Development, calibration and deployment of an electrical resistance tomography system for multiphase flow experiments
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Data
2020-04-15
Autores
Moura, Bruno Furtado de
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Universidade Federal do Espírito Santo
Resumo
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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Tomografia por impedância elétrica , desenvolvimento de aquisição de dados , escoamento multifásico