Vertical Axis Hydrokinetic Turbines
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Vertical Axis Hydrokinetic Turbines Numerical And Experimental Analyses
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Author : Mabrouk Mosbahi
language : en
Publisher: Bentham Science Publishers
Release Date : 2021-12-14
Vertical Axis Hydrokinetic Turbines Numerical And Experimental Analyses written by Mabrouk Mosbahi and has been published by Bentham Science Publishers this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-12-14 with Science categories.
This handbook is a guide to numerical and experimental processes that are used to analyze and improve the efficiency of vertical axis rotors. Chapters present information that is required to optimize the geometrical parameters of rotors or understand how to augment upstream water velocity. The authors of this volume present a numerical model to characterize the water flow around the vertical axis rotors using commercial CFD code in Ansys Fluent®. The software has been used to select adequate parameters and perform computational simulations of spiral Darrieus turbines. The contents of the volume explain the experimental procedure carried out to evaluate the performance of the spiral Darrieus turbine, how to characterize the water flow in the vicinity of the tested turbine and the method to assess the spiral angle influence on the turbine performance parameters. Results for different spiral angles (ranging from 10° to 40°) are presented. This volume is a useful handbook for engineers involved in power plant design and renewable energy sectors who are studying the computational fluid dynamics of vertical axis turbines (such as Darrieus turbines) that are used in hydropower projects. Key features: - 4 chapters that cover the numerical and experimental analysis of vertical axis rotors and hydrokinetic turbines - Simple structured layout for easy reading (methodology, models and results) - Bibliographic study to introduce the reader to the subject - A wide range of parameters included in experiments - A comprehensive appendix of tables for mechanical parameters, statistical models, rotor parameters and geometric details.
Vertical Axis Hydrokinetic Turbines
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Author : Mabrouk Mosbahi; Ahmed
language : en
Publisher:
Release Date : 2021-12-14
Vertical Axis Hydrokinetic Turbines written by Mabrouk Mosbahi; Ahmed and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-12-14 with categories.
This handbook is a guide to numerical and experimental processes that are used to analyze and improve the efficiency of vertical axis rotors. Chapters present information that is required to optimize the geometrical parameters of rotors or understand how to augment upstream water velocity. The authors of this volume present a numerical model to characterize the water flow around the vertical axis rotors using commercial CFD code in Ansys Fluent®. The software has been used to select adequate parameters and perform computational simulations of spiral Darrieus turbines. The contents of the volume explain the experimental procedure carried out to evaluate the performance of the spiral Darrieus turbine, how to characterize the water flow in the vicinity of the tested turbine and the method to assess the spiral angle influence on the turbine performance parameters. Results for different spiral angles (ranging from 10° to 40°) are presented. This volume is a useful handbook for engineers involved in power plant design and renewable energy sectors who are studying the computational fluid dynamics of vertical axis turbines (such as Darrieus turbines) that are used in hydropower projects. Key features: - 4 chapters that cover the numerical and experimental analysis of vertical axis rotors and hydrokinetic turbines - Simple structured layout for easy reading (methodology, models and results) - Bibliographic study to introduce the reader to the subject - A wide range of parameters included in experiments - A comprehensive appendix of tables for mechanical parameters, statistical models, rotor parameters and geometric details.
Computational Fluid Dynamic Simulation Of Vertical Axis Hydrokinetic Turbines
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Author : Edwin Lenin Chica Arrieta
language : en
Publisher:
Release Date : 2022
Computational Fluid Dynamic Simulation Of Vertical Axis Hydrokinetic Turbines written by Edwin Lenin Chica Arrieta and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with Electronic books categories.
Hydrokinetic turbines are one of the technological alternatives to generate and supply electricity for rural communities isolated from the national electrical grid with almost zero emission. These technologies may appear suitable to convert kinetic energy of canal, river, tidal, or ocean water currents into electricity. Nevertheless, they are in an early stage of development; therefore, studying the hydrokinetic system is an active topic of academic research. In order to improve their efficiencies and understand their performance, several works focusing on both experimental and numerical studies have been reported. For the particular case of flow behavior simulation of hydrokinetic turbines with complex geometries, the use of computational fluids dynamics (CFD) nowadays is still suffering from a high computational cost and time; thus, in the first instance, the analysis of the problem is required for defining the computational domain, the mesh characteristics, and the model of turbulence to be used. In this chapter, CFD analysis of a H-Darrieus vertical axis hydrokinetic turbines is carried out for a rated power output of 0.5 kW at a designed water speed of 1.5 m/s, a tip speed ratio of 1.75, a chord length of 0.33 m, a swept area of 0.636 m2, 3 blades, and NACA 0025 hydrofoil profile.
A Numerical Investigation Into The Effects Of Positioning And Rotation On The Performance Of Two Vertical Axis Hydrokinetic Turbines
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Author : Jody Soviak
language : en
Publisher:
Release Date : 2016
A Numerical Investigation Into The Effects Of Positioning And Rotation On The Performance Of Two Vertical Axis Hydrokinetic Turbines written by Jody Soviak and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
Numerical simulation allows investigation into the influence of separation distance and rotation on the performance of two vertical-axis hydrokinetic turbines. Compu- tational fluid dynamics is applied to calulate the lift and drag coefficients acting upon interacting NACA 0021 turbine blades for a Reynolds number of Red = 10, 000. To understand the effect of separation distance, large-eddy simulation of the flow around side-by-side and staggered cylinders, ReD = 3,000, and airfoils, Rec = 3,000, are also performed. Based upon the simulations, a drag reduction of 11.3% and 19.8% is determined for the downstream cylinder and airfoil, respectively. A reduction in Reynolds stresses is also observed for the staggered configuration compared to the side-by-side configuration. Due to computational resources of large-eddy simulation, the Reynolds averaged Navier-Stokes method is also applied to investigate the influence of separation distance and rotation on two vertical axis hydrokinetic turbines. The numerical simulations show that a drag reduction of 15.5% occurs when the non-dimensional spanwise and streamwise separation distances, based on turbine diameter, reach 1 and 2, respectively.
Effect Of Flow And Fluid Structures On The Performance Of Vertical River Hydrokinetic Turbines
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Author : Amir Hossein Birjandi
language : en
Publisher:
Release Date : 2013
Effect Of Flow And Fluid Structures On The Performance Of Vertical River Hydrokinetic Turbines written by Amir Hossein Birjandi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
Performance Analysis Of A High Solidity Diffuser Shrouded Vertical Axis Hydrokinetic Turbine Using Computational Fluid Dynamics
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Author :
language : en
Publisher:
Release Date : 2014
Performance Analysis Of A High Solidity Diffuser Shrouded Vertical Axis Hydrokinetic Turbine Using Computational Fluid Dynamics written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Mechanical engineering categories.
Improving The Performance Of H Darrieus Vertical Axis Turbines For Their Use In Isolation And Within Turbine Farms
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Author : Thierry Villeneuve
language : en
Publisher:
Release Date : 2021
Improving The Performance Of H Darrieus Vertical Axis Turbines For Their Use In Isolation And Within Turbine Farms written by Thierry Villeneuve and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
Vertical-axis turbines have gained increasing attention in the wind and hydrokinetic energy sectors in recent years. This type of turbine has several interesting advantages over the well-established horizontal-axis wind turbine concept and recent works have suggested that vertical-axis turbines could be favorable for applications in turbine farms. However, this technology is relatively young and more research and development is needed to fully assess their potential in turbine farms. Indeed, it is crucial to better characterize the performance of vertical-axis turbines, find ways to improve their aerodynamic efficiency and understand the different physical mechanisms affecting their wake recovery in order to draw informed conclusions about their eventual use in wind farms and hydrokinetic turbine farms. In this context, the present thesis aims at studying the impact of two design considerations on the efficiency and on the wake recovery of vertical-axis turbines: the use of detached end-plates and the effect of the blade support structures.Firstly, the effect of detached end-plates on the performance and on the wake recovery of a vertical-axis turbine is investigated. A detached end-plate consists of a thin stationary plate that is located very close to the tips of the turbine blades, but not in contact with them. Using numerical simulations (CFD), two geometries of detached end-plates are simulated on a vertical-axis turbine: a circular geometry and a semi-annular one. The results show that these two geometries of detached end-plates allow to significantly increase the efficiency of the vertical-axis turbine considered. The efficiency enhancement can be explained by the viscous interaction that takes place between the turbine bladesand the detached end-plates. This interaction increases the circulation and the lift near the blade tips,which also increases the power extracted from the flow. Regarding the wake, it is shown that the use of semi-annular detached end-plates leads to a faster velocity recovery downstream of the vertical-axis turbine considered. The viscous interaction between the blades and the semi-annular detached end-plates is favorable to the velocity that is induced in the spanwise direction in the turbine wake, and this velocity induction is beneficial to the wake re-energization. Consequently, the velocity recovery in the wake of the turbine with semi-annular detached end-plates is faster than that in the wake of the reference turbine (without detached end-plates).Secondly, always using numerical simulations, the effect of the design and of the position of the blade support structures (i.e., the struts) is investigated on a vertical-axis turbine. The results show that the struts are less detrimental to the turbine efficiency if they are located at the tips of the turbine blades, rather than at other intermediate positions along the blade span. Moreover, it is shown that the use of rounded blade-strut junction geometries allows to increase the turbine efficiency very significantly. Indeed, the use of rounded blade-strut junctions reduces the kinetic energy of the blade tip vortices, and thus, decreases the induced drag considerably. Therefore, rounded blade-strut junctions help to obtain a flow that is essentially two-dimensional over a significant portion of the turbine blades and they also help to reach very interesting efficiency values. Regarding the wake recovery, the position of the struts along the blade span affects the spatial distribution of the vorticity shed in the turbine wake.The results show that struts located at the blade tips are slightly detrimental to the wake recovery incomparison with struts located at other intermediate positions along the blade span. However, because of the significant increase in efficiency, the use of rounded tip struts remains a very interesting option for vertical-axis turbines.
Impact Of Active Deformable Blades On The Performance Of Vertical Axis Wind And Hydrokinetic Turbines
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Author : Seyed Vahid Banijamali
language : en
Publisher:
Release Date : 2023
Impact Of Active Deformable Blades On The Performance Of Vertical Axis Wind And Hydrokinetic Turbines written by Seyed Vahid Banijamali and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023 with categories.
This master's thesis focuses on improving the performance of vertical axis turbines. The proposed solution is to equip these turbines with deformable airfoils, which are capable of deforming at different azimuthal angles in order to achieve better efficiency. Two-thirds of the airfoil's chord is considered deformable, while one-third is considered undeformed at the leading edge. The airfoil undergoes active deformations such that the deformation can be applied and modified dynamically throughout the cycle. Thus, in one complete cycle, the airfoil may have different shapes with the trailing edge pointing inward or outward with different amplitudes. For the study, the commercial finite-volume software StarCCM+ is used and the 2D Unsteady Reynolds-Averaged Navier-Stokes (URANS) model is employed in order to characterize the turbine's behavior during rotation. An overset mesh technique is used in conjunction with radial basis function in order to deform and move the mesh with respect to the blade deformation. Various airfoils, including undeformed airfoils, morphed deformed airfoils, and dynamically deformable airfoils, are examined and compared with respect to their performance. Various factors such as the tip-speed ratio, airfoil amplitudes, and the periods where deformations are applied are discussed. Deformable airfoils can increase the efficiency of the turbine regardless of the tip speed ratio. When the turbine is operated at non-optimal tip speed ratios, the performance of the turbine is enhanced significantly. Nevertheless, an increase of 3.55% is still reported at the optimal tip speed ratio compared to undeformed airfoils.
The Effects Of Blade Configurations On Performance Of A Tidal Vertical Axis Turbine
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Author : Sepideh Amiritavasoli
language : en
Publisher:
Release Date : 2019
The Effects Of Blade Configurations On Performance Of A Tidal Vertical Axis Turbine written by Sepideh Amiritavasoli and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Electronic books categories.
Hydrokinetic energy contains the major uncontrolled source of renewable marine energy. The highest level of converter technology readiness offered in the last three decades is TRL8,Äì9, which is related to the first-generation horizontal axis converters. In low-depth calm waters, one of the best options to harvest tidal energy is vertical axis turbines. About 16% of the conceptual designs presented in the last 30¬†years apply this type of converter, which does not have a high level of technological readiness. In this study, a laboratory-designed vertical axis turbine has been introduced in which the effects of the number of blades, the blade profile, and attack angle on the performance of the turbine were analyzed. A 3D incompressible viscous turbulent computational finite volume approach is applied, with the spatial second-order and temporal first-order accuracies. The turbulent model k-œâ SST was used to obtain the flow inside the turbine. Rotors include two, three, and six blades with three different profiles, including NACA2421, NACA16021, and NACA0020. Computational results reveal that the turbine with three blades and an angle of attack of +8 using the NACA2421 profile has a maximum generation capacity of about 4¬†kW, with a strength factor of 0.4 and a power factor of about 20%. The capacity, however, was lower for a higher number of blades.
Adaptive Power Tracking Control Of Hydrokinetic Energy Conversion Systems
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Author : Mohammad Jahangir Alam Khan
language : en
Publisher:
Release Date : 2010
Adaptive Power Tracking Control Of Hydrokinetic Energy Conversion Systems written by Mohammad Jahangir Alam Khan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.