Global ETD Search

11	Analýza proudění v potrubí kruhového i nekruhového průřezu metodou využívající rozložení hustoty vířivosti po průřezu / Analysis of the Fluid Flow in Pipes Circular and Not Circular Cross-Section With Methods Using Distribution of the Vorticity Density Soukup, Lubomír Unknown Date (has links) The doctoral thesis deals with the analysis of the flow in the circular and not circular cross-section pipes by methods using the distribution of the vorticity density. This analysis is particularly focused on the derivation of the new velocity profiles formulas using the above mentioned method. In this work is presented a historical overview of the derived velocity profiles. This overview of already derived velocity profiles will be a fundamental benchmark for newly derived velocity profiles. These new velocity profiles are derived for the circular and not circular cross-section pipes and the derivation is based on the analogy of electromagnetic induction by using Biot-Savart law. It is necessary to apply this analogy at first on solitary vortex filament. By taking this step is possible to get the value of the induced velocity from one solitary vortex filament. Subsequently it is possible to obtain the value of the induced velocity from the vorticity wall and afterwards from the vorticity density distribution over the cross section. This work contains also the results of the experimental measurements of the velocity profiles, and of the CFD simulations. Experimentally measured results are used besides other for the selecting of the most suitable CFD computational model. Selected CFD model will be subsequently declared as a reference model and the valid velocity profiles for this model will serve with the experimentally measured data as a benchmark for the newly derived velocity profiles.
12	Analýza proudění v potrubí kruhového i nekruhového průřezu metodou využívající rozložení hustoty vířivosti po průřezu / Analysis of the Fluid Flow in Pipes Circular and Not Circular Cross-Section With Methods Using Distribution of the Vorticity Density Soukup, Lubomír January 2016 (has links) The doctoral thesis deals with the analysis of the flow in the circular and not circular cross-section pipes by methods using the distribution of the vorticity density. This analysis is particularly focused on the derivation of the new velocity profiles formulas using the above mentioned method. In this work is presented a historical overview of the derived velocity profiles. This overview of already derived velocity profiles will be a fundamental benchmark for newly derived velocity profiles. These new velocity profiles are derived for the circular and not circular cross-section pipes and the derivation is based on the analogy of electromagnetic induction by using Biot-Savart law. It is necessary to apply this analogy at first on solitary vortex filament. By taking this step is possible to get the value of the induced velocity from one solitary vortex filament. Subsequently it is possible to obtain the value of the induced velocity from the vorticity wall and afterwards from the vorticity density distribution over the cross section. This work contains also the results of the experimental measurements of the velocity profiles, and of the CFD simulations. Experimentally measured results are used besides other for the selecting of the most suitable CFD computational model. Selected CFD model will be subsequently declared as a reference model and the valid velocity profiles for this model will serve with the experimentally measured data as a benchmark for the newly derived velocity profiles.
13	Methodenentwicklung zur Simulation von Strömungen mit freier Oberfläche unter dem Einfluss elektromagnetischer Wechselfelder Beckstein, Pascal 16 February 2018 (has links) (PDF) Im Bereich der industriellen Metallurgie und Kristallzüchtung treten bei zahlreichen Anwendungen, wo magnetische Wechselfelder zur induktiven Beeinflussung von leitfähigen Werkstoffen eingesetzt werden, auch Strömungen mit freier Oberfläche auf. Das Anwendungsspektrum reicht dabei vom einfachen Aufschmelzen eines Metalls in einem offenen Tiegel bis hin zur vollständigen Levitation. Auch der sogenannte RGS-Prozess, ein substratbasiertes Kristallisationsverfahren zur Herstellung siliziumbasierter Dünnschichtmaterialien, ist dafür ein Beispiel. Um bei solchen Prozessen die Interaktion von Magnetfeld und Strömung zu untersuchen, ist die numerische Simulationen ein wertvolles Hilfsmittel. Für beliebige dreidimensionale Probleme werden entsprechende Berechnungen bisher durch eine externe Kopplung kommerzieller Programme realisiert, die für Magnetfeld und Strömung jeweils unterschiedliche numerische Techniken nutzen. Diese Vorgehensweise ist jedoch im Allgemeinen mit unnötigem Rechenaufwand verbunden. In dieser Arbeit wird ein neu entwickelter Methodenapparat auf Basis der FVM vorgestellt, mit welchem sich diese Art von Berechnungen effizient durchführen lassen. Mit der Implementierung dieser Methoden in foam-extend, einer erweiterten Version der quelloffenen Software OpenFOAM, ist daraus ein leistungsfähiges Werkzeug in Form einer freien Simulationsplattform entstanden, welches sich durch einen modularen Aufbau leicht erweitern lässt. Mit dieser Plattform wurden in foam-extend auch erstmalig dreidimensionale Induktionsprozesse im Frequenzraum gelöst. Metallurgie Kristallzüchtung Elektroprozesstechnik elektromagnetisches Prozessieren Optimierung Simulation RGS Ribbon-Growth on Substrate freie Oberfläche Interface-Tracking Induktion metallurgische MHD MHD Magnetodynamik Hydrodynamik Thermodynamik Magnetohydrodynamik OpenFOAM foam-extend Methodenentwicklung Softwareplattform Numerische Methoden Strömung mit freier Oberfläche Metalle Halbmetalle Silizium Wafer 3D METIS FVM Finite-Volumen-Methode elektromagnetische Wechselfelder zeitharmonische Anregung Frequenzraum Blockmatrizen diskontinuierliche Materialeigenschaften magnetische Permeabilität elektrische Leitfähigkeit eingebettete Diskretisierung GFM Ghost-Fluid-Methode Mehrfeldproblem Multi-Physics Biot-Savart Biot-Savart-Gesetz Biot-Savart-Induktoren überlagerte Gitter ALE Gitterbewegung Kopplung FAM Finite-Flächen-Methode RMF rotierendes Magnetfeld TMF wanderndes Magnetfeld Validierung Maxwell Maxwell-Gleichungen Navier-Stokes Navier-Stokes-Gleichung inkompressibel Schmelze Lorentz-Kraft Induktor Konduktor Induktionsspulen Wirbelströme Wirbelstromproblem PISO Oberflächenspannung semi-gekoppelter Lösungsalgorithmus Diskretisierung Skineffekt AC quasistatische Approximation Magneto-Quasistatik metallurgy crystal growth electromagnetic processing optimization Simulation RGS Ribbon-Growth on Substrate free-surface interface-tracking Induction metallurgical MHD MHD magnetodynamics hydrodynamics thermodynamics magnetohydrodynamics OpenFOAM foam-extend method development software platform numerical methods free-surface flow metals metalloids silicon wafer 3D METIS FVM Finite-Volumen-Method oscillating magnetic fields time-harmonic excitation frequency domain block-matrices discontinuous material properties magnetic permeability electrical conductivity embedded discretization GFM Ghost-Fluid-Method multi-physics Biot-Savart Biot-Savart-inductor overlapped meshes ALE mesh movement coupling FAM Finite-Area-Method RMF rotating magnetic field TMF traveling magnetic field validation Maxwell Maxwell-equations Navier-Stokes Navier-Stokes-equation incompressible melt melt flow Lorentz-force inductor conductor induction coil eddy-currents eddy-current problem PISO surface-tension semi-coupled solution discretization skin effect AC quasi-static approximation ddc:620 rvk:UF 4600
14	Methodenentwicklung zur Simulation von Strömungen mit freier Oberfläche unter dem Einfluss elektromagnetischer Wechselfelder Beckstein, Pascal 08 January 2018 (has links) Im Bereich der industriellen Metallurgie und Kristallzüchtung treten bei zahlreichen Anwendungen, wo magnetische Wechselfelder zur induktiven Beeinflussung von leitfähigen Werkstoffen eingesetzt werden, auch Strömungen mit freier Oberfläche auf. Das Anwendungsspektrum reicht dabei vom einfachen Aufschmelzen eines Metalls in einem offenen Tiegel bis hin zur vollständigen Levitation. Auch der sogenannte RGS-Prozess, ein substratbasiertes Kristallisationsverfahren zur Herstellung siliziumbasierter Dünnschichtmaterialien, ist dafür ein Beispiel. Um bei solchen Prozessen die Interaktion von Magnetfeld und Strömung zu untersuchen, ist die numerische Simulationen ein wertvolles Hilfsmittel. Für beliebige dreidimensionale Probleme werden entsprechende Berechnungen bisher durch eine externe Kopplung kommerzieller Programme realisiert, die für Magnetfeld und Strömung jeweils unterschiedliche numerische Techniken nutzen. Diese Vorgehensweise ist jedoch im Allgemeinen mit unnötigem Rechenaufwand verbunden. In dieser Arbeit wird ein neu entwickelter Methodenapparat auf Basis der FVM vorgestellt, mit welchem sich diese Art von Berechnungen effizient durchführen lassen. Mit der Implementierung dieser Methoden in foam-extend, einer erweiterten Version der quelloffenen Software OpenFOAM, ist daraus ein leistungsfähiges Werkzeug in Form einer freien Simulationsplattform entstanden, welches sich durch einen modularen Aufbau leicht erweitern lässt. Mit dieser Plattform wurden in foam-extend auch erstmalig dreidimensionale Induktionsprozesse im Frequenzraum gelöst. info:eu-repo/classification/ddc/620 ddc:620
15	Cálculo de campos elétricos e magnéticos nas proximidades de linhas de transmissão: uma abordagem analítica e numérica / Calculation of electric and magnetic fields in the proximity of transmission lines: an analytical and numerical approach Pereira, Arthur Melo 26 September 2017 (has links) Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-11-16T09:48:38Z No. of bitstreams: 2 Dissertação - Arthur Melo Pereira - 2017.pdf: 8324435 bytes, checksum: a36f9e13810ace212ce9d44a66fc2fb4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-11-16T09:49:04Z (GMT) No. of bitstreams: 2 Dissertação - Arthur Melo Pereira - 2017.pdf: 8324435 bytes, checksum: a36f9e13810ace212ce9d44a66fc2fb4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-11-16T09:49:04Z (GMT). No. of bitstreams: 2 Dissertação - Arthur Melo Pereira - 2017.pdf: 8324435 bytes, checksum: a36f9e13810ace212ce9d44a66fc2fb4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-09-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In a society dependent on electric energy for the execution of various daily activities, it is normal that its use is increasingly increasing over time. In order to carry out the transportation of all electric energy, it is essential to use transmission lines, which with increasing energy demand inevitably have tended to multiply throughout the world, and especially in Brazil, given its continental dimensions. Considering the function of the transmission lines for the electrical system, its importance in the context of the electric power supply is remarkable. However, the lines constitute one of the great emitting sources of electric and magnetic fields of low frequency, which has caused concern and has been motivating fact of several studies, like the realized in this work. Therefore, in view of the scenario presented in the previous paragraph, it is necessary to establish ways of calculating the fields more and more precisely. For the calculation of the electric field is used the Image Method, the Maxwell Potential Coefficients Method and the Coulomb Law, and for the magnetic field the Biot-Savart's Law is used. The results obtained for the electric and magnetic fields were for infinite rectilinear geometries, finite rectilinear and for the conductors taking the form of a catenary, the latter geometry being the most real model for the arrangement of the conductors in a line. In all cases treated, an analytical and numerical approach was performed, in order to allow the calculation of the three geometries with accuracy. Taking advantage of the methodology of calculation of the fields, in addition this work proposes a method of support to the monitoring of transmission lines. The method consists of using the Genetic Algorithm associated to the values of the electric and magnetic fields measured to determine the parameters of the line, such as: phase spacing, cable-soil height, equivalent conductor diameter, current and operating voltage. Given the simplicity of implementation when compared to other methods, the achievement of satisfactory results and the need for a single measuring device to monitor the transmission line, the proposed method proves to be viable and promising to carry out the line monitoring process. / Em uma sociedade dependente da energia elétrica para a execução de diversas atividades do cotidiano, é normal que a sua utilização seja cada vez mais crescente no decorrer do tempo. Para realizar o transporte de toda energia elétrica é imprescindível o uso de linhas de transmissão, que com o aumento da demanda de energia inevitavelmente tenderam a se multiplicar pelo mundo e em especial pelo território brasileiro, dadas as suas dimensões continentais. Tendo em vista a função das linhas de transmissão para o sistema elétrico, é notável a sua importância no contexto do fornecimento de energia elétrica. No entanto, as linhas constituem uma das grandes fontes emissoras de campos elétricos e magnéticos de baixa frequência, o que tem causado preocupação e tem sido fato motivador de diversos estudos, como o realizado neste trabalho. Portanto, diante do cenário apresentado no parágrafo anterior, se faz necessário estabelecer formas de calcular os campos de maneira cada vez mais precisa. Para o cálculo do campo elétrico utiliza-se o Método das Imagens, o Método dos Coeficientes de Potencial de Maxwell e a Lei de Coulomb, já para o campo magnético a Lei de Biot-Savart é empregada. Os resultados obtidos para os campos elétricos e magnéticos foram para as geometrias retilíneas infinitas, retilíneas finitas e para os condutores assumindo a forma de uma catenária, sendo que essa última geometria constitui o modelo mais real quanto à disposição dos condutores em uma linha. Em todos os casos tratados foram realizadas uma abordagem analítica e numérica, de maneira a possibilitar o cálculo das três geometrias com exatidão. Aproveitando-se da metodologia de cálculo dos campos, adicionalmente este trabalho propõe um método de apoio ao monitoramento de linhas de transmissão. O método consiste em utilizar o Algoritmo Genético associado aos valores dos campos elétrico e magnético medidos para determinar os parâmetros da linha, como: espaçamento entre fases, altura cabo-solo, diâmetro equivalente dos condutores, corrente e tensão de operação. Dada a simplicidade de implementação quando comparado a outros métodos, a obtenção de resultados satisfatórios e a necessidade de um único aparelho de medição para monitorar a linha de transmissão, o método proposto mostra-se viável e promissor para realizar o processo de monitoramento de linhas. Energia elétrica Linhas de transmissão Campo elétrico Campo magnético Método das imagens Lei de Coulomb Lei de Biot-Savart Catenária Monitoramento de linhas Algoritmo genético Electric energy Transmission lines Electric field Magnetic field Image method Maxwell potential coefficients method Coulomb's law Biot-Savart's law Catenary Line monitoring Genetic algorithm ENGENHARIAS::ENGENHARIA ELETRICA

Page generated in 0.0241 seconds