Implementation and Analysis of Mathematical Modeled Drive Train System in Type III Wind Turbines Using Computational Fluid Dynamics

In the global scenario, wind turbines and their aerodynamics are always subjected to constant research for increasing their efficiency which converts the abundant wind energy into usable electrical energy. In this research, an attempt is made to increase the efficiency through the changes in surface topology of wind turbines through computational fluid dynamics. Dimples on the other hand are very efficient in reducing air drag as is it evident from the reduction of drag and increase in lift in golf balls. The predominant factors influencing the efficiency of the wind turbines are lift and drag which are to be maximized and minimized respectively. In this research, surface of turbine blades are integrated with dimples of various sizes and arrangements and are analyzed using computational fluid dynamics to obtain an optimum combination. The analysis result shows that there is an increase in power with about 15% increase in efficiency. Hence, integration of dimples on the surface of wind turbine blades has helped in increasing the overall efficiency of the wind turbine.

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Detailed Analysis of the Wake Structure of a Straight-Blade H-Darrieus Wind Turbine by Means of Wind Tunnel Experiments and Computational Fluid Dynamics Simulations

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4037906 ◽

2017 ◽

Vol 140 (3) ◽

Cited By ~ 14

Author(s):

Alessandro Bianchini ◽

Francesco Balduzzi ◽

Giovanni Ferrara ◽

Lorenzo Ferrari ◽

Giacomo Persico ◽

...

Keyword(s):

Fluid Dynamics ◽

Experimental Data ◽

Computational Fluid Dynamics ◽

Wind Tunnel ◽

Wind Turbines ◽

Large Scale ◽

Vertical Axis ◽

Performance Estimation ◽

Small Scale ◽

Dynamics Simulations

Darrieus vertical axis wind turbines (VAWTs) have been recently identified as the most promising solution for new types of applications, such as small-scale installations in complex terrains or offshore large floating platforms. To improve their efficiencies further and make them competitive with those of conventional horizontal axis wind turbines, a more in depth understanding of the physical phenomena that govern the aerodynamics past a rotating Darrieus turbine is needed. Within this context, computational fluid dynamics (CFD) can play a fundamental role, since it represents the only model able to provide a detailed and comprehensive representation of the flow. Due to the complexity of similar simulations, however, the possibility of having reliable and detailed experimental data to be used as validation test cases is pivotal to tune the numerical tools. In this study, a two-dimensional (2D) unsteady Reynolds-averaged Navier–Stokes (U-RANS) computational model was applied to analyze the wake characteristics on the midplane of a small-size H-shaped Darrieus VAWT. The turbine was tested in a large-scale, open-jet wind tunnel, including both performance and wake measurements. Thanks to the availability of such a unique set of experimental data, systematic comparisons between simulations and experiments were carried out for analyzing the structure of the wake and correlating the main macrostructures of the flow to the local aerodynamic features of the airfoils in cycloidal motion. In general, good agreement on the turbine performance estimation was constantly appreciated.

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Investigation of Self-Starting Capability of Vertical Axis Wind Turbines Using a Computational Fluid Dynamics Approach

Journal of Solar Energy Engineering ◽

10.1115/1.4004705 ◽

2011 ◽

Vol 133 (4) ◽

Cited By ~ 34

Author(s):

Alexandrina Untaroiu ◽

Houston G. Wood ◽

Paul E. Allaire ◽

Robert J. Ribando

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Wind Turbine ◽

Wind Turbines ◽

Vertical Axis ◽

Mesh Deformation ◽

Operating Speed ◽

Vertical Axis Wind Turbine ◽

Vertical Axis Wind Turbines ◽

Turbine Performance

Vertical axis wind turbines have always been a controversial technology; claims regarding their benefits and drawbacks have been debated since the initial patent in 1931. Despite this contention, very little systematic vertical axis wind turbine research has been accomplished. Experimental assessments remain prohibitively expensive, while analytical analyses are limited by the complexity of the system. Numerical methods can address both concerns, but inadequate computing power hampered this field. Instead, approximating models were developed which provided some basis for study; but all these exhibited high error margins when compared with actual turbine performance data and were only useful in some operating regimes. Modern computers are capable of more accurate computational fluid dynamics analysis, but most research has focused on horizontal axis configurations or modeling of single blades rather than full geometries. In order to address this research gap, a systematic review of vertical axis wind-power turbine (VAWT) was undertaken, starting with establishment of a methodology for vertical axis wind turbine simulation that is presented in this paper. Replicating the experimental prototype, both 2D and 3D models of a three-bladed vertical axis wind turbine were generated. Full transient computational fluid dynamics (CFD) simulations using mesh deformation capability available in ansys-CFX were run from turbine start-up to operating speed and compared with the experimental data in order to validate the technique. A circular inner domain, containing the blades and the rotor, was allowed to undergo mesh deformation with a rotational velocity that varied with torque generated by the incoming wind. Results have demonstrated that a transient CFD simulation using a two-dimensional computational model can accurately predict vertical axis wind turbine operating speed within 12% error, with the caveat that intermediate turbine performance is not accurately captured.

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Wind Tower System With a Helical Wind Deflecting Structure, Computational Fluid Dynamics, and Experimental Studies

Journal of Energy Resources Technology ◽

10.1115/1.4025409 ◽

2013 ◽

Vol 136 (2) ◽

Author(s):

Majid Rashidi ◽

Jaikrishnan R. Kadambi ◽

David Kerze

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Wind Speed ◽

Wind Turbines ◽

Average Power ◽

Helical Structure ◽

Amplification Coefficient ◽

Convergence Criterion ◽

Outer Diameter ◽

Tower System

A wind tower system having a three dimensional heliacal wind deflecting structure is studies in this work. The purpose of the helical structure is to increase the natural wind speed and direct the follow of the wind toward two columns of horizontal-axis rooftop-size wind turbines that are installed in the grooves of the helical structure, diametrically opposed to each other. Computational fluid dynamics analyses were conducted to determine the influence of the helical structure on the wind speed reaching the turbines. A wind speed amplification coefficient was determined for a helical structure of 6.7 m outer diameter. The velocity profiles of the wind flow around the helical structure were determined under a postulated wind speed of 4.47 m/s. The flow was modeled as turbulent with a Reynolds Number of 2,052,167. Standard “k–ε” turbulent model with “near wall treatment” and “standard wall function” were adapted in all analysis. A “y+” value of 50 was held constant in all simulation. The grid-size effects on the accuracy of the results were examined. Convergence criterion was satisfied in each case. This study shows that the helical structure having an outer diameter of 6.7 m results in an average wind speed increase factor of 1.52. An experimental wind tower system was fabricated and installed at an elevation of 40 m above the ground. The wind tower system comprised of four identical rooftop size wind turbines, each having 1.6 KW name-plate-rating. A helical wind deflecting structure of 11 m tall, and 7 m in major diameter was used in fabrication of the tower. An active yaw-control mechanism was used to orient the tower into the prevailing wind. The experimental results show that as the result of the use of the wind deflecting structure, an average power amplification factor of 4.69 was obtained for the tower, in comparison with the standard standalone installation of the four wind turbines.

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Flow Velocity Simulation of Wind Turbines by Computational Fluid Dynamics (CFD)

International Journal of Engineering ◽

10.34259/ijew.21.8027378 ◽

2021 ◽

Vol 8 (02) ◽

pp. 73-78

Author(s):

Hammad ur Rahman ◽

◽

Syed Faisal Shah ◽

Abdullah Jamshaid ◽

Muhammad Usama ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Flow Velocity ◽

Wind Turbines ◽

Computational Fluid Dynamics Cfd

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Review on wind turbines with focus on drive train system dynamics

Wind Energy ◽

10.1002/we.1721 ◽

2014 ◽

Vol 18 (4) ◽

pp. 567-590 ◽

Cited By ~ 15

Author(s):

S. Struggl ◽

V. Berbyuk ◽

H. Johansson

Keyword(s):

System Dynamics ◽

Wind Turbines ◽

Drive Train ◽

Train System

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A Fully Coupled Computational Fluid Dynamics Method for Analysis of Semi-Submersible Floating Offshore Wind Turbines Under Wind-Wave Excitation Conditions Based on OC5 Data

Applied Sciences ◽

10.3390/app8112314 ◽

2018 ◽

Vol 8 (11) ◽

pp. 2314 ◽

Cited By ~ 5

Author(s):

Yin Zhang ◽

Bumsuk Kim

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Wind Turbine ◽

Wind Turbines ◽

Wind Wave ◽

Offshore Wind ◽

Wave Excitation ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines ◽

Fully Coupled

Accurate prediction of the time-dependent system dynamic responses of floating offshore wind turbines (FOWTs) under aero-hydro-coupled conditions is a challenge. This paper presents a numerical modeling tool using commercial computational fluid dynamics software, STAR-CCM+(V12.02.010), to perform a fully coupled dynamic analysis of the DeepCwind semi-submersible floating platform with the National Renewable Engineering Lab (NREL) 5-MW baseline wind turbine model under combined wind–wave excitation environment conditions. Free-decay tests for rigid-body degrees of freedom (DOF) in still water and hydrodynamic tests for a regular wave are performed to validate the numerical model by inputting gross system parameters supported in the Offshore Code Comparison, Collaboration, Continued, with Correlations (OC5) project. A full-configuration FOWT simulation, with the simultaneous motion of the rotating blade due to 6-DOF platform dynamics, was performed. A relatively heavy load on the hub and blade was observed for the FOWT compared with the onshore wind turbine, leading to a 7.8% increase in the thrust curve; a 10% decrease in the power curve was also observed for the floating-type turbines, which could be attributed to the smaller project area and relative wind speed required for the rotor to receive wind power when the platform pitches. Finally, the tower-blade interference effects, blade-tip vortices, turbulent wakes, and shedding vortices in the fluid domain with relatively complex unsteady flow conditions were observed and investigated in detail.

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