Capacitive Sensors for Multiphase Flow Measurement: A Review

Capacitive sensors are found in numerous applications, and they are capable of sensing several parameters. Multiphase flows occur in many industrial processes that require proper monitoring to improve the efficiency and safety of plants and equipment. Detailed (high-resolution) flow information is required from dedicated flow experiments at a laboratory scale to develop and validate flow modelings. In both cases, capacitive flow sensors have been applied to have a varying degree of flow detailing, e.g., from simple capacitive probes up to capacitive flow imaging and tomography. This article reviews the different capacitive sensors applied to multiphase flow measurement and imaging. Operating principles, sensor geometries, and capacitive measuring circuits are presented and discussed along with advantages and disadvantages, focusing on flow applications and possible flow parameters yielded from sensors. Some new trends in capacitive flow sensors are also presented.