Rigid polymeric blade for a wind turbine and method and apparatus to manufacture same
In an embodiment, a molding apparatus for a turbine blade includes first and second mold compartments defining a mold cavity when in a closed position, at least one of the first and second mold compartments including a micro-structured surface facing an interior of the mold cavity. The micro-structured surface includes an array of V-shaped channels, and the V-shaped channels have a maximum height of 200 micrometers. A turbine blade including integral micro-structured riblets and method for making the turbine blade is also provided.
1. A wind turbine blade comprising:
a major axis running along a longest dimension of the wind turbine blade;
integrally-formed riblets having a maximum height of 200 micrometers on the surface of the wind turbine blade;
wherein the integrally-formed riblets are polymeric and are of the same composition as a majority of the wind turbine blade;
wherein the wind turbine blade is configured to have a blade diameter of 100 feet to 557 feet;
wherein the wind turbine blade comprises a halogenated polyolefin polymer with a Tg over 200° C.
2. The wind turbine blade of claim 1 , wherein the riblets run perpendicular to the major axis of the blade plus or minus 20 degrees.
3. The wind turbine blade of claim 2 , wherein the wind turbine blade is exclusive of a film layer.
4. The wind turbine blade of claim 2 , wherein the riblets have peaks and valleys and the peak-to-valley distance is within plus or minus 10% of each other.