A novel water-fluid-driven triboelectric nanogenerator for lubrication condition monitoring of water-lubricated bearings

Abstract Water-lubricated bearings play a vital role in marine propulsion systems, significantly influencing operational reliability and environmental sustainability. Accurate and real-time monitoring of lubrication states in these bearings is essential to guarantee the safe operation of marine vessels. Nevertheless, current monitoring approaches primarily depend on laboratory-acquired static parameters, such as film thickness and pressure, which inadequately capture the dynamic lubrication variations encountered during actual navigation conditions. To overcome this limitation, an embedded cantilever beam-bouncing-ball triboelectric nanogenerator (CB-TENG) was developed as a self-powered sensor. The sensor's performance was validated through comprehensive simulation and experimental investigations, revealing that fluidinduced excitation can effectively stimulate structural vibrations within the CB-TENG. Importantly, the vibration characteristics exhibited clear and measurable dependence on the water film thickness. Under three representative lubrication regimes, the CB-TENG exhibited output signals with dominant frequencies aligning closely with the structure's natural frequency. The signal features showed observable differences among lubrication states, suggesting the feasibility of using the proposed device for condition differentiation and real-time monitoring in water-lubricated bearing systems. This research provides a novel theoretical foundation and technical approach to enhancing intelligent monitoring and reliability of marine water-lubricated bearing systems.