Wind turbine blade
AssigneeEnvision Energy (Denmark) ApS
InventorsMichael Friedrich, Peter Grabau
Life of this patent
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Abstract
A blade for a partial pitch wind turbine is described, wherein the blade has a truncated aerodynamic profile provided at the pitch junction of the blade. The truncated trailing edge acts to prevent the formation of a trailing edge gap during pitching between the trailing edges of the inner and outer blade sections of a partial pitch blade, thereby reducing the negative impact of air leakage, etc., when pitching a partial pitch blade.
Claims9
A partial pitch wind turbine blade of at least 35 meters length, the wind turbine blade having an aerodynamic airfoil profile with a leading edge and a trailing edge, the wind turbine blade comprising:
- an inner blade section;
- and
- an outer blade section,
- the blade sections coupled at a pitch junction such that the outer blade section is pitchable relative to the inner blade section,
- wherein said inner blade section comprises a truncated airfoil profile provided at said pitch junction, said outer blade section comprises a full airfoil profile portion leading to a truncated airfoil profile portion provided at said pitch junction, wherein the truncated airfoil profiles are provided at the trailing edge of said inner and outer blade sections so that they each provide a truncated trailing edge surface, and wherein said trailing edge is arranged such that the truncated trailing edge surface of said outer blade section projected along a longitudinal axis of the wind turbine blade at least partially intersects the truncated trailing edge surface of the inner blade section when said outer blade section is pitched less than or equal to a pre-defined angle relative to said inner blade section, wherein said pitch is limited to be less than or equal to said pre-defined angle under normal operation in order to prevent the formation of a trailing edge gap at the pitch junction between the trailing edges of the inner and outer blade sections for pitch angles below said pre-defined angle, said pre-defined angle being 8°.
A wind turbine comprising a wind turbine tower, a nacelle at the top of the tower, and a rotor with a plurality of partial pitch wind turbine blades wherein said partial pitch wind turbine blades comprising:
- an inner blade section;
- and
- an outer blade section,
- the inner and outer blade sections coupled at a pitch junction such that the outer blade section is pitchable relative to the inner blade section,
- wherein said inner blade section comprises a truncated airfoil profile provided at said pitch junction, said outer blade section comprises a full airfoil profile portion leading to a truncated airfoil profile portion provided at said pitch junction, wherein the truncated airfoil profiles are provided at the trailing edge of said inner and outer blade sections so that they each provide a truncated trailing edge surface, and wherein said trailing edge is arranged such that the truncated trailing edge surface of said outer blade section projected along a longitudinal axis of the wind turbine blade at least partially intersects the truncated trailing edge surface of the inner blade section when said outer blade section is pitched less than or equal to a pre-defined angle relative to said inner blade section, wherein said pitch is limited to be less than or equal to said pre-defined angle under normal operation in order to prevent the formation of a trailing edge gap at the pitch junction between the trailing edges of the blade sections for pitch angles below said pre-defined angle, said pre-defined angle being 8°.
Dependencies are inferred from the claim text.