The design of an electrical capacitance tomography sensor for use with media of high dielectric permittivity

This paper concerns the application of electrical capacitance tomography (ECT) for media of high dielectric permittivity such as water. The performance of an ECT sensor was analysed numerically for a range of dielectric materials (1 ≤ ε_r ≤ 80) and geometrical parameters. On the basis of numerical simulations an ECT sensor with internal electrodes was built. Experimental results concerned with imaging air voids in distilled water and water-continuous dispersions of oil, using a commercially available PTL tomography system, are presented. Effects arising from the conductivity of water are studied and prospects of using the ECT system in an 'electrical resistivity' mode for weakly conductive solutions are outlined.