wind rotor blade design theory
TRANSCRIPT
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Colorado School of Mines Adventure Engineering Physical Science Workshop for Teachers
Aerodynamics 2: Blade
Design
References:
NREL (Pat Moriarty, TonyJimenez)
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Colorado School of Mines Adventure Engineering Physical Science Workshop for Teachers
June 1920, 2007 Wind Energy 2
Blade Design Overview
Blade shape (3-dimensional)
Number of blades
Blade length
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Colorado School of Mines Adventure Engineering Physical Science Workshop for Teachers
June 1920, 2007 Wind Energy 3
Blade Shapes
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Colorado School of Mines Adventure Engineering Physical Science Workshop for Teachers
June 1920, 2007 Wind Energy 4
Airfoil Terminology
Chordc
Thickness
Camber
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Colorado School of Mines Adventure Engineering Physical Science Workshop for Teachers
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Sample Airfoils
Which of these blades have
more camber?
more thickness?
a longer chord?
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Colorado School of Mines Adventure Engineering Physical Science Workshop for Teachers
June 1920, 2007 Wind Energy 6
Lift vs. Drag
Lift force
Perpendicular to flow direction (airplane wing)
Drag force
Parallel to flow direction
Drag Machines less efficient
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Colorado School of Mines Adventure Engineering Physical Science Workshop for Teachers
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Number of Blades
More blades
Aesthetics
Noise
Aerodynamic
efficiency (Cp)
Fatigue loading
Fewer blades Cost
http://www.windpower.org/en/tour/design/concepts.htm
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Colorado School of Mines Adventure Engineering Physical Science Workshop for Teachers
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Solidity
Solidity is the ratio
of the area of the
blades to the swept
area (the area ofthe circle containing
the blades)
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Effect of Solidity
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Colorado School of Mines Adventure Engineering Physical Science Workshop for Teachers
June 1920, 2007 Wind Energy 10
Wake Aerodynamics
Turbine Wake
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Colorado School of Mines Adventure Engineering Physical Science Workshop for Teachers
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Height matters
Height above ground
affects wind speed
Double wind speed =
8 x power
31
2wind
P V A
Wind Speed, m/sHeightm504030201050
Surface
12.612.211.711108.8
Courtesy: Alternative Energy Institute
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Size
Larger turbines enjoy higher windspeeds (and economies of scale).