Aero-elastic Wind Turbine Design with Active Flaps for AEP
Maximization

McWilliam, Michael; Barlas, Thanasis K.; Madsen, Helge Aagaard; Zahle, Frederik

doi:10.5194/wes-2017-50

Cited by 3 publications

(1 citation statement)

References 14 publications

(18 reference statements)

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“…For many years, load alleviation strategies relied on pitch control; however, as the size of the blades and the inertias involved increase, the effectiveness of the pitch actuators to provide high‐frequency control authority deteriorates. In the last decade, the alternative of using trailing edge (TE) flaps as active 3 or passive devices 4 for alleviating loads and regulating or even optimizing power capture, 5 has been considered and investigated. The concept of TE flaps is known from the very early years of aviation as a means of increasing the lift of fixed wings during take‐off and landing 6 .…”

Section: Introductionmentioning

confidence: 99%

Simulation of oscillating trailing edge flaps on wind turbine blades using ranging fidelity tools

et al. 2020

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Recent research developments have indicated that substantial reduction of both the fatigue and ultimate loads can be achieved by adopting trailing edge (TE) flap control strategies. Their aeroelastic tools employ blade element momentum (BEM) aerodynamic models enhanced with a sectional 2D treatment of the TE flap, neglecting the 3D effect of the trailed vorticity in the vicinity of the moving flap. In the present paper, a cross comparison of the BEM‐based models used in the aeroelastic analysis tools against higher fidelity, free‐wake lifting line, and fully resolved CFD models is performed, with the aim to highlight limitations of the first. A second level of comparison assesses the differences among tools of the same level of fidelity from different research groups. Moreover, a number of engineering‐based correction models that are used in conjunction with BEM and account for the complex 3D trailed vorticity effect are assessed. Simulations of a stiff rotor configuration of the DTU 10 MW Reference Wind Turbine are performed for a prescribed, harmonic TE flap motion, and aerodynamic loads are compared at the sectional and rotor‐integrated level. For the studied stiff rotor with the chosen flaps configuration, the results of the code‐to‐code comparisons indicate that low‐fidelity BEM tools consistently predict 1P variations of the rotor thrust due to the TE flap motion, but fail to reproduce the details of the load distributions especially in the vicinity of the flap section. BEM‐based corrected models, which account for 3D‐induced velocity effects, provide load distribution predictions closer to higher fidelity free‐wake and CFD models.

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Section: Introductionmentioning

confidence: 99%

Simulation of oscillating trailing edge flaps on wind turbine blades using ranging fidelity tools

et al. 2020

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Active load alleviation potential of adaptive wind turbine blades using shape memory alloy actuators

et al. 2019

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Upscaling of wind turbine blades calls for implementation of innovative active load control concepts that will facilitate the flawless operation of the machine and reduce the fatigue and ultimate loads that hinder its service life. Based on aeroelastic simulations that prove the enhanced capabilities of combined individual pitch and individual flap control at global wind turbine scale level, a shape adaptive concept that encompasses an articulated mechanism consisting of two subparts is presented. Shape memory alloy (SMA) actuators are investigated and assessed as means to control the shape adaptive mechanism at airfoil section level in order to alleviate the developed structural loads. The concept is embedded in the trailing edge region of the blade of a 10‐MW horizontal axis wind turbine and acts as a flap mechanism. Numerical simulations are performed considering various wind velocities and morphing target shapes and trajectories for both normal and extreme turbulence conditions. The results prove the potential of the concept, since the SMA controlled actuators can accurately follow the target trajectories. Power requirements are estimated at 0.22% of the AEP of the machine, while fatigue and ultimate load reduction of the flap‐wise bending moment at the blade root is 27.6% and 7.4%, respectively.

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Distributed Aerodynamic Control using Active Trailing-Edge Flaps for Large Wind Turbines

Feil

Abbas

Bortolotti

et al. 2020

J. Phys.: Conf. Ser.

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This work presents a numerical framework to investigate distributed aerodynamic control devices for application in large wind turbines. Tool capabilities were extended to facilitate multiple aerodynamic polar tables. The airfoil aerodynamics characteristics were automatically determined, and blade-pitch, generator-torque, and trailing-edge-flap controllers were tuned in-the-loop according to a specific blade design. This automated workflow allows analysis and optimization of trailing-edge flaps, enabling codesign studies. Results targeted reductions of root-flap-bending moment derivatives. The applied trailing-edge-flap control reduced the standard deviation of root-flap-bending moments by more than 6% and benefit related parameters, e.g., reduce blade-tip deflections, by up to 8%. Because of varying thrust distributions along the blade span, different flap designs have nonlinear characteristics in terms of the control objective and show best performance when located at the radial position with maximum thrust. In general, larger flaps provide a greater influence to reduce the target control objective.

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Aero-elastic Wind Turbine Design with Active Flaps for AEP Maximization

Cited by 3 publications

References 14 publications

Simulation of oscillating trailing edge flaps on wind turbine blades using ranging fidelity tools

Simulation of oscillating trailing edge flaps on wind turbine blades using ranging fidelity tools

Active load alleviation potential of adaptive wind turbine blades using shape memory alloy actuators

Distributed Aerodynamic Control using Active Trailing-Edge Flaps for Large Wind Turbines

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