Finite element modelling of multielectrode capacitive systems for flow imaging

The CAD of a complex multielectrode arrangement for flow imaging is explored using the finite element method (FEM). This electrode arrangement forms the primary sensor subsystem for an electrical capacitive tomography (ECT) system. Results are presented in the form of sensor's performance parameters as functions of its various geometric parameters. The performance parameters include the standing and normalised capacitances, ratio of the maximum to minimum capacitance of the sensor (Kc) and the sensor's spatial sensitivity distributions. Extensive computer simulation studies were undertaken in calculating these parameters, and the techniques in finite element (FE) model definition, mesh generation and refinement, error minimisation and checking are highlighted in the paper in relation to the effective and efficient use of the FEM. Detailed results for a particular sensor design are compared with an experimental prototype and found to give good agreement. The response of the sensor to various flow regimes is also presented and analysed to optimise its performance for image reconstruction