Evaluation of Electrical Capacitance Tomography Sensors for Concentric Annulus

Electrical capacitance tomography (ECT) sensor is commonly used with circular or square pipes or vessels. In this paper, an ECT sensor of concentric annulus shape is presented. To investigate the effect of the configuration of electrodes and the measuring strategy on the quality of reconstructed images, the ECT sensors with internal-external electrodes (IEE) and external electrodes (EE) are investigated. For the IEE sensor, six different measuring strategies are considered. The capacitance between different electrode pairs is calculated for some typical permittivity distributions using a finite element method (FEM). The obtained capacitance data are then used to reconstruct images using Landweber iteration algorithm. The sensitivity distributions for the IEE and EE sensors are analyzed. Simulation results show that the IEE sensor with 12 external electrodes and four internal electrodes combining with an external-opposite strategy can reconstruct good images for most permittivity distributions.