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Reduced Order Structural Modeling of Wind Turbine BladesJonnalagadda, Yellavenkatasunil 2011 August 1900 (has links)
Conventional three dimensional structural analysis methods prove to be expensive for the preliminary design of wind turbine blades. However, wind turbine blades are large slender members with complex cross sections. They can be accurately modeled using beam models. The accuracy in the predictions of the structural behavior using beam models depends on the accuracy in the prediction of their effective section properties. Several techniques were proposed in the literature for predicting the effective section properties. Most of these existing techniques have limitations because of the assumptions made in their approaches.
Two generalized beam theories, Generalized Timoshenko and Generalized Euler-Bernoulli, for the static analysis based on the principles of the simple 1D-theories are developed here. Homogenization based on the strain energy equivalence principle is employed to predict the effective properties for these generalized beam theories. Two efficient methods, Quasi-3D and Unit Cell, are developed which can accurately predict the 3D deformations in beams under the six fundamental deformation modes: extension, two shears, torsion and two flexures. These methods help in predicting the effective properties using the homogenization technique. Also they can recover the detailed 3D deformations from the predictions of 1D beam analysis.
The developed tools can analyze two types of slender members 1) slender members with invariant geometric features along the length and 2) slender members with periodically varying geometric features along the length. Several configurations were analyzed for the effective section properties and the predictions were validated using the expensive 3D analysis, strength of materials and Variational Asymptotic Beam Section Analysis (VABS). The predictions from the new tools showed excellent agreement with full 3D analysis. The predictions from the strength of materials showed disagreement in shear and torsional properties. Explanations for the same are provided recalling the assumptions made in the strength of materials approach.
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Reducing the environmental impact of wind turbine bladesLiu, Pu January 2017 (has links)
Wind energy, one of the most promising sources of clean energy, has developed rapidly over the last two decades. Wind turbines (WT) are arguably clean during operation, offering minimal pollution and zero CO2 emissions, but significant amounts of energy are used and CO2 emitted during their manufacture, and, furthermore, the turbines are environmentally problematic at end-of-life (EoL), especially the blades. WT blades are mainly made with composite materials comprising thermosetting resin and glass fibre. They are lightweight and strong but problematic to recycle. Large volumes of waste will be generated when these WT blades are decommissioned and environmental concerns have been raised. The main aim of this study is to understand the environmental impact of wind turbine blades and to find solutions to reduce it. A quantitative method is adopted, first evaluating the WT blade waste inventory then calculating its environmental impact, and finally analysing the differences between all possible EoL options in terms of environmental and financial performance. The results firstly identify the global wind turbine blade waste inventory with detailed generation time and location which could help policy makers to gain an understanding of the size and severity of this problem. Secondly, the outputs indicate where most impact is generated and identify what to prioritise to reduce waste and reduce environmental impact, which is of value to blade manufacturers and other stakeholders. Moreover, this work highlights previous incorrect assumptions and provides findings to build on for future work. Thirdly, ‘optimal’ EoL options for the WT blade waste have been characterized: the current ‘optimal’ EoL option is life extension; mechanical recycling is the current ‘optimal’ recycling option; chemical recycling will be the ‘optimal’ option for the future. Future research is suggested as aiming to improve the performance of recycled fibre or to reduce the energy consumption of recycling processes.
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Small-scale Wind Energy Portable Turbine (SWEPT)Kishore, Ravi Anant 24 May 2013 (has links)
Large Scale Wind Turbines (LSWTs) have been extensively examined for decades but very few studies have been conducted on the small scale wind turbines (SSWTs) especially for the applications near ground level where wind speed is of order of few meters per second. This study provides the first systematic effort towards design and development of SSWTs (rotor diameter<50 cm) targeted to operate at low wind speeds (<5 m/s). An inverse design and optimization tool based on Blade Element Momentum theory is proposed. The utility and efficacy of the tool was validated by demonstrating a 40 cm diameter small-scale wind energy portable turbine (SWEPT) operating in very low wind speed range of 1 m/s-5 m/s with extremely high power coefficient. In comparison to the published literature, SWEPT is one of the most efficient wind turbines at the small scale and very low wind speeds with the power coefficient of 32% and overall efficiency of 21% at its rated wind speed of 4.0 m/s. It has very low cut-in speed of 1.7 m/s. Wind tunnel experiments revealed that SWEPT has rated power output of 1 W at 4.0 m/s, and it is capable of producing power output up to 9.3 W at wind speed of 10 m/s. The study was further extended to develop a piezoelectric wind turbine which operates below 2.0 m/s wind speed. The piezoelectric wind turbine of overall dimension of 100mm x 78mm x 65mm is capable of producing peak electric power of about 450 microwatt at the rated wind speed of 1.9 m/s. / Master of Science
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An Assessment of Surface Ice Sheet Loads and Their Effects on an Offshore Wind Turbine StructureWells, Eric M. January 2012 (has links)
No description available.
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Optimization of the Layout of Large Wind Farms using a Genetic AlgorithmMittal, Anshul 17 May 2010 (has links)
No description available.
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The Optimization of Offshore Wind Turbine Towers Using Passive Tuned Mass DampersYilmaz, Onur Can 29 August 2014 (has links)
Increasing energy demand and carbon emissions have driven the development of alternative energy solutions. One promising technology is wind energy. Wind energy technology developments has advanced substantially since the 1980s. Offshore wind turbines have become a major research focus, due to the promising offshore wind resource. However, challenges in offshore wind energy have arisen due to the additional wave loading and strong wind loads. Structural control systems have been implemented and researched in order to decrease dynamic response of these systems. The previous studies were successful at decreasing fatigue loads in the tower and support structure of offshore wind turbines. Giving these results, it is still unknown if the reduced loading enabled by structural control systems can allow for reduced material costs in the major structural components.
This research examines on an offshore wind turbine's tower-monopile structure by adding several configurations of passive tuned mass dampers, while simultaneously reducing the thickness of the structure in order to reduce costs. A range of candidate tower-monopile systems are created, and simulated in FAST-SC with and without passive tuned mass dampers. Fatigue and ultimate loads are calculated and analyzed. A variety of design criteria are considered including fatigue and ultimate loads, as well as local and global buckling. The results demonstrate that the tower-monopile thickness may be reduced up to 6.2% and still satisfy all design criteria.
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PERFORMANCE ASSESSMENT OF THE CASE WESTERN RESERVE UNIVERSITYWIND TURBINE AND CHARACTERIZATION OF WIND AVAILABILITYWo, Chung 21 February 2014 (has links)
No description available.
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Site Specific Design Optimization Of A Horizontal Axis Wind Turbine Based On Minimum Cost Of EnergySagol, Ece 01 January 2010 (has links) (PDF)
This thesis introduces a design optimization methodology that is based on minimizing the Cost of Energy (COE) of a Horizontal Axis Wind Turbine (HAWT) that is to be operated at a specific wind site. In the design methodology for the calculation of the Cost of Energy, the Annual Energy Production (AEP) model to calculate the total energy generated by a unit wind turbine throughout a year and
the total cost of that turbine are used. The AEP is calculated using the Blade Element Momentum (BEM) theory for wind turbine power and the Weibull
distribution for the wind speed characteristics of selected wind sites. For the blade profile sections, either the S809 airfoil profile for all spanwise locations is used or NREL S-series airfoil families, which have different airfoil profiles for different spanwise sections, are used,. Lift and drag coefficients of these airfoils are obtained by performing computational fluid dynamics analyses. In sample
design optimization studies, three different wind sites that have different wind speed characteristics are selected. Three scenarios are generated to present the effect of the airfoil shape as well as the turbine power. For each scenario, design optimizations of the reference wind turbines for the selected wind sites are performed the Cost of Energy and Annual Energy Production values are
compared.
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Design of a shrouded wind turbine for low wind speeds / Jacobus Daniel HumanHuman, Jacobus Daniel January 2014 (has links)
The use of renewable energy is promoted worldwide to be less dependent on fossil fuels and
nuclear energy. Therefore research in the field is driven to increase efficiency of renewable energy
systems.
This study aimed to develop a wind turbine for low wind speeds in South Africa. Although
there is a greater tendency to use solar panels because of the local weather conditions, there are
some practical implications that have put the use of solar panels in certain areas to an end. The
biggest problem is panel theft. Also, in some parts of the country the weather is more suitable to
apply wind turbines.
Thus, this study focused on the design of a new concept to improve wind turbines to be appropriate
for the low wind speeds in South Africa. The concept involves the implementation of a
concentrator and diffuser to a wind turbine, to increase the power coefficient. Although the wind
turbine was not tested for starting speeds, the implementation of the shroud should contribute to
improved starting of the wind turbine at lower wind speeds.
The configuration were not manufactured, but simulated with the use of a program to obtain
the power production of the wind turbine over a range of wind speeds. These values were compared
to measured results of a open wind turbine developed for South Africa.
The most important matter at hand when dealing with a shrouded wind turbine is to determine
if the overall diameter or the blade diameter of the turbine should be the point of reference. As
the wind turbine is situated in a shroud that has a larger diameter than the turbine blades, some
researchers believe that the overall diameter should be used to calculate the efficiency.
Theory was revised to determine the available energy in the shroud after initial calculations
showed that the power coefficients should have been higher than the open wind turbine with the
same total diameter. A new equation was derived to predict the available energy in a shroud.
The benefits of shrouded wind turbines are fully discussed in the dissertation content. / MSc (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
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Design of a shrouded wind turbine for low wind speeds / Jacobus Daniel HumanHuman, Jacobus Daniel January 2014 (has links)
The use of renewable energy is promoted worldwide to be less dependent on fossil fuels and
nuclear energy. Therefore research in the field is driven to increase efficiency of renewable energy
systems.
This study aimed to develop a wind turbine for low wind speeds in South Africa. Although
there is a greater tendency to use solar panels because of the local weather conditions, there are
some practical implications that have put the use of solar panels in certain areas to an end. The
biggest problem is panel theft. Also, in some parts of the country the weather is more suitable to
apply wind turbines.
Thus, this study focused on the design of a new concept to improve wind turbines to be appropriate
for the low wind speeds in South Africa. The concept involves the implementation of a
concentrator and diffuser to a wind turbine, to increase the power coefficient. Although the wind
turbine was not tested for starting speeds, the implementation of the shroud should contribute to
improved starting of the wind turbine at lower wind speeds.
The configuration were not manufactured, but simulated with the use of a program to obtain
the power production of the wind turbine over a range of wind speeds. These values were compared
to measured results of a open wind turbine developed for South Africa.
The most important matter at hand when dealing with a shrouded wind turbine is to determine
if the overall diameter or the blade diameter of the turbine should be the point of reference. As
the wind turbine is situated in a shroud that has a larger diameter than the turbine blades, some
researchers believe that the overall diameter should be used to calculate the efficiency.
Theory was revised to determine the available energy in the shroud after initial calculations
showed that the power coefficients should have been higher than the open wind turbine with the
same total diameter. A new equation was derived to predict the available energy in a shroud.
The benefits of shrouded wind turbines are fully discussed in the dissertation content. / MSc (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
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