Ring-shaped single-electrode triboelectric nanogenerator (RSE-TENG) for energy harvesting and liquid flow rate monitoring of gas-liquid two-phase flow

Online measurement of liquid flow rate in high-speed gas-liquid two-phase flow remains a considerable challenge for practical engineering applications. Owing to the non-linear and non-smooth characteristics, it is not easy to achieve effective measurement of liquid-phase flow without separation of gas-liquid two-phase using conventional methods. An alternative, the solid/liquid-based triboelectric nanogenerator, has a great potential for self-powered sensing of liquid states. Herein, a ring-shaped single-electrode triboelectric nanogenerator (RSE-TENG) by combining contact electrification (CE) and electrostatic induction is designed for energy harvesting and parameter monitoring of gas-liquid two-phase flow. The RSE-TENG can achieve stable short-circuit current and open-circuit voltage peaks of 24 µA and 344 V, respectively. And a self-powered real-time liquid-phase flow monitoring system with a measurement range of 4~20 mL/min for gas-liquid two-phase flow is developed based on the RSE-TENG. It has the advantages of simple structure, low cost, fast response time, and can achieve effective non-contact measurement of liquid-phase flow without separation of gas-liquid two-phase. This measurement method based on the electric signal of triboelectricity at the solid-liquid interface can provide guidance and reference for the related research on fluid mechanics.