scholarly journals A Parametric Study on Power Variation for Model Wind Turbine Arrays

2000 ◽  
Author(s):  
Dominic DeLucia
Keyword(s):  
Wind Turbine ◽  
Parametric Study ◽  
Power Variation ◽  
Turbine Arrays

scholarly journals Parametric Study on a Performance of a Small Counter-Rotating Wind Turbine

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3880
Author(s):  
Michał Pacholczyk ◽  
Dariusz Karkosiński
Keyword(s):  
Wind Turbine ◽  
Parametric Study ◽  
Rotor Blades ◽  
Speed Ratio ◽  
Outer Diameter ◽  
Axial Distance ◽  
Computational Domain ◽  
Dynamic Interactions ◽  
Computational Fluids Dynamics ◽  
Large Eddy

A small Counter-Rotating Wind Turbine (CRWT) has been proposed and its performance has been investigated numerically. Results of a parametric study have been presented in this paper. As parameters, the axial distance between rotors and a tip speed ratio of each rotor have been selected. Performance parameters have been compared with reference to a Single Rotor Wind Turbine (SRWT). Simulations were carried out with Computational Fluids Dynamics (CFD) solver and a Large Eddy Scale approach to model turbulences. An Actuator Line Model has been chosen to represent rotors in the computational domain. Summing up the results of simulation tests, it can be stated that when constructing a CRWT turbine, rotors should be placed at a distance of at least 0.5 D (where D is rotor outer diameter) or more. One can then expect a noticeable power increase compared to a single rotor turbine. Placing the second rotor closer than 0.5 D guarantees a significant increase in power, but in such configurations, dynamic interactions between the rotors are visible, resulting in fluctuations in torque and power. Dynamic interactions between rotor blades above 0.5 D are invisible.

scholarly journals Parametric Study of Eddy Current Brakes for Small-Scale Household Wind Turbine Systems

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6633
Author(s):  
Huiseop Jeong ◽  
Hoseong Ji ◽  
Sanghyun Choi ◽  
Joonho Baek
Keyword(s):  
Wind Turbine ◽  
Eddy Current ◽  
Parametric Study ◽  
Rotational Speed ◽  
Magnetic Flux Density ◽  
Small Scale ◽  
Turbine Generator ◽  
Disk Thickness ◽  
Wind Turbine Generator ◽  
Braking Torque

The design and application of eddy current brakes (ECBs) should be simple; further, ECBs should be used semi-permanently. This study aimed to determine major parameters for designing an ECB that can be applied to a small-scale wind turbine generator. To this end, an ECB was developed that could actuate without additional power, thus improving the efficiency of the generator. A series of simulations were conducted for a parametric study to pre-design ECBs suitable for small wind turbines. The six parameters chosen were disk thickness, number of magnets, radial location of magnets from center of disk, magnet pole arrangement, magnetic flux density, and rotational speed. The simulations were conducted on COMSOL Multiphysics. The results indicated that the number of magnets and magnet pole arrangements can significantly affect the performance curve of ECBs. Moreover, the disk thickness and rotational speed are linearly proportional to the braking torque.

scholarly journals A Simulation Study on Risks to Wind Turbine Arrays from Thunderstorm Downbursts in Different Atmospheric Stability Conditions

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5407
Author(s):  
Nan-You Lu ◽  
Lance Manuel ◽  
Patrick Hawbecker ◽  
Sukanta Basu
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Transition Period ◽  
Atmospheric Stability ◽  
Bending Moment ◽  
Stability Conditions ◽  
Wind Fields ◽  
Worst Case ◽  
Large Eddy Simulation Model ◽  
Turbine Arrays

Thunderstorm downbursts have been reported to cause damage or failure to wind turbine arrays. We extend a large-eddy simulation model used in previous work to generate downburst-related inflow fields with a view toward defining correlated wind fields that all turbines in an array would experience together during a downburst. We are also interested in establishing what role contrasting atmospheric stability conditions can play on the structural demands on the turbines. This interest is because the evening transition period, when thunderstorms are most common, is also when there is generally acknowledged time-varying stability in the atmospheric boundary layer. Our results reveal that the structure of a downburst’s ring vortices and dissipation of its outflow play important roles in the separate inflow fields for turbines located at different parts of the array; these effects vary with stability. Interacting with the ambient winds, the outflow of a downburst is found to have greater impacts in an “average” sense on structural loads for turbines farther from the touchdown center in the stable cases. Worst-case analyses show that the largest extreme loads, although somewhat dependent on the specific structural load variable considered, depend on the location of the turbine and on the prevailing atmospheric stability. The results of our calculations show the highest simulated foreaft tower bending moment to be 85.4 MN-m, which occurs at a unit sited in the array farther from touchdown center of the downburst initiated in a stable boundary layer.

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