rotor blade 300 is described geometrically inter alia by a profile chord 322. The profile chord 322 is defined as the connecting line between the central point of the trailing edge 304 and that point 324 of the leading edge 302 which is furthest away from the central point of the trailing edge 304.

[0069] The profile has a rounded geometry at the leading edge 302. The profile has a straight surface at the trailing edge 304. The trailing edge may alternatively also have two or more surfaces which are arranged at an angle to one another. In particular, the trailing edge may have two surfaces which include an angle with one another, wherein one of said surfaces includes an angle with the pressure side and the other surface includes an angle with the suction side. On the pressure side and on the suction side, said angles each form in particular a sharp end edge at which the attached flow departs from the profile. The trailing edge may also be of arched form. Trailing edges formed in this way are advantageously demoldable. Such a profile is referred to as flat back profile since the trailing edge 304 is substantially flat. In the case of a trailing edge 304 formed in this way, the thickness 310 of the trailing edge 304 can be determined directly by the spacing between the suction side 306 and the pressure side 308.

[0070] The Gurney flap 312 is arranged at the transition from the pressure side 308 to the trailing edge 304. The Gurney flap 312 extends from a root point 314 to a tip point 316. The root point 314 of the Gurney flap 312 is arranged on the rotor blade 300. The tip point 316 of the Gurney flap 312 is to be understood as meaning a distal end of the Gurney flap 312, and thus faces away from the rotor blade 300.

[0071] The Gurney flap 312 has a height 318. The height 318 is defined as the distance between the root point 314 and the tip point 316. The arrangement of the Gurney flap 312 is furthermore determined by an angle 320. The angle 320 between the height 318, or the direction of the height 318, of the Gurney flap 312 and the profile chord 322, which angle is determined proceeding from the leading edge 302, may in particular be between 90° and 170°. In the present exemplary embodiment, the angle 320 is approximately 100°.

[0072] The rotor blade 300′ shown in FIG. 7 differs from the rotor blade shown in FIG. 6 by the profile geometry at the trailing edge 304′. The profile geometry is distinguished by rounded corners. The thickness 310 of the trailing edge 304′ is understood as meaning the distance between the profile contour of the pressure side 308 and the profile contour of the suction side 306 orthogonal to the profile chord 322 at that point of the rotor blade depth T at which a free pressure-side flow prevails during operation.

[0073] FIG. 8 shows a rotor blade 300″ with a closed trailing edge 304″. The thickness 310 of the trailing edge 304″ is to be understood as meaning the distance between the profile contour of the pressure side 308 and the profile contour of the suction side 306 orthogonal to the profile chord 322 at that point of the rotor blade depth T at which a free pressure-side flow prevails during operation.

[0074] FIG. 9 shows a schematic view of a design region for the ratio of the height 318 of the Gurney flap 312 and the thickness 310 of a trailing edge 304, 304′, 304″. The relative blade length is plotted on the abscissa in a value range of 0% to 35%. The ratio of the height 318 of the Gurney flap 312 and the thickness 310 of the trailing edge 304, 304′, 304″ is plotted on the ordinate in a value range between 0% and 30%.

[0075] A first design region 400, which is defined by a first upper limit-value line 402 and a first lower limit-value line 404, is illustrated in the diagram. The upper limit-value line 402 of the first design region 400 is preferably characterized by the following relationship:

[00002]$f_{\max }\left(\frac{r}{R}\right)=-2.7777*{\left(\frac{z}{Z}\right)}^2+0.2813*\left(\frac{z}{Z}\right)+0.2421$

[0076] The lower limit-value line 404 of the first design region 400 is preferably characterized by the following relationship:

[00003]$f_{\min }\left(\frac{r}{R}\right)=-5.148*{\left(\frac{z}{Z}\right)}^2+0.5389*\left(\frac{z}{Z}\right)+0.0356$

[0077] In these relationships, r/R represents the relative radius position, this being the relative radius position with the rotor blade hub taken into consideration. Accordingly, the total rotor radius, with the rotor blade hub and the rotor blade length taken into consideration, is the reference length. The variable r is for example the distance to the considered position, in meters, from the axis of rotation of the rotor, and R is the sum of rotor blade length and distance from the blade flange to the axis of rotation. The ratio z/Z represents the relative blade length in the above-stated relationship. The variable z is for example the distance to the considered position, in meters, from the blade flange, and Z is the rotor blade length.

[0078] The second design region 410 is arranged within the first design region 400. The second design region is defined by the second upper limit-value line 412 and the second lower limit-value line 414.

REFERENCE SIGNS

[0079] 100 Wind turbine

[0080] 102 Tower

[0081] 104 Nacelle

[0082] 106 Rotor

[0083] 108 Rotor blades

[0084] 110 Spinner

[0085] 200 Rotor blade

[0086] 202 Trailing edge

[0087] 204 Rotor blade flange

[0088] 206 Pressure side

[0089] 210 Circular-cylindrical profile

[0090] 212 Flat back profile

[0091] 214 Gurney flap

[0092] 300, 300′, 300″ Rotor blade

[0093] 302 Leading edge

[0094] 304 Trailing edge

[0095] 306 Suction side

[0096] 308 Pressure side

[0097] 310 Thickness of the trailing edge

[0098] 312 Gurney flap

[0099] 314 Root point of the Gurney flap

[0100] 316 Tip point of the Gurney flap

[0101] 318 Height of the Gurney flap

[0102] 320 Angle

[0103] 322 Profile chord

[0104] 324 Leading-edge point

[0105] 400 First design region

[0106] 402 First upper limit-value line

[0107] 404 First lower limit-value line

[0108] 410 Second design region

[0109] 412 Second upper limit-value line

[0110] 414 Second lower limit-value line

[0111] D Rotor blade thickness

[0112] L Rotor blade length

[0113] T Rotor blade depth