Water Volume Fraction Estimation in Two-Phase Flow Based on Electrical Capacitance Tomometry

An important parameter in the study of multiphase flows is the volume fraction, which is defined by the ratio between the volume occupied by a specific phase and the total volume of the mixture. This is a fundamental parameter that appears in most of the flow models and frequently is applied to assist flow pattern identification routines as well as to estimate two-phase flow rates. This paper presents a water volume fraction estimation method based on electrical capacitance tomography (ECT) called electrical capacitance tomometry (ECTM). An electrode combining strategy using rotating electrodes has been implemented to transform a 12-electrode sensor into a 2-electrode sensor, simplifying the measurement hardware circuit. This strategy increases the signal-to-noise ratio and consequently improves the measurement quality. Moreover, the proposed ECTM method needs just 12 capacitance measurements and three iteration steps to converge, providing confidence in real-time applications. Simulations using COMSOL Multiphysics software and experimental results allow us to evaluate the performance of the proposed water volume fraction measurement method which presents smaller absolute errors than the conventional ECT method.