Wind turbine

• US 5,533,865 A
• Filed: 10/06/1994
• Issued: 07/09/1996
• Est. Priority Date: 11/04/1993
• Status: Expired due to Fees

• Current Assignee: Stork Product Engineering BV (Fluor Corporation)
• Original Assignee: Stork Product Engineering BV (Fluor Corporation)
• Inventors: Dassen, Antonius G. M., Hagg, Franklin
• Primary Examiner(s): Denion, Thomas E.
• Assistant Examiner(s): Sgantzos, Mark
• Application Number:
  US08/319,107
• Time in Patent Office: 642 Days
• Field of Search: 416/62, 416/228, 416/236 R, 244/198, 244/199, 244/200
• US Class Current: 416/228
• CPC Class Codes: F03D 1/0608 characterised by their aerodynamic shape
• CPC Class Codes: F03D 1/0675 of the blades
• CPC Class Codes: F05B 2250/183 zigzag
• CPC Class Codes: F05B 2260/96 Preventing, counteracting or reducing vibration or noise
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

In order to reduce the noise nuisance caused during operation by rotor blades of a rotor of a wind turbine the rear edge of each blade is irregularly formed. In particular the saw-tooth form with a top angle smaller than about 150° and preferably 10° is found to produce a considerable noise reduction.

Claims

1. A wind turbine comprising a rotor having a plurality of blades which each have a front edge and a rear edge, wherein the rear edge has a saw-tooth form having a plurality of saw teeth over at least a part thereof and wherein the saw teeth have a hexagonal cross section.

2. A wind turbine as claimed in claim 1, wherein the blades have in cross section a curved part acting as a suction side and a part that is flatter in comparison to the curved part, and a plane of the saw teeth lies roughly in an imaginary plane extending through the curved part.

3. A wind turbine as claimed in claim 2, wherein an edge thickness of the saw teeth is smaller than 4 mm.

4. A wind turbine as claimed in claim 2, wherein a top angle α

of each of the saw teeth is less than about 150°

.

5. A wind turbine as claimed in claim 2, wherein a top angle α

of each of the saw teeth is about 10°

.

6. A wind turbine as claimed in claim 2, wherein the saw teeth form part of a separate element fixed to a blade.

7. A wind turbine as claimed in claim 6, wherein an edge thickness of the saw teeth is smaller than 4 mm.

8. A wind turbine as claimed in claim 6, wherein a top angle α

of each of the saw teeth is less than about 150°

.

9. A wind turbine as claimed in claim 6, wherein a top angle α

of each of the saw teeth is about 10°

.

10. A wind turbine as claimed in claim 2, wherein the saw teeth are cut into the blade.

11. A wind turbine as claimed in claim 10, wherein an edge thickness of the saw teeth is smaller than 4 mm.

12. A wind turbine as claimed in claim 10, wherein a top angle α

of each of the saw teeth is less than about 150°

.

13. A wind turbine as claimed in claim 10, wherein in the case of a blade with a particular intended length of a chord, the cutting-in of the saw teeth begin at a point at 80-95% of the length of the chord and the saw teeth end at a point at 105-120% of the length of the chord.

14. A wind turbine as claimed in claim 13, wherein a position of the point of cutting-in of the saw teeth is chosen partly subject to the thickness of the blade.

15. A wind turbine as claimed in claim 1, wherein an edge thickness of the saw teeth is smaller than 4 mm.

16. A wind turbine as claimed in claim 1, wherein saw teeth differ from other saw teeth.

17. A wind turbine as claimed in claim 1, wherein a pattern of the rear edge is sinus-shaped.

18. A wind turbine as claimed in claim 1, wherein a top angle α

of each of the saw teeth is less than about 150°

.

19. A wind turbine as claimed in claim 1, wherein a top angle α

of each of the saw teeth is about 10°

.