Blade pitch

About: Blade pitch is a research topic. Over the lifetime, 5321 publications have been published within this topic receiving 63134 citations.

Wind turbine and method for measuring the pitch angle of a wind turbine rotor blade

Abstract: A method for measuring the pitch angle of a wind turbine rotor blade (5) is provided, wherein at least one image of at least part of the rotor blade (5) is acquired by a camera (37) from a defined position and the pitch angle is calculated by means of data from the at least one image.

Apparatus and method for operation of a wind turbine

Abstract: A method for operating a wind turbine is provided. The wind turbine includes a rotor including at least one rotor blade and a pitch drive system coupled to the at least one rotor blade. The pitch drive system is adapted for pitching the rotor blade. The method includes: determining an actual value of a first variable indicative of an overspeed state of the wind turbine; determining an actual value of a second variable of the wind turbine correlated to the rate of change over time of the first variable; and, estimating an occurrence of an overspeed state of the wind turbine from at least the determined actual values of the first and second variables. The pitch drive system pitches the rotor blade for aerodynamically braking the rotor based on the result of the estimation.

Variable camber tandem blade bow for turbomachines

Abstract: Multiple flat-plate blade rows of pitch adjustable blades are offset mounted in a manner such that when flat-plate blades in adjacent rows are aligned at a specific pitch setting, respective flat-plate blades of the adjacent rows nearly mate. The offset between the flat-plate blade rows functions to produce unequal pitch angle settings of the blades of adjacent rows which, in turn, function to produce the result that the respective flat-plate blades which nearly mate, in combination, produce a blade configuration which has an effective camber.

Effects of wind shear on wind turbine rotor loads and planetary bearing reliability

Abstract: Recent studies suggest that wind shear and the resulting pitch moments increase bearing loads and thereby contribute to premature wind turbine gearbox failure. In this paper, we use momentum-based modeling approaches to predict the pitch moments from wind shear. The non-dimensionalized results, which have been validated against accepted aeroelastic results, can be used to determine thrust force, pitch moment and power of a general rotor as a function of the wind shear exponent. Even in extreme wind shear (m = 1), the actual thrust force and power for a typical turbine (R* < 0.5) were within 8% and 20% of the nominal values (those without wind shear), respectively. The mean pitch moment increased monotonically with turbine thrust, rotor radius and wind shear exponent. For extreme wind shear (m = 1) on a typical turbine (R* = 0.5), the mean pitch moment is ~25% the product of thrust force and rotor radius. Analysis of wind shear for a typical 750 kW turbine revealed that wind shear does not significantly affect bearing loads because it counteracts the effects of rotor weight. Furthermore, even though general pitch moments did significantly increase bearing loads, they were found to be unlikely to cause bearing fatigue. Analyses of more common low wind-speed cases suggest that bearing under-loading and wear are more likely to contribute to premature bearing failure than overloading and classical surface contact fatigue. Copyright © 2015 John Wiley & Sons, Ltd.