An Interdigital Conductance Sensor for Measuring Liquid Film Thickness in Inclined Gas–Liquid Two-Phase Flow

This study proposes an interdigital conductance sensor (ICS) for measuring the thickness of a liquid film with a nonuniform distribution of inclined gas–liquid two-phase flow. To optimize the electric field distribution of the sensor, an interdigital structure is introduced on the ring electrode base. Initially, a finite element model is employed to compare the ICS with the traditional ring electrode sensor, demonstrating that the ICS exhibits a broader range in high field strength distribution area, rendering it more suitable for quantifying variations in liquid film thickness. The parameters such as the width and height of the interfingers, as well as the number of interfinger, are optimized to achieve an optimal distribution of sensitivity field for the sensor. Subsequently, dynamic experiments involving inclined gas–liquid two-phase flow and static experiments for sensor calibration were conducted. The optimized ICS is employed for the measurement of inclined gas–liquid two-phase flow and compared with image processing results for liquid film thickness determination. The obtained results demonstrate the accurate capability of the ICS in measuring nonuniformly distributed liquid film thicknesses. This study presents a novel tool for multiphase flow measurement.