Analysis of an electrical charge tomography system for measuring low concentrations in two phase flow fluids

Abstract

In this paper, two tomography techniques called Electrical Capacitance Tomography (ECT) and Electrical Charge Tomography (ECAT) are presented for two-phase imaging. Both systems consist of a set of electrodes that excite the inner section of the probe with a time-variant voltage. In the case of ECT, a difference in capacitance is measured based on the objects flowing through the pipe. In the case of the ECAT system, a second set of electrodes are evenly distributed across the full section of the probe in order to induce electric charges across the pipe that are measured instantaneously and simultaneously. Simulation results indicate that the suggested system provides more accurate images compared to the one generated by the Electrical Capacitance Tomography (ECT) system, where in some cases, the average error difference between the image obtained from ECAT system to the original image can be about 4.122% compared to the average error of 8.4% from the ECT system. The fact that the measurement of the electrical charges can be achieved much faster than the capacitance measurements used in ECT systems makes the technique attractive for next generation tomography systems targeting real-time applications.