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1
Chaath, Alaaeddin. "Improving the Design of Wind Turbine Plants : Future Design of Wind Turbine Plants." Thesis, Högskolan i Halmstad, Energivetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-31084.
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Applying the new ideas developed by the present study on the current design of WTP can lead to satisfactory results and give flexibility in terms of producing more electrical power during periods of low/medium wind velocity. The innovative ideas and methods included in the present work reveal the features of the future renewable energy designs that could, in the few coming years, revolutionize the field of wind turbine designs worldwide. Also, increase the capacity factor significantly, since the application of these ideas in areas where wind class II and III blows have proven to be very effective. Especially, when compares the result of new ideas with the current wind turbine designs. Testing the innovative ideas regarding the future wind turbines on a current WTP achieved a good results in increasing electric energy production over the year. For example applies the new ideas on a WTP model Enercon (E-101) will achieve an annual increase around 20% of electric power generation (wind class II, Cp = 36), i.e. when wind speed is ranging from 0-10 m/s (Level C – option 02) the production improved at the highest value, reaching up to +46%. Also, in Level B the generation of electricity witnessed an increase up to 10% when the wind velocity being always between level C with a minimum of 10 meters per second and Level A (Level A is the maximum output value, which is changing from one turbine type to the other).
2
Gwon, Tae gyun. "Structural Analyses of Wind Turbine Tower for 3 kW Horizontal Axis Wind Turbine." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/600.
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Structure analyses of a steel tower for Cal Poly's 3 kW small wind turbine is presented. First, some general design aspects of the wind turbine tower are discussed: types, heights, and some other factors that can be considered for the design of wind turbine tower. Then, Cal Poly's wind turbine tower design is presented, highlighting its main design features. Secondly, structure analysis for Cal Poly's wind turbine tower is discussed and presented. The loads that are specific to the wind turbine system and the tower are explained. The loads for the static analysis of the tower were calculated as well. The majority of the structure analysis of the tower was performed using the finite element method (FEM). Using Abaqus, commercial FEM software, both static and dynamic structural analyses were performed. A simplified finite element model that represents the wind turbine tower was created using beam, shell, and inertia elements. An ultimate load condition was applied to check the stress level of the tower in the static analysis. For the dynamic analysis, the frequency extraction was performed in order to obtain the natural frequencies and the mode shapes of the tower. Using the results, the response spectrum analysis and the transient dynamic analysis, which are based on the modal superposition method, were performed in order to see the structure's response for earthquakes that are likely to happen at the wind turbine installation site.
3
Schmidt, Michael Frank. "Economic optimization of wind turbine design." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19740.
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El-Bardisi, Mansour Mohamed Mansour. "Reduction of wind turbine noise through design." Thesis, City University London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332781.
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Lee, Donghoon. "Multi-flexible-body analysis for applications to wind turbine control design." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04052004-180040/unrestricted/lee%5Fdonghoon%5F200312%5Fphd.pdf.
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Shaheen, Mohammed Mahmoud Zaki Mohammed. "Design and Assessment of Vertical Axis Wind Turbine Farms." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439306478.
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Olivieri, David Allen. "Design and testing of a concentrator wind turbine." Thesis, Open University, 1991. http://oro.open.ac.uk/54560/.
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Wind energy, being an indirect form of solar energy would initially seem a very promising form of energy. Unfortunately, it suffers from the problem of dilution. Wind turbine designers naturally try to compensate for this by increasing the size of the rotor to capture more of the kinetic energy of the wind. A major constraint in conventional wind turbine design is the reduction in rotational speed as the size of the rotor is increased. This means expensive gear boxes are unavoidable. The rotor also becomes considerably more complicated in design and heavier as the size increases, to mitigate working stresses. Flow concentrators have been investigated in an attempt to alleviate wind turbine design problems, but flow concentrators usually incur the expense of high structural weight and size. The Helical Vortex Wind Concentrator (HVWC) is a recent addition to the list of flow concentrator types and its economic potential is, as yet unknown. The principle of the HVWC has been demonstrated in a series of wind tunnel tests. The wind tunnel tests involved a direct comparison between the performance of a wind turbine with and without an HVWC attached. During these tests a definite increase in power out was observed when the concentrator was attached to the wind turbine. Previous to these successful wind tunnel tests, other wind tunnel and field tests had been conducted on less successful designs. These other tests were important in the development of the current theory and design or the HVWC. Future research will need to investigate both physical and economic limitations of this type of wind concentrator.
8
Peng, Li. "Analysis and Design of Offshore Jacket Wind Turbine." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11612.
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Offshore wind is an attractive source of renewable energy. In order to harvest this abundant energy source wind turbine farms are needed. In order to extend the application of offshore fixed wind turbine (OFWT) in deep water where winds are stronger and steadier, there are research works on fixed wind turbine which is ongoing on larger water depth like 70-100m. The focus in this thesis is analyses to support design of OFWT jacket substructure piled to the seabed, with a particular focus the modeling and ultimate capacity behavior of such facilities subjected to extreme wind and wave forces. During modelling, Genie and USFOS are applied to re-design and modify the finite element model of wind turbine substructure given by Aker Solutions. New design jacket substructures are both for the intermediate water depth 70 meters and 100 meters with the soil and pile modelling based on the Ekofisk data. Based on design load case, both of the static pushover analysis and API design code check is performed on the jacket substructure model to check the ultimate capacity. The pushover analysis is performed through nonlinear finite elemnt code USFOS. The API code check is based on hand calculation.The response of the jacket substructures under design load case is most interested in, which could indicate the critical position on jacekt, furthermore the effect of the direction and size of the wind and wave load. Meanwhile, through comaprission of results, the two methods could confirm each other, which could help to get the deeper understanding of ULS of offshore jacket structure.
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Sæta, Eivind. "Design of Airfoil for downwind wind turbine Rotor." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12883.
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This thesis is on the design of an airfoil for a downwind wind turbine rotor with thin flexible wings, for offshore floating conditions. It has been suggested that such a system would to be lighter, simpler and allow for the use of more efficient airfoils. There has been a significant amount of work done at NTNU to develop a high-lift airfoil. These are airfoils with very high lift-to-drag ratios. They operate very efficiently at their design angle, but tend to not work well over a range of angles and conditions, and have a sudden and dramatic stall characteristic. In this thesis, it is attempted to pick up the work done with the high-lift profiles at NTNU in the 1980s, and develop a new profile which has performance in the high-lift range, but with a much smoother stall and more stable characteristics, and to do so for the typical conditions expected for the suggested turbine. A fictitious 5 MW version of the suggested turbine was created and analyzed with the blade element momentum method (BEM). This gave informative results about the conditions the new airfoil must operate in. The high-lift technology and the earlier reports from NTNU were studied. Based on this knowledge and the numerical values from the BEM calculations, a serious of new airfoils were developed. By using the simulation programs Xfoil and Fluent (CFD), it was possible to modify and test a large number of airfoils and find the desired qualities.It was possible to design airfoils that had performance in the high-lift range, while maintaining stable operation and having a soft stall, and also increase the lift coefficient to be able to design for lower angles of attack. The profiles created here appear to be suitable for wind turbines, and provide an impressive increase in performance compared to traditional airfoils.Extra effort was put into making airfoils that were unaffected by roughness, air properties and Reynolds number, as stable performance in varying conditions are necessary for wind turbine blades. This was done by using adverse pressure gradients to control the point of transition.A slow stall was achieved by letting the pressure recovery distribution gradually approach the local ideal Stratford distribution when moving back over the airfoil. This caused the flow separate at the back first, and then the separation would grow gradually forward with increasing angle of attack.The inclusion of a separation ramp also worked very well together with the high-lift design, and allowed for an increased lift coefficient and more stable operation during the region of early stall.The most successful profile created appears to be the AR profile. It combines a diverged Stratford distribution with a separation ramp and a pressure spike at the nose to control transition. It has a wider range, stalls later and softer, and has a much more stable performance with varying conditions compared to the original HOG profile from NTNU. At the design point, the maximum performance is reduced only 5.9 % compared to the HOG. For higher and lower angles of attack, and increased values of roughness and turbulence, the AR has an all round higher performance than the HOG. It appears to be usable for wind turbines, and would increase the maximum airfoil performance by up to 40 % compared to commonly used NACA profiles. More good profiles were made, with varying thickness, stall and performance. Depending on the exact local requirements of an application, this report offers several interesting profiles to choose from. For instance, the D2 profile has round shape and over 16 % thickness, it has an even softer stall than the conventional wind turbine profiles, and would increase the maximum airfoil performance by up to ~34%. This profile would also be usable for upwind turbines.It was found that there is a big potential for manipulating the high-lift technology to give various shapes and performances. The usability of these profiles therefore appears to be wider than previously assumed.
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Kachhia, Bhaveshkumar Mahendrabhai. "Design and tribological issues in wind turbine bearings." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0076.
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Grandes bague de roulement utilisés dans éolienne sont l'un des éléments de transmission de charge importantes de ces machines tournantes. Ces roulements fonctionnent grâce à des cycles de charge et de la fréquence et de l'expérience des défis complexes tribologiques sévères. Le coût de remplacement de ces paliers est très élevé et conduit aussi à quantité importante de temps d'arrêt. Il est donc important de comprendre certains des principaux problèmes de conception et tribologiques de ces roulements. Quatre points type de roulement de l'anneau de contact de rotation a été considéré comme une base de référence pour cette étude pour démontrer les questions de contact de troncature et d'échec de la cage pour les roulements de hauteur. Un palier de contact à deux points de remplacement est proposé d'éliminer le contact troncature et de réduire la force de la cage accumulation. Les méthodes de conception et d'analyse démontré dans cette étude peuvent être facilement étendus à lacet paliers ainsi que d'autres grands roulements utilisés dans l'industrieLarge slewing ring bearings used in wind turbine are one of the important load transmitting elements of these rotating machines. These bearings operate through complex load and frequency cycles and experience severe tribological challenges. The cost of replacement of these bearings is very high and also leads to significant amount of down-time. It is therefore important to understand some of the major design and tribological issues in these bearings. Four-point contact slewing ring bearing type has been considered as a baseline for this study to demonstrate contact truncation and cage failure issues for pitch bearings. An alternate two-point contact bearing is proposed to eliminate contact truncation and reduce the cage force build-up. The design and analysis methods demonstrated in this study can be easily extended to yaw bearings as well as other large bearings used in the industry
11
Zhang, Hui. "Wind turbine adaptive blade integrated design and analysis." Thesis, Northumbria University, 2013. http://nrl.northumbria.ac.uk/21439/.
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This project aims to develop efficient and robust tools for optimal design of wind turbine adaptive blades. In general, wind turbine adaptive blade design is an aero-structure coupled design process, in which, the evaluation of aerodynamic performance cannot be carried out precisely without structural deformation analysis of the adaptive blade. However, employing finite element analysis (FEA) based structural analysis commercial packages as part of the aerodynamic objective evaluation process has been proven time consuming and it results in inefficient and redundant design optimisation of adaptive blades caused by elastic-coupled (bend-twist or stretch-twist) iteration. In order to achieve the goal of wind turbine adaptive blade integrated design and analysis, this project is carried out from three aspects. Firstly, a general geometrically linear model for thin-walled composite beams with multi-cell, non-uniform cross-section and arbitrary lay-ups under various types of loadings is developed for implementing structural deformation analysis. After that, this model is validated by a simple box-beam, single- and multi-cell wind turbine blades. Through validation, it denotes that this thin-walled composite beam model is efficient and accurate for predicting the structural deformations compared to FEA based commercial packages (ANSYS). This developed beam model thus provides more probabilities for further investigations of dynamic performance of adaptive blades. Secondly in order to investigate the effects of aero elastic tailoring and implanting elastic coupling on aerodynamic performance of adaptive blades, auxiliary software tools with graphical interfaces are developed via MATLAB codes. Structural/material characteristics and configurations of adaptive blades (i.e. elastic coupling topology, layup configuration and material properties of blade) are defined by these auxiliary software tools. By interfacing these software tools to the structural analysers based on the developed thin-walled composite beam model to an aerodynamic performance evaluator, an integrated design environment is developed. Lastly, by using the developed thin-walled composite beam model as a search platform, the application of the decoupled design method, a method of design of smart aero-structures based on the concept of variable state design parameter, is also extended.
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Du, Yingkang. "An Orthogonal Savonius-type Wind Turbine: Design and Experiments." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459510710.
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Veldkamp, Herman Frederik. "Chances in wind energy : a probabilistic approach to wind turbine fatigue design /." [Delft] : DUWIND Delft Univ. Wind Energy Research Inst, 2006. http://www.gbv.de/dms/bs/toc/520167805.pdf.
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Fossum, Peter Kalsaas. "Aeroelastic analysis of an offshore wind turbine : Design and Fatigue Performance of Large Utility-Scale Wind Turbine Blades." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18547.
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Aeroelastic design and fatigue analysis of large utility-scale wind turbine blades are performed. The applied fatigue model is based on established methods and is incorporated in an iterative numerical design tool for realistic wind turbine blades. All aerodynamic and structural design properties are available in literature. The software tool FAST is used for advanced aero-servo-elastic load calculations and stress-histories are calculated with elementary beam theory.According to wind energy design standards, a turbulent wind load case is implemented. Fatigue loads are estimated based on 100% availability and a site-specific annual wind distribution. Rainflow cycle counting and Miner’s sum for cumulative damage prediction is used together with constant life diagrams tailored to actual material S-N data. Material properties are based on 95% survival probability, 95% confidence level, and additional material safety factors to maintain conservative results. Fatigue performance is first evaluated for the baseline blade design of the 10MW NOWITECH reference wind turbine. Results show that blade damage is dominated by tensile stresses due to poorer tensile fatigue characteristics of the shell glass fiber material. The interaction between turbulent wind and gravitational fluctuations is demonstrated to greatly influence the damage. The need for relevant S-N data to closely predict such blade stress cycle events is investigated to avoid non-conservative conclusions. State-of-art wind turbine blade trends are discussed and different designs of the NOWITECH baseline blade are analyzed in a parametric study focusing on fatigue performance and material costs.
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Rynkiewicz, Mateusz. "Design of PM generator for avertical axis wind turbine." Thesis, Uppsala universitet, Elektricitetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-177309.
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The task in this project is to design a generator for a vertical axis wind turbine withpower rated to 20kW at a wind speed of 10m/s. The project is conducted at theDivision of Electricity at Uppsala University with collaboration from ElectricGeneration AB. The design has just a few moving parts, which decreases maintenancecosts and increases its toughness. The turbine absorbs wind from every direction butits rotation speed ratio is lower than horizontal axis wind turbines. It means that thegenerator must be bigger and therefore more expensive. Price is an importantcriterion for the generator. Neodymium magnets are expensive so the amount of thismaterial must be limited.Several designs have been simulated but one final design has proven the mostpromising. It fulfills all specifications such as efficiency above 95%, 20kW outputpower and it also has a relatively low amount of hard magnetic material.A design with a single row of cables per slot was decided upon to eliminate heatpockets between cable rows, which can occur in designs with two cable rows perslot. It would be interesting to study designs with two or more cable rows per slot, asit could lead to a smaller and more efficient machine.
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Duran, Serhat. "Computer-aided Design Of Horizontal-axis Wind Turbine Blades." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12605790/index.pdf.
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Designing horizontal-axis wind turbine (HAWT) blades to achieve satisfactory
levels of performance starts with knowledge of the aerodynamic forces acting on
the blades. In this thesis, HAWT blade design is studied from the aspect of
aerodynamic view and the basic principles of the aerodynamic behaviors of
HAWTs are investigated.
Blade-element momentum theory (BEM) known as also strip theory, which is
the current mainstay of aerodynamic design and analysis of HAWT blades, is used
for HAWT blade design in this thesis.
Firstly, blade design procedure for an optimum rotor according to BEM theory
is performed. Then designed blade shape is modified such that modified blade will
be lightly loaded regarding the highly loaded of the designed blade and power
prediction of modified blade is analyzed. When the designed blade shape is
modified, it is seen that the power extracted from the wind is reduced about 10%
and the length of modified blade is increased about 5% for the same required
power.
BLADESIGN which is a user-interface computer program for HAWT blade
design is written. It gives blade geometry parameters (chord-length and twist
distributions) and design conditions (design tip-speed ratio, design power
coefficient and rotor diameter) for the following inputspower required from a turbine, number of blades, design wind velocity and blade profile type (airfoil type). The program can be used by anyone who may not be intimately concerned with the concepts of blade design procedure and the results taken from the program can be used for further studies.
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Di, Pietro Joshua (Joshua Michael). "Structural analysis and design of floating wind turbine systems." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/50575.
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Thesis (S.M. in Mechanical Engineering and Naval Architecture and Marine Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (p. 139-140).
As oil supply rates approach potential maximums and the global detrimental effects of carbon emitting energy technology are becoming more comprehensively understood, the world is searching for environmentally benign energy technology which can be reliably and economically harvested. Deep water offshore wind is a vast, reliable and potentially economical energy source which remains globally untapped. In order to harvest this resource, potential floating turbine systems must be analyzed and designed for economic production and deployment, reliable operation, and adequate service life. The Laboratory of Ship and Platform Flow (LSPF) has created trusted hydrodynamic modeling software used to perform a Pareto Optimization which resulted in an optimized Floating Wind Turbine (FWT) design which is a Tension Leg Platform (TLP); hereto called MIT TLP-1. This thesis details the structural design aspects of Floating Wind Turbines (FWT) in a rationally based optimization approach for incorporation into existing LSPF hydrodynamic optimization approaches. A steel structural design is created based on the geometry and loading of the MIT TLP-1 for a 10m significant wave height. The design is based on similar system analysis, classic linear structural theory, American Bureau of Shipping rules and American Petroleum Institute recommended practices. The design is verified using Finite Element Analysis (FEA). The results of this work show that the MIT TLP-1 design is technically feasible from a structural integrity, performance and producibility standpoint.
by Joshua Di Pietro.
S.M.in Mechanical Engineering and Naval Architecture and Marine Engineering
18
Dey, Soumitr. "Wind Turbine Blade Design System - Aerodynamic and Structural Analysis." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307440410.
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Caboni, Marco. "Probabilistic design optimization of horizontal axis wind turbine rotors." Thesis, University of Glasgow, 2016. http://theses.gla.ac.uk/7338/.
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Considerable interest in renewable energy has increased in recent years due to the concerns raised over the environmental impact of conventional energy sources and their price volatility. In particular, wind power has enjoyed a dramatic global growth in installed capacity over the past few decades. Nowadays, the advancement of wind turbine industry represents a challenge for several engineering areas, including materials science, computer science, aerodynamics, analytical design and analysis methods, testing and monitoring, and power electronics. In particular, the technological improvement of wind turbines is currently tied to the use of advanced design methodologies, allowing the designers to develop new and more efficient design concepts. Integrating mathematical optimization techniques into the multidisciplinary design of wind turbines constitutes a promising way to enhance the profitability of these devices. In the literature, wind turbine design optimization is typically performed deterministically. Deterministic optimizations do not consider any degree of randomness affecting the inputs of the system under consideration, and result, therefore, in an unique set of outputs. However, given the stochastic nature of the wind and the uncertainties associated, for instance, with wind turbine operating conditions or geometric tolerances, deterministically optimized designs may be inefficient. Therefore, one of the ways to further improve the design of modern wind turbines is to take into account the aforementioned sources of uncertainty in the optimization process, achieving robust configurations with minimal performance sensitivity to factors causing variability. The research work presented in this thesis deals with the development of a novel integrated multidisciplinary design framework for the robust aeroservoelastic design optimization of multi-megawatt horizontal axis wind turbine (HAWT) rotors, accounting for the stochastic variability related to the input variables. The design system is based on a multidisciplinary analysis module integrating several simulations tools needed to characterize the aeroservoelastic behavior of wind turbines, and determine their economical performance by means of the levelized cost of energy (LCOE). The reported design framework is portable and modular in that any of its analysis modules can be replaced with counterparts of user-selected fidelity. The presented technology is applied to the design of a 5-MW HAWT rotor to be used at sites of wind power density class from 3 to 7, where the mean wind speed at 50 m above the ground ranges from 6.4 to 11.9 m/s. Assuming the mean wind speed to vary stochastically in such range, the rotor design is optimized by minimizing the mean and standard deviation of the LCOE. Airfoil shapes, spanwise distributions of blade chord and twist, internal structural layup and rotor speed are optimized concurrently, subject to an extensive set of structural and aeroelastic constraints. The effectiveness of the multidisciplinary and robust design framework is demonstrated by showing that the probabilistically designed turbine achieves more favorable probabilistic performance than those of the initial baseline turbine and a turbine designed deterministically.
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Nicholson, John Corbett. "Design of wind turbine tower and foundation systems: optimization approach." Thesis, University of Iowa, 2011. https://ir.uiowa.edu/etd/1042.
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A renewed commitment in the United States and abroad to electricity from renewable resources, such as wind, along with the recent deployment of very large turbines that rise to new heights, makes obtaining the most efficient and safe designs of the structures that support them ever more important. Towards this goal, the present research seeks to understand how optimization concepts and Microsoft Excel's optimization capabilities can be used in the design of wind turbine towers and foundations. Additionally, this research expands on the work of previous researchers to study how considering the tower and foundation as an integral system, where tower support conditions are not perfectly rigid, affects the optimal design. Specifically, optimization problems are formulated and solved with and without taking into account the effect of deflections, resulting from the foundation's rotational and horizontal stiffness, on natural frequency calculations. The general methodology used to transcribe the design of wind turbine towers and foundations into an optimization problem includes: 1) collecting information on design requirements and parameter values 2) deciding how to analyze the structure 3) formulating the optimization problem 4) implementation using Microsoft Excel. Key assumptions include: 1) use of an equivalent lumped mass method for estimating natural frequency 2) International Electrotechnical Commission (IEC) 61400-1 extreme loading condition controls design (i.e. fatigue loading condition is not considered) 3) extreme loads are obtained from manufacturer provided structural load document that satisfies loading cases outlined in IEC 61400-1 4) wind forces on the tower are calculated in accordance with IEC 61400-1 5) optimization variables are continuous. The sum of the tower material and fabrication cost and the total foundation cost is taken as the objective function. Important conclusions from this work include: 1) optimization concepts and Microsoft Excel's optimization capabilities can be used to obtain reasonable conceptual level designs and cost estimates 2) detailed designs and cost estimates could be achieved using a solver capable of handling discrete optimization problems 3) considering the tower and foundation as an integral system results in a more expensive, but safer, design 4) for the assumed parameter values, the constraint on the tower's natural frequency was found to control the tower design and the bearing capacity constraint was found to control the foundation design 5) relaxing or tightening the limit on the natural frequency will result in the greatest benefit or penalty, respectively, on the optimum solution.
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Van, Zyl Willem Sternberg. "Concrete wind turbine towers in Southern Africa." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/96021.
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Thesis (MEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Exponential growth of the global wind turbine market has led to a significant increase in the capacity of wind turbine generators. Modern turbines require higher support structures as higher wind speeds combined with longer blades are necessary to increase their generating capacity. The standard 80-90 m tower is thus not economically viable anymore. Transportation logistics of large steel towers has led to concrete towers becoming a viable option. There are currently no design codes dealing exclusively with the design of concrete wind turbine towers. The aim of this project is to investigate and highlight important aspects of the design process of a normally reinforced high strength concrete wind turbine tower. The tower was designed using nonlinear finite element modelling as a design tool to accurately design the tower for various loads and load cases. An analytical design method was developed that can be used in the preliminary design stage. Finally, the importance of the soil-structure interaction was investigated through a sensitivity analysis. It was found that the formation of cracks greatly affected the stiffness of the structure and that the reduction in stiffness increased the deflection significantly. It was also found that a structure that has sufficient strength to resist the ULS loads may not necessarily comply with the maximum deflection limit for the SLS. The concrete strength class required was not only determined by the maximum compression stress the concrete would experience, but also by the stiffness required to ensure that the tower frequency is within the turbine’s working frequency. The dynamic behaviour of the tower was also affected by the formation of cracks. The fundamental frequency of the tower was reduced by 46% after the SLS loads were applied. It was found that the soil preparation for the foundation plays a vital role in ensuring that the tower frequency is not reduced to a level where it falls outside the turbine working frequency.
AFRIKAANSE OPSOMMING: Die eksponensiële groei van die globale wind turbine mark het gelei tot ʼn beduidende toename in die opwekkingskapasiteit van wind turbine kragopwekkers. Moderne turbines benodig hoër ondersteuningstrukture om hulle opwekkingskapasiteit te verhoog en daarom is die standaard 80-90 m toring nie meer geskik nie. Die vervoer logistiek van groot staal torings het daartoe gelei dat beton torings ʼn lewensvatbare opsie geword het. Daar is huidiglik geen ontwerpkodes wat uitsluitlik handel met die ontwerp van beton wind turbine torings nie. Die doel van hierdie projek is om die ontwerp proses van ʼn bewapende hoë sterkte beton wind turbine toring te ondersoek en belangrike aspekte uit te lig. Die toring word ontwerp deur ʼn nie-liniêre eindige element model te gebruik as ʼn ontwerp hulpmiddel, om die toring akkuraat te ontwerp vir verskeie laste en lasgevalle. ʼn Analitiese ontwerpmetode is ontwikkel wat gebruik kan word in die voorlopige ontwerpfase. Laastens is die grond-struktuur interaksie ondersoek deur ʼn sensitiwiteitsanalise. Daar is gevind dat die vorming van krake die styfheid van die struktuur aansienlik beïnvloed en dat die vermindering in styfheid die defleksie beduidend vermeerder. Daar is ook gevind dat ʼn struktuur wat voldoende sterkte het om die uiterste lastoestande te weerstaan, nie noodwendig voldoen aan die maksimum defleksiegrens vir die diens lastoestande nie. Die beton sterkte klas wat benodig is, is nie net bepaal deur die maksimum druk spanning wat die beton sal ondervind nie, maar ook deur die styfheid wat vereis word om te verseker dat die toring se frekwensie binne die turbine se werksfrekwensie val. Die dinamiese gedrag van die toring is ook beïnvloed deur die vorming van krake. Die fundamentele frekwensie van die toring is verlaag met 46% nadat die diens lastoestande toegepas is. Daar is gevind dat die grond voorbereiding vir die fondasie ʼn belangrike rol speel om te verseker dat die toring se frekwensie nie verlaag word tot ʼn vlak waar dit buite die turbine se werksfrekwensie val nie.
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Lack, L. W. "The design of wind turbine rotors in relation to fatigue." Thesis, University of Reading, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371440.
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Hand, M. Maureen. "Variable-speed wind turbine controller systematic design methodology : a comparison of non-linear and linear model-based designs /." Golden, CO : National Renewable Energy Laboratory, 1999. http://www.nrel.gov/docs/fy99osti/25540.pdf.
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Nel, Emma. "Design and analysis of small scale wind turbine support structures." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71848.
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Thesis (MScEng)--Stellenbosch University, 2012ENGLISH ABSTRACT: A technology that has advanced immeasurably as a result of the necessity for green energy production is the harnessing of wind energy. One of the most important aspects of a wind turbine is its supporting structure. The tower of a wind turbine needs to be sufficiently reliable and structurally sound to ensure that the design life of the wind turbine machine is unaffected. The tower also needs to be of the correct height to ensure that the full potential of energy capture is realised. The supporting structure of a wind turbine constitutes up to as much as 30% of the total costs of a wind turbine. The most common wind turbine supporting structures seen worldwide today are Steel Monopole Towers. The large cost proportion of the tower compels the industry to investigate the most feasible alternative supporting tower structures and thus prompted the research developed in this thesis. In this thesis the focus is on small scale wind turbines (<50kW), more specifically, a 3kW Wind Turbine. The proposed alternative design the support structures of small scale wind turbines to the presently used Steel Monopole tower was a Steel Lattice tower. Both a Steel Lattice and Steel Monopole Tower was designed for a 3kW Wind Turbine using rational design methods determined from pertinent sections of the South African design codes. The Tower designs needed to incorporate the details of the element connections, so as to encompass all of the cost parameters accurately. The foundation design of each of the towers was also required from the point of view of cost analysis completeness, and ended up playing a critical role in the feasibility analysis. To validate the design methods, the two towers were modelled in the finite element package Strand7 and a number of different analyses were performed on the two towers. The analyses included linear static, nonlinear static, natural frequency and harmonic frequency analyses. The towers were assessed for a number of different load case combinations and were examined in terms of stress states, mass participation factors and deflections, to mention a few, for the worst loading combination cases that were encountered. Once a final design was reached for both the Steel Lattice and Steel Monopole Towers, each element from which they were made was assessed from a structural viewpoint to determine manufacturing and construction costs. The cost analysis was conducted by means of asking a number of leading construction companies for unit prices for each of the identified elements to be assessed. The fabrication and construction of each of the Towers was then compared to determine which one was more feasible, in terms of each design aspect considered as well as looking at the complete end product. It was found that the Steel Lattice Tower was more feasible from the points of view of fabrication, and construction, as well as having a far more cost effective foundation. This was a positive conclusion from the perspective of the proposal for a more feasible alternative to the presently used Steel Monopole Towers. The outcome of the research conducted here could certainly prove to be worth considering from a wind farm development perspective, with particular focus on the up and coming Wind Industry developments in South Africa.
AFRIKAANSE OPSOMMING: As gevolg van die noodsaaklikheid vir die produksie van volhoubare energie is ʼn tegnologie wat met rasse skrede vooruitgegaan het die vir die benutting van windenergie. Een van die belangrikste aspekte van 'n windturbine is die ondersteunende struktuur. Die toring van 'n windturbine moet funksioneel en struktureel betroubaar wees om te verseker dat die ontwerpleeftyd van die windturbine masjien nie nadelig beïnvloed word nie. Die toring moet ook die regte hoogte wees om te verseker dat die volle potensiaal van die wind energie in meganiese energie omgesit word. Die koste van die ondersteunende struktuur van 'n windturbine verteenwoordig tot 30% van die totale koste van 'n windturbine. Die mees algemene vorm van ondersteunende strukture vir windturbines wat vandag wêreldwyd teëgekom word, is die van 'n enkel staal buisvormige toring. Die groot koste‐komponent van die toring dwing die industrie om ondersoek in te stel na die mees koste effektiewe prakties uitvoerbare alternatief vir die ondersteunende toring struktuur. Hierdie aspek van die struktuur konseptualisering het gelei tot die navorsing wat in hierdie tesis onderneem is. Die fokus van die navorsing is op klein skaal windturbines (<50kW), en meer spesifiek op 'n 3kW windturbine model. Die alternatiewe ontwerp wat ontwikkel is vir klein skaal wind turbines se ondersteunende structure, is 'n staal vakwerk toring as alternatief vir die staal buisvormige toring. Beide 'n staal vakwerk en staal buisvormige toring vir 'n 3kW wind turbine is ontwerp deur rasionele ontwerp metodes. Die toepaslike gedeeltes van die Suid‐Afrikaanse ontwerp kodes is hiervoor gebruik. Die ontwerp vir die toring moet die besonderhede van die element verbindings in ag neem en die nodige koste parameters moet akkuraat bepaal word. Die ontwerp van die fondament van elke toring is ook noodsaaklik vir die volledigheid van die koste‐ontleding en dit speel ook 'n kritieke rol in die gangbaarheid analise. Om die ontwerp metodes te bevestig, is die twee tipes torings in die eindige element pakket, Strand7, gemodelleer en 'n aantal verskillende ontledings vir die twee torings is uitgevoer. Die ontledings sluit lineêr en nie‐lineêr statiese ontledings asook natuurlike frekwensie en dinamiese ontledings onder harmoniese belastings in. Die torings is vir 'n aantal verskillende lasgevalkombinasies ondersoek en in die spannings toestande, massadeelname faktore en defleksies vir die ergste laskombinasie gevalle wat ondervind is, is geassesseer. Sodra 'n finale ontwerp vir beide die staal vakwerk en staal buisvormige toring voltooi is, is elke element beoordeel uit 'n strukturele en materiaal oogpunt om die kostes daarvan te bepaal. Die koste‐analise is baseer op data wat voorsien is deur 'n aantal vooraanstaande konstruksiemaatskappye op 'n prys per eenheid basis vir elk van die geïdentifiseerde elemente wat geassesseer moes word. Die vervaardiging en konstruksie van elke toring is dan vergelyk om te bepaal watter een die mees haalbaar is, in terme van elke toepaslike ontwerpsaspek en deur ook die volledige eindproduk te evalueer. Daar is bevind dat die staal vakwerk toring uit die oogpunt van vervaardiging en konstruksie, asook as gevolg van 'n meer koste‐effektiewe fondament, die voorkeur alternatief verteenwoordig het. Dit was 'n positiewe gevolgtrekking uit die oogpunt van die soeke na 'n ander alternatief as die buisvormige staal torings wat tans algemeen in gebruik is. Die uitkoms van hierdie navorsing verdien oorweging uit ʼn windplaas ontwikkelingsperspektief, met ʼn spesifieke fokus op die opkomende ontwikkelinge in die wind energie industrie in Suid‐Afrika.
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Norström, Parliden Jonas, and Mateusz Rynkiewicz. "Design of PM generator for a vertical axis wind turbine." Thesis, Uppsala universitet, Elektricitetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-180910.
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The task in this project is to design a generator for a vertical axis wind turbine withpower rated to 20kW at a wind speed of 10m/s. The project is conducted at theDivision of Electricity at Uppsala University with collaboration from ElectricGeneration AB. The design has just a few moving parts, which decreases maintenancecosts and increases its toughness. The turbine absorbs wind from every direction butits rotation speed ratio is lower than horizontal axis wind turbines. It means that thegenerator must be bigger and therefore more expensive. Price is an importantcriterion for the generator. Neodymium magnets are expensive so the amount of thismaterial must be limited.Several designs have been simulated but one final design has proven the mostpromising. It fulfills all specifications such as efficiency above 95%, 20kW outputpower and it also has a relatively low amount of hard magnetic material.A design with a single row of cables per slot was decided upon to eliminate heatpockets between cable rows, which can occur in designs with two cable rows perslot. It would be interesting to study designs with two or more cable rows per slot, asit could lead to a smaller and more efficient machine.
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Colley, Gareth. "Design, operation and diagnostics of a vertical axis wind turbine." Thesis, University of Huddersfield, 2012. http://eprints.hud.ac.uk/id/eprint/17547/.
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The need for sustainable energy sources becomes greater each year due to the continued depletion of fossil fuels and the resulting energy crisis. Solutions to this problem are potentially in the form of wind turbines which have been receiving increased support at a micro level. At present a number of wind turbines are being developed that are of cross-flow vertical axis operation which have shown significant increases in performance compared to existing technologies. From an extensive literature review a number of key issues have been highlighted which are concerned with design, operation and diagnostics of this new wind power technology which have been used to formulate the scope of this research. A design procedure for a cross-flow machine that features both a multi-blade rotor and fixed outer stator guide vanes has been derived in which both rotor and stator blade profiles have been generated for a low wind speed urban application. Using these blade profiles a prototype wind turbine has been fabricated and used for full scale development testing. In the presented work both experimental and numerical investigations have been carried out to determine the operational characteristics of this new technology. The experimental data obtained under controlled laboratory conditions has been used to validate a Computational Fluid Dynamic (CFD) model which has been used throughout. A flow field analysis of the machine has highlighted large asymmetries in both pressure and velocity about the central axis of the machine in both stationary and rotating frames of reference. This has identified primary inefficiencies within the design which limit the torque generating capability of the rotor due to blockage effects and downstream blade interactions. This asymmetry has been quantified in the form asymmetry ratio and used to determine downstream rotor effects and the optimum location of multiple wind turbines which is seen to be x/D >10 in order to minimize performance reductions. The torque and power generation capabilities of the machine have been characterised at both 'design' and ‘offdesign' conditions in which individual blade torque contributions have been quantified. This has highlighted specific energy transfer zones within the turbine namely at a few key blades on the windward side of the rotor. It has also shown counter-rotating torques generated on the leeward side of the machine at specific blade positions during the cycle. Overall performance has been quantified in which a maximum CT = 1.7 and CP = 0.24 has been observed which has some similarities to the Savonius rotor. Geometric effects on torque and power response have been quantified in which a strong dependence on stator blade number is noticed. Further, maximum performance output of the machine is generated at the baseline design condition. Using torque response data a multiple regression model has been developed in which a design equation for crossflow rotor torque has been derived which can be used during the conceptual design phase. Finally, the effectiveness of a two-dimensional transient CFD model to predict cross-flow wind turbine rotor blade loss has been evaluated against full scale experimental data. It has shown that from analysis in the frequency domain specific blade faults can be recognised which agrees well with experimental data obtained. The use of this model for wind turbine performance emulation has been described.
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Jaen, Sola Pablo. "Advanced structural modelling and design of wind turbine electrical generators." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28677.
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This thesis concentrates on direct drive electrical generators for wind energy applications. A variety of wind turbine configurations and generator topologies are reviewed. Direct drive renewable energy converters introduce a low speed, high torque input into the electrical machine. Due to this, these generators have to be larger and more robust than their high speed counterparts. With very large airgap closing forces, a very stiff structure capable of withstanding the stress is necessary. As a result very heavy machines, with structural ('inactive') material dominating the electromagnetically 'active' material are designed. In this thesis a stiffness approach is introduced which combines electromagnetic stiffness and structural stiffness for different modes of deflection. This is used to minimise mass of the generator by trading stiffness of rotor and stator structures. Design tools are presented, validated and utilised to model lightweight supporting structures ('inactive material') for high torque radial flux permanent magnet synchronous generators. Different structural layouts are statically studied, compared and optimised. Making use of low density materials, such as composites, a simplified generator structure is designed and contrasted with its optimised steel counterpart. As a rotating piece machinery forming part of a bigger and more complex machine, electrical generators are subject to dynamic and external forces coming from the wind turbine rotor. The optimised steel design is looked at from a dynamic viewpoint. Discussions and conclusions highlight the potential design solutions that can be adopted to minimise the mass and therefore the cost of these machines.
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Parker, Nicholas W. (Nicholas William). "Extended tension leg platform design for offshore wind turbine systems." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40369.
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Thesis (S.M. in Naval Architecture and Marine Engineering and Mechanical Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (p. 85).
The rise of reliable wind energy application has become a primary alternative to conventional fossil fuel power plants in the United States and around the world. The feasibility of building large scale wind farms has become increasingly dependent on location. The ideal locations require placement in desolate areas with limited or no visibility from surrounding communities, and with the presence of a consistent wind-enriched climate. Deployments of wind turbines in an offshore environment where water depths exceed 30 meters satisfy these requirements. Studies have shown that existing offshore wind turbine systems are limited to shallower coastal waters by the cost of constructing and installing the support structures. This thesis provides a continued parametric analysis of floating platforms for the support of offshore wind turbine systems. In particular, the Tension Leg Platform design will be optimized. Optimization is achieved through the coupling of wave-body interaction theory for the platform along with the aerodynamic performance of a 5-Megawatt wind turbine in the frequency domain. The study provides comparisons over a variety of initial tether tensions and the dynamic response and performance of the platform in several sea states.
(cont.) Statistical quantities are evaluated to ensure these tensions provide adequate forces in storms for various sea states where the significant wave heights can be expected to be 5 meters or greater. The Tension Leg Platform is substantially resistant to heave, pitch and roll motions; therefore, methods of damping the larger surge and sway responses are presented and discussed.
by Nicholas W. Parker.
S.M.in Naval Architecture and Marine Engineering and Mechanical Engineering
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Anbreen, Faiqa. "Design of airborne wind turbine and computational fluid dynamics analysis." Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=1606691.
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Wind energy is a promising alternative to the depleting non-renewable sources. The height of the wind turbines becomes a constraint to their efficiency. Airborne wind turbine can reach much higher altitudes and produce higher power due to high wind velocity and energy density. The focus of this thesis is to design a shrouded airborne wind turbine, capable to generate 70 kW to propel a leisure boat with a capacity of 8-10 passengers. The idea of designing an airborne turbine is to take the advantage of higher velocities in the atmosphere.
The Solidworks model has been analyzed numerically using Computational Fluid Dynamics (CFD) software StarCCM+. The Unsteady Reynolds Averaged Navier Stokes Simulation (URANS) with K-ϵ turbulence model has been selected, to study the physical properties of the flow, with emphasis on the performance of the turbine and the increase in air velocity at the throat. The analysis has been done using two ambient velocities of 12 m/s and 6 m/s. At 12 m/s inlet velocity, the velocity of air at the turbine has been recorded as 16 m/s. The power generated by the turbine is 61 kW. At inlet velocity of 6 m/s, the velocity of air at turbine increased to 10 m/s. The power generated by turbine is 25 kW.
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Wiratama, I. Kade. "Aerodynamic design of wind turbine blades utilising nonconventional control systems." Thesis, Northumbria University, 2012. http://nrl.northumbria.ac.uk/11375/.
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As a result of the significant growth of wind turbines in size, blade load control has become the main challenge for large wind turbines. Many advanced techniques have been investigated aiming at developing control devices to ease blade loading. Individual pitch control system, adaptive blades, trailing edge microtabs, morphing aerofoils, ailerons, trailing edge flaps, and telescopic blades are among these techniques. Most of the above advanced technologies are currently implemented in, or are under investigation to be utilised, for blade load alleviation. The present study aims at investigating the potential benefits of these advanced techniques in enhancing the energy capture capabilities rather than blade load alleviation. To achieve this goal the research is carried out in three directions: (i) development of a simulation software tool suitable for wind turbines utilising nonconventional control systems, (ii) development of a blade design optimisation tool capable of optimising the topology of blades equipped with nonconventional control systems, and (iii) carrying out design optimisation case studies with the objective of power extraction enhancement towards investigating the feasibility of advanced technologies, initially developed for load alleviation of large blades, for power extraction enhancement. Three nonconventional control systems, namely, microtab, trailing edge flap and telescopic blades are investigated. A software tool, AWTSim, is especially developed for aerodynamic simulation of wind turbines utilising blades equipped with microtabs and trailing edge flap as well as telescopic blades. As part of the aerodynamic simulation of these wind turbines, the control system must be also simulated. The simulation of the control system is carried out via solving an optimisation problem which gives the best value for the controlling parameter at each wind turbine run condition. Developing a genetic algorithm optimisation tool which is especially designed for wind turbine blades and integrating it with AWTSim, a design optimisation tool for blades equipped with nonconventional control system is constructed. The design optimisation tool, AWTSimD, is employed to carry out design case studies. The results of design case studies reveal that for constant speed rotors, optimised telescopic blades are more effective than flaps and microtabs in power enhancement. However, in comparison with flap and microtabs, telescopic blades have two disadvantages: (i) complexity in telescopic mechanism and the added weight and (ii) increased blade loading. It is also shown that flaps are more efficient than microtabs, and that the location and the size of flaps are key parameters in design. It is also shown that optimisation of the blade pretwist has a significant influence on the energy extraction enhancement. That is, to gain the maximum benefit of installing flaps and microtabs on blades, the baseline blades must be redesigned.
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Weng, Bowen. "AN OFFSHORE FLOATING WIND TURBINE PLATFORM PROTOTYPE: DESIGN AND EXPERIMENTATION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1467896225.
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Mewburn-Crook, Anthony. "The design and development of an augmented vertical axis wind turbine." Thesis, Kingston University, 1990. http://eprints.kingston.ac.uk/20541/.
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The augmented vertical axis wind turbine resulted from a survey of the problems of existing wind turbines, and the identification of the design criteria that it should be inherently safe and reliable. It should be self-starting in low winds and continue to run in high Winds, and it should be environmentally acceptable. The design consisted of a vertical axis rotor, with five vertical and five horizontal blades, surrounded by an augmentor which contained eight converging stators and a dome desigried to increase the flow rate through the rotor, and to decrease the pressure at exit from the rotor. Extensive model tests showed that the wind turbine had attractive operating characteristics, which were confirmed by a prototype machine with a 6m diameter rotor rated at 10kW. However, a detailed analysis of the design and costs showed that it was too expensive. An analysis of an idealised augmented vertical axis wind turbine showed that there was potential for increasing the performance and decreasing costs. Measurements of the detailed flow field through the rotor and around the augmentor demonstrated that augmentation was by means of an increased pressure drop across the rotor, combined with an increased mass flow rate through it. The efficiency of the upstream part of the rotor was also increased by the augmentor. The benefits of turbulent mixing in the wake of the turbine between the external flowfield and the flow through the turbine were also recognised. Major modifications to the design of the augmentor and rotor resulted in two types of wind turbine which maintained the attractive operating characteristics and appeared to be commercially viable. The designs offer particular benefits in terms of inherent safety and reliability. The potential of cost effective, large multi¬megawatt machines is also recognised. The work has also provided further insight into wind turbine augmentation, and in the design and development of vertical axis rotors.
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Deng, Yun. "Design optimization of a micro wind turbine using computational fluid dynamics." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B4098770X.
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Deng, Yun, and 鄧昀. "Design optimization of a micro wind turbine using computational fluid dynamics." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B4098770X.
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Marnett, Markus [Verfasser]. "Multiobjective Numerical Design of Vertical Axis Wind Turbine Components / Markus Marnett." Aachen : Shaker, 2012. http://d-nb.info/1067735100/34.
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Samson, Jonathan. "Control design and energy optimisation of a buoyant airborne wind turbine." Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30823.
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Airborne Wind Energy Systems (AWES) aim to capture the wind energy potential at high altitudes by using a combination of tethers and bespoke aerofoils. In contrast to conventional horizontal axis wind turbines (HAWT), the tower is replaced with lightweight tethers resulting in a reduction in both the overall mass, and more importantly cost of the system. Currently, there is significant interest from a number of key stakeholders, both academic and industrial, aiming to optimise an airborne wind energy design that captures the wind energy resource found at high altitudes. Two key issues will drive the development of these systems, flight stability and power maximisation. Therefore, the control strategy for these systems will be imperative for reducing costs and optimising system performance. Through collaboration with Altaeros Energies, this thesis addresses the outstanding stability and performance optimisation for a specific AWES known as the Buoyant Airborne Wind Turbine (BAWT). There are three key contributions within this work. Firstly, a comprehensive literature review of different airborne systems is provided with specific consideration given to power optimisation and dynamic stability. This results in a detailed understanding of the BAWT plant model through the introduction of two force ratio's relating the buoyancy contribution to the aerodynamic contribution on system loads across the operating envelope. The model development is then expanded on to discuss the question of system stability and power optimisation. This is addressed via the development of a hierarchical control structure for the BAWT, which is broken into three distinct regions, low level control, medium level control and high level control. At the lowest level, flight stability, which is vital to providing optimum conditions for energy generation, is guaranteed using a multivariable controller. This is carried out through the development of a PID controller using two methods, a frequency domain method known as MPID and an optimal control scheme, LQR. The results of this chapter inform the interaction of the controller with the underlying plant dynamics. Finally, the broader issue of BAWT optimisation is addressed by implementing a hierarchical control architecture which builds upon the multivariable flight stability controller developed in Chapter 5. Medium level control is implemented using a hierarchical model predictive control scheme (MPC) which provides set-points to the low level controller in roll, pitch and altitude. These set-points are provided such that they are bounded within the defined envelope of operation to ensure that loads on the shroud are not increased beyond acceptable levels i.e. extreme tether loads due to high altitudes. The question of power optimisation is then addressed through the formulation of an Extremum seeking control (ESC) scheme which derives an optimal altitude for the system. This altitude is determined by trading off generated power from the rotor against power losses incurred by reeling the tether in/out at high wind speeds. Implementing a hierarchical control scheme of this type provides an example of how different control techniques can be combined to provide a degree of self-regulation whilst simultaneously providing system stability and power optimisation. Ultimately, this will increase autonomous operation of the BAWT which will help to reduce system costs and make this technology more viable in a competitive marketplace.
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Kluger, Jocelyn Maxine. "Synergistic design of a combined floating wind turbine - wave energy converter." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111692.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 241-251).
Offshore energy machines have great potential: higher capacity factors, more available space, and lower visual impacts than onshore machines. This thesis investigates how combining a wave energy converter (WEC) with a floating wind turbine (FWT) may produce offshore renewable energy cost savings. Attaching the WEC to the FWT greatly reduces the WEC's steel frame, mooring lines, electric transmission lines, and siting/permitting costs, which may comprise 56% of a standalone WEC's cost. A 5 MW FWT currently requires up to 1700 tons of platform steel and 5700 tons of ballast concrete for stabilization in the ocean. This required material may be reduced if the WEC stabilizes the FWT. This thesis addresses several challenges to designing a combined FWT-WEC. First, parameter sweeps for optimizing ocean machine performance are limited by high dimensionalities and nonlinearities, including power takeoff control and wave viscous forcing, which normally require computationally expensive time-domain simulations. This thesis develops a statistical linearization approach to rapidly compute machine dynamics statistics while accounting for nonlinearities in the frequency domain. It is verified that the statistical linearization method may capture significant dynamics effects that are neglected by the traditional Taylor series linearization approach, while computing the results approximately 100 times faster than time domain simulations. Using Morison's equation for wave viscosity and quasi-steady blade-element/momentum theory for rotor aerodynamics, we find that viscous effects and nonlinear aerodynamics may increase the FWT motion and tower stress by up to 15% in some wind-sea states compared the the Taylor series linearized system. Second, the WEC must stabilize rather than destabilize the FWT. This thesis investigates the dynamics statistics of dierent FWT-WEC configurations using a long wavelength, structurally coupled model. It is shown that simultaneous targeted energy transfer from both the FWT and waves to the WEC when the WEC and FWT are linked by a tuned spring is unlikely. That being said, this thesis considers heave-mode oscillating water column WEC's that are linked to the FWT platform by 4-bar linkages, so that the FWT and WEC's are uncoupled for small heave motions and rigidly coupled in all other degrees of freedom. It is shown that this configuration allows the WEC to move with a large amplitude in its energy harvesting degree of freedom, and therefore harvest a significant amount of power without significantly increasing the FWT motion in the same direction. In the rigidly-connected modes, the WEC inertial resistance to motion must be greater than the wave forcing, as these properties are transmitted to the FWT. Third, the WEC requires power robustness in dierent sea states. Typical WEC's require control schemes to maintain good power performance when the ocean wave dominant frequency differs from the WEC resonant frequency. This thesis introduces a nonlinearity into the WEC design that passively increases power adaptability in dierent sea states. While the optimized nonlinear WEC requires 57% more steel than the optimized linear WEC, the nonlinear WEC produces 72% more power on average, resulting in a 3% lower levelized cost of energy. Further optimization of the nonlinear WEC may find improved performance. This thesis determines that attaching a single linear hinged floating spar oscillating water column to the FWT reduces the levelized cost of energy from $0.31/kWh for the standalone system to $0.27/kWh (13%) without changing stress on the FWT tower. Attaching a single nonlinear hinged floating spar oscillating water column to the FWT reduces the levelized cost of energy to $0.26/kWh (16%) and reduces the lifetime equivalent fatigue stress on the FWT tower from 32.4 MPa to 31 MPa (5%). A 6-unit array of the nonlinear WEC's encircling the FWT platform may generate an average of 400 kW while reducing the FWT tower stress by over 50%. In wave tank experiments, the response statistics of four dierent combined FWT-WEC configurations are measured, verifying the FWT-WEC dynamics model.
by Jocelyn Maxine Kluger.
Ph. D.
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Tang, Xinzi. "Aerodynamic design and analysis of small horizontal axis wind turbine blades." Thesis, University of Central Lancashire, 2012. http://clok.uclan.ac.uk/7127/.
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The exploitation of small horizontal axis wind turbines provides a clean, prospective and viable option for energy supply. Although great progress has been achieved in the wind energy sector, there is still potential space to reduce the cost and improve the performance of small wind turbines. An enhanced understanding of how small wind turbines interact with the wind turns out to be essential. This work investigates the aerodynamic design and analysis of small horizontal axis wind turbine blades via the blade element momentum (BEM) based approach and the computational fluid dynamics (CFD) based approach. From this research, it is possible to draw a series of detailed guidelines on small wind turbine blade design and analysis. The research also provides a platform for further comprehensive study using these two approaches. The wake induction corrections and stall corrections of the BEM method were examined through a case study of the NREL/NASA Phase VI wind turbine. A hybrid stall correction model was proposed to analyse wind turbine power performance. The proposed model shows improvement in power prediction for the validation case, compared with the existing stall correction models. The effects of the key rotor parameters of a small wind turbine as well as the blade chord and twist angle distributions on power performance were investigated through two typical wind turbines, i.e. a fixed-pitch variable-speed (FPVS) wind turbine and a fixed-pitch fixed-speed (FPFS) wind turbine. An engineering blade design and analysis code was developed in MATLAB to accommodate aerodynamic design and analysis of the blades. The linearisation for radial profiles of blade chord and twist angle for the FPFS wind turbine blade design was discussed. Results show that, the proposed linearisation approach leads to reduced manufacturing cost and higher annual energy production (AEP), with minimal effects on the low wind speed performance. Comparative studies of mesh and turbulence models in 2D and 3D CFD modelling were conducted. The CFD predicted lift and drag coefficients of the airfoil S809 were compared with wind tunnel test data and the 3D CFD modelling method of the NREL/NASA Phase VI wind turbine were validated against measurements. Airfoil aerodynamic characterisation and wind turbine power performance as well as 3D flow details were studied. The detailed flow characteristics from the CFD modelling are quantitatively comparable to the measurements, such as blade surface pressure distribution and integrated forces and moments. It is confirmed that the CFD approach is able to provide a more detailed qualitative and quantitative analysis for wind turbine airfoils and rotors. With more advanced turbulence model and more powerful computing capability, it is prospective to improve the BEM method considering 3D flow effects.
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Yilmaz, Eftun. "Benchmarking of Optimization Modules for Two Wind Farm Design Software Tools." Thesis, Högskolan på Gotland, Institutionen för kultur, energi och miljö, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hgo:diva-1946.
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Optimization of wind farm layout is an expensive and complex task involving several engineering challenges. The layout of any wind farm directly impacts profitability and return of investment. Several software optimization modules in line with wind farm design tools in industry is currently attempting to place the turbines in locations with good wind resources while adhering to the constraints of a defined objective function. Assessment of these software tools needs to be performed clearly for assessing different tools in wind farm layout design process. However, there is still not a clear demonstration of benchmarking and comparison of these software tools even for simple test cases. This work compares two different optimization software namely openWind and WindPRO commercial software tools mutually.
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Hu, Weifei. "Reliability-based design optimization of composite wind turbine blades for fatigue life under wind load uncertainty." Diss., University of Iowa, 2015. https://ir.uiowa.edu/etd/1854.
Full textAbstract:
The objectives of this study are (1) to develop an accurate and efficient fatigue analysis procedure that can be used in reliability analysis and reliability-based design optimization (RBDO) of composite wind turbine blades; (2) to develop a wind load uncertainty model that provides realistic uncertain wind load for the reliability analysis and the RBDO process; and (3) to obtain an optimal composite wind turbine blade that satisfies target reliability for durability under the uncertain wind load. The current research effort involves: (1) developing an aerodynamic analysis method that can effectively calculate detailed wind pressure on the blade surface for stress analysis; (2) developing a fatigue failure criterion that can cope with non-proportional multi-axial stress states in composite wind turbine blades; (3) developing a wind load uncertainty model that represents realistic uncertain wind load for fatigue reliability of wind turbine systems; (4) applying the wind load uncertainty model into a composite wind turbine blade and obtaining an RBDO optimum design that satisfies a target probability of failure for a lifespan of 20 years under wind load uncertainty. In blade fatigue analysis, resultant aerodynamic forces are usually applied at the aerodynamic centers of the airfoils of a blade to calculate stress/strain. However, in reality the wind pressures are applied on the blade surface. A wind turbine blade is often treated as a typical beam-like structure for which fatigue life calculations are limited in the edge-wise and/or flap-wise direction(s). Using the beam-like structure, existing fatigue analysis methods for composite wind turbine blades cannot cope with the non-proportional multi-axial stress states that are endured by wind turbine blades during operation. Therefore, it is desirable to develop a fatigue analysis procedure that utilizes detailed wind pressures as wind loads and considers non-proportional multi-axial stress states in fatigue damage calculation. In this study, a 10-minute wind field realization, determined by a 10-minute mean wind speed V10 and a 10-minute turbulence intensity I10, is first simulated using Veers’ method. The simulated wind field is used for aerodynamic analysis. An aerodynamic analysis method, which could efficiently generate detailed quasi-physical blade surface pressures, has been developed. The generated pressures are then applied on a high-fidelity 3-D finite element blade model for stress and fatigue analysis. The fatigue damage calculation considers the non-proportional multi-axial complex stress states. A detailed fatigue damage contour, which indicates the fatigue failure locally, can be obtained using the developed fatigue analysis procedure. As the 10-minute fatigue analysis procedure is deterministic in this study, the calculated 10-minute fatigue damage is determined by V10 and I10. It is necessary to clarify that the rotational speed of the wind turbine blade is assumed to be constant (12.1 rpm) and the pitch angle is fixed to be 0 degree for different wind conditions, since the rotational speed control and pitch angle control have not been considered in this study. For predicting the fatigue life of a wind turbine, a fixed Weibull distribution is widely used to determine the percentage of time the wind turbine experiences different mean wind speeds during its life-cycle. Meanwhile, fixed turbulence intensities are often used based on the designed wind turbine types. These simplifications, i.e., fixed Weibull distribution and fixed turbulence intensities, ignore the realistic uncertain wind load when designing a reliable wind turbine system. In the real world, both the mean wind speed and turbulence intensity vary constantly over one year, and their annual distributions are different at different locations and in different years. Thus, it is necessary to develop a wind load uncertainty model that can provide a realistic uncertain wind load for designing reliable wind turbine systems. In this study, 249 groups of measured wind data, collected at different locations and in different years, are used to develop a dynamic wind load uncertainty model. The dynamic wind load uncertainty model consists of annual wind load variation and wind load variation in a large spatiotemporal range, i.e., at different locations and in different years. The annual wind load variation is represented by the joint probability density function of V10 and I10. The wind load variation in a large spatiotemporal range is represented by the probability density functions of five parameters, C, k, a, b, and τ, which determine the joint probability density function of V10 and I10. In order to obtain the RBDO optimum design efficiently, a deterministic design optimization (DDO) procedure of a composite wind turbine blade has been first carried out using averaged percentage of time (probability) for each wind condition. A wind condition is specified by two terms: 10-minute mean wind speed and 10-minute turbulence intensity. In this research, a probability table, which consists of averaged probabilities corresponding to different wind conditions, is referred as a mean wind load. The mean wind load is generated using the dynamic wind load uncertainty model. During the DDO process, the laminate thickness design variables are tailored to minimize the total cost of composite materials while satisfying the target fatigue lifespan of 20 years. It is found that, under the mean wind load condition, the fatigue life of the initial design is only 0.0004 year. After the DDO process, even though the cost at the DDO optimum design is increased by 31.5% compared to that at the initial design, the predicted fatigue life at the DDO optimum design is significantly increased to 19.9995 years. Reliability analyses of the initial design and the DDO optimum design have been carried out using the wind load uncertainty model and Monte Carlo simulation. The reliability analysis results show that the DDO procedure reduces the probability of failure from 100% at the initial design to 49.9% at the DDO optimum design considering only wind load uncertainty. In order to satisfy the target 2.275% probability of failure, it is necessary to further improve the fatigue reliability of the composite wind turbine blade by RBDO. Reliability-based design optimization of the composite wind turbine blade has been carried out starting at the DDO optimum design. Fatigue hotspots for RBDO are identified among the laminate section points, which are selected from the DDO optimum design. Local surrogate models for 10-minute fatigue damage have been created at the selected hotspots. Using the local surrogate models, both the wind load uncertainty and manufacturing variability has been included in the RBDO process. It is found that the probability of failure is 50.06% at the RBDO initial design (DDO optimum design) considering both wind load uncertainty and manufacturing variability. During the RBDO process, the normalized laminate thickness design variables are tailored to minimize the total cost of composite materials while satisfying the target 2.275% probability of failure. The obtained RBDO optimum design reduces the probability of failure from 50.06% at the DDO optimum design to 2.28%, while increasing the cost by 3.01%.
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Poole, Sean Nichola. "Optimisation of a mini horizontal axis wind turbine to increase energy yield during short duration wind variations." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/7036.
Full textAbstract:
The typical methodology for analytically designing a wind turbine blade is by means of blade element momentum (BEM) theory, whereby the aerofoil angle of attack is optimized to achieve a maximum lift-to-drag ratio. This research aims to show that an alternative optimisation methodology could yield better results, especially in gusty and turbulent wind conditions. This alternative method looks at increasing the aerofoil Reynolds number by increasing the aerofoil chord length. The increased Reynolds number generally increases the e_ectiveness of the aerofoil which would result in a higher or similar lift-to-drag ratio (even at the decreased angle of attacked require to maintain the turbine thrust coe_cient). The bene_t of this design is a atter power curve which causes the turbine to be less sensitive to uctuating winds. Also, the turbine has more torque at startup, allowing for operatation in lower wind speeds. This research is assumed to only be applicable to small wind turbines which operated in a low Reynolds number regime (<500 000), where Reynolds number manipulation is most advantageous.
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Mondrago, Quevedo Monica. "Probabilistic modelling of geotechnical conditions for offshore wind turbine support structures." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9205.
Full textAbstract:
The geotechnical conditions of the soil can fluctuate greatly across the wind
farm. This is an issue since geotechnical modelling is the base of the structural
design of an offshore wind farm, and the efficient installation of the wind
turbines depends on its accuracy. This paper deals with the characterization of
the seabed, predicting the soil properties over the total affected area by a wind
farm, with the challenge to reduce the required data samples in the site
investigation under the number of installed wind turbines, to reduce its cost.
It is compared the prediction outcome from two different interpolation methods,
kriging and radial basis function, assessing their accuracy by the Mean-Squared
Error and the Goodness-of-Prediction Estimate, as well as with a visual
examination of their mapping; obtaining higher accuracy for radial basis function
and reducing to half the required sample points, from the initial value of installed
wind turbines.
In a second stage it is studied the soil effect over the foundation, analyzing the
results from a FEA, where different geometries of the structure are compared
submitted to different load cases to check its limit states. Those results show
that the foundation cost can increase four times due to the soil conditions,
taking into account only the steel volume, and demonstrating how important is
the soil characterization in the foundation design, as it gives the chance to
relocate those wind turbines that require more expensive foundations.
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Ximenes, Fernando Silveira. "Design de difusor aerodinâmico compacto para uma turbina eólica de pequena escala." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/182436.
Full textAbstract:
Este trabalho tem como proposta desenvolver um difusor aerodinâmico compacto para uma turbina eólica de pequena escala, objetivando alcançar um melhor start rotacional (menor torque de partida para rotacionar) em baixas velocidades de vento. Um difusor é uma estrutura em forma de aro envolta ao rotor da turbina eólica, sua função é amplificar a captação e aceleração do vento, explorando os efeitos aerodinâmicos das zonas de vórtices de baixa pressão na saída do difusor. O estudo concentrar-se-á na manipulação da geometria dos difusores, analisando como seu design impacta no seu comportamento aerodinâmico impacta na capacidade do difusor equacionar as zonas de alta e baixa pressão ao longo de sua estrutura, essa relação é determinante para o efeito aerodinâmico que acelera o escoamento de ar, resultando em um start rotacional em baixas velocidade de vento. O ponto de partida para este trabalho são os estudos desenvolvidos por Ohya et al. (2010) sobre difusores compactos-flangeados (compact-type brimmed diffuser) para turbinas eólicas, denominado Wind-lens Technology. Para alcançar os objetivos, esta pesquisa vai utilizar simulações por CFD com software de túnel de vento virtual e ensaios experimentais em túnel de vento físico para avaliar o comportamento dinâmico (turbina + difusor). Foram desenvolvidas dezenove geometrias a partir de uma área construtiva padronizada para o design de difusores. Desenvolveu-se também, a partir dos resultados encontrados, um MFI (microseparador de fluxo interno), que consiste em uma estrutura adicional com função de potencializar as zonas de vórtices (baixa pressão) no plano de saída do escoamento de ar dos difusores. Os resultados mostraram que a manipulação da geometria do difusor produziu resultados promissores em comparação com o modelo de referência, alcançando em algumas geometrias de difusores um melhor start rotacional. O MFI mostrou-se eficaz para potencializar as zonas de baixa pressão e melhorou o start rotacional. Ao final, definiu-se dois modelos de difusores e suas respectivas versões com MFI como as melhores opções para o start rotacional.This work aims to develop a compact wind turbine for a turbine and a small scale, aiming at a better rotational start at low wind speeds (lower starting torque to rotate). A diffuser is a rim-shaped structure wrapped around the wind turbine rotor, its function is to amplify the wind uptake and acceleration, exploiting the aerodynamic effects of the low-pressure vortex zones at the diffuser outlet. The study will focus on the manipulation of the diffuser geometry, analyzing how its design impacts on its aerodynamic behavior, especially on the diffuser's ability to equate the high and low pressure zones along its structure, this relation is decisive for the aerodynamic effect that accelerates the air flow, resulting in a rotational start at low wind speeds. The basis for this work are studies developed by Ohya et al. (2010) on compact-flanged diffusers for wind turbines, called Wind-lens Technology. To achieve the objectives, this research will use CFD simulations with virtual wind tunnel software and experimental tests in physical wind tunnel to evaluate the dynamic behavior (turbine + diffuser). Nineteen geometries were developed from a standardized design area for the design of diffusers. An MFI (internal flow microseparator) has also been developed, which is an additional structure whose function is to potentiate the low pressure zones of the diffusers. The results showed that the manipulation of the diffuser geometry produced promising results in comparison to the reference model, reaching in some conditions superior results in RPM and initial start. The MFI proved to be effective in boosting the low pressure zones and improved the initial start. At the end, two models of diffusers and their respective versions with MFI were defined as the best options for the initial start.
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Taylor, D. "The design and testing of a horizontal axis wind turbine with sailfoil blades." Thesis, Open University, 1985. http://oro.open.ac.uk/54193/.
Full textAbstract:
The work contained in this thesis covers the design, development and testing of a horizontal axis wind turbine (HAWT) with Sailfoil blades. Included is a brief history of wind turbine technology, its revival, a review of current wind energy developments and a literature survey of previous work on wind turbines with sail type blades. The Sailfoil blade consists of a framework of a leading edge D spar and a rigid trailing edge spar over which is stretched a fabric sock, forming a wing-like surface. The aerodynamic performance theories of HAWTs are described, as is the aerodynamic, structural and mechanical design of a 4 metre diameter, 3 bladed HAWT with Sailfoil blades. A wind turbine test facility was designed and developed for free air testing of wind turbines and is described. Free air tests were carried out on the Sailfoil wind turbine on the test facility to obtain power coefficient versus tip speed ratio curves and power versus wind speed curves for the wind turbine. These are presented and compared to predicted values.
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Vianna, Neto Julio Xavier. "Wind turbine blade geometry design based on multi-objective optimization using metaheuristics." reponame:Repositório Institucional da UFPR, 2013. http://hdl.handle.net/1884/30337.
Full textAbstract:
Abstract: The application of Evolutionary Algorithms (EAs) to wind turbine blade design can be interesting, by reducing the number of aerodynamic-to-structural design loops in the conventional design process, hence reducing the design time and cost. Recent developments showed satisfactory results with this approach, mostly combining Genetic Algorithms (GAs) with the Blade Element Momentum (BEM) theory. The general objective of the present work is to define and evaluate a design methodology for the rotor blade geometry in order to maximize the energy production of wind turbines and minimize the mass of the blade itself, using for that purpose stochastic multi-objective optimization methods. Therefore, the multi-objective optimization problem and its constraints were formulated, and the vector representation of the optimization parameters was defined. An optimization benchmark problem was proposed, which represents the wind conditions and present wind turbine concepts found in Brazil. This problem was used as a test-bed for the performance comparison of several metaheuristics, and also for the validation of the defined design methodology. A variable speed pitch-controlled 2.5 MW Direct-Drive Synchronous Generator (DDSG) turbine with a rotor diameter of 120 m was chosen as concept. Five different Multi-objective Evolutionary Algorithms (MOEAs) were selected for evaluation in solving this benchmark problem: Non-dominated Sorting Genetic Algorithm version II (NSGA-II), Quantum-inspired Multi-objective Evolutionary Algorithm (QMEA), two approaches of the Multi-objective Evolutionary Algorithm Based on Decomposition (MOEA/D), and Multi-objective Optimization Differential Evolution Algorithm (MODE). The results have shown that the two best performing techniques in this type of problem are NSGA-II and MOEA/D, one having more spread and evenly spaced solutions, and the other having a better convergence in the region of interest. QMEA was the worst MOEA in convergence and MODE the worst one in solutions distribution. But the differences in overall performance were slight, because the algorithms have alternated their positions in the evaluation rank of each metric. This was also evident by the fact that the known Pareto Front (PF) consisted of solutions from several techniques, with each dominating a different region of the objective space. Detailed analysis of the best blade design showed that the output of the design methodology is feasible in practice, given that flow conditions and operational features of the rotor were as desired, and also that the blade geometry is very smooth and easy to manufacture. Moreover, this geometry is easily exported to a Computer-Aided Design (CAD) or Computer-Aided Engineering (CAE) software. In this way, the design methodology defined by the present work was validated.
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Shih, Sung-Hua, and 施松樺. "Wind Turbine Blade Design and Analysis." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/98290356246100649174.
Full textAbstract:
碩士國立屏東科技大學
機械工程系
94
In recent years, we have been facing gradual shortages of fossil fuels; as a result, prices have risen rapidly. Various governments have been doing their utmost to seek, and develop, alternative source of energy. At present, the wind turbine has the most advanced technology among all of the alternative energy devices, as well as low pollution levels and limitless regeneration. In this paper, we show the design of a wind turbine blade that can best generate electric power. This paper utilizes commercial software GAMBIT and FLUENT, to built and analyze model flow fields. The NACA-4412 airfoil was chosen as the study’s designed wind turbine blade. We show how to design section pitch angle, and angle of attack, by analyzing various relative wind velocity angles, to influent the blade. The result indicates that the wind turbine blade based on the Betz optimum blade design, i.e. the blade with twist angle, will generate more electric power than will blades with no twist angle.
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Huang, Jyun-Lin, and 黃俊霖. "Creative Design of Wind Turbine Drive Mechanism." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/67454428455641144498.
Full textAbstract:
碩士崑山科技大學
機械工程研究所
105
Being an island surrounded by sea water, Taiwan is abundant in natural and stable wind energy resources. Wind turbine generator installation is therefore a promising industry in Taiwan. Traditional wind turbine generator has gearbox to increase or reduce speed, so wind speed application range is narrow, lower or higher wind speed cannot be used. This paper focuses on CVT used in the wind turbine generator, and servomotor controls the speed ratio of the CVT, so the wind speed application range is wider. Control system design includes the stable speed ratio control and power-split control strategy for the CVT, the generator can have the stable speed and power-split function, so the optimal efficiency of generation can be obtained. In the end, this paper further discusses the creative design for the CVT system used in the wind turbine generator and its future application.
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Tan, Hao, and 譚皓. "A Study of Wind-Resistant Design Codes for Wind Turbine Towers." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/12478651261590995319.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
99
Taiwan is an island which located in tropical cyclone position in the Pacific monsoon belt. Taiwan’s wind conditions influence by the sea and the land of great. There have the strong northeast monsoon in winter, the southwest monsoon and typhoon comes in summer. Each of these forces of nature are a threat and damage to Taiwan’s buildings. Because of greenhouse effect and global warming, scientists are frantically looking for combination of renewable energy. Although Taiwan gets threat by the hurricane, but enjoy the unique wind conditions. Natural, environmentally friendly, non-polluting wind resources, can help Taiwan open another piece of the sky. In order to ensure that people's lives and property, and taking into account the economic and social development considerations, one can effectively reduce hurricane damage, and also meet the needs of society and people expect the wind-resistant design specifications, without saying the importance. In this study, ultra-high-type buildings will be designed based on wind resistance, especially in the structure of ultra-high wind turbine tower, and will focus on the wind turbine tower by the different states under the action of wind-induced, resulting in the failure mechanism and its dynamic behavior analysis. It hopes this study and discussion of the results, enabling the country's future on the wind turbine tower design-related research in the field, can be beneficial and help.
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Phillips, Derek Grant. "An investigation on diffuser augmented wind turbine design." 2003. http://hdl.handle.net/2292/1940.
Full textAbstract:
Diffuser Augmented Wind Turbines (DAWTs) are one of many concepts to have been proposed to reduce the cost of renewable energy. As the most commercially viable, they have been the focus of numerous theoretical, computational, and experimental investigations. Although intimated in these studies to be able to augment the power output of a wind turbine, the extent of this power increase, or augmentation, the factors influencing DAWT performance, the optimal geometric form and their economical benefit remained unanswered. It is these issues that have been addressed in this investigation. In reviewing historic investigations on DAWTs it has been identified that excessive wind tunnel blockage, inappropriate measurement technique, varied definitions of augmentation, and the inclusion of predicted performance based on incorrect assumptions have in general led to the overstatement of DAWT performance in those studies. In reassessing the performance of the most advanced of those DAWT designs, Grumman's DAWT 45, it has been calculated that the actual performance figures for the 2.62 exit-area-ratio and 0.488 length-to-diameter ratio DAWT were an available augmentation of 2.02, a shaft augmentation of 0.64 and a diffuser efficiency of 56%. By contrast, the development of the Mo multi-slotted DAWT in this investigation has yielded a design whose shaft augmentation of 1.38 was achieved by a diffuser with exit-area-ratio of only 2.22 and overall length-to-diameter ratio of 0.35. Such performance improvement has been obtained by gaining both an understanding of the flow characteristics of DAWTs and the geometric influences. More specifically it has been shown that: the velocity across the blade-plane is greater than the free-stream velocity and increases towards the rotor periphery; that the rotor thrust or disc loading impacts upon diffuser performance by altering the flow behaviour through it; and that DAWTs are able to maintain an exit pressure coefficient more negative than that attainable by a conventional bare turbine. The net result is that DAWTs encourage a greater overall mass-flow as well as extract more energy per unit of mass-flow passing through the blade-plane than a conventional bare turbine. The major drivers of DAWT performance have been shown to be the ability of the design to maximise diffuser efficiency and produce the most sub-atmospheric exit pressure possible. Parametric investigation of the various DAWT geometric components has shown peak performance to be obtained when: the external flow is directed radially outward by maximising the included angle of the external surface in conjunction with a radially orientated exit flap; by applying boundary-layer control to a trumpet shaped diffuser via a pressurised cavity within the double-skin design of the multi-slotted DAWT; having an exit-area-ratio of the order of 2.22; and by employing an inlet contraction with inlet-area-ratio matched to the mass-flow passing through the DAWT under peak operating conditions. To translate the available augmentation into shaft power a modified blade element method has been developed using an empirically-derived axial velocity equation. The resulting blade designs whose efficiencies reached 77%, twice those of Grumman, highlight the accuracy of the modified blade element method in calculating the flow conditions at the blade-plane of the multi-slotted DAWT. It was also noted that the rotor efficiencies remain below 'best practice' and therefore offer the potential for further increases in shaft augmentation. However, in order to achieve such gains, a number of limitations present in the current method must be addressed. In assessing the likely commercial suitability of the multi-slotted DAWT a number of real-world influences have been examined. Shown to have little if any effect on DAWT performance were Reynolds number, ground proximity and wind shear. Turbulence in the onset flow on the other hand had the beneficial effect of reducing separation within the diffuser. Finally, DAWT performance was assessed under yaw misalignment where it was shown that the multi-slotted DAWT performed favourably in comparison to that associated with a conventional bare turbine. The major drawback identified in the DAWT concept by this investigation was its drag loading and the fact that drag and augmentation were interdependent. The result is that the cost of a conventional DAWT is dictated by the necessity to withstand an extreme wind event despite the fact that augmentation is only required up to the rated wind speed. The overall conclusion drawn was that in order to optimise a DAWT design economically, and therefore make the DAWT concept a commercial reality, a creative solution that minimises drag under an extreme wind event would be required.
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Chou, Hsin-Hsien, and 周欣賢. "Small Wind Turbine blades Design and Performance analysis." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/62020228480802550778.
Full textAbstract:
碩士中華技術學院
飛機系統工程研究所
96
ABSTRACT The present research is to address the new innovation of wind turbine blade design in order to maximize the capacity of 1KW of Whisper-H80 wind turbine blades by redesigning the turbine blades with light weight composite material. Series tests of newly designed turbine blades were conducted under the circumstance of artificial wind. Carefully compared and evaluated the relationship of the power generated by the wind turbine with the angles variation of the blades. Modifications of the blade’s angle and output loading could bring out the maximum efficiency of the wind turbine. The aerodynamic analysis of turbine blades was based on self-developed unsteady flow field equations. However, to analyze aerodynamic characteristics of the blades, the two-dimensional airfoil section values were first simulated. According to the aerodynamic characteristics of wind angle of attack, based on the Blade Element Momentum Theory, a detailed aerodynamic analysis as well as the ideal power generation efficiency could be calculated by studying the rotation speed of turbine blades with regard to the wind speed and the setting angles. The turbine blades were first designed and produced according to the best geometric appearance to the public. The wind turbine blades were made by high strength and lower weight composite material which was affiliated with ply by dry-type long fiber fabrics being the structural shape of the blades’ main body. By comparing hand lay-up method and resin transfer molding method of enhancing the wind turbine blades strength, we decided that hand lay-up method should have been the final method because this method not only reduced weight, but it also brought out maximum hardness on the final products.