Complex Admittance Detection of Horizontal Oil-Water Two-Phase Flows Using a Capacitance Sensor

Capacitance sensors have been widely used in the measurement of two-phase flows encountered in industrial processes due to their advantages of non-intrusiveness and quick response. In this paper, an equivalent circuit model of a concave capacitance sensor for stratified oil-water flow is established. Based on this model, the effects of the excitation signal frequency on the fluid admittance are investigated to optimize the geometric structure of the concave capacitance sensor. A capacitance sensor system is designed to simultaneously detect the real (Re) and the imaginary (Im) parts of the oil-water complex admittance. The Re and Im response signals of the capacitance sensor are collected in the dynamic experiment of horizontal oil-water flows. The influences of the flow pattern and the excitation frequency on the measurement of fluid complex admittance are experimentally explored.