Contact-less transfer of energy has always been a desired feature for systems that require reliable and durable power transfer across their moving parts. In rotary equipment in particular, slip-rings are the established solution with off-the-shelf and customised solutions readily available in the market. Despite the mature technology, slip-rings suffer wear and are prone to arcing, making frequent maintenance a necessity. In this project a rotating transformer is proposed as an alternative solution for contact-less transfer of energy across the revolving frame of an airborne electronic-scanning radar. This thesis is based on the hypothesis that the Phase-Shifted Full Bridge (PSFB) topology can efectively utilise the parasitic components of the rotating transformer to achieve efficient (over 90%) power conversion at the kW range. The first part of this work concentrates on the study of the magnetic interface and its electrical properties. Initially the magnetic structure of the transformer is studied in order to gain understanding of the effects of the physical layout of the component to its electrical behaviour. The problems of low magnetising and increased leakage inductance are quantified by measurements, calculations and finite element analysis. An accurate electrical model is built and used to calculate the transformer voltage and current gain. The second part of the research programme aims at the compilation of a design strategy for a PSFB incorporating a rotating transformer. An algorithm is presented, that optimises the magnetic component structure in order to achieve minimum switching losses and spread the conduction losses between the transformer and power switches. The last stage involves the evaluation of the design algorithm through prototyping and testing. Some topological variations are tested and compared with the original conventional PSFB converter. The thesis concludes with a discussion of the results and future challenges.

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 11, 2007) Includes bibliographical references.

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Computational fluid dynamics (CFD) is used in this thesis to model wind and tidal stream turbines and to investigate tidal turbine fence performance. There are two primary objectives of this work. The first is to develop and validate an actuator line method for the simulation of wind and tidal turbines which applies the blade forces to the flow field without the need for a regularisation kernel. The second is to examine tidal fences using, in part, the newly developed actuator line method. A potential flow equivalence method for determining the relative velocity to the blade chord and flow angle at the rotor blades in the actuator line method is proposed and validated. Results for simulations using this method compare favourably with those from both experiments and alternative computational methods, although the present model’s results deviate from experimental results in the vicinity of the blade tips. A CFD-embedded blade element-momentum tool is used to design rotors for operation in infinitely wide tidal fences spanning a tidal channel. Rotors are designed for fences with several different blockage ratios, with those designed for high blockage flows having greater solidity than those designed for operation in fences with lower blockage. It is found that designing rotors for operational blockage conditions can significantly improve the power output achieved by a tidal fence. Improved power output for higher blockage conditions is achieved by the application of greater thrust to the flow. Actuator line simulations of short (up to 8 turbines) fences with varying intra-rotor spacing and number of rotors confirm that hydrodynamic performance of the rotors improves as the spacing is reduced and as rotors are added to a fence. The position of a rotor within the fence impacts its performance; rotors at the ends of a fence extract reduced power compared to those at the centre of the fence, particularly for tip speed ratios greater than the design tip speed ratio.

The theme of the diploma thesis "Effect of energy care on building prices" is the design and assessment of several measures, two of which generally lead to lower heating costs. The diploma thesis deals with evaluation of the current state of the family house and determination of PENB before the construction modifications and subsequently after the construction modifications, defining subsequent measures for energy saving implementation, both in terms of energy, economic and also environmental.

This master’s thesis deals with side channel pumps. Derivated formula of specific energy is supplemented by other equations and the results of CFD simulation. Further are analysed the mechanism of energy transfer from the impeller and external characteristics of the pump.

This diploma thesis deals with the impact of thermal insulation on expenses relateted to the operation of the weekend house. Theoretical part describes options of thermal insulation systems, insulation methodes, describes structural prices and costs. Practical part of this thesis describes heat costs on specific weekend house situated in Karlovy Vary region. Thermal insulations are designed in three different variants. Calculation of costs of every designed insulation systém is included in this thesis. In next part of thesis is calculated return of investment for every designed solution. In conclusion of the diploma thesis are compared impacts of thermal insulation on expenses ralated to the operation of the weekend house.

This diploma thesis deals with insulation of the house and it's costs. First part relates to the developement of the construction, the current trends in the construction of houses, prices of energy and heating options. Next part relates with insulation system ETICS, the way of it's implementation and thermal assessment with basic names. Thermal insulation is designed in six variants. The work includes thermal assessment in original condition and the assessment of new condition modified by adding thermal insulation with it's economic return. In conclusion, the diploma thesis evaluates the payback period of insulation.

Les propriétés de transport à haute température dans les gaz et/ou dans les plasmas ont une importance capitale dans différents domaines, à savoir dans le domaine de technologie de coupure à arc, plasmas de coupure, de soudure ou de gravure. La connaissance des coefficients de transport est nécessaire pour toute modélisation faisant intervenir les équations hydrodynamiques. Dans le cadre de la théorie cinétique des gaz dilués, une solution approchée de l’équation intégro-différentielle de Boltzmann régissant les fonctions de distribution a été proposée par Chapman-Enskog. Les coefficients de transport sont calculés classiquement par la méthode de Chapman-Enskog via les intégrales de collision. Dans le cadre de notre étude nous avons développé, dans un premier temps, un code numérique permettant l’obtention de ces intégrales de collision en tenant compte des singularités qui peuvent apparaître dans le calcul des sections efficaces relatives aux interactions entre les particules constituant les gaz et/ou les plasmas. Dans un second temps nous avons étudié l’influence du choix des paramètres des potentiels d’interaction sur les coefficients de transport. Par la suite, nous avons utilisé le code numérique ainsi développé pour évaluer les coefficients de transport du plasma d’hélium en étudiant l’influence du choix de la méthode de calcul de composition chimique sur ces coefficients. Enfin, un modèle simplifié d’une interaction entre une onde électromagnétique et un plasma d’hélium a été proposé comme une application directe des coefficients de transport. / Transport properties at high temperature in gases and/or in plasmas are of very importance in various fields, namely in the field of breaking technology in arc, cutting plasma, welding or burning. Knowledge of transport coefficients is necessary for any modeling involving hydrodynamic equations. As part of the kinetic theory of diluted gas, an approximate solution of the integro-differential Boltzmann equation governing distribution functions was proposed by Chapman-Enskog. Transport coefficients are classically computed using the method of Chapman-Enskog through the collision integrals. In our study we have developed, initially, a numerical code to obtain these collision integral taking into account the singularities that may occur in the calculation of the cross sections relating to interactions between particles forming the gas and/or plasmas. Secondly, we have studied the influence of the choice of parameters of interaction potentials on transport coefficients. Subsequently, we have used the numerical code developed for evaluating and helium plasma transport coefficients by studying the influence of the choice of method for calculating chemical composition on these coefficients. Finally, a simplified model of an interaction between an electromagnetic wave and a helium plasma has been proposed as a direct application of the transport coefficients.

This thesis deals with the computational comparison of the energy performance of buildings of various construction materials. The work aims at assessing the building as a thermal system. The theoretical part describes the methods for calculating the energy performance of buildings. The experimental part of the work focuses on quantifying the heat consumption of specific buildings in terms of thermal stability and it is later compared with the results calculated in accordance with the applicable technical standards.