Gas-Liquid Two-Phase Flow Monitoring Using Sub-THz Radar Imaging

Two-phase flow monitoring is widely present in various industrial processes. The most popular methods used to estimate flow parameters can be divided into the noncontact and the contact -based modalities. Conductance-based and capacitive sensors are the most popular contact-based techniques used to provide flow parameter estimations. Among the noncontact sensors, optical-based systems are commonly utilized for multiphase flow classification. However, contact-based systems require specific proprieties from the analyzed fluid mixture such as high conductivity or low conductivity and they must be attached to the tube, so accurate measurements can be provided. On the other hand, optical devices lack robustness against ambient light conditions and might require complex computational processing pipelines. In this work, gas-liquid two-phase flow monitoring based on radar technology is proposed. Characteristic flow velocity distributions associated with different two-phase flows are remotely recognized by studying the reflected sub-THz signals that are phase-modulated by the moving gas-liquid interface. Experimental results confirm the feasibility of the proposed scheme for the identification of different gas-liquid two-phase flows using sub-THz radar imaging.