On the Design of Horizontal Axis Two-Bladed Hinged Wind Turbines

Hinged two-bladed wind turbines are not necessarily free of disturbing vibrations. The combination of elastic or built-in blade coning with blade flapping about a conventional teeter hinge produces periodic blade angular velocity variations in the blade tip path plane with associated vibrations and dynamic loads. The paper discusses and evaluates various hinge configurations for two-bladed rotors and shows why the conventional teeter hinge leads to nonuniform blade angular velocity in the blade tip path plane. The solution to this problem adopted for two-bladed helicopter rotors, though complex, could be of interest for large wind turbines. A much simpler solution, calling for the suppression of blade flapping by passive blade cyclic pitch variation produced by a strong negative pitch-flap coupling, was found to be practical for upwind tail vane stabilized two-bladed wind turbines.

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Numerical Simulations of Novel Conning Designs for Future Super-Large Wind Turbines

Applied Sciences ◽

10.3390/app11010147 ◽

2020 ◽

Vol 11 (1) ◽

pp. 147

Author(s):

Zhenye Sun ◽

Weijun Zhu ◽

Wenzhong Shen ◽

Qiuhan Tao ◽

Jiufa Cao ◽

...

Keyword(s):

Wind Turbines ◽

Cone Angle ◽

Angle Of Attack ◽

Normal Direction ◽

Velocity Decomposition ◽

New Concepts ◽

Blade Tip ◽

Tip Position ◽

Large Wind ◽

Lower Angle

In order to develop super-large wind turbines, new concepts, such as downwind load-alignment, are required. Additionally, segmented blade concepts are under investigation. As a simple example, the coned rotor needs be investigated. In this paper, different conning configurations, including special cones with three segments, are simulated and analyzed based on the DTU-10 MW reference rotor. It was found that the different force distributions of upwind and downwind coned configurations agreed well with the distributions of angle of attack, which were affected by the blade tip position and the cone angle. With the upstream coning of the blade tip, the blade sections suffered from stronger axial induction and a lower angle of attack. The downstream coning of the blade tip led to reverse variations. The cone angle determined the velocity and force projecting process from the axial to the normal direction, which also influenced the angle of attack and force, provided that correct inflow velocity decomposition occurred.

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On the dynamics of the pitch control loop in horizontal-axis large wind turbines

Proceedings of the 2005, American Control Conference, 2005. ◽

10.1109/acc.2005.1470037 ◽

2005 ◽

Cited By ~ 12

Author(s):

S. Suryanarayanan ◽

A. Dixit

Keyword(s):

Wind Turbines ◽

Horizontal Axis ◽

Control Loop ◽

Pitch Control ◽

Large Wind

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Flow Characteristics Study of Wind Turbine Blade with Vortex Generators

International Journal of Aerospace Engineering ◽

10.1155/2016/6531694 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Hao Hu ◽

Xin-kai Li ◽

Bo Gu

Keyword(s):

Wind Turbine ◽

Wind Turbines ◽

Horizontal Axis ◽

Vortex Generators ◽

Propeller Shaft ◽

Horizontal Axis Wind Turbine ◽

Separation Line ◽

Blade Root ◽

Pneumatic Power ◽

Large Wind

The blade root flow control is of particular importance to the aerodynamic characteristic of large wind turbines. The paper studies the feasibility of improving blade pneumatic power by applying vortex generators (VGs) to large variable propeller shaft horizontal axis wind turbines, with 2 MW variable propeller shaft horizontal axis wind turbine blades as research object. In the paper, three cases of VGs installation are designed; they are scattered in different chordwise position at the blade root, and then they are calculated, respectively, with CFD method. The results show that VGs installed in the separation line upstream, with the separation line of the blade root as a benchmark, show a better effect. Pneumatic power of blades increases by 0.6% by installing VGs. Although the effect on large wind turbines is not obvious, there is a space for optimization.

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Blade Tip Flow and Noise Prediction by Large-Eddy Simulation in Horizontal Axis Wind Turbines

Engineering Turbulence Modelling and Experiments 6 ◽

10.1016/b978-008044544-1/50066-2 ◽

2005 ◽

pp. 689-698

Author(s):

O. Fleig ◽

M. Iida ◽

C. Arakawa

Keyword(s):

Large Eddy Simulation ◽

Wind Turbines ◽

Horizontal Axis ◽

Noise Prediction ◽

Eddy Simulation ◽

Large Eddy ◽

Horizontal Axis Wind Turbines ◽

Blade Tip

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Predictions of Low-Frequency and Impulsive Sound Radiation From Horizontal-Axis Wind Turbines

Journal of Solar Energy Engineering ◽

10.1115/1.3266284 ◽

1982 ◽

Vol 104 (2) ◽

pp. 124-130 ◽

Cited By ~ 1

Author(s):

R. Martinez ◽

S. E. Widnall ◽

W. L. Harris

Keyword(s):

Wind Turbines ◽

Low Frequency ◽

Theoretical Models ◽

Horizontal Axis ◽

Time Signals ◽

Horizontal Axis Wind Turbines ◽

Acoustic Output ◽

Blade Loads ◽

Large Wind ◽

Good Agreement

This paper develops theoretical models to predict the radiation of low-frequency and impulsive sound from horizontal-axis wind turbines due to three sources: (i) steady blade loads, (ii) unsteady blade loads due to operation in a ground shear, (iii) unsteady loads felt by the blades as they cross the tower wake. These models are then used to predict the acoustic output of MOD-I, the large wind turbine operated near Boone, N. C. Predicted acoustic time signals are compared to those actually measured near MOD-I; good agreement is obtained.

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A Procedure for the Development of Control-Oriented Linear Models for Horizontal-Axis Large Wind Turbines

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2745852 ◽

2006 ◽

Vol 129 (4) ◽

pp. 469-479 ◽

Cited By ~ 10

Author(s):

Shashikanth Suryanarayanan ◽

Amit Dixit

Keyword(s):

Wind Turbines ◽

Linear Models ◽

Horizontal Axis ◽

Modeling Procedure ◽

Aerodynamic Interaction ◽

Horizontal Axis Wind Turbines ◽

Stiffness Characteristics ◽

Mechanical Elements ◽

Large Wind ◽

Bem Theory

In this work we describe a methodology to construct control-oriented, multi-input, multi-output linear models representing the dynamics of variable-speed, pitch-controlled horizontal-axis wind turbines (HAWT). The turbine is treated as an interconnection of mechanical elements with distributed mass, damping, and stiffness characteristics. The behavior of the structural components of the turbine is approximated as that of their dominant modes and the wind-blade aerodynamic interaction is modeled using the Blade Element Momentum (BEM) theory. The modeling procedure explicitly exploits the horizontal-axis configuration and constraints imposed thereof. The models developed using the outlined procedure are parametrized based on a handful of parameters that are often used to specify mass/stiffness distributions and geometry. The predictions of the linear models so constructed are validated against that of an established nonlinear model. The use of the modeling procedure in addressing problems of immediate interest to the wind turbine industry is presented.

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