New progress of the digital electrical capacitance tomography system for gas/liquid two phase flow

Abstract

Electrical capacitance tomography (ECT) is gaining acceptance as a laboratory and industry tool to analyze gas/liquid two phase flow. To overcome the shortcomings of the existing analogue ECT system, a new 16-electrode digital electrical capacitance tomography system based on FPGA and DSP is designed. The new scheme can easily realize single frequency and multi-frequency excitation and demodulation. Furthermore, two kinds of methods for multi-frequency demodulation, DFT demodulation and digital quadrature demodulation, are discussed deeply. Static and dynamic experiments under condition of single frequency are carried out to verify the performance of the digital ECT system. Experimental results show that this system is of high precision and stability.