Study On Three-dimensional Electrical Resistance Tomography Measuring Technique

Electrical Resistance Tomography (ERT) is one of the Process Tomography techniquesbased on the principle of resistance measurement. ERT is adequate for the two-phase flowwhose continuous phase is conductive and can obtain the2D/3D visual information formulti-phase media component parameter in the closed pipe and process vessel. This techniquehas the advantages of non-invasive measurement, fast in response, low in cost, easy toimplement, safety in performance, so it has wide application prospects.At present most ERT researches are practically on2D case because of simplicity. But inmost cases, we need to get the3D information which cannot be directly obtained from2Dreconstruction. So the development trend of ERT is3D observation and image reconstructionfor the object field. The work presented in this thesis is an attempt to tackle3D ERTmeasurement aiming at developing a tool that can be used for3D ERT system design andmeasurement. The key contributions of this work are as follows:1．Analyzing the axial potential and sensitivity of three typical electrode sensorstructures. Analyzing the impacts of several electrode structural parameters on the distributionof sensitivity. The structural parameters include the total numbers of electrodes layers, thespace between two layers, the materials and shape of electrode, the size of electrodes and soon.2．Based on the ANSYS tool and using the APDL language，developed a multi-layeredelectrode structure model for3D ERT measurement. In this paper a four-layered electrodestructure is used. Each layer has16same sized electrodes evenly mounted on the inside wallof the flow pipe. ERT forward problem is solved by exciting the four layers of electrodessimultaneously. 3．ERT inverse problem is performed by using a linear back-projection algorithm.2Dimages of each electrode layer are obtained.3D ERT image is formed by interpolating thespace according the obtained2D ERT images. And then, reference to the evaluationparameters of2D image reconstruction, confirmed the quality evaluation parameters of3Dimage reconstruction, to evaluate the quality of simulation.4．Based on the MATLAB GUI interface tool, developed a simulation platform that canperform the modeling of water-oil two phase flow, modeling of ERT sensor structure, voltagemeasurement,3D-ERT image reconstruction and display.