Rotor blade assembly for mitigating stall-induced vibrations

Patent metadata

Field	Value
Publication number	US-12104571-B2
Application number	US-202118014400-A
Country	US
Kind code	B2
Filing date	Jun 29, 2021
Priority date	Jul 7, 2020
Publication date	Oct 1, 2024
Grant date	Oct 1, 2024

Abstract

A rotor blade assembly for mitigating stall-induced vibrations of a wind turbine during standstill includes at least one protrusion secured to the leading-edge of a rotor blade and defining an extended leading edge. The protrusion(s) wraps around a portion of the rotor blade from the suction side to the pressure side of the rotor blade. The protrusion(s) has a root-side face and a tip-side face disposed opposite thereof. The root-side face is arranged at an angle relative to a chordwise reference line. The angle is greater than zero degrees and less than or equal to 45 degrees with respect to the chordwise reference line. The protrusion(s) is configured to affect a chordwise airflow and thereby mitigate a stall-induced vibration.

First claim

What is claimed is:

1. A rotor blade assembly of a wind turbine, the rotor blade assembly comprising:
a rotor blade defining a body extending between a root and a tip and having surfaces defining a suction side, a pressure side, a leading edge, and a trailing edge, the rotor blade also defining a chordwise reference line extending between the leading edge and the trailing edge;
at least one protrusion secured at the leading edge or the trailing edge of the rotor blade and defining an extended leading or trailing edge, the at least one protrusion wrapping around a portion of the rotor blade from the suction side to the pressure side, the at least one protrusion having a root-side face and a tip-side face disposed opposite thereof, the root-side face being arranged at an angle relative to the chordwise reference line, the angle being greater than zero degrees and less than or equal to 45 degrees with respect to the chordwise reference line, wherein the at least one protrusion comprises:
a flap element operably coupled thereto via a pivot element, the flap element comprising:
a root side flap portion disposed within a recess of the root side face when the flap element is in a first flap position, the root side flap portion having a second flap position defined by a distance between the root side flap portion and the root side face when the rotor blade is in a stalled condition, and
a tip side flap portion disposed within a recess of the tip side face when the flap element is in the first flap position, the second flap position being defined by a distance between the tip side flap portion and the tip side face when the rotor blade is in the stalled condition.

2. The rotor blade assembly of claim 1 , wherein the at least one protrusion has a first arcuate profile and a second arcuate profile, the second arcuate profile defining a suction-side offset adjacent the suction side of the rotor blade, a pressure-side offset adjacent the pressure side of the rotor blade, and an intermediate offset, the intermediate offset being is greater than the pressure-side and suction-side offsets, wherein the offsets define a distance between the second arcuate profile and the surface of the rotor blade, wherein the first and second arcuate profiles define a protrusion profile which has a crescent shape.

3. The rotor blade assembly of claim 1 , wherein the intermediate offset is at least 5% of a chord of the rotor blade, the chord being the chord of the rotor blade at a spanwise mounting position of the at least one protrusion.

4. The rotor blade assembly of claim 1 , wherein the at least one protrusion is one of a plurality of protrusions, wherein the plurality of protrusions are distributed across a tip region of the rotor blade.

5. The rotor blade assembly of claim 1 , wherein the at least one protrusion is one of a plurality of protrusions, wherein the spacing between each protrusion of the plurality of protrusions is at least three times a chord length of the rotor blade.

6. The rotor blade assembly of claim 1 , wherein the at least one protrusion defines a protrusion profile, the at least one protrusion further comprising:
a profile extension extending in a spanwise direction from the protrusion profile, the profile extension tapering in a spanwise direction.

7. The rotor blade assembly of claim 6 , wherein the profile extension further comprises a plenum in fluid communication with an airflow.

8. The rotor blade assembly of claim 1 , wherein the at least one protrusion has a length along the suction side of the rotor blade of 10% or more of a chord to 40% or less of the chord of the rotor blade.

9. The rotor blade assembly of claim 1 , wherein the at least one protrusion is movably coupled to the rotor blade, the at least one protrusion having a retreated operating position and a deployed operating position, the rotor blade assembly further comprising:
an actuating mechanism configured to transition the at least one protrusion between the retreated operating position and the deployed operating position.

10. The rotor blade assembly of claim 9 , wherein the actuating mechanism comprises an air scoop configured to receive a portion of an airflow at an angle to the chordwise reference line, and wherein, in response to receiving the portion of the airflow, the at least one protrusion is transitioned to the deployed operating position.

11. The rotor blade assembly of claim 1 , wherein the at least one protrusion is pivotably coupled to the rotor blade via a pivot member, the rotor blade assembly further comprising:
a pivot stop configured to restrict a swiveling of the at least one protrusion.

12. The rotor blade assembly of claim 11 , further comprising:
a motivating element positioned to facilitate the transition of the at least one protrusion between a normal operating position and a stalled operating position.

13. The rotor blade assembly of claim 1 , wherein the at least one protrusion further comprises:
a plurality of vortex perforations, each of the plurality of vortex perforations having a vortex-bore axis oriented perpendicular to the root-side face, wherein the plurality of vortex perforations generate a plurality of vortices in response to an airflow at an angle to the chordwise reference line.

14. The rotor blade assembly of claim 1 , wherein the at least one protrusion further comprises:
a plurality of passage perforations, each of the plurality of passage perforations having a passage-bore axis oriented parallel to the chordwise reference line, the plurality of passage perforations defining a plurality of flow paths for an airflow parallel to the chordwise reference line.

15. The rotor blade assembly of claim 1 , wherein the flap element further comprises a motivating element positioned to facilitate a transition of the flap element between the first and second flap positions.

16. The rotor blade assembly of claim 1 , wherein the at least one protrusion further comprises:
a plurality of vortex perforations, each vortex perforation of the plurality of vortex perforations comprising a vortex-bore axis oriented perpendicular to the root-side face; and
a plenum member coupled between the tip-side face of the at least one protrusion and the tip-side flap portion, the plenum member being fluidly coupled to the plurality of vortex perforations when the flap element is in the second flap position.

17. A wind turbine, comprising:
a tower;
a nacelle mounted atop the tower; and
a rotor mounted to the nacelle, the rotor comprising a rotatable hub having a plurality of rotor blade assemblies secured thereto, each of the rotor blade assemblies comprising:
a rotor blade defining a body extending between a root and a tip and having surfaces defining a suction side, a pressure side, a leading edge, and a trailing edge, the rotor blade also defining a chordwise reference line extending between the leading edge and the trailing edge; and
at least one protrusion secured at the leading edge or the trailing edge of the rotor blade and defining an extended leading edge or trailing edge, the at least one protrusion wrapping around a portion of the rotor blade from the suction side to the pressure side, the at least one protrusion having a root-side face and a tip-side face disposed opposite thereof, the root-side face being arranged at an angle relative to the chordwise reference line, the angle being greater than zero degrees and less than or equal to 45 degrees with respect to the chordwise reference line, wherein the at least one protrusion comprises:
a flap element operably coupled thereto

Assignees

• Lm Wp Patent Holding As
• Lm Wind Power As

Inventors

• Herrig Andreas
• Stettner Martin
• Hallissy Benjamin Patrick

Classifications

• F05B2240/303

  Details of the leading edge · CPC title

• F05B2240/3052

  adjustable · CPC title

• F05B2240/3062

  Vortex generators · CPC title

• Y02E10/72

  Wind turbines with rotation axis in wind direction · CPC title

• F05B2240/30

  Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor · CPC title