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L'augmentation de la vitesse de croisière des hélicoptères à architecture conventionnelle (rotor principal et rotor anticouple) atteint aujourd'hui une asymptote. Le concept X3, associant 2 hélices et une aile pour alléger la charge du rotor principal, propose une solution viable économiquement, qui s'appuie sur l'utilisation de technologies éprouvées telles que le rotor Spheriflex® du Dauphin. Les essais en vol menés sur le démonstrateur X3 ont montré un bon comportement en performances et en qualités de vol de ce type de rotor, mais un niveau de charges très importants dans les commandes de vol. Pour limiter la masse à vide, la solution de surdimensionner toutes les pièces mécaniques n'est pas envisageable. Ce travail de thèse propose d'étudier les opportunités de réduction des efforts de commandes.Afin de pouvoir réduire ces efforts, il a été nécessaire de comprendre leur origine et de proposer une modélisation qui permette de les prédire. Des mesures expérimentales réalisées sur le démonstrateur X3 ont permis d'identifier les excitations aérodynamiques et le comportement dynamique des pales en torsion. Les phénomènes responsables de l'augmentation des efforts de commande ont été identifiés, ce qui a permis de corriger le modèle de calcul des efforts de commande HOST actuellement utilisé par Airbus Helicopters.A partir du logiciel HOST corrigé et de la compréhension des phénomènes physiques, des solutions technologiques pour réduire les efforts de commandes ont été étudiées. Deux familles de solutions sont alors considérées : l'optimisation du système de commandes de vol et la réduction des efforts dans les bielles de pas. L'optimisation du système de commandes de vol permet d'obtenir une réduction significative des efforts de commandes grâce à un algorithme d'optimisation de l'architecture de placement des servocommandes. L'étude de la réduction des efforts dans les bielles de pas montre que le choix de l'équilibre appareil conduit à des opportunités de réduction des efforts de commandes, alors que la modification du design de pale n'apporte pas de réduction notable et engendre une diminution des performances en stationnaire. / Nowadays, the increase of cruise speed for conventional helicopters (main rotor and anti-torque rear rotor) reaches an asymptote. The X3 concept proposed by Airbus Helicopters is a hybrid helicopter combining 2 propellers at the tip of small wings in order to unload the main rotor. This solution is economically viable because it reuses well-proven technologies such as the Spheriflex rotor, already used on the Dolphin family for many years. X3 flight tests have shown a good behavior of the rotor concerning performances as well as handling qualities, but control loads in the rotor system were significantly higher in cruise conditions than for conventional helicopters. In order to save the payload, over-sizing of the mechanical parts in order to withstand these loads can't be an appropriate solution. The work presented in this thesis deals with the problematic of control loads reduction.In order to reduce the control loads, the first step is to highlight the roots of these loads and to get a predictive tool over the whole flight domain. Experimental measurements from X3 flight tests give the aerodynamic loads on the blade sections, leading to understand the blades torsional dynamic behavior in several flight test cases (cruise, turns and high speed flight). Phenomena responsible for the increase of control loads are then identified, and the rotor computation tool HOST used at Airbus Helicopters is corrected to predict accurately control loads over the conventional as well as the high speed helicopter flight domain.The corrected rotor computation tool HOST, associated with the physical comprehension of the blade torsional dynamics, is used to quantify the possible solutions proposed for control loads reduction. Two main ways are studied: the optimization of the control system architecture and the reduction of pitch link loads. The optimization of control system architecture shows a dramatic reduction of control loads in the servo actuators and in the non-rotating scissors, thanks to an optimization algorithm developed during this thesis. The reduction of pitch link loads study shows that the optimization of the helicopter equilibrium leads to drastic reduction, whereas the modification of blade design does not show any significant reduction even at high speed.

Improving the wind turbine blade design has a significant effect on the efficiency of the wind turbine. This is a challenging multi-disciplinary optimization problem. During the blade design process, the aerodynamic shapes, sizing of the structural members, and material composition must all be determined and optimized. Some previous blade design methods incorporate the wind turbine's static response with an added safety factor to account for neglected dynamic effects. Others incorporate the dynamic response, but in general is limited to a few design cases. By not fully incorporating the dynamic response of the wind turbine, the final turbine blade design is either too conservative by overemphasizing the dynamic effects or infeasible by failing to adequately account for these effects. In this work, we propose two methods which efficiently incorporate the dynamic response into the optimization routine. The first method involves iteratively calculating damage equivalent fatigue that are fixed during the optimization process. We also demonstrate the training and use of a surrogate model to efficiently estimate the fatigue damage and extreme events in the design process. This surrogate model has been generalized to be used for different rated turbines, and can predict the fatigue damage of a wind turbine with less than 5% error. In general, these alternative, more efficient methods have been shown to be an adequate replacement of the more computationally expensive method of calculating the dynamic response of the turbine within the optimization routine.

The majority of present-day horizontal axis wind turbine blade tips are simple designs based on historical trends. There is, however, some evidence that varying the design of the tip can result in significant changes in performance characteristics such as power output, noise, and structural loading. Very few studies have tested this idea on an actual rotating blade and there is much to be investigated. Thus, a project was devised to examine experimentally the effect of various tip designs on an operational rotating wind turbine rotor. A tapered, twisted blade 1.6 m in length was custom designed for use in the UW Wind Energy Research Facility using the blade element momentum (BEM) method. A coupling mechanism was designed such that the outer 10% of each blade could be exchanged to evaluate the effect of different tip designs. A set of three blades was fabricated out of fibre-reinforced plastic, while the tips were machined out of maple wood on a CNC milling machine. The blade was evaluated with a standard rectangular tip to establish baseline performance against which to compare the alternative tip configurations. The three-bladed rotor was tested at shaft speeds from 100 rpm to 240 rpm in wind speeds up to the facility maximum of 11.1 m/s. The rotor was found to have a maximum power coefficient of 0.42 at a tip speed ratio of 5.3 and a 1.45 kW rated power at a wind speed of 11 m/s. The performance was compared to predictions made using the BEM method with airfoil data generated using a modified Viterna method and the Aerodas method. While the Aerodas data was capable of predicting the power fairly accurately from 5 m/s to 10 m/s, the modified Viterna method predicted the entire curve much more accurately. Two winglet designs were also tested. The first (called Maniaci) was designed by David Maniaci of Pennsylvania State University and the other (called Gertz) was designed by the author. Both winglets were found to augment the power by roughly 5% at wind speeds between 6.5 m/s and 9.5 m/s, while performance was decreased above and below this speed range. It was calculated that the annual energy production could be increased using the Maniaci and Gertz winglets by 2.3% and 3%, respectively. Considering the preliminary nature of the study the results are encouraging and it is likely that more optimal winglet designs could be designed and evaluated using the same method. More generally, this study proved that the blades with interchangeable tips are capable of being used as an evaluation testbed for alternative wind turbine blade tip designs.

In this thesis, the turbine blade design eligible for ocean current conditions is proposed using blade element momentum theory. in the beginning, the performance of water turbines is evaluated by CFD (computational fluid dynamics) package code, so as to design the suitable turbine under various conditions. The blade design encompasses parameters of the hydrofoil selection and blade shape which affect the turbine performance. Shortly following the investigation of the aforementioned parameters, the turbine¡¦s performance with radius of two meter is also studied. The current conditions include the yaw and the pitch angle of the turbine relative to the current flow direction, as well as the periodic flow conditions on the performance of the water turbine. Lastly, the electricity generation is estimated by the present device. The results show that hydrofoils with less changes in the angle of attack with respect to the lift-drag ratio help enhance the turbine¡¦s performance. The feedback mechanism is added to the blade design procedure to make sure that the turbine design caters to the best angle of attack. A turbine with two-meter radius can garner 34% of the sea current energy at most, living up to the project goal of exceeding the efficiency of 30%. The simulated test indicates that the adequate enlargement of the blade not only sustains the maximal efficiency, but it also lowers the stress imposed on the blade. Given the ocean current conditions, it is also shown that the turbine¡¦s efficiency is proportional to the cubic cosine incident angle of inflow velocity alongside with the enlargement of the turbine radius. When it comes to the current electricity generation, from the in-situ measurement data, the current maximal velocity near the sea region is around 1.3 m/s. If incorporated with the self excited induction generator with the efficiency of 55%, a one-meter-radius turbine is estimated to be able to generate 530W at most, while a two-meter-radius turbine is estimated to generate 2.5KW. However, the use of the permanent magnet generator can produce 45% more electricity than a self excited induction generator.

The majority of present-day horizontal axis wind turbine blade tips are simple designs based on historical trends. There is, however, some evidence that varying the design of the tip can result in significant changes in performance characteristics such as power output, noise, and structural loading. Very few studies have tested this idea on an actual rotating blade and there is much to be investigated. Thus, a project was devised to examine experimentally the effect of various tip designs on an operational rotating wind turbine rotor. A tapered, twisted blade 1.6 m in length was custom designed for use in the UW Wind Energy Research Facility using the blade element momentum (BEM) method. A coupling mechanism was designed such that the outer 10% of each blade could be exchanged to evaluate the effect of different tip designs. A set of three blades was fabricated out of fibre-reinforced plastic, while the tips were machined out of maple wood on a CNC milling machine. The blade was evaluated with a standard rectangular tip to establish baseline performance against which to compare the alternative tip configurations. The three-bladed rotor was tested at shaft speeds from 100 rpm to 240 rpm in wind speeds up to the facility maximum of 11.1 m/s. The rotor was found to have a maximum power coefficient of 0.42 at a tip speed ratio of 5.3 and a 1.45 kW rated power at a wind speed of 11 m/s. The performance was compared to predictions made using the BEM method with airfoil data generated using a modified Viterna method and the Aerodas method. While the Aerodas data was capable of predicting the power fairly accurately from 5 m/s to 10 m/s, the modified Viterna method predicted the entire curve much more accurately. Two winglet designs were also tested. The first (called Maniaci) was designed by David Maniaci of Pennsylvania State University and the other (called Gertz) was designed by the author. Both winglets were found to augment the power by roughly 5% at wind speeds between 6.5 m/s and 9.5 m/s, while performance was decreased above and below this speed range. It was calculated that the annual energy production could be increased using the Maniaci and Gertz winglets by 2.3% and 3%, respectively. Considering the preliminary nature of the study the results are encouraging and it is likely that more optimal winglet designs could be designed and evaluated using the same method. More generally, this study proved that the blades with interchangeable tips are capable of being used as an evaluation testbed for alternative wind turbine blade tip designs.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O projeto aerodinÃmico de um rotor eÃlico visa a otimizaÃÃo dos parÃmetros de funcionamento, para que este forneÃa uma maior eficiÃncia no regime de operaÃÃo em que à utilizado. O presente trabalho consiste na criaÃÃo de um software em linguagem C++, por meio do ambiente de desenvolvimento integrado C++Builder, atravÃs de um mÃtodo clÃssico de projeto de turbinas eÃlicas baseado na Teoria do Momento do Elemento de Pà (BEM). O software fornece ao usuÃrio dados geomÃtricos de construÃÃo, como curvas de afilamento e torÃÃo da pà com base nos dados dos aerofÃlios utilizados. A anÃlise da curva de potÃncia à feita e mostrada atravÃs de um grÃfico caracterÃstico. O software prediz as alteraÃÃes de desempenho devido Ãs perdas pela ponta e pela raiz da pÃ, e tambÃm informa, entre outras coisas, a distribuiÃÃo das cargas mÃximas ao longo da mesma, de acordo com a faixa de operaÃÃo desejada pelo usuÃrio. A potÃncia fornecida pelo aerogerador pode ser calculada atravÃs de dados de velocidade dos ventos. / The aerodynamic design of a wind rotor aims to optimize the operating parameters, so that this provides a more efficient system operation in which it is used. This work consists in creating a software in C + + language through the integrated development environment C + + Builder, via a classic method of wind turbines design based on the Blade Element Momentum Theory (BEM). The software provides the user with geometric data for building, such as curved taper of the blade and torsion based on the airfoils data used. The power curve analysis is performed and displayed via a characteristic plot. The software predicts performance changes due to losses by the tip and the root of the blade, and also shows, among other things, the distribution of maximum loads along the blade, in the operating range desired by the user. The power delivered by the turbine can be calculated using wind speed data.

A typical approach to optimize wind turbine blades separates the airfoil shape design from the blade planform design. This approach is sequential, where the airfoils along the blade span are pre-selected or optimized and then held constant during the blade planform optimization. In contrast, integrated blade design optimizes the airfoils and the blade planform concurrently and thereby has the potential to reduce cost of energy (COE) more than sequential design. Nevertheless, sequential design is commonly performed because of the ease of precomputation, or the ability to compute the airfoil analyses prior to the blade optimization. This research investigates two integrated blade design approaches, the precomputational and free-form methods, that are compared to sequential blade design. The first approach is called the precomputational method because it maintains the ability to precompute, similar to sequential design, and allows for partially flexible airfoil shapes. This method compares three airfoil analysis methods: a panel method (XFOIL), a Reynolds-averaged Navier-Stokes computational fluid dynamics method (RANS CFD), and using wind tunnel data. For each airfoil analysis method, there are two airfoil parameterization methods: the airfoil thickness-to-chord ratio and blended airfoil family factor. The second approach is called the free-form method because it allows for fully flexible airfoil shapes, but no longer has the ease of precomputation as the airfoil analyses are performed during the blade optimization. This method compares XFOIL and RANS CFD using the class-shape-transformation (CST) method to parameterize the airfoil shapes. This study determines if the precomputational method can capture the majority of the benefit from integrated design or if there is a significant additional benefit from the free-form method. Optimizing the NREL 5-MW reference turbine shows that integrated design reduce COE significantly more than sequential design. The precomputational method improved COE more than sequential design by 1.6%, 2.8%, and 0.7% using the airfoil thickness-to-chord ratio, and by 2.2%, 3.3%, and 1.4% using the blended airfoil family factor when using XFOIL, RANS CFD, and wind tunnel data, respectively. The free-form method improved COE more than sequential design by 2.7% and 4.0% using the CST method with XFOIL and RANS CFD, respectively. The additional flexibility in airfoil shape reduced COE primarily through an increase in annual energy production. The precomputational method captures the majority of the benefit of integrated design (about 80%) for minimal additional computational cost and complexity, but the free-form method provides modest additional benefits if the extra effort is made in computational cost and development time.

The main objective of the thesis is to verify the hydraulic inducer designs and to determine its effect on the cavitation characteristics of the pump. To increase the suction capability and cavitation resistance, the inducer is placed in front of the impeller centrifugal pump. Its role is to protect the impeller against the cavitation. The literary part of the thesis analyzes the issue of cavitation, its origin, development and termination of the cavitation bubble with so-called implosion. Special attention is devoted to describtion of cavitation effect occuring at the hydrodynamic pumps. In the theoretical part, the author is then dealing with the general principles and so far used approaches to the inducer design. The practical part of the thesis describes the process and the derivation of own designs of cylindrical inducer. The aim of the used, unconventional approaches to the inducer design is to achieve a constant pressure field and specific energy of the inducer design output. Partial variants of inducer blades design geometry are tested by the controlled calculation with CFD.

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