Toward Electrical Capacitance Tomography of Water-Dominated Multiphase Vertical Flows

Imaging of multiphase flows holding water as continuous phase (i.e., water-dominated flows) is very challenging for conventional electrical capacitance tomography (ECT) due to the high permittivity of water. In this paper, we introduce a new approach, based on the multi-frequency excitation of ECT sensors, for imaging and real-time monitoring of water-dominated columnar or slug vertical flows. The proposed method exploits differences between measurements obtained at distinct frequencies caused by the Maxwell-Wagner-Sillars effect, which is present in multiphase flows with at least one conducting phase. To illustrate this new approach, several numerical simulations are carried out for two-phase and three-phase mixtures containing air, methylamine, and/or oil as dispersed phases and with water as the continuous phase. Experimental results are also provided to validate the findings.