Twin Fiber Optic Liquid Film Sensor for Simultaneous Measurement of Local Film Thickness and Interfacial Wave Velocity

Abstract

A twin fiber otpic liquid film sensor system has been developed, which is able to measure the local thickness and the interfacial wave velocity of liquid film in gas-liquid annular two-phase flows simultaneously. This sensor system consists of two independent mono-fiber optic sensors. Each mono-fiber optic sensor can distinguish only the crest and the trough of the interfacial wave and can measure the film thickness at these parts. A propagation velocity of the interfacial wave has been measured by a time-of-flight method. Both simulation experiments and applications of this sensor system to an actual air-water annular two-phase flow in a vertical tube have shown that the simultaneous measurements of the local thickness and the interfacial wave velocity of the liquid film can be done accurately.