Doutorado em Engenharia Mecânica

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Navegando Doutorado em Engenharia Mecânica por Autor "Belich Junior, Humberto"

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    Development, calibration and deployment of an electrical resistance tomography system for multiphase flow experiments
    (Universidade Federal do Espírito Santo, 2020-04-15) Moura, Bruno Furtado de; Martins, Marcio Ferreira; https://orcid.org/000000023023222X; http://lattes.cnpq.br/7325983059020104; https://orcid.org/0000-0003-1912-3732; http://lattes.cnpq.br/4593797108698590; Silva, Wellington Betencurte da; https://orcid.org/0000-0003-2242-7825; http://lattes.cnpq.br/6900925458823632; Dutra, Julio Cesar Sampaio; https://orcid.org/0000-0001-6784-4150; http://lattes.cnpq.br/5331990513570911; Oliveira, Luiz Affonso Henderson Guedes de; https://orcid.org/0000-0003-2690-1563; http://lattes.cnpq.br/7987212907837941; Belich Junior, Humberto; https://orcid.org/0000-0002-8795-1735; http://lattes.cnpq.br/3879935393431243; Ramos, Rogerio; https://orcid.org/0000000344932435; http://lattes.cnpq.br/2975022316691139; Palma, Francisco Hernán Sepúlveda; https://orcid.org/0000-0002-1930-3859
    Electrical Impedance Tomography (EIT) is a soft-field tomography technique for imaging in industrial and medical applications. The method consists of injecting a bidirectional known current through electrodes inside a domain and measuring the subsequent voltages at the boundaries formed due to these injections, considering only non-ionizing radiation, unlike hard-field tomography. These measurements are acquired by a data acquisition system and are used to solve an inverse problem. The result is a distribution of the conductivities inside the domain. Thus, the image is formed by differences in electrical conductivity that may be present in this distribution. The present work aims to develop a data acquisition system and reconstruction software focused on multiphase flow measurement. A low-cost EIT system is developed, capable of 30.61 images/s with a signal-to-noise ratio of 57.47 dB. Further, the performance of the system is evaluated and it is drawn new guidelines from a validated model to develop the next version of the hardware. To extend the frequency response of the system, the parasitic capacitances, which are unavoidable and usually unwanted capacitance that exists between the parts of an electronic component or circuit, must be compensated or eliminated from the circuits. Methods to directly measure these quantities are scarce and limited. Therefore, a technique to statistically estimated with Maximum a Posterior and Markov Chain Monte Carlo method is presented in this work as an alternative. Since there is a concern in estimating sharp images by determining the position of the boundary, a new statistical and recursive application based on the particle filter is presented to estimate the conductivities inside the domain. The results demonstrated the capability of reconstructing fast-moving inclusions properly.
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    Formação de poeira no empilhamento de materiais a granel
    (Universidade Federal do Espírito Santo, 2022-06-29) Leão, Rodrigo Xavier de Almeida; Belich Junior, Humberto; https://orcid.org/0000-0002-8795-1735; http://lattes.cnpq.br/3879935393431243; https://orcid.org/0000-0002-0408-0410; http://lattes.cnpq.br/5311312721609904; Mesquita, Andre Luiz Amarante; Martins, Marcio Ferreira; https://orcid.org/000000023023222X; http://lattes.cnpq.br/7325983059020104; Passos, Carlos Augusto Cardoso; https://orcid.org/0000-0002-6303-3569; http://lattes.cnpq.br/2528679879816545; Machado, Luis Paulo Silveira; Amorim, Leandro Silva
    This is a study on the formation of dust that occurs during the stacking of bulk materials. Dust formation occurs by the suspension of microparticles easily transported to the atmosphere and over large distances by low-intensity air currents. Presents authorial methods for modeling and analysis of dust formation, including the development of a Lagrangian Particle Displacement Model (MLDP), analytical solution of the pressure field, computational solution of the velocity field through Computational Fluid Dynamics (CFD), evaluation of air flow regions, a model for the induced air flow and the mapping of particle dimensions capable to be transport by the fluid medium. The results demonstrate that if the stacking has a drop height greater than the critical one, the boundary layer acceleration at the core-fluid interface gives rise to a pressure gradient leading to the formation of a toroidal vortex near the impact zone, follow by expansion and detachment of the dust boundary layer. The velocity field undergoes a meaningful change and develops ascending updrafts and preferential escape paths for the microparticles. The probability of the process generating dust depends fundamentally on the physical dimensions of the stacking, as well as the type and granulometry of the material whose collisions between the grains generates nanoparticles that remain suspended in the surrounding air, altering the nearby environment and the dust’s ability to diffuse.