Measurement of multi-phase distribution using an integrated dual-modality sensor

Electrical capacitance tomography (ECT) and electrical resistance tomography (ERT) have been developed separately as non-intrusive and/or non-invasive imaging techniques in the past. One of their applications is to measure multi-phase flows. The conventional ECT and ERT modalities are implemented individually. While ECT can be used to visualise permittivity distributions and ERT to visualise conductivity distributions, in many cases a material distribution cannot be described simply by a permittivity or conductivity distribution, but a combination of permittivity and conductivity. While it has been attempted to develop an ECT/ERT dual modality system, an ECT sensor and an ERT sensor are used separately. This paper presents an integrated ECT/ERT dual-modality sensor with 8 capacitance electrodes and 8 resistance electrodes. To evaluate the performance of the integrated ECT/ERT sensor, simulations were carried out using COMSOL. It has also been tested using a data acquisition system with an impedance analyser (HP4192A), which can take capacitance and resistance measurements simultaneously. From the measurements, a permittivity distribution and a conductivity distribution can be generated for the same location. Experiments results are given for imaging gas-oil, gas-water, and gas-milk two-phase distributions and gas-oil-water three-component distributions.