The Experts below are selected from a list of 579321 Experts worldwide ranked by ideXlab platform
Mats Leijon - One of the best experts on this subject based on the ideXlab platform.
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evaluation of different turbine concepts for wind power
Renewable & Sustainable Energy Reviews, 2008Co-Authors: Sandra Eriksson, Hans Bernhoff, Mats LeijonAbstract:Every year the number of installed wind power plants in the world increases. The horizontal axis wind turbine is the most common type of turbine but there exist other types. Here, three different wind Turbines are considered; the horizontal axis wind turbine and two different concepts of vertical axis wind Turbines; the Darrieus turbine and the H-rotor. This paper aims at making a comparative study of these three different wind Turbines from the most important aspects including structural dynamics, control systems, maintenance, manufacturing and electrical equipment. A case study is presented where three different Turbines are compared to each other. Furthermore, a study of blade areas for different Turbines is presented. The vertical axis wind turbine appears to be advantageous to the horizontal axis wind turbine in several aspects.
Andrei Dragomirescu - One of the best experts on this subject based on the ideXlab platform.
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performance assessment of a small wind turbine with crossflow runner by numerical simulations
Renewable Energy, 2011Co-Authors: Andrei DragomirescuAbstract:Most of the classical wind Turbines are not able to start at wind speeds as low as 2–3 m/s. Other Turbines, like Savonius, have a low maximum efficiency, which renders them useless in poor wind conditions. Therefore, new turbine designs are required to harvest wind power even when the wind speed is low. A wind turbine having a crossflow runner, similar to the Banki water turbine, is studied numerically in this work in order to estimate its performance. The results obtained suggest that this turbine has a considerable high starting torque and its maximum power coefficient is comparable to those of horizontal axis wind Turbines. Based on the results obtained, some improvements of the design are proposed in order to further increase turbine performance.
Ha Thu Le - One of the best experts on this subject based on the ideXlab platform.
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fundamental time domain wind turbine models for wind power studies
Renewable Energy, 2007Co-Authors: Surya Santoso, Ha Thu LeAbstract:One critical task in any wind power interconnection study involves the modelling of wind Turbines. This paper provides the most basic yet comprehensive time–domain wind turbine model upon which more sophisticated models along with their power and speed control mechanisms, can be developed. For this reason, this paper concentrates on the modelling of a fixed-speed wind turbine. The model includes turbine's aerodynamic, mechanical, and electrical components. Data for the rotor, drive-train, and electrical generator are given to allow replication of the model in its entirety. Each of the component-blocks of the wind turbine is modelled separately so that one can easily expand the model to simulate variable-speed wind Turbines or customise the model to suit their needs. Then, an aggregate wind turbine model, or wind farm, is developed. This is followed by four case studies to demonstrate how the models can be used to study wind turbine operation and power grid integration issues. Results obtained from the case studies show that the models perform as expected.
Yongle Li - One of the best experts on this subject based on the ideXlab platform.
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Wake Effect of a Horizontal Axis Wind Turbine on the Performance of a Downstream Turbine
Energies, 2019Co-Authors: Haojun Tang, K.m. Shum, Yongle LiAbstract:This paper presents wind tunnel tests on the wake characteristics of a three-blade horizontal axis wind turbine and the wake effect on the performance of a downstream turbine. For a single turbine model, the performance was determined and this was followed by measurement of the wind characteristics including velocities, turbulence intensities, and correlation in the wake flow field. Subsequently, taking two horizontal axis wind Turbines in a tandem arrangement into account, their performance was tested and the aerodynamic mechanism was discussed. The results showed that the upstream turbine with blades set at a small pitch angle provided smaller disturbance to the flow, but as the blade turned faster, larger changes in the velocity and the turbulence intensity occurred in its wake due to the more frequent disturbance of the wind turbine. The correlation of wake velocities in the turbine swept area also obviously decreased from the free-stream situation. For the downstream turbine, the output power loss largely depended on the wake characteristics of the upstream turbine, which was closely related to lower wind velocities or higher turbulence intensities. The decrease in correlation of the streamwise velocity within the blade swept area is accompanied by the increased correlation of the tangential velocity, which may be beneficial to the downstream turbine’s performance.
Christos τ Georgakis - One of the best experts on this subject based on the ideXlab platform.
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wind Turbines and seismic hazard a state of the art review
Wind Energy, 2016Co-Authors: Evangelos Katsanos, Sebastian Thons, Christos τ GeorgakisAbstract:Wind energy is a rapidly growing field of renewable energy, and as such, intensive scientific and societal interest has been already attracted. Research on wind turbine structures has been mostly focused on the structural analysis, design and/or assessment of wind Turbines mainly against normal (environmental) exposures while, so far, only marginal attention has been spent on considering extreme natural hazards that threat the reliability of the lifetime-oriented wind turbine's performance. Especially, recent installations of numerous wind Turbines in earthquake prone areas worldwide (e.g., China, USA, India, Southern Europe and East Asia) highlight the necessity for thorough consideration of the seismic implications on these energy harnessing systems. Along these lines, this state-of-the-art paper presents a comparative survey of the published research relevant to the seismic analysis, design and assessment of wind Turbines. Based on numerical simulation, either deterministic or probabilistic approaches are reviewed, because they have been adopted to investigate the sensitivity of wind Turbines' structural capacity and reliability in earthquake-induced loading. The relevance of seismic hazard for wind Turbines is further enlightened by available experimental studies, being also comprehensively reported through this paper. The main contribution of the study presented herein is to identify the key factors for wind Turbines' seismic performance, while important milestones for ongoing and future advancement are emphasized. Copyright © 2016 John Wiley & Sons, Ltd.
