Wind turbine rotor blade with passively modified trailing edge component
A wind turbine rotor blade includes a root portion and an airfoil portion extending from the root portion and defined by a leading edge and a trailing edge. The airfoil portion further includes a main foil section and a trailing edge section that is pivotally connected to the main foil section along a span-wise extending hinge line. A passive torsion element is coupled between the main foil section and the trailing edge section. The torsion element is biased to a neutral position wherein the trailing edge section is pivoted chord-wise to a low wind speed position relative to the main foil section. The trailing edge section is self-actuating from the low wind speed position to an increased wind speed position relative to the main foil section as a function of the biasing force of the torsion element and wind speed over the airfoil section.
1. A wind turbine rotor blade, comprising:
a root portion;
an airfoil portion extending from said root portion and defined by a leading edge and a trailing edge;
said airfoil portion further comprising a main foil section having a suction side surface and a pressure side surface, and a trailing edge section that is pivotally connected to said main foil section along a span-wise extending hinge line interface;
a passive torsion element coupled between said main foil section and said trailing edge section, said torsion element biased to a neutral position wherein said trailing edge section is pivoted chord-wise to a low wind speed position towards said pressure side surface of said main foil section; and
said trailing edge section being self-actuating from said low wind speed position to an increased wind speed aerodynamic position relative to said main foil section as a function of the biasing force of said passive torsion element and wind speed over said airfoil section; and
wherein said hinge line interface comprises a rounded face defined on said trailing edge section that is nested within a rounded recess defined in said main foil section.
2. The wind turbine blade as in claim 1 , comprising a plurality of said pivotally connected trailing edge sections aligned span-wise along said trailing edge, each of said trailing edge sections comprising a respective said passive torsion element.
3. The wind turbine blade as in claim 1 , wherein said torsion element is configured such that at a design optimum wind speed for said blade, said trailing edge section is in an in-line position with said main foil section with respect to a chord-wise axis of said blade.
4. The wind turbine blade as in claim 3 , wherein said increased wind speed position is defined between said low wind speed position and said in-line position.
5. The wind turbine blade as in claim 4 , further comprising a stop defined between said trailing edge section and said main foil section that prevents movement of said trailing edge section beyond said in-line position.
6. The wind turbine blade as in claim 1 , wherein said torsion element comprises a torsion spring.
7. The wind turbine blade as in claim 1 , wherein said torsion element comprises a resilient member preformed into said neutral position.
8. The wind turbine blade as in claim 1 , wherein said main foil section extends at least 50% of the blade chord taken from said leading edge along the span of said blade.
9. A wind turbine rotor blade, comprising:
a root portion;
an airfoil portion extending from said root portion and defined by a leading edge and a trailing edge;
said airfoil portion further comprising a main foil section and a trailing edge section that is pivotally connected to said main foil section along a span-wise extending hinge line, said hinge line delineating said main foil section from said trailing edge section;
a passive torsion element coupled between said main foil section and said trailing edge section, said torsion element biased to a neutral position wherein said trailing edge section is pivoted chord-wise to a low wind speed position relative to said main foil section;
said trailing edge section being self-actuating from said low wind speed position to an increased wind speed position relative to said main foil section as a function of the biasing force of said passive torsion element and wind seed over said airfoil section; and
wherein said resilient member is a strip member that extends span-wise between said trailing edge section and said main foil section.
10. A wind turbine, comprising:
a plurality of rotor blades, each said rotor blade having a root portion connected to a rotor hub and an airfoil portion extending radially outward from said root portion and defined by a leading edge and a trailing edge;
said airfoil portion further comprising a main foil section having a pressure side surface and a suction side surface, and a trailing edge section that is pivotally connected to said main foil section along a span-wise extending hinge line interface;
a passive torsion element coupled between said main foil section and said trailing edge section, said torsion element biased to a neutral position wherein said trailing edge section is pivoted chord-wise to a low wind speed position towards said pressure side surface of said main foil section; and
said trailing edge section being self-actuating from said low wind speed position to an increased wind speed aerodynamic position relative to said main foil as a function of the biasing force of said passive torsion element and wind speed over said airfoil section; and
wherein said hinge line interface comprises a rounded face defined on said trailing edge section that is nested within a rounded recess defined in said main foil section.
11. The wind turbine as in claim 10 , wherein said rotor blades comprise a plurality of said pivotally connected trailing edge sections aligned span-wise along said trailing edge, each of said trailing edge sections comprising a respective said passive torsion element.
12. The wind turbine as in claim 10 , wherein said torsion element is configured such that at a design optimum wind speed for said blades, said trailing edge section is in an in-line position with said main foil section with respect to a chord-wise axis of said blade.
13. The wind turbine as in claim 12 , wherein said increased wind position is defined between said low wind speed position and said in-line position.
14. The wind turbine as in claim 13 , further comprising a stop defined between said trailing edge section and said main foil section that prevents movement of said trailing edge section beyond said in-line position.
15. The wind turbine as in claim 10 , wherein said torsion element comprises a torsion spring.
16. The wind turbine as in claim 10 , wherein said torsion element comprises a resilient member preformed into said neutral position.
17. The wind turbine as in claim 16 , wherein said resilient member is a strip member that extends span-wise between said trailing edge section and said main foil section.
18. The wind turbine as in claim 10 , wherein said main foil section extends at least 50% of the blade chord taken from said leading edge along the span of said blade.