Download or read book Vertical Axis Hydrokinetic Turbines Numerical and Experimental Analyses written by Mabrouk Mosbahi and published by Bentham Science Publishers. This book was released on 2021-12-14 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Vertical Axis Hydrokinetic Turbines written by Mabrouk Mosbahi; Ahmed and published by . This book was released on 2021-12-14 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Advances of Science and Technology written by Mulatu Liyew Berihun and published by Springer Nature. This book was released on 2022-01-01 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: This two-volume set of LNICST 411 and 412 constitutes the refereed post-conference proceedings of the 9th International Conference on Advancement of Science and Technology, ICAST 2021, which took place in August 2021. Due to COVID-19 pandemic the conference was held virtually. The 80 revised full papers were carefully reviewed and selected from 202 submissions. The papers present economic and technologic developments in modern societies in 7 tracks: Chemical, Food and Bioprocess Engineering; Electrical and Electronics Engineering; ICT, Software and Hardware Engineering; Civil, Water Resources, and Environmental Engineering ICT; Mechanical and Industrial Engineering; Material Science and Engineering; Energy Science, Engineering and Policy.

Download or read book Computational Fluid Dynamic Simulation of Vertical Axis Hydrokinetic Turbines written by Edwin Lenin Chica Arrieta and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Small Wind and Hydrokinetic Turbines written by Philip Clausen and published by IET. This book was released on 2021-11-30 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is huge potential for smaller wind turbines to provide clean energy around the world. Small wind turbines come in a variety of designs, and have similarities in principles and technology to small hydrokinetic turbines (SHKTs). SHKTs, in turn, can play an important role in hydropower. Small wind and hydrokinetic systems can even work together, for example, to power farms, communities, campuses, rural as well as remote rural areas, and island regions.

Download or read book Wind Turbine Design written by Ion Paraschivoiu and published by Presses inter Polytechnique. This book was released on 2002 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: The depletion of global fossil fuel reserves combined with mounting environmental concerns has served to focus attention on the development of ecologically compatible and renewable alternative sources of energy. Wind energy, with its impressive growth rate of 40% over the last five years, is the fastest growing alternate source of energy in the world since its purely economic potential is complemented by its great positive environmental impact. The wind turbine, whether it may be a Horizontal Axis Wind Turbine (HAWT) or a Vertical Axis Wind Turbine (VAWT), offers a practical way to convert the wind energy into electrical or mechanical energy. Although this book focuses on the aerodynamic design and performance of VAWTs based on the Darrieus concept, it also discusses the comparison between HAWTs and VAWTs, future trends in design and the inherent socio-economic and environmental friendly aspects of wind energy as an alternate source of energy.

Download or read book A Numerical Investigation Into the Effects of Positioning and Rotation on the Performance of Two Vertical axis Hydrokinetic Turbines written by Jody Soviak and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book CFD for Wind and Tidal Offshore Turbines written by Esteban Ferrer and published by Springer. This book was released on 2015-06-09 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book encompasses novel CFD techniques to compute offshore wind and tidal applications. Computational fluid dynamics (CFD) techniques are regarded as the main design tool to explore the new engineering challenges presented by offshore wind and tidal turbines for energy generation. The difficulty and costs of undertaking experimental tests in offshore environments have increased the interest in the field of CFD which is used to design appropriate turbines and blades, understand fluid flow physical phenomena associated with offshore environments, predict power production or characterise offshore environments, amongst other topics.

Download or read book Performance Analysis of a High Solidity Diffuser Shrouded Vertical Axis Hydrokinetic Turbine Using Computational Fluid Dynamics written by and published by . This book was released on 2014 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Flow and Fluid Structures on the Performance of Vertical River Hydrokinetic Turbines written by Amir Hossein Birjandi and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improving the Performance of H Darrieus Vertical axis Turbines for Their Use in Isolation and Within Turbine Farms written by Thierry Villeneuve and published by . This book was released on 2021 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book The Low Head Vertical Axis Hydro Turbine written by Nova Energy Limited and published by . This book was released on 1985 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aerodynamics of Wind Turbines 2nd edition written by Martin O. L. Hansen and published by Routledge. This book was released on 2013-05-13 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural response of the wind turbine structure. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method is also covered, as are eigenmodes and the dynamic behaviour of a turbine. The new material includes a description of the effects of the dynamics and how this can be modelled in an ?aeroelastic code?, which is widely used in the design and verification of modern wind turbines. Further, the description of how to calculate the vibration of the whole construction, as well as the time varying loads, has been substantially updated.

Download or read book The Effects of Blade Configurations on Performance of a Tidal Vertical Axis Turbine written by Sepideh Amiritavasoli and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Frontiers in Computational Fluid Structure Interaction and Flow Simulation written by Tayfun E. Tezduyar and published by Springer Nature. This book was released on 2023-11-01 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational fluid-structure interaction (FSI) and flow simulation are challenging research areas that bring solution and analysis to many classes of problems in science, engineering, and technology. Young investigators under the age of 40 are conducting much of the frontier research in these areas, some of which is highlighted in this volume. The first author of each chapter took the lead role in carrying out the research presented. Some of the topics explored include Direct flow simulation of objects represented by point clouds Computational investigation of leaflet flutter in thinner biological heart valve tissues High-fidelity simulation of hydrokinetic energy applications High-resolution isogeometric analysis of car and tire aerodynamics Computational analysis of air-blast-structure interaction Heart valve computational flow analysis with boundary layer and leaflet contact representation Computational thermal multi-phase flow for metal additive manufacturing This volume will be a valuable resource for early-career researchers and students — not only those interested in computational FSI and flow simulation, but also other fields of engineering and science, including fluid mechanics, solid mechanics, and computational mathematics – as it will provide them with inspiration and guidance for conducting their own successful research. It will also be of interest to senior researchers looking to learn more about successful research led by those under 40 and possibly offer collaboration to these researchers.

Download or read book An Evaluation of the U S Department of Energy s Marine and Hydrokinetic Resource Assessments written by National Research Council and published by National Academies Press. This book was released on 2013-04-23 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing renewable energy development, both within the United States and abroad, has rekindled interest in the potential for marine and hydrokinetic (MHK) resources to contribute to electricity generation. These resources derive from ocean tides, waves, and currents; temperature gradients in the ocean; and free-flowing rivers and streams. One measure of the interest in the possible use of these resources for electricity generation is the increasing number of permits that have been filed with the Federal Energy Regulatory Commission (FERC). As of December 2012, FERC had issued 4 licenses and 84 preliminary permits, up from virtually zero a decade ago. However, most of these permits are for developments along the Mississippi River, and the actual benefit realized from all MHK resources is extremely small. The first U.S. commercial gridconnected project, a tidal project in Maine with a capacity of less than 1 megawatt (MW), is currently delivering a fraction of that power to the grid and is due to be fully installed in 2013. As part of its assessment of MHK resources, DOE asked the National Research Council (NRC) to provide detailed evaluations. In response, the NRC formed the Committee on Marine Hydrokinetic Energy Technology Assessment. As directed in its statement of task (SOT), the committee first developed an interim report, released in June 2011, which focused on the wave and tidal resource assessments (Appendix B). The current report contains the committee's evaluation of all five of the DOE resource categories as well as the committee's comments on the overall MHK resource assessment process. This summary focuses on the committee's overarching findings and conclusions regarding a conceptual framework for developing the resource assessments, the aggregation of results into a single number, and the consistency across and coordination between the individual resource assessments. Critiques of the individual resource assessment, further discussion of the practical MHK resource base, and overarching conclusions and recommendations are explained in An Evaluation of the U.S. Department of Energy's Marine and Hydrokinetic Resource Assessment.

Download or read book Impact of Active Deformable Blades on the Performance of Vertical Axis Wind and Hydrokinetic Turbines written by Seyed Vahid Banijamali and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.