Wind turbine blade

Patent metadata

Field	Value
Publication number	US-9617974-B2
Application number	US-201214360125-A
Country	US
Kind code	B2
Filing date	Nov 15, 2012
Priority date	Nov 23, 2011
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

A wind turbine blade is described having noise reduction features. The blade has a plurality of projecting serrations provided at the blade trailing edge to reduce the scattering noise produced during operation of the blade, wherein the serrations have a plurality of through-going apertures defined in the serration body. The apertures act to provide a pressure equalization effect at the serrations between the suction and pressure sides. This pressure equalization provides for improved noise reduction performance, as well as a reduction in mechanical stresses and strains which may be experienced by the serrations, increasing serration lifetime.

First claim

The invention claimed is:

1. A wind turbine blade for a rotor of a wind turbine having a substantially horizontal rotor shaft, the rotor comprising a hub, from which the wind turbine blade extends substantially in a radial direction when mounted to the hub, the wind turbine blade extending in a longitudinal direction parallel to a longitudinal axis and having a tip end and a root end,
the wind turbine blade comprising a profiled contour including a pressure side and a suction side, as well as a leading edge and a trailing edge with a chord having a chord length extending therebetween, the profiled contour, when being impacted by an incident airflow, generating a lift,
wherein the wind turbine blade further comprises a plurality of serrations provided at the trailing edge of the contour, said serrations projecting free of said trailing edge, said plurality of serrations operable to reduce noise generated during operation of the blade by modulation of the airflow at the trailing edge of the contour, said plurality of serrations each comprising a substantially triangular serration body having a proximal base end located adjacent said trailing edge and a distal tip end projecting away from said trailing edge and serration side edges extending between said proximal base end and said distal tip end,
wherein at least one through-going aperture is defined in said substantially triangular serration body between said base end and said tip end.

2. The blade of claim 1 , wherein the serration body comprises a pressure side surface and a suction side surface, wherein said at least one through-going aperture extends from said pressure side surface to said suction side surface, wherein said at least one through-going aperture acts to equalise pressure between said pressure side surface and said suction side surface.

3. The blade of claim 1 , wherein said at least one through-going aperture is defined such that the width of the aperture is greater than or equal to the depth of the aperture.

4. The blade of claim 1 , wherein said serrations are configured such that said at least one through-going aperture comprises less than or equal to 25% of the area of an outline of the serration body.

5. The blade of claim 1 , wherein at least one of said through-going apertures is selected from the following: a circular aperture; an oval aperture; a substantially rectangular aperture.

6. The blade of claim 1 , wherein said serrations comprise at least one primary array of through-going apertures arranged in a longitudinal direction between the proximal base end of the serration and the distal tip end of the serration, and at least one secondary array of through-going apertures arranged adjacent said primary array.

7. The blade of claim 6 , wherein said at least one primary array extends along a central longitudinal axis of the serration body between said proximal base end and said distal tip end.

8. The blade of claim 6 , wherein said primary array comprises at least one of the following: an elongate aperture oriented with a primary axis extending in a direction between the proximal base end and the distal tip end; at least one substantially circular aperture.

9. The blade of claim 6 , wherein said at least one secondary array is located between said at least one primary array and one of said side edges of the serration body, wherein said at least one secondary array comprises at least one substantially elongate aperture, and wherein said at least one elongate aperture of said at least one secondary array is arranged such that a primary axis of said at least one aperture extends in a substantially lateral direction from adjacent said at least one primary array towards said side edge of the serration body.

10. The blade of claim 1 , wherein said profiled contour has a blunt trailing edge comprising a trailing edge surface extending between the pressure side and the suction side of the contour at said trailing edge, wherein the proximal base ends of said plurality of serrations are located at the pressure side and/or the suction side of said trailing edge surface.

11. The blade of claim 10 , wherein a first subset of said plurality of serrations are provided at the pressure side of said trailing edge surface, and a second subset of said plurality of serrations are provided at the suction side of said trailing edge surface.

12. The blade of claim 1 , wherein an air permeable material is provided within said at least one aperture.

13. The blade of claim 1 , wherein at least a first array of said plurality of serrations is moveable relative to the trailing edge of the blade.

14. The blade of claim 1 , wherein an air permeable material is provided within said at least one through-going aperture.

15. A wind turbine having at least one wind turbine blade as claimed in claim 1 .

Assignees

• Lm Wp Patent Holding As

Inventors

• Singh Ashish

Classifications

• F05B2240/32

  with roughened surface · CPC title

• Y02E10/721

  Cross-Sectional Technologies · mapped topic

• F03D1/0633 Primary

  of the blades · CPC title

• F03D1/0683 Primary

  Mechanical Engineering · mapped topic

• F05B2260/96

  Preventing, counteracting or reducing vibration or noise · CPC title