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Modelo de baixa dimensão para análise dinâmica de painel cilíndrico simplesmente apoiado / Low dimensional model for dynamic analysis of cylindrical panel simply supportedSattler, Henrique Araújo Rodrigues 27 August 2015 (has links)
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Previous issue date: 2015-08-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work is a study of linear and nonlinear free vibration of a cylindrical panel simply supported subjected to a dependent loading time. From the full potential and kinetic energy functional of a cylindrical panel to determine the system's equations of motion, whereas the field of deformations of the cylindrical panel follows the non-linear theory for Donnell shallow shell. For discretization of the cylindrical panel moving system of equations is performed a test procedure able to obtain the fields axial and circumferential displacements from a modal expansion radial displacement field, creating a low-dimensional discretized model. Determine the radial displacement field from perturbation techniques that provides the nonlinear modes which couple to the linear vibration mode of the system from the quadratic and cubic non-linearities present in the cylindrical panel equilibrium equations. With this system of equations is reduced to a partial differential equation as a function of the expansion of the modal amplitudes for the radial displacement being discretized then the Galerkin method. They present the results of various free, linear and non-linear vibrations, and forced into a cylindrical simply supported panel, showing the remarkable influence of the modal coupling in modal solution to this radial displacement and the panel geometry. / Neste trabalho, realiza-se um estudo das vibrações livres, lineares e não lineares, e forçadas de um painel cilíndrico simplesmente apoiado submetido a um carregamento dependente do tempo. A partir dos funcionais de energia potencial total e cinética de um painel cilíndrico, determinam-se as equações de movimento do sistema, considerando que o campo de deformações do painel cilíndrico segue a teoria não linear de Donnell para cascas abatidas. Para obter a discretização do sistema de equações de movimento do painel cilíndrico, realiza-se um procedimento analítico capaz de obter os campos de deslocamentos axial e circunferencial a partir de uma expansão modal para campo de deslocamento radial, criando um modelo discretizado de baixa dimensão. Determina-se o campo de deslocamentos radiais a partir de técnicas de perturbação que fornece os modos não lineares que se acoplam ao modo linear de vibração do sistema a partir das não linearidades quadráticas e cúbicas presentes nas equações de equilíbrio do painel cilíndrico. Com isto o sistema de equações é reduzido para uma equação diferencial parcial em função das amplitudes modais da expansão para o deslocamento radial, sendo discretizada, em seguida, pelo método de Galerkin. Apresentam-se diversos resultados das vibrações livres, lineares e não-lineares, e forçadas para um painel cilíndrico simplesmente apoiado, mostrando a marcante influência do acoplamento modal presente na solução modal para os deslocamentos radiais e da geometria do painel.
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Tvorba 3D modelu budovy s využitím laserového skenování / Creation of 3D model of building using laser scanningSabo, Stanislav January 2016 (has links)
The aim of this thesis is to scan the part of the interior and exterior of the Faculty of Electrical Engineering and Communication building using the FARO Focus3D X 130 scanner, and the creation of a 3D model in the WGS 84 system. Subsequently, methods, status and utilization research of this technology and point cloud processing software is provided. The collected data are processed in the SCENE. Three-dimensional model is designed using the Pointfuse and Microstation V8i programs. In the end, the registration accuracy of the scans and the resulting 3D model accuracy are evaluated.
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Un modèle de liaisons fortes tridimensionnel pour les cuprates supraconducteurs monocouches à base de lanthane. / A three-dimensional tight-binding model for single-layer La-based cuprate superconductorsPhotopoulos, Raphaël 27 September 2019 (has links)
Dans cette thèse, nous construisons un modèle de liaisons fortes tridimensionnel minimal pour les cuprates supraconducteurs monocouches à base de lanthane. Celui-ci prend en compte huit orbitales, dont deux d'entre elles impliquent les ions oxygène apicaux. L'optimisation des paramètres microscopiques permet de reproduire presque parfaitement la bande de conduction tridimensionnelle telle qu'elle a été obtenue à partir des calculs DFT. Nous discutons la façon dont chacun des paramètres entrant en jeu dans ce modèle multi-bandes influence la bande de conduction, et nous montrons que la forme particulière de sa dispersion contraint les valeurs des paramètres. Nous mettons alors en évidence que la détermination standard d'un modèle effectif à une bande au travers d'un traitement perturbatif converge lentement en raison de la valeur relativement faible du gap de transfert de charges. A ce stade, cela nous permet, en revanche, de lever le voile sur l'origine microscopique des amplitudes de saut des électrons au sein des plans et en-dehors des plans. Une approche alternative au calcul des paramètres microscopiques de saut du modèle effectif de liaisons fortes est présentée et mise à contribution. Il en résulte que l'accord avec la DFT est préservé à condition que les amplitudes de saut de plus longue portée soient conservées. Une comparaison avec les modèles existants est également effectuée. La surface de Fermi, mettant en exergue des domaines décalés qui alternent en taille et en forme, est comparée à l'expérience. De plus, la densité d'états du modèle est aussi calculée. Une analyse plus approfondie du modèle est réalisée au travers d'une étude en couplage faible des instabilités magnétiques. Les calculs sont effectués sur de grandes cellules et nous avons trouvé une compétition parmi plusieurs instabilités magnétiques tridimensionnelles dans la région d’intérêt du dopage en trous accessible expérimentalement. Bien qu'à notre connaissance cela ne semble pas avoir été évoqué expérimentalement, nous montrons à l'issue de notre étude, que la tendance du modèle à former des ondes de densité de spin incommensurables tridimensionnelles est la plus forte à proximité du dopage 1/8. / In this thesis, we construct a minimal three-dimensional tight-binding model for single-layer La-based cuprate superconductors. It entails eight orbitals, two of them involving apical oxygen ions. Parameter optimization allows to almost perfectly reproduce the three-dimensional conduction band as obtained from DFT. We discuss how each parameter entering this multiband model influences it, and show that the peculiar form of its dispersion severely constraints the parameter values. We then evidence that standard perturbative derivation of an effective one-band model is poorly converging because of the comparatively small value of the charge transfer gap. Yet, this allows us to unravel the microscopical origin of the in-plane and out-of-plane hopping amplitudes. An alternative approach to the computation of the tight-binding parameters of the effective model is presented and worked out. It results that the agreement with DFT is preserved provided longer-ranged hopping amplitudes are retained. A comparison with existing models is performed, too. The Fermi surface, showing staggered pieces alternating in size and shape, is compared to experiment. The density of states is calculated as well. The model is further analyzed through a weak coupling study of magnetic instabilities. It is performed on large clusters and competition between several three-dimensional magnetic instabilities in the hole-doping region of experimental interest is found. We show that the tendency to form a three-dimensional incommensurate spin density wave is strongest in the vicinity of 1/8 doping.
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Intoxications médicamenteuses volontaires répétées : une conduite addictive plutôt que suicidaire. Phénotypage clinique et modélisation comportementale par une approche dimensionnelle / Repeated self-poisoning : an addictive rather than a suicidal behavior. Clinical phenotyping and behavioral modeling using a dimensional approachPennel, Lucie 03 November 2016 (has links)
Les intoxications médicamenteuses volontaires répétées (IMVr) constituent un problème de santé publique croissant, mais sous-évalué et traité comme une conduite suicidaire, alors qu’elles appartiendraient au registre des addictions. Notre travail abonde dans ce sens en montrant que les suicides alcoolisés se font principalement par IMV et correspondent au deliberate self-harm syndrom ; les suicidants récidivants se distinguent par un névrosisme et un attachement anxieux typiques des addictions ; les IMVr même suicidaires témoignent d’une relation addictive aux médicaments ; le facteur le plus prédictif d’IMV serait de l’avoir envisagée. Conceptualisé de façon translationnelle et argumenté par une approche pharmacologique, nous proposons un modèle dimensionnel des conduites suicidaires, intégré au continuum des addictions, confirmant l’hypothèse initiale et l’intérêt d’un raisonnement transnosographique diagnostique et thérapeutique dans le champ des pathologies mentales. / Repeated Self-poisoning (RSP) constitute an under evaluated but growing public health problem, treated as a suicidal rather than an addictive behavior. Our work brings arguments by showing that suicides involving alcohol are mainly by self-poisoning and correspond to deliberate self-harm syndrome; repeat suicide attempters are identified by a neuroticism and anxious attachment typically found in addicts; even suicidal RSP shows addictive behavior involving medicines; the best predictor of self-poisoning is having thought about it. Conceptualized through a translational approach and supported by pharmacological arguments, we propose a multidimensional model of suicidal behaviors, that could integrate the continuum of addictive behaviors. This confirms the initial hypothesis and the viability of a transnosographic concept for diagnosis and treatment of mental illnesses.
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Hur porträtteras flyktingar från olika områden i svensk media? : en kritisk diskursanalys / How are refugees from different areas portrayed in Swedish media? : a critical discourse analysisMalmgren, Lisa January 2022 (has links)
Denna studie syftar till att analysera diskursen kring flyktingar i media. Mer specifikt jämförs diskursen i artiklar kring flyktingar från Syrien respektive flyktingar från Ukraina. Artiklarna bryts ner i avsikt att finna återkommande mönster. Två teman kan utläsas som återkommande: dels porträttering av flyktingar som utsatta, dels porträttering av flyktingar som en belastning. I studien används ramverket kritisk diskursanalys som är såväl en modell som en teori - där relationen mellan språkbruk och maktutövning i samhället analyseras. Inom den kritiska diskursanalysen används analysverktyget Faircloughs tredimensionella modell som beskriver språkbruk i tre dimensioner: text, diskursiv praktik och social praktik. I denna studie ligger huvudfokuset på att analysera texten, men den diskursiva och sociala praktiken analyseras och diskuteras också. Resultatet av studien indikerar att flyktingar från Ukraina och Syrien porträtteras något olika i tidningarna Aftonbladet och Dagens Nyheter. Syriska flyktingar porträtteras i högre utsträckning som en belastning än ukrainska flyktingar / This study aims to analyse the discourse on refugees in the media. More specifically, it compares the discourse in articles on refugees from Syria and refugees from Ukraine. The articles are broken down to find recurring patterns. Two themes can be identified as recurring: portrayal of refugees as vulnerable and portrayal of refugees as a burden. The study uses the framework of critical discourse analysis, which is a model as well as a theory that analyses the relationship between language use and the exercise of power in society. Within critical discourse analysis, the analytical tool Fairclough's three-dimensional model is used, which describes language use in three dimensions: text, discursive practice, and social practice. In this study, the focus is on analysing the text, but the discursive and social practices are also analysed and discussed. The results of the study indicate that refugees from Ukraine and Syria are portrayed somewhat differently in the newspapers. Syrian refugees are portrayed as a burden to a greater extent than Ukrainian refugees.
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Wave-Associated Seabed Behaviour near Submarine Buried PipelinesShabani, Behnam January 2008 (has links)
Master of Engineering (Research) / Soil surrounding a submarine buried pipeline consolidates as ocean waves propagate over the seabed surface. Conventional models for the analysis of soil behaviour near the pipeline assume a two-dimensional interaction problem between waves, the seabed soil, and the structure. In other words, it is often considered that water waves travel normal to the orientation of pipeline. However, the real ocean environment is three-dimensional and waves approach the structure from various directions. It is therefore the key objective of the present research to study the seabed behaviour in the vicinity of marine pipelines from a three-dimensional point of view. A three-dimensional numerical model is developed based on the Finite Element Method to analyse the so-called momentary behaviour of soil under the wave loading. In this model, the pipeline is assumed to be rigid and anchored within a rigid impervious trench. A non-slip condition is considered to exist between the pipe and the surrounding soil. Quasi-static soil consolidation equations are then solved with the aid of the proposed FE model. In this analysis, the seabed behaviour is assumed to be linear elastic with the soil strains remaining small. The influence of wave obliquity on seabed responses, i.e. the pore pressure and soil stresses, are then studied. It is revealed that three-dimensional characteristics systematically affect the distribution of soil response around the circumference of the underwater pipeline. Numerical results suggest that the effect of wave obliquity on soil responses can be explained through the following two mechanisms: (i) geometry-based three-dimensional influences, and (ii) the formation of inversion nodes. Further, a parametric study is carried out to investigate the influence of soil, wave and pipeline properties on wave-associated pore pressure as well as principal effective and shear stresses within the porous bed, with the aid of proposed three-dimensional model. There is strong evidence in the literature that the failure of marine pipelines often stems from the instability of seabed soil close to this structure, rather than from construction deficiencies. The wave-induced seabed instability is either associated with the soil shear failure or the seabed liquefaction. Therefore, the developed three-dimensional FE model is used in this thesis to further investigate the instability of seabed soil in the presence of a pipeline. The widely-accepted criterion, which links the soil liquefaction to the wave-induced excess pressure is used herein to justify the seabed liquefaction. It should be pointed out that although the present analysis is only concerned with the momentary liquefaction of seabed soil, this study forms the basis for the three-dimensional analysis of liquefaction due to the residual mechanisms. The latter can be an important subject for future investigations. At the same time, a new concept is developed in this thesis to apply the dynamic component of soil stress angle to address the phenomenon of wave-associated soil shear failure. At this point, the influence of three-dimensionality on the potentials for seabed liquefaction and shear failure around the pipeline is investigated. Numerical simulations reveal that the wave obliquity may not notably affect the risk of liquefaction near the underwater pipeline. But, it significantly influences the potential for soil shear failure. Finally, the thesis proceeds to a parametric study on effects of wave, soil and pipeline characteristics on excess pore pressure and stress angle in the vicinity of the structure.
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Wave-Associated Seabed Behaviour near Submarine Buried PipelinesShabani, Behnam January 2008 (has links)
Master of Engineering (Research) / Soil surrounding a submarine buried pipeline consolidates as ocean waves propagate over the seabed surface. Conventional models for the analysis of soil behaviour near the pipeline assume a two-dimensional interaction problem between waves, the seabed soil, and the structure. In other words, it is often considered that water waves travel normal to the orientation of pipeline. However, the real ocean environment is three-dimensional and waves approach the structure from various directions. It is therefore the key objective of the present research to study the seabed behaviour in the vicinity of marine pipelines from a three-dimensional point of view. A three-dimensional numerical model is developed based on the Finite Element Method to analyse the so-called momentary behaviour of soil under the wave loading. In this model, the pipeline is assumed to be rigid and anchored within a rigid impervious trench. A non-slip condition is considered to exist between the pipe and the surrounding soil. Quasi-static soil consolidation equations are then solved with the aid of the proposed FE model. In this analysis, the seabed behaviour is assumed to be linear elastic with the soil strains remaining small. The influence of wave obliquity on seabed responses, i.e. the pore pressure and soil stresses, are then studied. It is revealed that three-dimensional characteristics systematically affect the distribution of soil response around the circumference of the underwater pipeline. Numerical results suggest that the effect of wave obliquity on soil responses can be explained through the following two mechanisms: (i) geometry-based three-dimensional influences, and (ii) the formation of inversion nodes. Further, a parametric study is carried out to investigate the influence of soil, wave and pipeline properties on wave-associated pore pressure as well as principal effective and shear stresses within the porous bed, with the aid of proposed three-dimensional model. There is strong evidence in the literature that the failure of marine pipelines often stems from the instability of seabed soil close to this structure, rather than from construction deficiencies. The wave-induced seabed instability is either associated with the soil shear failure or the seabed liquefaction. Therefore, the developed three-dimensional FE model is used in this thesis to further investigate the instability of seabed soil in the presence of a pipeline. The widely-accepted criterion, which links the soil liquefaction to the wave-induced excess pressure is used herein to justify the seabed liquefaction. It should be pointed out that although the present analysis is only concerned with the momentary liquefaction of seabed soil, this study forms the basis for the three-dimensional analysis of liquefaction due to the residual mechanisms. The latter can be an important subject for future investigations. At the same time, a new concept is developed in this thesis to apply the dynamic component of soil stress angle to address the phenomenon of wave-associated soil shear failure. At this point, the influence of three-dimensionality on the potentials for seabed liquefaction and shear failure around the pipeline is investigated. Numerical simulations reveal that the wave obliquity may not notably affect the risk of liquefaction near the underwater pipeline. But, it significantly influences the potential for soil shear failure. Finally, the thesis proceeds to a parametric study on effects of wave, soil and pipeline characteristics on excess pore pressure and stress angle in the vicinity of the structure.
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Modélisation de la régression des combustibles liquéfiables dans un moteur hybride / Modeling of liquefying fuel regression rates in hybrid propulsionLestrade, Jean-Yves 13 December 2012 (has links)
Le dimensionnement préliminaire d’un propulseur hybride passe par une phase d’essais à échelle réduite afin de caractériser entre autre la loi de régression du couple oxydant/combustible envisagé pour remplir les besoins de la mission en terme de performances, durée de fonctionnement, etc. Afin de limiter le recours à ces campagnes expérimentales onéreuses et génératrices de délais pour les industriels, il est nécessaire de développer des outils numériques fiables permettant de prévoir rapidement, sous différentes conditions de fonctionnement et géométries de chambre de combustion, la loi de régression d’un couple oxydant/combustible. L’objectif de cette thèse est de proposer une modélisation monodimensionnelle du mécanisme de régression des combustibles liquéfiables. Cette classe de combustibles offre des vitesses de régression trois à cinq fois plus élevées que celles rencontrées avec les combustibles généralement utilisés en propulsion hybride (PBHT par exemple). Ce modèle se base alors sur le transport de la phase gazeuse et du film liquide se développant sur le combustible solide, la vitesse de régression dépendant des transferts de masse et d’énergie entre ces trois phases. Afin de valider cette approche et l’architecture du code Hydres conçu pour la résolution de ce modèle et la prévision des performances propulsives d’un moteur hybride, des campagnes expérimentales ont été réalisées sur les bancs d’essais Hycarre et Hycom. Ces essais ont également permis de développer une technique de mesure permettant l’obtention de la vitesse de régression instantanée du combustible, conduisant à la restitution de la loi de régression instantanée du couple oxydant/combustible. / The preliminary design of a hybrid rocket engine requires lab-scale tests to characterize the regression law of the oxidizer/fuel pair intended to fulfil the mission needs in terms of performances, etc. To limit these costly and potentialy delaying experimental campaigns, it is necessary to develop reliable numerical tools to quickly predict the regression law of the oxidiser/fuel pair under different operating conditions and with different combustion chamber geometries. The objective of the thesis is to develop a one-dimensional model of the regression mechanism of liquefying fuels. These particular fuels offer regression rates three to five times higher than those found with classic polymers used in hybrid propulsion (eg. HTPB). The model is based on the transportof the gaseous flow and the liquid film which is developing along the solid fuel grain. The regression rate depends on mass and energy transfers between these three phases. To validate this approach and the Hydres numerical tool, specifically designed to solve this model and forecast the performances of a hybrid engine, experimental tests were performed with the Hycarre and Hycom facilities. These tests also allowed for the development of a technique to measure the instantaneous regression rate of the solid fuel, providing directly the instantaneous regression law of the oxidizer/fuel pair.
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Análise da deslocabilidade lateral de edifícios de múltiplos andares com modelos tridimensionais de barra / Analysis of lateral displaceability of multi-storey building with bar tridimensional modelsAvilla, Marcella Caon 31 August 2016 (has links)
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Previous issue date: 2016-08-31 / Não recebi financiamento / The structural modeling of mult-storey buildings using the simplified model in which the
slabs is calculated in isolation and their efforts transferred to a three-dimensional frames is
now overcome by the state of the art computational analysis. Currently even with structures
formed by bar elements (three-dimensional frames) it is possible to make the analysis
considering the effect monolithic of concrete structures or operating as a whole. For certain
cases, it is essential to consider all the structural elements participating in the bracing to the
structure is presented stable in the horizontal actions combined with vertical actions, such as
the flat slabs systems.Through of analysis examples of structures of buildings with multiple
floors in reinforced concrete are presented advantages in performing three-dimensional
modeling, comparing the results obtained with the simplified models. It shows the importance
of considering the slab stiffness in flat slabs systems and how the distribution of efforts to
change the three-dimensional model. Analyses are done using commercial software tool
allowing verify quantitative variation of structural materials. Finally an analysis is made of
the examples made showing the main differences in the new models. / A modelagem estrutural de edifícios de múltiplos andares usando o modelo simplificado no
qual o pavimento é calculado de forma isolada e seus esforços transferidos para um pórtico
tridimensional hoje está superada pelo estado da arte da análise computacional. Atualmente
mesmo com estruturas constituídas por elementos de barras (pórticos tridimensionais) já é
possível fazer a análise considerando o efeito monolítico das estruturas de concreto, ou seja,
funcionando com um todo. Para determinados casos, é fundamental a consideração de todos
os elementos estruturais participando do contraventamento para que a estrutura se apresente
estável frente às ações horizontais combinadas com as ações verticais, como, por exemplo, os
sistemas de lajes lisas. Por meio das análises de alguns exemplos de estruturas de edifícios de
múltiplos pavimentos de concreto armado são apresentadas as vantagens em se realizar a
modelagem tridimensional, comparando-se os resultados obtidos com os dos modelos
simplificados. Mostra-se a importância da consideração da rigidez da laje em sistemas de lajes
lisas e como a distribuição de esforços se altera no modelo tridimensional. As análises são
feitas através de ferramenta computacional comercial permitindo assim verificar a variação de
quantitativo de materiais estruturais. Por fim é feita uma análise dos exemplos realizados
mostrando as principais diferenças encontradas nos novos modelos.
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Desenvolvimento de modelo numerico tridimensional e eliptico para o estudo de escoamentos no interior de dutos cilindricos / Development of three-dimensional and elliptical numerical model for the study of fluid flow in cylindrical ductsLopes, Gabriela Cantarelli 27 June 2008 (has links)
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Previous issue date: 2008 / Resumo: Processos que envolvem escoamentos de fluidos no interior de dutos estão presentes em muitas aplicações industriais. Na indústria petroquímica um desses processos que vem se tornando cada vez mais importante é o craqueamento catalítico de frações pesadas do petróleo, já que as converte em frações leves e mais nobres. Por causa da crescente demanda mundial por gasolina e GLP e à sua alta rentabilidade para uma refinaria de petróleo, unidades de craqueamento catalítico em leito fluidizado (FCC) estão presentes em todo o mundo. Testes experimentais costumam ser usados no estudo dos fenômenos envolvidos nesse processo. Porém esse tipo de análise possui alto custo, que pode ser reduzido com o uso de simulações computacionais em seu estudo inicial. Assim, o objetivo deste trabalho foi desenvolver um modelo tridimensional e elíptico, em linguagem Fortran, capaz de fornecer dados para a análise preliminar de escoamentos no interior de reatores de FCC. Na modelagem desses problemas são usadas equações diferenciais parciais, e essas não possuem solução analítica conhecida, sendo necessário o emprego de métodos numéricos para esse fim. Neste trabalho foi usado o Método dos Volumes Finitos, que tem a função de substituir as equações diferenciais parciais por equações algébricas aplicadas a pequenos volumes de controle finitos pertencentes ao domínio. Uma das maiores dificuldades encontradas no tratamento numérico de escoamentos incompressíveis é a determinação de um campo de pressão que satisfaça a Equação da Continuidade. Esse problema foi resolvido fazendo-se uso da abordagem acoplp.da de solução. Para análise do modelo foram obtidos perfis numéricos de velocidade e pressão para fluidos escoando em regimes laminar e turbulento, que foram validados usando-se os dados obtidos com a solução analítica das equações, por correlações (semi-) empíricas ou por dados experimentais, conforme cada um dos casos. Notou-se que o modelo representa muito bem casos laminares, e gue 11.oS casos turbulentos foi necessário um maior refino da malha próximo a parede do tubo. Também foram feitas simulações para que se pudessem observar as características tridimensionais, elípticas e transientes da modelagem do escoamento. De maneira geral o modelo se mostrou bastante rápido, convergindo em poucas iterações.
Palavras-Chave: Fluidodinâmica computacional; dutos cilíndricos; modelo tridimensional e elíptico; método dos Volumes Finitos; solução acoplada; turbulência / Abstract: Processes involving fluid flow in tubes are present in many industrial applications. In petrochemical industry one of these processes that are becoming more and more important is the fluid catalytic cracking of heavy petroleum fractions. This fact is due to the process capacity to convert heavy fractions in light and valuable ones. Because of the increasingly worldwide demand for gasoline and LPG and its high yield for a petroleum refinery, fluid catalytic cracking (FCC) units are present in the whole world. Experimental tests are used in the study of the phenomena involved in this processo However this kind of analysis has high cost which can be reduced by using computational simulations in its initial study. Thus, the aim of this work was the development of a three-dimensional and elliptical mo dei in Fortran language in order to provide data for fluid flow preliminary analysis in FCC reactors. Partial differential equations were used in the modeling of these problems. These equations do not have known analytical solution, being necessary therefore the use of numerical methods. In this work the Finite Volume Method were applied with this purpose. This method has as a role to substitute the partial differential equations of the mo dei for algebric equations applied to small finite control volumes of the domain. One of the biggest difficulties found in the numerical treatment of incompressible fluid flows is the determination of apressure field that satisfies the Continuity Equation. This problem was solved using the coupled solution approach. For model analysis, numerical velocity and pressure proJ:iles for laminar and turbulent flows were obtained, that had been validated using the data obtained through the analytical solution of the equations, by empirical correlations or by experimental data, according to each one of the cases. The model represented well laminar cases, and in the turbulent ones the mesh had to be more refined near the tube wall. Other simulations were performed, in aQalyzing the three-dimensional, elliptical and transient model characteristics. In general, the mo dei was very fast, converging in a few interations.
Keywords: Computational fluid dyn~mic; cylindrical ducts; three-dimensional and elliptical model; Finite Volume Method; coupled solution; turbulence / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química
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