Dissertações em Engenharia Mecânica (Mestrado) - PPGEM/ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2342
O Mestrado Acadêmico pertence ao Programa de Pós-Graduação em Engenharia Mecânica (PPGEM) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).
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Navegando Dissertações em Engenharia Mecânica (Mestrado) - PPGEM/ITEC por Orientadores "MESQUITA, André Luiz Amarante"
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Item Acesso aberto (Open Access) Análise da forma da partícula na aplicação do Método dos Elementos Discretos (DEM)(Universidade Federal do Pará, 2013-08-06) SANTOS, Elias Gomes dos; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662This work analyzes the effect of particle shape through the Discrete Element Method (DEM). Are employed four particles with different shapes and sphericity – one spherical and three non-spherical. The repose angle is the main tool to evaluating of the flow. The analysis starts with the calibration of the spherical particle using available literature data, then theses calibrated parameters are employed for the flow simulation of the non-spherical particles. Comparisons are performed on the computational effort, and this information is used to verify the advantages that the spherical particle provides on the three other shapes. In this scenario, procedures were developed to help in the calibration process of the repose angle, based in the knowledge of the sensitivity of some DEM parameters. The results show the influence of non-spherical shapes and, mainly, that is possible to obtain with the spherical shape, similar flows to the non-spherical shapes with computational gain.Item Acesso aberto (Open Access) Análise experimental sobre velocidade de captura em sistemas de transporte pneumático(Universidade Federal do Pará, 2006) GOMES, Luiz Moreira; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662The transport velocity is one of the most important parameters in the pneumatic transport of solids. The success of the particulates materials conveying depends on the prediction or the determination of the minimum velocity of transport. The velocity above of that necessary to the steady transport of solid particles leads to a great energy consumption due to an increased pressure drop of the system, solids degradation and abrasion of solids and of the tube. On the other hand, a velocity below of this boundary-value certainly will result on the deposition of solid particles for bottom of the tube and its consequently blockage. In this work, a technique to measure the minimum pickup velocity of solid particles in horizontal pneumatic conveying has been developed. It is based on visual observation of the particles behavior when occurring the capture, on measures of the velocity of operation of the gas and the mass of captured particles. The qualitative analysis of some parameters is made still that influence in the pickup velocity of particles, allowing a bigger understanding of the involved phenomena.Item Acesso aberto (Open Access) Análise técnico-econômica da substituição parcial do combustível diesel pelo gás natural em motores marítimos na região amazônica(Universidade Federal do Pará, 2007-12-07) FRANCO, Alcides Canêjo Linhares; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662The international experience indicates the existence of five main elements related to the expansion of the natural gas consumption as following: a) availability of natural gas reserve; b) restriction offers of other energy ones (especially for the electricity generation); c) concern with the environment by a environmental legislation more rigorous, each day; d) the investments attraction by the private companies permission for the distribution and commercialization of the natural gas; e) the generalized permission for the industry, attracting private companies, because of the opportunity of the investment. In this scene, the construction of the gas line Coari (extraction base) Urucu-Manaus with about 670 kilometers of total extension that will be ready on April of 2008, as divulged by Petrobras on 05/21/2007 and will carry 4.7 million cubic meters per day of natural gas in the first phase of operation. The foreseen total investment is of R$2.4 billions. The natural gas will substitute the diesel and the combustible oil used, mainly, in the production of great part of the consumed electric energy in the Amazon State. It will be used also in the industrial and commercial processes, as well as supplying, with safety, auto-machine vehicles (automobiles, pickups, light trucks, bus). This last application stimulated this research, that establish a technical-economic analysis of the partial substitution of the fuel diesel by the natural gas in maritime engines in the Amazon Region, because the boats are vehicles that cross the rivers of this Region and are used for load and passengers transportation. First, it is demonstrated that it is possible, in technical conditions, the conversion of the diesel engines to consume the diesel mixed with natural gas to the taxes of substitution of diesel for natural gas from 5% to 90%, using available technologies that are in the Brazilian market, under the view of energy and environment performances. Later it presents an economic analysis of the conversion, considering the reservoirs for natural gas compressed - NGC offered in the national market and the kits of conversion. The research reveals: a) the economic viability of the enterprise if the weights and the volumes of the natural gas reservoirs are neglected, especially the first one; b) the no economic viability, considering the transport of the reservoirs, in the boats, that had no financial results because of the prices of the taxes resulting of the space occupied by the volumes and the weights of these reservoirs.Item Acesso aberto (Open Access) Caracterização das propriedades de fluxo da lama vermelha para fins de dimensionamento de silos: aplicação para tremonhas cônicas(Universidade Federal do Pará, 2013-10-07) LOBATO, Júlio César Mendes; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662One of the factors that affect the flow of bulk solids in silos is the moisture content, which stands out by favoring the formation of cohesive arches. In this sense, the aim of this work focused on determining the flow properties of the product red mud and its classification as to its flowability due to the variation of moisture content. Having the moisture influence on the flow in conical hoppers lined with smooth metal plates and UHMW (Ultra High Weight Polyethylene molecular ). To that end we used the direct shear apparatus "Jenike Shear Cell", along with the two wall surfaces. To determine the factor flow from the hopper and the angle of inclination to the horizontal, we used the graphics methodology proposed by Jenike for mass flow. And in determining the minimum diameter of the hopper, we applied the equations proposed by Jenike and Enstad. It was found that red mud is cohesive and has flow type hard with little variation for levels of moisture studied. The roughness of parades tested had a mild influence on the slope of the hopper. While the results of diameter variation experienced hopper relative moisture levels analyzed for red mud. From the observations made to flow in the silo acrylic model has been found that it rises to the level of moisture becomes more difficult the flow of red mud product.Item Acesso aberto (Open Access) Construção de um modelo de dispersão de poluentes na Baía do Guajará(Universidade Federal do Pará, 2005-12-19) BATISTA, Adriano Gomes; SENA, Manoel José dos Santos; http://lattes.cnpq.br/2349287816857909; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662The sea and coastal environment of Brazil have suffered a process of considerable environmental degradation in the last years. This degradation was caused by the growing environmental pressure on the sea and the continental natural resources that have overwhelmed the limited capacity of the ecosystems to absorb the impacts. In the specific case of the Bay of Guajará, located in the Estuaries Guajará, in the area delimited by the Bay of Marajó and for the rivers Pará and Guamá, these risks are associated mainly to the pollution originating from of the city of Belém and the petroleum derived pollution caused by transport operations. In the case of the Bay of Guajará, it is known that there are sewer spillings periodically caused by the tide. Because this pollution is caused by the tide, there is little that can be done to correct or soften the effects of this problem. The numeric models consider the complexity of the physical phenomena that govern the operation of the coastal environment, and have been used as tools in hydrodynamic simulation with recognized importance in coastal administration. This application can support several studies: the understanding of the dispersing processes of pollutants; the implantation of systems of monitoring of water quality; the plan of action in cases of a oil spillage; and the effects of alterations in the geometry of channels and bays and estuaries. The objective of this work is to explain these subjects and to describe the necessary stages for the construction of a numeric model of dispersion in the Bay of Guajará using the tools of the Systems of Geographical Information and the Method of Finite Elements.Item Acesso aberto (Open Access) Interação CFD-DEM em fluidização: aplicação para o setor mineral(Universidade Federal do Pará, 2013) CASTELO BRANCO JÚNIOR, Alan Mota; VAZ, Jerson Rogério Pinheiro; http://lattes.cnpq.br/1623983294183975; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662The particle fluidization process is widely used in the industry, mainly due to the high heat and mass transfer rates between the phases. The coupling between the Computational Fluid Dynamics (CFD) and the Discrete Element Method (DEM) has become attractive for the simulation of fluidization, because in this case the particles movement is analyzed in a more direct way than in other types of approaches. The main problem with the CFD-DEM coupling is the high demand for computational capacity in order to track the movement of all the particles in the system, what it leads to the use of some strategies to reduce the simulation time which in case of incorrect usage can prejudice the results. The present work deals with the application of the CFD-DEM coupling in the analysis of alumina fluidization, which is an important problem for the mineral sector. It were analyzed several parameters capable of influencing the results and the simulation time like the time steps, the drag models, the particle size distribution, the spring constant, the usage of representative particles bigger than the actual particles, etc. The DEM model used was the Linear Spring Dashpot model (LSD). All the simulations were carried out with the software ANSYS FLUENT 14.5 and the results obtained were compared with experimental data and the data available in the literature. These results allowed to verify the capability of the Linear Spring Dashpot Model for predicting the global behavior of alumina beds and reducing the simulation time, since the model parameters are defined adequately.