Wind turbine rotor assembly and blade having acoustic flap

• US 20070065290A1
• Filed: 09/22/2005
• Published: 03/22/2007
• Est. Priority Date: 09/22/2005
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (GE Vernova, Inc.)
• Original Assignee: General Electric Company
• Inventors: Herr, Stefan
• Granted Patent: US 7,458,777 B2
• Time in Patent Office: Days
• US Class Current: 416/223.R
• CPC Class Codes: F03D 1/0633 of the blades
• CPC Class Codes: F03D 1/0675 of the blades
• 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

A wind turbine includes a rotor assembly having at least one blade with a blade body defining a leading edge and a trailing edge and adapted for movement in response to a wind flow over the body to produce electricity. A rigid acoustic flap extends outward from the trailing edge, and a distal end of the acoustic flap is substantially smooth and continuous. The flap reduces acoustic noise generated by the blade in use.

Claims

1. A blade for a wind turbine, said blade comprising:

a blade body defining a leading edge and a trailing edge and adapted for movement in response to a wind flow over the body to produce electricity; and

a rigid acoustic flap extending outward from the trailing edge, wherein a distal end of the acoustic flap is substantially smooth and continuous.

2. The blade of claim 1 wherein the acoustic flap is fabricated from one of plastic material and a metallic material.

3. The blade of claim 1 wherein the blade body defines a chord distance between the leading edge and the trailing edge, and a distal end of the acoustic flap extends for a distance from the trailing edge of about 3% of the chord distance.

4. The blade of claim 1 wherein the blade body defines a chord distance between the leading edge and the trailing edge, the acoustic flap having a thickness about 0.3% or less of the chord distance.

5. The blade of claim 1 wherein the body includes an outer surface, the acoustic flap secured to and substantially flush with the outer surface.

6. The blade of claim 1 the blade body includes a high pressure side and a low pressure side, the acoustic flap secured to the high pressure side.

7. The blade of claim 1 wherein the acoustic flap is secured adjacent the trailing edge on the blade body.

8. A rotor assembly for a wind turbine, said rotor comprising:

a plurality of blades rotatable about an axis in response to wind impinging upon the blades, wherein at least one of the blades comprises;

a blade body defining a leading edge, a trailing edge and a chord distance therebetween; and

a rigid acoustic flap secured to the blade body and extending outward from the trailing edge for a specified fraction of the chord distance, thereby reducing trailing edge noise broadband and tonality as the blade is rotated.

9. The rotor assembly of claim 8 wherein a distal end of the acoustic flap is substantially smooth.

10. The rotor assembly of claim 8 wherein a distal end of the acoustic flap extends for a distance from the trailing edge of about 3% of the chord distance.

11. The rotor assembly of claim 9 wherein the acoustic flap is formed from a sheet of material having a thickness of about 0.3% or less of the chord distance.

12. The rotor assembly of claim 9 wherein the trailing edge includes an outer surface, the acoustic flap secured in a substantially flush position with respect to the outer surface.

13. The rotor assembly of claim 9 the blade body includes a high pressure side and a low pressure side, the acoustic flap secured to the high pressure side adjacent the trailing edge.

14. The rotor assembly of claim 9 wherein the acoustic flap is secured adjacent the trailing edge on the blade body.

15. A wind turbine comprising:

a rotatable shaft coupled to a generator; and

at least one blade coupled to the shaft and movable by wind for the generation of electricity, the at least one blade comprising;

a body defining a leading edge, a trailing edge and a chord distance therebetween, the body having a high pressure side and a low pressure side; and

a rigid acoustic flap secured to the high pressure side and extending outward from the trailing edge to a smooth distal end, thereby reducing trailing edge noise broadband and tonality.

16. The turbine of claim 15 wherein a distal end of the acoustic flap extends for a distance from the trailing edge of about 3% of the chord distance.

17. The turbine of claim 15 wherein the acoustic flap is formed from a sheet of material having a thickness of about 0.3% or less of the chord distance.

18. The turbine of claim 15 wherein the trailing edge includes an outer surface, the acoustic flap secured in a substantially flush position with respect to the outer surface.

19. The turbine of claim 15 wherein the acoustic flap is secured adjacent the trailing edge on the blade body.

20. The turbine of claim 15 wherein the acoustic flap is fabricated from one of a metallic material and a plastic material.