A LEADING EDGE DEVICE, METHODS OF MANUFACTURING AND INSTALLING THE LEADING EDGE DEVICE AND A WIND TURBINE BLADE

Abstract

This invention relates to a leading edge device, a wind turbine blade, a method of manufacturing the leading edge device and a method of installing the leading edge device. The leading edge device comprises an erosion shield having an inner surface and an outer surface. The leading edge device further comprises a number of airflow modifying elements each having a local outer surface and a local inner surface. The airflow modifying elements has a 2D-profile or a 3D-profile extending in the circumference direction and/or in the longitudinal direction.

Claims

1. A leading edge device for a wind turbine blade or a blade section, comprising an erosion shield extending in a longitudinal direction from a first end to a second end and further in a circumference direction from a first edge to a second edge, the erosion shield has an inner surface and an opposite facing outer surface arranged between said first and second ends, wherein the erosion shield is configured to be attached to a leading edge surface of the wind turbine blade characterised in that at least one airflow modifying element projects from said outer surface, the at least one aerodynamic element having a first profile, wherein said at least one airflow modifying element and said erosion shield are integrally formed.

2. The leading edge device according to claim 1, characterised in that said at least one airflow modifying element extends along the outer surface in at least the length or circumference direction, wherein said first profile has a local thickness extending from said outer surface to a local outer surface of the at least one airflow modifying element.

3. The leading edge device according to claim 1, characterised in that said first profile forms a substantially two-dimensional shaped body extending substantially in the circumference direction.

4. The leading edge device according to claim 1, characterised in that said first profile forms a substantially three-dimensional shaped body extending in the longitudinal direction and further in the circumference direction.

5. The leading edge device according to claim 3, characterised in that said body is covered with a protective coating and/or covered with a laminate of layers.

6. The leading edge device according to claim 1, characterised in that said at least one airflow modifying element comprises an array of airflow modifying elements arranged along the outer surface.

7. The leading edge device according to claim 6, characterised in that the first profile of said array of airflow modifying elements varies along the longitudinal direction and/or the circumference direction.

8. A wind turbine blade for a wind turbine, the wind turbine blade comprising at least one blade section extending in a longitudinal direction from a blade root or a tip end to an opposite end and further in a chordwise direction from a leading edge to a trailing edge, the wind turbine blade having a length of at least 35 meters measured between the blade root and the tip end, wherein the wind turbine blade has a first side surface defining a pressure side and a second side surface defining a suction side, wherein a leading edge surface is arranged between the first and second side surfaces, characterised a leading edge device according to claim 1 is arranged at said leading edge surface.

9. A method of manufacturing a leading edge device, comprising the steps of: providing an erosion shield extending in a longitudinal direction from a first end to a second end and further in a circumference direction from a first edge to a second edge, the erosion shield has an inner surface and an opposite facing outer surface arranged between said first and second ends, wherein the erosion shield is configured to be attached to a leading edge surface of the wind turbine blade, providing at least one airflow modifying element comprising a body with a first profile, the body having at least one local outer surface, integrating said erosion shield and said at least one airflow modifying element to form the leading edge device such that at least one airflow modifying element projects from said outer surface of the erosion shield.

10. The method according to claim 9, characterised in that said erosion shield and said at least one airflow modifying element are manufactured as a single piece in a common process, or as individual pieces in separate processes.

11. The method according to claim 9, characterised in that at least a part of the at least one airflow modifying device is manufactured by three-dimensional printing and/or by three-dimensional machining of a base element.

12. The method according to claim 10, characterised in that the at least one airflow modifying element is sandwiched between layers of the erosion shield or attached to a layer of the erosion shield.

13. The method according to claim 12, characterised in that the method further comprises at least: applying a protective coating over at least one of said outer surface and said at least one local outer surface, or laying up at least one outer layer of a protective material over at least one of said outer surface and said at least one local outer surface.

14. A method of installing a leading edge device on a wind turbine blade, the method comprising the steps of: providing a leading edge device according to claim 1, preparing a leading edge surface on at least blade section of the wind turbine blade for attachment of the leading edge device, positioning the leading edge device on said leading edge surface and attaching the leading edge device to said wind turbine blade.

15. The method according to claim 14, characterised in that the method further comprises the step of: removing an old leading edge device or an old erosion shield from the wind turbine blade prior to preparing said leading edge surface.

Description

DESCRIPTION OF DRAWINGS

[0097] The invention is explained in detail below with reference to embodiments shown in the drawings, in which

[0098] FIG. 1 shows a wind turbine,

[0099] FIG. 2 shows an exemplary embodiment of the wind turbine blade having a base aerodynamic profile,

[0100] FIG. 3 shows a leading edge device for attachment to the wind turbine blade with a first embodiment of the first and second edges,

[0101] FIG. 4 shows the leading edge device with a second embodiment of the first and second edges,

[0102] FIG. 5 shows the leading edge device configured for attachment to the tip end,

[0103] FIG. 6 shows a second embodiment of the airflow modifying element,

[0104] FIG. 7 shows a third embodiment of the airflow modifying element,

[0105] FIG. 8 shows an alternative third embodiment of the airflow modifying element,

[0106] FIG. 9 shows the wind turbine blade with a number of leading edge extending along the leading edge,

[0107] FIG. 10 shows a cross-sectional view of a first embodiment of the erosion shield and the airflow modifying elements,

[0108] FIG. 11 shows a cross-sectional view of a second embodiment of the erosion shield and the airflow modifying elements,

[0109] FIG. 12 shows a cross-sectional view of a third embodiment of the erosion shield and the airflow modifying elements,

[0110] FIG. 13 shows a cross-sectional view of a fourth embodiment of the erosion shield and the airflow modifying elements,

[0111] FIG. 14 shows a cross-sectional view of a fifth embodiment of the airflow modifying elements, and

[0112] FIG. 15 shows an exemplary method of installing the leading edge device on the wind turbine blade.

LIST OF REFERENCES

[0113] 1. Wind turbine [0114] 2. Wind turbine tower [0115] 3. Nacelle [0116] 4. Hub [0117] 5. Wind turbine blades [0118] 6. Pitch bearing [0119] 7. Blade root [0120] 8. Tip end [0121] 9. Leading edge [0122] 10. Trailing edge [0123] 11. Blade shell [0124] 12. Pressure side [0125] 13. Suction side [0126] 14. Blade root portion [0127] 15. Aerodynamic blade portion [0128] 16. Transition portion [0129] 17. Blade length of wind turbine blade [0130] 18. Chord length of wind turbine blade [0131] 19. Leading edge device [0132] 20. Erosion shield [0133] 21. Airflow modifying elements [0134] 22. First end [0135] 23. Second end [0136] 24. First edge [0137] 25. Second edge [0138] 26. Inner surface [0139] 27. Outer surface [0140] 28. Serrations [0141] 29. Further airflow modifying element [0142] 30. Body [0143] 31. Inner layer [0144] 32. Outer layer [0145] 33. Profile [0146] 34. Old erosion shield [0147] 35. Old leading edge device [0148] 36. Leading edge surface [0149] 37. Recess

[0150] The listed reference numbers are shown in abovementioned drawings where no all reference numbers are shown on the same figure for illustrative purposes. The same part or position seen in the drawings will be numbered with the same reference number in different figures.

DETAILED DESCRIPTION OF THE DRAWINGS

[0151] FIG. 1 shows a modern wind turbine 1 comprising a wind turbine tower 2, a nacelle 3 arranged on top of the wind turbine tower 2, and a rotor defining a rotor plane. The nacelle 3 is connected to the wind turbine tower 2, e.g. via a yaw bearing unit. The rotor comprises a hub 4 and a number of wind turbine blades 5. Here three wind turbine blades are shown, but the rotor may comprise more or fewer wind turbine blades 5. The hub 4 is connected to a drive train, e.g. a generator, located in the wind turbine 1 via a rotation shaft.

[0152] The hub 4 comprises a mounting interface for each wind turbine blade 5. A pitch bearing unit 6 is optionally connected to this mounting interface and further to a blade root of the wind turbine blade 5.

[0153] FIG. 2 shows a schematic view of the wind turbine blade 5 which extends in a longitudinal direction from a blade root 7 to a tip end 8. The wind turbine blade 5 further extends in a chordwise direction from a leading edge 9 to a trailing edge 10. The wind turbine blade 5 comprises a blade shell 11 having two opposite facing side surfaces defining a pressure side 12 and a suction side 13 respectively. The blade shell 11 further defines a blade root portion 14, an aerodynamic blade portion 15, and a transition portion 16 between the blade root portion 14 and the aerodynamic blade portion 15.

[0154] The blade root portion 14 has a substantially circular or elliptical cross-section (indicated by dashed lines). The blade root portion 14 together with a load carrying structure, e.g. a main laminate combined with a shear web or a box beam, are configured to add structural strength to the wind turbine blade 5 and transfer the dynamic loads to the hub 4. The load carrying structure extends between the pressure side 12 and the suction side 13 and further in the longitudinal direction.

[0155] The blade aerodynamic blade portion 15 has an aerodynamically shaped cross-section (indicated by dashed lines) designed to generate lift. The cross-sectional profile of the blade shell 11 gradually transforms from the circular or elliptical profile into the aerodynamic profile in the transition portion 16.

[0156] The wind turbine blade 5 has a blade length 17 of at least 35 metres, preferably at least 50 metres, measured in the longitudinal direction. The wind turbine blade 5 further has a chord length 18 as function of the blade length 17 measured in the chordwise direction, wherein the maximum chord length is found between the blade aerodynamic blade portion 15 and the transition portion 16.

[0157] FIG. 3 shows a leading edge device 19 for attachment to the wind turbine blade 5 which comprises an erosion shield 20 and a number of airflow modifying elements 21. The erosion shield 20 extends from a first end 22 to a second end 23 in a longitudinal direction and further from a first edge 24 to a second edge 25 in a circumference direction. The erosion shield 20 has an inner surface 26 facing a leading edge surface (shown in FIG. 15) of the wind turbine blade 5 and an opposite facing outer surface 27. The inner surface 26 is shaped to conform to the blade surface of the leading edge area.

[0158] The airflow modifying elements 21 project from the outer surface 27 and each have a local outer surface 27′. Each airflow modifying element 21 has a body with an aerodynamic profile having a local length, a local width and a local height.

[0159] Here, the first and second edges 24, 25 are formed as straight edges extending in the longitudinal direction of the leading edge device 19.

[0160] FIG. 4 shows the leading edge device 19 with a second embodiment of the first and second edges 24′, 25′. Here, a number of serrations 28 are distributed along the longitudinal direction and project from the first and second edges 24′, 25′, respectively, towards the trailing edge 10. The serrations 28 are integrally formed by the erosion shield 20. The serrations 28 are shaped to improve the airflow over the first and second edges 24, 25.

[0161] The leading edge devices 19 of FIGS. 3 and 4 are configured to be attached to a part of the leading edge 9, preferably at a distance from the tip end 8 or the root end (shown in FIG. 2). FIG. 5 shows an alternative position of the leading edge device 19. Here, the leading edge device 19 is configured to be attached to a tip end area. The leading edge device 19 may, for example, be arranged at the tip end 8 and extend towards the root end 7.

[0162] FIG. 6 shows a second embodiment of the airflow modifying element 21′ of the leading edge device 19. Here, the airflow modifying element 21′ extends substantially in the circumference direction from a local first edge 24 to a local second edge 25′. The local thickness of the airflow modifying element 21′ tapers off towards the local first and second edges 24′, 25′, respectively.

[0163] The local first edge 24′ is optionally aligned with the first edge 24 of the erosion shield 20. The local first edge 24′ is positioned at a first chordwise length from the leading edge 9. Similarly, the local second edge 25′ is optionally aligned with the second edge 25 of the erosion shield 20. The local second edge 25′ is positioned at a second chordwise length from the leading edge 9.

[0164] Here, the local first and second edges 24′, 25′ are aligned in the chordwise direction, but may be offset relative to each other.

[0165] FIG. 7 shows a third embodiment of the airflow modifying element 21″, wherein the airflow modifying element 21″ form part of a combined airflow modifying element extending along a portion of the pressure and suction sides 12, 13. Here, a further airflow modifying element 29 is aligned with the local first edge 24′ of the airflow modifying element 21″. Further, another further airflow modifying element 29 is aligned with the local second edge 25′ of the airflow modifying element 21″. The airflow modifying element 21″ together with the further airflow modifying elements 29 form the combined airflow modifying element. Thereby, extending the airflow modifying element towards the trailing edge 10.

[0166] Here, a further airflow modifying element 29 is arranged on both the pressure and suction sides 12, 13. However, the further airflow modifying element 29 may be arranged on only the pressure side 12 or the suction side 13.

[0167] In an alternative configuration, the further airflow modifying elements 29 form part of the airflow modifying element 21′.

[0168] FIG. 8 shows an alternative third embodiment of the airflow modifying element 21″, wherein the further airflow modifying element 29′ extend over the trailing edge 10 and further along a part of the pressure and suction sides 12, 13. Thereby, forming an airflow modifying element extending around the circumference of the wind turbine blade 5.

[0169] FIG. 9 shows the wind turbine blade 5 with a number of leading edge devices 19 extending along a portion of the leading edge 9. Here, a continuous leading edge device 19 or an array of leading edge devices 19 are positioned along the leading edge 9.

[0170] The leading edge devices 19 are arranged between 20% to 100%, preferably between 40% to 100%, of the blade length measured from the blade root 7.

[0171] FIG. 10 shows a cross-sectional view of a first embodiment of the erosion shield 20′ and the airflow modifying elements 21″′. Here, the erosion shield 20′ comprises an inner layer 31 and an outer layer 32. The inner layer 31 extends along the inner surface 26. The airflow modifying elements 21″′ are formed by a body 30 having a 3D-profile, as indicated in FIGS. 3-5, extending in the longitudinal direction, the thickness direction and further in the circumference direction. Here, the bodies 30 are shaped to as a continuous element forming the outer layer 32 of the erosion shield 30 wherein the body 30 forms a continuous outer surface 27″.

[0172] The body 30 may alternatively be shaped to form the inner layer 31 instead.

[0173] FIG. 11 shows a cross-sectional view of a second embodiment of the erosion shield 20″ and the airflow modifying elements 21″″. Here, the body 30′ is sandwiched between the outer layer 32′ and the inner layer 31. The outer layers 32′ extend along the inner layer 31 between the bodies 30′ and further along the local outer surfaces 27′ of each body 30.

[0174] Here, the bodies 30′ are shaped apart by a distance to form the airflow modifying elements 21″″.

[0175] FIG. 12 shows a cross-sectional view of a third embodiment of the erosion shield 20″′ and the airflow modifying elements 21″″. Here, the inner layer 31′ and the outer layer 32′ extend both over the local outer surfaces 27′ of the bodies 30′.

[0176] The body 30′ of the airflow modifying element 21″″ is here arranged on the inner surface 26′ so that it faces the leading edge surface (shown in FIG. 15).

[0177] FIG. 13 shows a cross-sectional view of a fourth embodiment of the erosion shield 20 and the airflow modifying elements 21. Here, the airflow modifying elements 21 are formed by a body 33 having a 2D-profile, as indicated in FIGS. 6-8, extending in the thickness direction and further in the circumference direction.

[0178] As indicated in FIGS. 10-14, the leading edge device 19 comprises an array of airflow modifying elements 21 formed by the body 30, 33.

[0179] The body 33 has a substantially uniform profile along its local length. For example, the body 33 may have substantially rectangular profile, as indicated in FIG. 13. The body 33′ may also have a substantially round profile, e.g. semi-elliptical or semi-circular, as indicated in FIG. 13. The body 33″ may also have a substantially triangular profile, as indicated in FIG. 13.

[0180] The erosion shield 20 is here formed as a multi-layered erosion shield comprising a number of layers arranged in a stack.

[0181] Here, the body of the airflow modifying element 21 is attached to the outer layer 32 of the erosion shield 20.

[0182] FIG. 14 shows a cross-sectional view of a fifth embodiment of the airflow modifying elements 21. Here, the dimensions of one or more of the airflow modifying elements 21 vary along the local length.

[0183] As illustrated, the local thickness of the bodies 33″, 33″′, 33″″ may vary from a minimum local thickness to a maximum local thickness. The dimensions and, optionally, the profile of the airflow modifying elements 21 are thus varied along the length of the wind turbine blade 5.

[0184] FIG. 15 shows an exemplary method of installing the leading edge device 19 on the wind turbine blade 5. The wind turbine blade 5 is preferably manufactured with a basic leading edge profile, as indicated in FIG. 15.

[0185] Existing wind turbine blades 5 may be provided with an old leading edge protection, such as an erosion shield 34 or a leading edge device 35 with a basic profile, as indicated in FIG. 15(a). When upgrading the wind turbine blade 5, the old erosion shield 34 or leading edge device 35 is removed (indicated by arrow) in an initial step.

[0186] Afterwards, any damages in the leading edge surface 36 are repaired and the leading edge surface 36 is then prepared for attachment of the leading edge device 19, as indicated in FIG. 15(b).

[0187] Finally, the leading edge device 19 is then positioned on the leading edge surface 36 and attached to the wind turbine blade 5, as indicated in FIG. 15(c).

[0188] If no leading edge protection exists, then any damages in the leading edge surface 36 are repaired and the leading edge surface 36 is then prepared for attachment of the leading edge device 19, as indicated in FIG. 15(b).

[0189] For new wind turbine blades 5, the original leading edge surface 36′ is prepared for attachment of the leading edge device 19 in a post-moulding process. This may include forming a recess 37 in the leading edge surface 36′. The leading edge device 19 is afterwards at least partly positioned in the recess 37 and subsequently attached to the wind turbine blade 5.

[0190] The abovementioned embodiments may be combined in any combinations without deviating from the present invention.