On maritime vessels, external factors such as explosions, collisions, and grounding can cause the emulsification of lubricating oil by seawater pollution, which can affect the lubrication of a ship’s thrust bearing. To explore the influence of the mixed emulsification of lubricating oil and seawater on the lubrication performance of thrust bearings, this study conducted an emulsification experiment, from which the viscosity equation of the oil–water mixture was obtained. A thermal hydrodynamic model (THD) of bearings considering oil–water mixed emulsification was established, and the Finite Difference Method (FDM) was used for analysis. The results show that according to the characteristics of the manifold, the mixture is divided into water-in-oil (W/O) and oil-in-water (O/W). In the W/O flow with higher viscosity, the film thickness becomes higher, but the power loss increases. In the O/W manifold with low viscosity, the thin film easily causes mixed friction. In the demulsification stage of the mixed liquid, the thickness loss of the film is huge, and the collision between the thrust-bearing pad and the inference plate may cause the pad to be ablated. The influence of specific heat capacity on temperature is greater than the temperature rise caused by viscosity.
As key components in efforts to achieve green and sustainable development in machinery, water-lubricated stern bearings are increasingly replacing traditional oil-lubricated bearings. However, water’s inherent properties—such as low viscosity and poor film-forming ability—can induce severe friction-induced vibration and noise under specific operational conditions. These issues not only accelerate wear but also compromise the vessel’s reliability and acoustic stealth, thereby limiting their wider application. This paper provides a comprehensive review of the research progress relating to friction-induced vibration in water-lubricated bearings. It delves into the underlying mechanisms, critiques the primary methodologies used in numerical simulations, summarizes key experimental approaches, and synthesizes the prevailing vibration suppression strategies. Finally, the study clearly outlines existing challenges and proposes directions for future research.
This review provides a comprehensive evaluation of the key technologies and latest advances in cemented carbide bearings for marine environments, such as navigation equipment and deep-sea operations. Given the rigorous performance requirements imposed on bearings by the extreme conditions of marine environments, including high hydrostatic pressure, seawater corrosion and abrasive wear, this paper explores the developments within carbide material systems. It focuses on analyzing the limitations of traditional WC-Co alloys in seawater, as well as the potential and challenges of alternative binder systems such as WC-Ni and WC-high Entropy Alloys (HEAs) in enhancing corrosion resistance and comprehensive mechanical properties. Building on this foundation, the research sorts out the tribological behavior of cemented carbides under seawater lubrication, explaining the influence of the tribocorrosion mechanism on friction characteristics. Meanwhile, it also explores reliability enhancement strategies through surface modifications like coatings and texturing, and discusses the challenges associated with life prediction models. Through tribopair experiments between cemented carbides and various bearing materials, the application orientation of cemented carbides is clarified, which provides a selection framework for carbide bearing applications in different marine scenarios. Finally, the paper summarizes the current technological bottlenecks and core scientific issues, offering insights for future research and development directions in this field.