Made available in DSpace on 2016-08-31T13:33:43Z (GMT). No. of bitstreams: 1 DaniloSP_DISSERT.pdf: 1541140 bytes, checksum: a3ab0c19a32a7eaf392690513de9a9a5 (MD5) Previous issue date: 2015-07-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study is to evaluate different strategies for adaptive control in order to contribute to better performance controllers with synchronous generators with uncertainties of the parameters or disturbances. The permanent magnet synchronous generators are growing in the market for wind power generation, this being the necessary motivation for choosing this plant. A study and analysis of subsystems of wind energy conversion are performed, and the model of the wind turbine, the mechanical transmission system and synchronous generator are described. The project strategy with conventional control is performed and will be the target of comparison for the implemented adaptive control strategies / O objetivo deste trabalho é avaliar diferentes estratégias de controle adaptativo a fim de contribuir para a melhoria do desempenho de controladores de geradores síncronos com incertezas dos parâmetros ou perturbações. Os geradores síncronos de ímã permanente estão crescendo rapidamente no mercado de geração de energia eólica, sendo a motivação necessária para a escolha desta planta. Um estudo e análise dos subsistemas de conversão de energia eólica são realizados, sendo descrito o modelo da turbina eólica, do sistema de transmissão mecânico e do gerador síncrono. O projeto com estratégia de controle convencional é abordado e será alvo de comparação para as estratégias de controle adaptativo implementadas

Made available in DSpace on 2016-08-31T13:33:44Z (GMT). No. of bitstreams: 1 EdnardoPR_DISSERT.pdf: 2329567 bytes, checksum: ab9bc3145d3823983047e9d57956c8d0 (MD5) Previous issue date: 2015-01-30 / Fundação de Apoio a Pesquisa do Estado do Rio Grande do Norte / The connection of wind generators might cause significant influences in the profile voltages, voltage unbalance, loading and the electrical losses in radial power distribution systems. This fact requires a specific study, called Hosting Capacity, which aims to analyze the maximum limit of the power increase on the network that makes the performance of the system acceptable to the established quality limits. This work shows an IEEE radial distribution system behavior, composed of 13 bus, in steady state, when a synchronous wind machine is engaged on the bus 680 in two ways: directly connected to the network and connected through the frequency converter. For each type of connection the power factor was varied from 0.9 capacitive to inductive 0.9. The parameters analyzed in connection bar were the degree of voltage unbalance, the losses in the system and the profile of voltages on the bus 680 for each case . The simulations were performed using the program Distribution Network Analysis with Generation Aeolian-Electric - ANAREDGEE, which was developed and validated with own results of the IEEE. It was found that there was a reduction in the degree of unbalance for all simulated situations, when compared to the original value of the system status, not exceeded the limits determined by imbalances entities NEMA, ANSI, IEEE and ANEEL. Regarding the profile of voltages in the various system buses, there was a slight decrease in some situations. In the original system, the voltage level of the phase B in the bus 680 exceeded the 5% voltage given by ANEEL, with a value of 1.0529 p.u. With the machine connected directly, there was an increase of this value in all simulations with different power factor, while the connection through frequency converter might causa a reduction of the phase B voltage levels to below 1.05 pu in situations where the power factors were equal to 0.9 capacitive and unitary. The system losses were reduced in all cases, but showed lower values when the synchronous machine was integrated into the system by frequency convertor. It was also observed a significant reduction in the degree of system imbalance after connecting the synchronous machine, this reduction, in most cases, occurred in proportion to the increase in power injected into the connection bar / A conexão de geradores eólio-elétricos pode causar influências significativas no perfil de tensões, desequilíbrio de tensão, no carregamento e nas perdas elétricas em sistemas de distribuição de energia radiais. Este fato requer um estudo específico, denominado Hosting Capacity, que tem por finalidade analisar o limite máximo do incremento de potência na rede que torna a performance do sistema aceitável para os limites de qualidade estabelecidos. Este trabalho demonstra o comportamento do sistema de distribuição radial do IEEE, composto de 13 barras, em regime permanente, quando uma máquina eólica síncrona é acoplada na barra com o maior nível de tensão do sistema, de duas formas distintas: diretamente conectada à rede e conectada por meio de conversor de frequência. Para cada tipo de conexão o fator de potência foi variado de 0.9 capacitivo a 0.9 indutivo. Os parâmetros analisados na barra de conexão foram o grau de desequilíbrio de tensão, as perdas no sistema e o perfil das tensões. As simulações foram realizadas através do programa Análise de Redes de Distribuição com Geração Eólio-Elétrica - ANAREDGEE, que foi desenvolvido e validado com resultados próprios do IEEE. Verificou-se que houve uma redução no grau d e desequilíbrio para todas as situações simuladas, quando comparadas ao valor da situação original do sistema, não superado os limites de desequilíbrios determinados por entidades como NEMA, ANSI, IEEE e ANEEL. Com relação ao perfil das tensões nas diversas barras do sistema, houve uma ligeira diminuição em algumas situações. No sistema original, o valor de tensão na fase B da barra 680 superava os 5% de sobretensão determinado pela ANEEL, apresentando um valor de 1,0529 p.u. Com a máquina diretamente conectada houve um aumento deste valor em todas as simulações com diferentes fatores de potência, enquanto que a conexão por meio de conversor de frequência possibilitou uma diminuição dos níveis de tensão da fase B para valores abaixo de 1,05 p.u. nas situações em que os fatores de potência eram iguais a 0.9 capacitivo e unitário. As perdas no sistema foram reduzidas em todos os casos, entretanto apresentaram menores valores quando a máquina síncrona era integrada ao sistema por meio de conversor de frequência. Foi observado também uma redução considerável do grau de desequilíbrio do sistema após a conexão da máquina síncrona, esta redução, na maioria dos casos, se deu de forma proporcional ao aumento da potência injetada na barra de conexão

Made available in DSpace on 2016-08-31T13:33:44Z (GMT). No. of bitstreams: 1 SauloLR_Dissert.pdf: 2026827 bytes, checksum: 844a5bebdb8c74bcc97253da6842843e (MD5) Previous issue date: 2015-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work is carried out a detailed study of the electrical and mechanical behavior of a doubly fed induction machine that operates as wind generator (DFIG), when it is faced with disturbances from both the grid as wind variations. The dynamic analysis becomes closer to the wind turbine connection to a three-phase electrical network containing several bars. The wind turbine has a classical control system, commonly found in the literature, which is to use PI controllers. From the junction of the control system, the power grid model and the turbine model, serial information will be analyzed. The way the system is designed makes possible, simply, changes of parameters and characteristics of the systems, making it possible to perform simulation of many different wind turbines. By the representation adopted of the electrical grid, it was possible to simulate different types of disturbances, enabling a detailed analysis of the system response in front of the disturbances / Nesse trabalho é realizado um estudo detalhado do comportamento elétrico e mecânico de uma máquina de indução duplamente alimentada que opera como gerador eólico (DFIG), quando esta se encontra diante de perturbações provenientes tanto da rede elétrica quanto de variações de vento. A análise da dinâmica torna-se mais detalhada com a conexão do aerogerador a uma rede elétrica trifásica que contem diversas barras. O aerogerador possui um sistema clássico de controle, comumente encontrado na literatura, que é a utilização de controladores do tipo PI. A partir da junção do sistema de controle, do modelo da rede elétrica e do modelo do aerogerador, uma série de dados serão analisados, tais como velocidade de rotação, corrente e potências fornecidas pelo DFIG, tensão elétrica nos barramentos, dentre outros. Ao utilizar uma representação trifásica na rede elétrica, qualquer forma de perturbação elétrica é facilmente implementada e analisada. A forma como o sistema foi elaborado viabiliza, de maneira simples, modificações de parâmetros e características dos sistemas, tornando possível realizar simulação de diversos modelos de aerogeradores. Através da representação adotada na rede elétrica, foi possível simular diferentes tipos de perturbações, viabilizando uma análise detalhada da resposta do sistema diante das mesmas

Ce mémoire de thèse constitue une contribution à l'investigation des génératrices destinées à une application éolienne en mer. Le but est de rechercher les solutions optimales dans un domaine de recherche vaste contenant entre huit et onze variables d'optimisation, tout en respectant un cahier de charge bien précis. Afin d'y parvenir, un modèle multi-physique a été développé permettant la détermination des distributions du champ électromagnétique et de température dans les topologies de génératrices choisies avec prise en considération des non-linéarités des matériaux. La méthode des constantes localisées couplée aux fonctions d'interpolations a été choisie comme solution offrant un bon rapport temps de calculs/précision, prenant ainsi en considération les caractéristiques des matériaux (thermiques et magnétiques). Le modèle développé a été couplé à un algorithme d'optimisation génétique, NSGAII, permettant dans un premier temps ; d'investiguer le poids nécessaire des aimants permanents et des parties actives de deux topologies de génératrices synchrones à aimant permanent où dans la première les aimants sont montés en surfaces et dans la seconde insérés en concentration de flux, trois puissances différentes ont été investiguées 5, 8 et 15 [MW]. Dans un second temps, l'intégration d'un multiplicateur de vitesse magnétique dans la chaîne de conversion éolienne a été étudiée à travers la même approche optimale utilisée précédemment tout en comparant le poids nécessaires des aimants permanents pour ce type d'entrainement avec celle des topologies à attaque directe (sans multiplicateur de vitesse). / The aim of this PhD report is the investigation of electrical generators dedicated to an offshore wind turbine application. The main goal is to find optimal solutions in a vast research domain containing between eight and eleven optimization variables, while respecting a the imposed constraints. In order to achieve this goal, a multi-physics model was developed allowing the determination of the electromagnetic and temperature fields distributions in the selected topologies. Lumped models coupled to the interpolation functions were chosen as a solution offering a good computation time / precision ratio, thus taking into consideration the characteristics of the materials (thermal and magnetic). The developed model was coupled to a genetic optimization algorithm, NSGAII, allowing at first; the investigation of the necessary permanent magnets weight and the active parts one of two permanent magnet synchronous generator topologies where in the first the magnets are mounted in surfaces and in the second inserted in order to have flux concentration, three different powers have been investigated 5, 8 and 15 [MW]. Second, the integration of a magnetic gear in the wind energy conversion chain was studied using the same optimal approach previously used, while comparing the weight required of permanent magnets for this type of training with that of direct drive topologies (without gearbox).

O experimento Unsteady Aerodynamics Experiment Phase VI, realizado no ano de 2000 pelo Laboratório Nacional norte-americano para as Energias Renováveis (NREL) no túnel de vento Ames da NASA, foi reproduzido numericamente neste trabalho. O objetivo é o estudo das características da esteira aerodinâmica produzida pela turbina eólica de duas pás e 10 metros de diâmetro, operando à velocidade de rotação constante de 72 RPM, sujeita a uma velocidade de corrente livre do vento uniforme de 9 m/s, em um túnel de vento cuja seção de testes mede 36,6 m de largura por 24,4 m de altura e o comprimento mede 170 m. Para isso, foi utilizado o programa comercial ANSYS FLUENT versão 13.0, baseado no Método dos Volumes Finitos para a solução numérica das Equações de Navier-Stokes em regime transiente em conjunto com a Simulação de Grandes Escalas (SGE) para resolver a turbulência. As geometrias de todos os componentes da máquina foram criadas em software CAD. Um domínio móvel em forma de disco, contendo as pás do rotor e o hub da máquina, foi criado separadamente, e posteriormente inserido no domínio principal, estático, usando a ferramenta Moving Mesh disponível no software FLUENT. Ambos os domínios foram preenchidos por malhas compostas por tetraedros. Dados provenientes das simulações numéricas foram comparados aos dados experimentais de velocidade fornecidos por dois anemômetros sônicos instalados 5,8 m à jusante do rotor, ao que foi verificada boa concordância, com diferenças da ordem de 1% para o anemômetro 1 e 6% para o anemômetro 2. Resultados de velocidade na linha de centro do túnel e perfis de velocidade à jusante foram comparados com recente estudo numérico, e revelam diferenças importantes entre dados obtidos pela SGE, principalmente no que se refere à detecção de picos e flutuações relacionados às escalas turbulentas, e dados obtidos através da modelagem clássica da turbulência, RANS. As perturbações ultrapassaram a marca dos 10 diâmetros à jusante e atingiram o final do domínio localizado a 15 diâmetros. A esteira não apresentou simetria axial, e o ponto de maior redução na velocidade do escoamento foi detectado fora da linha de centro do rotor. / The Unsteady Aerodynamics Experiment Phase VI, which has been carried out in 2000 by the US National Renewable Energy Laboratory (NREL) at the NASA Ames wind tunnel, has been numerically reproduced. The purpose of this work is to study the characteristics of the wind wake produced by the 10 meter two bladed wind turbine, operating at a constant rotational speed of 72 RPM, subject to a free stream wind velocity of 9 m/s, inside a wind tunnel in which dimensions are 36.6 m in width, 24.4 m in height and length of 170 m. To achieve that, the ANSYS FLUENT version 13.0 commercial code, based in the Finite Volume Method to numerically solve the Navier-Stokes equations in transient state, has been used, together with the Large Eddy Simulation (LES) to characterize the turbulence. Geometries of all the machine components have been created in CAD software. A disc shaped moving domain, containing the blades and hub, has been created separately, and later inserted into the main, static domain, using the Moving Mesh tool available in the software. Both domains have been filled with meshes composed by tetrahedra. Data collected at the numerical simulations have been compared to experimental wind speed data provided by two sonic anemometers installed 5.8 m downstream from the rotor, for which a good agreement has been found, with differences of approximately 1% to the anemometer 1 and 6% to the anemometer 2. Results of wind velocity at the tunnel centerline and velocity profiles downstream have been compared with recent numerical study, and show important differences between data obtained by LES, especially with regard to the detection of peaks and fluctuations related to the turbulent scales, and data obtained by the classic turbulence modeling, RANS. Disturbances have passed the 10 diameter mark and reached the end at the domain located at 15 diameters. The wake did not show axial symmetry and the point of maximum reduction in the flow speed was detected outside the rotor centerline.

Feitosa, Erialdo de Oliveira. Energia eólica aplicada ao bombeamento da água para irrigação por gravidade na agricultura familiar. 2014. 107 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia Agrícola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2014. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-23T16:52:19Z No. of bitstreams: 1 2014_dis_eofeitosa.pdf: 2679430 bytes, checksum: a127ee0b0b7829a2d2ed216e57412a26 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-06-23T16:52:50Z (GMT) No. of bitstreams: 1 2014_dis_eofeitosa.pdf: 2679430 bytes, checksum: a127ee0b0b7829a2d2ed216e57412a26 (MD5) / Made available in DSpace on 2016-06-23T16:52:50Z (GMT). No. of bitstreams: 1 2014_dis_eofeitosa.pdf: 2679430 bytes, checksum: a127ee0b0b7829a2d2ed216e57412a26 (MD5) Previous issue date: 2014 / The use of wind energy is today a reality in the Brazilian energetic context, because it meets the requirement of complementarity to the national energy system and its exploitation generates relatively few environmental impacts. In this context family agriculture, which lives together with semiarid, passes per great bottlenecks with relation to the access, and the cost of two resources fundamental for its development, water and energy. This project was developed with bias in the supply of water and energy to small rural properties focused on horticultural. So that wind energy can be an important solution for the process of production of agriculture, because it can supply the needs of the small producer. Thus the objective of this research was to investigate the possibility of a wind turbine to generate electricity to put in action an water pumping system which represses water to an elevated reservoir, and possibly could be used for irrigation per gravity drip. It was used a 1 kW wind generator power, model H3.1-1KW, Hummer mark, where it and the pumping system were installed at the Federal University of Ceará, Campus do Pici. With the experimental arrangement ready, it was conducted to collect data on wind speed, current and voltage generated by, and pressure and flow rate of the motor pump. As a result it was verified a pumped volume averaged 3750.5 L day-1. Concluding that can be used in irrigated horticultural production family agriculture and would also be useful in animal production and consumption own. This conclusion presents wind power as a good alternative for family agriculture live with the semiarid in the sense which will enable the use of renewable energy linked the rational use of water. / O uso da energia eólica é hoje uma realidade no contexto energético brasileiro, pois atende o requisito de complementaridade ao sistema nacional de energia e sua exploração gera relativamente poucos impactos ambientais. Neste contexto a agricultura familiar que convive com semiárido passa por grandes gargalos com relação ao acesso, e o custo de dois recursos fundamentais para o seu desenvolvimento, água e energia. Este projeto foi desenvolvido com viés no fornecimento de água e energia para pequenas propriedades rurais focadas em hortículas. De modo que a energia eólica possa ser uma solução importante para o processo de produção da agricultura, pois pode suprir as necessidades do pequeno produtor. Assim o objetivo desta pesquisa foi verificar um aerogerador na geração de energia elétrica para acionamento de um sistema de bombeamento de água, o qual realizava o recalque da água para um reservatório elevado, e que possa ser utilizado na irrigação por gotejamento gravitacional. Utilizou-se um aerogerador de 1 kW de potência, modelo H3.1-1KW, marca Hummer, onde o mesmo e o sistema de bombeamento foram instalados na Universidade Federal do Ceará, Campus do Pici. Com o arranjo experimental pronto, foi efetuada a coleta de dados da velocidade do vento, corrente e tensão do aerogerador, e pressão e vazão do conjunto motobomba. Como resultado verificou-se o volume bombeado em média de 3.750,5 L dia-1. Concluindo que o mesmo pode ser usado na produção irrigada de hortículas da agricultura familiar e também seria útil na produção animal e próprio consumo. Enfim a energia eólica apresenta-se como uma boa alternativa para o agricultor familiar conviver com o semiárido, no sentido que possibilitará o uso de energia renovável atrelada ao uso racional da água.

Le sujet de la thèse est le développement d'un outil numérique qui permet de modéliser l'écoulement autour des pales d'éoliennes. Nous nous sommes intéressés à la résolution des équations de Navier-Stokes en incompressible sur des maillages de type octree où les échelles plus petites en proche parois ont été modélisées par la méthode dite des wall functions. Un procédé d'adaptation automatique du maillage (AMR) a été développé pour affiner le maillage dans les zones où la vorticité est plus importante. Le modèle de structure d'une pale d'éolienne a été également implémenté et couplé avec le modèle fluide car une application de l'outil numérique est l'étude des effets des rafales de vent sur les pales d'éolienne. Un travail expérimental a été mené sur une éolienne avec une mesure de vent en amont. Ces données permettent ainsi de calibrer et valider les modèles numériques développés dans la thèse. / The subject of the thesis is the development of a numerical tool that allows to model the flow around wind blades. We are interested in the solving of incompressible Navier-Stokes equations on octree grids, where the smallest scales close to the wall have been modelled by the use of the so-called Wall Functions. An automatic Adaptive Mesh Refinement (AMR) process has been developed in order to refine the mesh in the areas where the vorticity is higher. The structural model of a real wind blade has also been implemented and coupled with the fluid model. Indeed, an application of the numerical tool is the study of the effects of wind gusts on blades. An experimental work has been conducted with an in-service wind turbine with the measurement of wind speed upstream. This data will allow to calibrate and validate the numerical models developed in the thesis.

Ce travail vise à modéliser la propagation du vent par des techniques de simulation de CFD dans des tissus urbains contrastés à l’échelle du quartier (450m × 450m) afin d'évaluer les impacts de la morphologie urbaine sur le potentiel énergétique éolien. Face aux problèmes environnementaux locaux et globaux, le développement des énergies renouvelables devient de plus en plus urgent à l’échelle mondiale. Notre objectif est d’adapter la morphologie urbaine au développement du captage de l’énergie éolienne. Pour ce faire, deux questions fondamentales sont posées : quels sont les impacts de la morphologie urbaine sur l'écoulement du vent dans la ville ? Comment évaluer le potentiel énergétique éolien de la ville ? Nous partons d’une synthèse bibliographie sur les trois domaines : l'énergie éolienne urbaine, la morphologie urbaine et la simulation aéraulique. Les avantages et les inconvénients des éoliennes urbaines sont discutés. Des indicateurs de morphologie urbaine sont ainsi proposés. Les méthodes de simulation CFD (Mécanique des fluides numérique) sur l'écoulement du vent autour de bâtiments sont présentées. Des nouvelles technologies et des méthodes d'intégration architecturale de petites éoliennes sont ainsi présentées. Pour valider notre modèle, nous faisons une étude approfondie des paramètres du code ANSYS FLUENT avec la référence des données d’un benchmark issu d'expérimentations en soufflerie. Plusieurs méthodes de vérification avant et après les simulations sont proposées. Après validation de notre modèle, des simulations de formes simples sont faites. Avec un bâtiment, deux bâtiments et trois bâtiments, les impacts de différents paramètres simples de configuration sont analysés. En raison de leur efficacité et de leur faisabilité, l'évaluation énergétique est principalement faite au-dessus des toits de bâtiments. Les effets de la concentration du vent au-dessus des toits sont ainsi évalués. Nous simulons ensuite des modèles morphologiques plus complexes, par l’évaluation du potentiel éolien dans six quartiers de formes urbaines typiques dans le monde et favorables pour exploiter l'énergie éolienne. Treize indicateurs morphologiques ayant potentiellement une influence sur l'écoulement du vent sont proposés. Des analyses de cohérence entre les indicateurs morphologiques et les indicateurs d'évaluation de l'énergie éolienne au-dessus des toits sont faites. Ensuite, des variantes de formes urbaines typiques sont étudiées. L’influence de certaines modifications de ces prototypes sur le potentiel éolien est étudiée et les prototypes les plus favorables pour l'exploitation de l'énergie éolienne sont proposés. L'énergie éolienne dans un quartier existant à Pekin est ensuite évaluée. Des conditions locales (formes physiques, climat, aspects socio-économiques) sont considérées pour évaluer la faisabilité du développement de l’énergie éolienne. L'emplacement et le choix des techniques d’éoliennes urbaines adaptées sont discutés. Enfin, une méthode mathématique basée sur des paramètres morphologiques simples est présentée pour évaluer le potentiel éolien au-dessus des toits. L'indicateur de l'impact d'obstacle des bâtiments est défini. La cohérence entre les résultats de la méthode mathématique et ceux de la simulation CFD est enfin analysée. / This work concentrates on wind flow simulation by CFD techniques in different urban fabrics at the neighborhood scale (450m × 450m), in order to assess the impacts of urban morphology on wind energy potential. Facing local and global environmental problems, the development of renewable energy is becoming increasingly urgent and important. Our goal is to adapt the urban morphology in the development of urban wind energy. To do so, two fundamental questions are aroused: What are the impacts of urban morphology on the wind flow in the city? How to evaluate the urban wind power? We start with a summary of bibliography on three areas: urban wind energy, urban morphology and CFD (Computational fluid dynamics) simulation. The advantages and disadvantages of different urban wind turbines are discussed. Some new technologies and methods of architectural integration of small wind turbine are presented. Indicators of urban morphology are proposed. The methods of CFD simulation of wind flow around buildings are presented. To validate our model of air flow simulation, we start with a study of the numerical simulation parameters with the reference of a benchmark of wind tunnel experiments. Several methods of verification before and after the CFD simulation are presented. After validation of our model, we begin to simulate some simple forms. With one, two and three buildings, the impacts of different simple configurations parameters are analyzed. Considering the effectiveness and feasibility, wind energy assessment is mainly taken over the roofs of buildings. The combined effects of altitude and wind concentration above the roof, are evaluated. We then simulate more complex morphological models, by assessing the wind potential in six neighborhoods that are urban forms both worldwide typical and favorable for wind energy development. Morphological indicators that potentially affect the wind flow are proposed. Analysis of coherence are made between these indicators and the values of the coefficient of increase of wind speed and of the wind power indicator above the roof. Then, some prototypes of basic urban forms from real neighborhoods are studied. The influence of some modifications of these prototypes on the wind energy potential is analyzed, and the most favorable conditions for the exploitation of wind power prototypes are recommended. Then, wind energy in a real neighborhood in Beijing is evaluated. Local conditions (physical forms, climate, social-economic aspects) are considered to assess the feasibility of developing wind energy. The location and the choice of techniques suitable urban wind turbines are discussed. Finally, a mathematical method based on some simple morphological parameters is presented, in order to assess wind potential above the rooftops. The obstacle impact indicator of the buildings is defined. The coherence between the results of the simplified mathematical method and those of CFD simulation are analyzed.

Étant donné l'urgence environnementale, le développement des énergies renouvelables s'est fortement accru ces dernières années. L'implantation de champs d'éoliennes est notamment en pleine expansion dans toute l'Europe. Ces éoliennes, de structure diélectrique et métallique et de grande taille, peuvent avoir un impact significatif sur les systèmes radiofréquences. En particulier, les systèmes de radionavigation et de surveillance opérés par la DGAC (VOR, radar) doivent cohabiter avec de nouveaux champs d'éoliennes. En effet, ces dernières influent sur le champ électromagnétique des systèmes et peuvent dégrader leurs performances (multitrajets, masquages... ). Il est alors important de pouvoir quantifier ces dégradations, en particulier dans le cas du VOR où les multitrajets engendrent une erreur de relèvement. Dans ce travail de thèse, un simulateur électromagnétique appelé VERSO (VOR ERror SimulatOr) est développé. Il permet d'estimer l'impact d'objets diffractants, en particulier d'éoliennes, sur le signal VOR. Dans la littérature, différentes techniques de modélisation sont proposées pour prédire ces phénomènes. Certaines sont trop approximatives, d'autres trop coûteuses en temps. Ainsi, le choix des techniques utilisées dans ce simulateur a été guidé par le compromis entre précision et temps de calcul. L'équation parabolique est utilisée pour modéliser la propagation de la source jusqu'aux éoliennes afin de prendre en compte le relief. Ensuite, une méthode d'optique physique sur matériaux diélectriques est mise en œuvre pour calculer le champ diffracté par ces objets. Le modèle électromagnétique de l'éolienne et les hypothèses inhérentes aux méthodes utilisées par VERSO ont été validés aux fréquences VHF (VOR) par comparaison avec la méthode des moments qui fait office de référence. Une extension de VERSO pour les systèmes radars a été abordée. Par conséquent des validations similaires à ces fréquences ont été réalisées. Plus spécifiquement, un modèle de pale d'éolienne prenant en compte la présence du parafoudre est proposé aux fréquences VOR et radar. Les effets de masquage sont eux aussi quantifiés pour ces 2 domaines de fréquences. Il est notamment démontré que l'effet de masquage pour des éoliennes alignées radialement à un VOR est négligeable. Cette approximation ainsi que le modèle de pale sont ensuite utilisés dans le programme VERSO. Ce dernier est validé à l'aide de contrôles en vol sur un scénario de 9 éoliennes implantées à 5 km du VOR de Boulogne-sur-Mer. Une étude quantitative de l'impact de chaque partie des éoliennes est menée afin de discriminer la source majoritaire d'erreur VOR. On constate notamment qu'à grande distance du VOR dans le scénario d'observation considéré, le mât constitue le principal contributeur en terme de champ diffracté et d'erreur VOR. Enfin, une étude statistique sur l'erreur VOR a permis d'obtenir un simulateur de scénarios qui donne l'erreur maximale avec une confiance fixée, en minimisant le nombre de simulations à effectuer. Pour accélérer cette méthode, une expression analytique approchée de l'erreur VOR maximum a été développée en fonction de la distance d'implantation et de la hauteur du mât de l'éolienne. Cette dernière étude fournit une méthode rapide pour évaluer l'impact de la construction d'un champ d'éoliennes quelconque à proximité de systèmes de l'aviation civile. / Considering the ecological emergency, the renewable energy development has greatly increased for a decade. In particular, the windfarms implantation rapidly expands in Europe. These windturbines are large obstacles composed by dielectric and metallic materials. So their impact on electromagnetic devices is significant. The radionavigation systems for the civil aviation services are particularly concerned. However, they have to work side with new windfarms. Actually, these latter cause scattering effects on the electromagnetic signals and can degrade the performances of these equipments (multipaths, shadowing effects etc.). Thus, quantifying these degradations is crucial, particularly on the VOR devices where multipath effects cause an error on the azimuth. In this thesis work, an electromagnetic simulator called VERSO (VOR ERror SimulatOr) is developed. It can estimate the impact of scattering objects, especially windturbines, on the VOR signal. In literature, several techniques are proposed to model these phenomena: some make coarse approximations and some others are memory intensive. Thus, the choice over the methods used in VERSO is a compromise between precision and memory requirement. The parabolic equation is used to model the propagation from the source to the windturbines so as to take the relief into account. A physical optic based method is used to compute the field scattered by these objects. The electromagnetic model of the windturbine and the hypothesis due to the methods used by VERSO have been validated in the VHF (VOR) frequency by comparison with the method of moments, which is the reference. An extension of VERSO for the radar systems is introduced. Consequently similar validations have been performed at radar frequencies. In particular, a windturbine blade model taking into account the lightning protection is proposed for the VOR and the radar frequencies. The shadowing effects are also quantified in both frequency domains. Especially, a demonstration that the shadowing effects due to radially implemented windturbines can be neglected around a VOR beacon is proposed. This approximation and the blade model are used for the implementation of VERSO. This simulator is validated by comparison with measurements on 9 windturbines built 5~km far from a VORC in Boulogne-sur-Mer (France). A study is performed to quantify the influence of each part of the windturbine. The mast is shown to be the main contributor regarding to the electromagnetic field and the VOR error. Finally, parametric simulations are performed and analytic expressions are proposed to describe the evolution of the maximum VOR error with respect to the mast size and the distance VOR-windturbine. The latter study gives some key parameters that need to be considered for the elaboration of a windfarm building plan close to civil aviation systems for the project to be viable.

O presente trabalho realiza um estudo do desempenho aerodinâmico da turbina eólica de duas pás e 10 m de diâmetro da UAE Phase VI, testada pelo NREL no túnel de vento NASA Ames, através do uso de dinâmica dos fluidos computacional (CFD). Para tanto são apresentados conceitos fundamentais para análise da performance do aerogerador, a metodologia aplicada para a análise numérica e os resultados obtidos. O modelo geométrico da turbina foi inserido em ambiente computacional num domínio com as mesmas dimensões da seção de testes do túnel de vento. A esse domínio foi empregada uma malha de elementos tetraédricos. A modelagem numérica e as simulações foram efetuadas através do código comercial ANSYS FLUENT 13.0 e utilizaram as equações médias de Reynolds e modelos de turbulência k  SST e Spalart-Allmaras. A turbina simulada possui ângulo de giro (yaw) e de cone de 0°. Os casos simulados foram de turbina com ângulos de passo das pás de 0° e 3°, para velocidades de ar na entrada do domínio de 5 m/s, 7 m/s e 9 m/s. As simulações foram feitas em regime transiente utilizando o método de malha móvel. Dados provenientes da simulação numérica são comparados aos dados experimentais de empuxo, torque e potência, divulgados pelo laboratório. Os modelos de turbulência testados apresentaram boa concordância com os resultados experimentais de empuxo. O torque e a potência foram bem previstos para velocidades de entrada do domínio baixas, mas foram subdimensionados para velocidades mais altas. A separação da camada limite foi prevista por ambos os modelos. Na comparação com resultados obtidos com outros autores para o mesmo caso, o início de descolamento da camada limite se deu antes do previsto. A metodologia adotada nas simulações numéricas realizadas mostrou-se adequada e representativa nas análises desse estudo. / This study makes a CFD analysis of the aerodynamic performance of the NREL UAE Phase VI two-bladed wind turbine, which have been tested in the NASA Ames wind tunnel. Fundamental concepts on the evaluation of turbine performance, the applied methodology for the numerical analysis and the results are presented. A numerical model has been inserted in a computational environment that has the same dimensions as the real wind tunnel section, and a tetrahedral mesh has been created to fill this domain. Numerical modeling and the simulations have been performed using the ANSYS FLUENT 13.0 commercial code, making use of the RANS equations and the k  SST and Spalart-Allmaras turbulence models. The simulated turbine has 0 degrees of cone and yaw angle. Simulations were performed in unsteady state using the moving mesh technique. Results are compared to experimental data regarding to thrust, torque and power. The k  SST and Spalart-Allmaras turbulence models have shown good agreement with experimental values of thrust. Torque and power have been adequately predicted to lower free flow velocities, but have been underpredicted to higher velocities. Separation of the boundary layer has been adequately predicted by both models, but the beginning of the separation occurred earlier than expected in comparison with results of other authors to the same case. The methodology used in the numerical simulations proved to be adequate and representative in this study.