The performance was predicted of a wind-turbine, intended for electrical power generation, the rotor of which is similar in configuration to the rotor of an autogyro or gyrocopter as originated by Cierva. Hence the rotor axis of spin is tilted downwind, for maximum power production, by an angle of 400 degree to 500 degree relative to the vertical with power regulation by modulation of the tilt angle. Because the rotor of a Cierva turbine generates lift the simple, non-twisted, fixed-pitch blades 'fly' and are self supporting thereby eliminating flap-wise bending moments when the blades are hinged at their roots. It was found from the analysis that it is possible to reduce tower bending moments relative to a conventional horizontal axis turbine of equal power output and also, for equal maximum hub heights and blade tip altitudes, a Cierva turbine is capable, at a prescribed wind speed, of a greater power output than a conventional horizontal axis machine. For example a Cierva rotor 56 % greater in diameter than an otherwise comparable conventional horizontal axis rotor of equal solidity has a maximum output approximately 100 % greater close to the cut in wind speed of 4 m/s dropping to about 50 % greater at 12 m/s.
The predicted performance of Cierva-rotor wind turbines
Wind Engineering ; 21 , 2 ; 89-101
1997
13 Seiten, 13 Bilder, 12 Quellen
Article (Journal)
English
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