Orientador: Milton Mori / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-21T06:39:27Z (GMT). No. of bitstreams: 1 GonzalezSilva_German_D.pdf: 4427269 bytes, checksum: bb45c122c3faad0613f060ad4cbd3b61 (MD5) Previous issue date: 2012 / Resumo: O objetivo principal desta tese é propor uma metodologia para aplicar simulação de grandes escalas (LES) em uma unidade de craqueamento catalítico industrial. Para atingir este objetivo, iniciou-se propondo uma metodologia para a construção da malha, sendo uma malha quase-uniforme. As malhas propostas foram implementadas para minimizar o esforço computacional e procedimento para a refinação uniforme no domínio do sistema. Inicialmente, foi estudada a fluidodinâmica de um leito fluidizado gás-sólido na escala de laboratório sem reação química, utilizando Simulação de Grandes Escalas. Com base nos resultados numéricos obtidos a partir de resultados da escala de laboratório foi aplicado o modelo cinético de 4 lump em uma simulação CFD tridimensional para um reator industrial FCC, utilizando LES para a fase gasosa, e considerando o catalisador como uma fase contínua (Euleriana). Os pacotes de simulação utilizados foram Ansys ICEM versão 13 para a construção da malha e Ansys CFX versão 13 para o pós-processamento dos resultados. No pós-processamento dos resultados foi proposta uma metodologia para determinar as médias azimutais das variáveis em planos perpendiculares ao escoamento e finalmente foram validadas as simulações com dados reportados na literatura. As principais conclusões do trabalho foram que foi possível diminuir o tamanho da malha e o tempo de processamento. Notou-se também que, ao usar malhas com discretização quase-uniforme não foi necessário fazer um refinamento de malha elevado, nem refinar perto da parede para o sistema gás-sólido / Abstract: The main objective of this thesis is to propose a methodology in how to apply Large Eddy Simulation (LES) on a unit of catalytic cracking. In order to achieve this, it was proposed an alternative way of constructing the computational mesh, by using quasi-uniform meshes. The proposed meshes were implemented to minimize the computational effort and procedure for refining them in the entire domain of the system. Initially it was studied the fluid dynamics of a lab scale gas-solid system without chemical reaction, using Large Eddy Simulation. Based on the numerical results obtained from lab scale results it was implemented the 4 lump kinetic model in a three dimensional CFD simulation of an FCC industrial reactor, using LES for the gas phase and considering the catalyst as a continuous phase (Eulerian). The simulation packages used were Ansys ICEM, version 13 for mesh construction and Ansys CFX 13 for computation and post-processing of the results. In the data post-processing it was proposed a methodology for calculating average values of fluctuating variables between two circular sections in the azimuthal direction. The results were compared with data reported in literature. The main conclusions of the results showed that it was possible to decrease the mesh size and the computational time. It was also noticed that by using quasi-uniform discretization it was not necessary to make a high mesh refinement near the wall for a gas-solid system / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química

Steel hollow section members filled with concrete have been frequently used in recent construction industry as columns and beams and beam-columns because of their superior performance and constructability. Previous research demonstrated that such system has large energy absorption capacity which is critical in the event of an earthquake. By filling steel RHS with concrete, the failure of the steel shell due to local buckling can be delayed and the ductility of the concrete core can be improved as a result of the confinement of the steel shell. This type of composite section may be used in various structures including frames of high rise buildings, bridges, offshore structures, cast-in-situ piles in foundation etc. Design methods for concrete-filled steel tubular sections are recommended in a number of code of practices. Due to the significant differences in the material properties between normal strength concrete and high strength concrete, there is a need to study the behaviour of composite sections with higher strength concretes. The study emphasises ultimate strength, ductility, post-failure strength reserve and interface bond. It also emphasises ductility and post-failure strength of the composite beams due to the brittle behaviour of higher strength concretes when compared to normal strength concrete. Spreadsheet graph were used to present the results such as load versus strains, load versus deflections etc. In this thesis analytical study is presented on the calculation of ultimate moment of resistance of the concrete-filled RHS beams. Among the main considerations of the derivation, the steel portion was assumed either elastic-perfectly plastic or perfectly plastic and concrete carries no strength in the tensile zone. At the interface both full bond and partial bond were assumed for comparison. Efforts were also made to calculate the midspan deflections of the composite beams. Simple analytical expressions derived from this study can be coded to a prgrammable calculator or in a small spreadsheet program for design use. Finite element studies were carried out by using a proprietorship software package ANSYS. In the analysis of concrete-filled, three types of elements with large deformation and nonlinear capabilities were used. A plastic shell element, a solid concrete element with cracking and crushing capabilities, and a nonlinear spring contact element were used to model the steel shell, the concrete core and the interface respectively. / Doctor of Philosophy (PhD)

Orientador: Rubens Maciel Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-09T08:31:02Z (GMT). No. of bitstreams: 1 Rezende_RodrigoAlvarenga_M.pdf: 6027055 bytes, checksum: dc80f298be40be05219c739478682c4d (MD5) Previous issue date: 2006 / Resumo: A Prototipagem Rápida consiste na reprodução física de objetos tridimensionais de geometria livre, a partir de um projeto inicial (design), modelado por auxílio de computador. A Prototipagem Rápida é uma tecnologia moderna que une métodos e equipamentos adequados a fim de oferecer, como principais atrativos, alta qualidade e redução de custos de produtos manufaturados. São diversos os métodos existentes e os materiais aplicáveis. Este trabalho apresenta um novo método de fabricação de protótipos, a Termolitografia. Baseada na irradiação de laser de CO2 na região espectral do infravermelho sobre resinas termossensíveis, a Termolitografia oferece importantes vantagens quando comparada a outros processos, principalmente no que se refere ao estado físico da amostra logo após a irradiação do laser. Este processo apresenta duas grandes vantagens que são a não-contração da amostra após ser curada e a ausência de tratamento pós-cura. A cura localizada é o fenômeno de confinamento da energia transmitida pelo laser realizando a cura do material somente em uma região desejada. O controle da cura localizada é a chave para o sucesso e para a garantia de protótipos de alta qualidade. Para ajustá-la e otimizá-la, é necessário o domínio de parâmetros físicos do material empregado e de parâmetros operacionais do laser de CO2. O estudo da combinação dos efeitos, por exemplo, da variação da proporção dos componentes da amostra, da sua temperatura de cura, além de fatores operacionais como a velocidade de varredura, o diâmetro e a potência do feixe laser, é o alvo principal deste trabalho. As simulações facilitam a compreensão de como cada variável pode interferir na construção do protótipo, e determinam faixas de valores para os parâmetros as quais implicam em melhores resultados no final do processo. O trabalho de seleção destes valores é importante para a futura continuidade de estudo experimental do processo termolitográfico / Abstract: Rapid Prototyping consists on a physical replication of three-dimensional objects with free geometry, from an initial design, modeled by computer assistance. Rapid Prototyping is a modern technology that unifies methods and suited equipments in order to offer as main attractive high quality and cost-reduction of manufactured products. There are many techniques and raw materials applicable. This work presents a new method of prototypes fabrication, the Termolithography. Based on CO2 laser irradiation at the infrared spectral region onto thermosensitive resins, Thermolithography offers important advantages if compared with other processes, mainly those ones respected to the non-contraction effect of the sample after being cured and the absence of a post cure treatment. The localized cure is the phenomenon of confinement of energy transmitted by laser beam performing the curing only on a desired region at the sample. The control of the localized cure is the key for the success and for the guarantee of high quality prototypes. In order to fit and optimize it, it is necessary the domain of physical properties of the applied material and the domain of the CO2 laser operational parameters. The study of combination of the involved effects, for instance, the variation of amount of the components in the sample, the cure temperature, beside operational parameters as scanning velocity, the laser beam diameter and power, are the main target of this work. Simulations become easier the comprehension of how each variable can affect during the building of prototype and to determine the best range of values which implicate in better final result of the process. The selection of these values is very important to the continuity of this work / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Das Campusnetz - neue Strukturen und Funktionen Neues vom WWW-Server Umstellung der HOME-Verzeichnisse vom NFS ins AFS AFS löst NFS ab! Neue Rechnersysteme - zur allgemeinen Nutzung Superskalarrechner - Inbetriebnahme und Nutzungsmöglichkeiten PC-Integration via SAMBA-Server CD-ROM im Netz Die Programmpakete MATHEMATICA und ANSYS Ueberblick ueber /uni/global-Software Ein weihnachtliches Problem?

Possibilities of modeling non-linear behavior of concrete within standard room temperatures and increased fire-load values using FEM software ANSYS are studied. Temperature dependences of material models are considered. Fire resistance of reinforced concrete and concrete-steel composite construction is analyzed. Fire loads are defined in accordance with relevant standards. Non-linear structural transient analyses are calculated after temperatures were determined by transient thermal analyses. Results obtained from analyses of simple reinforced concrete structure are compared with approach of isotherm 500 °C method.