Introduction to wind turbine blade design

Jensen, F.; Branner, Kim

doi:10.1016/b978-0-08-103007-3.00009-4

Cited by 14 publications

(21 citation statements)

References 21 publications

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“…The data used in this study is available [16]. The data given is time, temperature and measured degree of cure.…”

Section: Data Availabilitymentioning

confidence: 99%

Cure characterisation and prediction of thermosetting epoxy for wind turbine blade manufacturing

Jørgensen,

Mikkelsen,

Andersen

2023

IOP Conf. Ser.: Mater. Sci. Eng.

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In the wind industry, the increasing length of turbine blades and the use of thick composite sections make it vital to understand the thermoset and the underlying curing process. In this study, the curing of a specific thermoset epoxy for application in wind turbine blades is characterised by differential scanning calorimetry. The thermoset is analysed under dynamic and isothermal conditions to determine the complex cure behaviour under these various conditions. The data is fitted to determine firstly; the cure kinetics of the material through a kinetic model. Secondly; the phenomenon of the glass transition temperature Tg is studied to predict the development of Tg as a function of the degree of cure. Thirdly, a Diffusion-Kinetic model was utilised to make more accurate cure predictions based on the interaction between kinetic chemical reactions and diffusion control affecting the reaction rate through the incorporation of the glass transition temperature. A simple experimental framework for validating the diffusion-kinetic model was used to make a final validation of the model predictions on a larger scale. A set of final parameters is presented for application in a full diffusion-kinetic model for cure predictions and simulations beyond this study.

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“…The data used in this study is available [16]. The data given is time, temperature and measured degree of cure.…”

Section: Data Availabilitymentioning

confidence: 99%

Cure characterisation and prediction of thermosetting epoxy for wind turbine blade manufacturing

Jørgensen,

Mikkelsen,

Andersen

2023

IOP Conf. Ser.: Mater. Sci. Eng.

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“…Furthermore, the velocity profile exhibits a noticeable degree of symmetry around the wake center. These two characteristics serve as the foundation for the commonly used analytical wake models [8][9][10]. In contrast, for wind turbine wakes located deeper within the wind farm (e.g., the fifth and ninth rows as depicted in Figure 3), a noticeable upward shift of the wake center becomes apparent in the far wake region of the wind turbine.…”

Section: Phenomenon Of Upward Shift Of Wind Turbine Wakes On Wind Farmsmentioning

confidence: 99%

“…Analytical wake models are crucial for designing wind farm layouts and optimizing wind farm controls [2,7]. Most analytical models [8][9][10][11] compute velocity deficit using a single-wake expansion rate, assuming a symmetric vertical distribution about the hub height without accounting for the influences from the atmospheric inflow or the ground. In the pioneering work by Lissaman [12], approaches to account for the ground and nonuniform inflow effects were suggested: (1) modeling the retarding effect of the ground on wake expansion using an imaging technique; (2) assuming the streamwise deficit distribution for the boundary layer inflow being identical to the uniform inflow; and (3) employing distinct upper and lower wake expansion rates to account for the vertical variation of turbulence intensity.…”

Section: Introductionmentioning

confidence: 99%

Upward Shift of Wind Turbine Wakes in Large Wind Farms

Wang,

Yang

2023

Energies

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A detailed description of wake characteristics is essential for optimizing wind farm performance. Compared with the wake of a stand-alone wind turbine, less attention has been paid to wind turbine wakes in large wind farms. In this work, we investigate the vertical position of wakes for wind turbines in large wind farms with different streamwise turbine spacings and ground roughness lengths using large-eddy simulation with an actuator disk model. The simulation results reveal an upward shift of the wake center (defined as the position with the maximum velocity deficit) for the wind turbine deeply arrayed in the wind farm. Larger upward shifts of the wake center are observed for wind turbines in further downstream rows and wind turbines installed on the ground with higher roughness, for which the wake expands at a higher rate. It is conjectured that the upward shift of the wake center is caused by the upward shift of the turbulence-dominated momentum entrainment region and the constraint of ground on wake expansion. An analytical wake model incorporating the upward-shifting wake center was developed. In the proposed model, different expansion rates are employed for the lower and upper wake regions. The upward shift of the wake center is directly taken into account using the large-eddy simulation results. The comparison with the large-eddy simulation results demonstrates the importance of accounting for the upward shift of the wake center in analytical wake models.

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“…This hypothesis is from an operational perspective, supported by the wind turbine owners (WTOs), who are reporting a gradually increasing amount of transverse cracks. Believed to be the root cause of these transverse cracks are, among others, the out-of-plane deformations in the large double curved trailing edge aerodynamic sandwich panels on the pressure side within the max-chord region and towards the root -referred to here as breathing [4]. These deformations, often referred to as 3D longitudinal out-of-plane bending, leads to critical bending stresses in the area, where the trailing edge panels are connected/kinked into the stiff cylindrical root section.…”

Section: Introductionmentioning

confidence: 99%

Large-scale fatigue testing of a retrofitted 3^rd shear web in a 34m wind turbine blade section

Waldbjørn,

Berggreen,

Ahmed

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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Utilizing a fatigue-rated multi-axial strong-floor based test rig, the effect of a retro-fitted fish-mouth third shear-web geometry detail located within the double-curved trailing edge sandwich panels are evaluated in an inner 15m root section from a 34m wind turbine blade manufactured by SSP Technology. From previous research, a load configuration is identified, capable of triggering the breathing/pumping deformations in the trailing edge panels within the root and transition zone, which will drive the propagation on the shear-web disbonding mechanism. Investigation and evaluation of the shear web disbonding and associated mitigation are acquired through strain gauges, wire potentiometer and digital image correlation (DIC) measurements inside the root section.

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Introduction to wind turbine blade design

Cited by 14 publications

References 21 publications

Cure characterisation and prediction of thermosetting epoxy for wind turbine blade manufacturing

Cure characterisation and prediction of thermosetting epoxy for wind turbine blade manufacturing

Upward Shift of Wind Turbine Wakes in Large Wind Farms

Large-scale fatigue testing of a retrofitted 3^rd shear web in a 34m wind turbine blade section

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Introduction to wind turbine blade design

Cited by 14 publications

References 21 publications

Cure characterisation and prediction of thermosetting epoxy for wind turbine blade manufacturing

Cure characterisation and prediction of thermosetting epoxy for wind turbine blade manufacturing

Upward Shift of Wind Turbine Wakes in Large Wind Farms

Large-scale fatigue testing of a retrofitted 3rd shear web in a 34m wind turbine blade section

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Product

Resources

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Large-scale fatigue testing of a retrofitted 3^rd shear web in a 34m wind turbine blade section