Is 2D impedance tomography a reliable technique for two-phase flow?

Impedance tomography consists in reconstructing the conductivity distribution from electrical data which characterize the electrical response of a medium to arbitrary excitations. Impedance tomography is an ill-conditioned problem and designing a tomograph therefore requires the quantitative knowledge of the sensitivity of the reconstruction to the measurements noise. The numerical conditioning of an original and accurate algorithm has been studied. This algorithm does not suffer from the shortcomings already identified in the literature. It is shown that for media encompassing inclusions which is a typical situation in two-phase flows, the necessary accuracy for the measurements if far beyond any technological reach. Moreover, within these high requirements for accuracy, some side effects must be carefully controlled or compensated and relevant procedures are provided. Furthermore, reconstruction artifacts are shown and they are found to derive from the unavoidable three-dimensional (3D) nature of the electric field. For all these reasons, it is concluded that impedance tomography has very low potentialities as an accurate phase fraction distribution measuring technique in any arbitrary two-phase flows. (orig.)