Multi-physics coupling effect on morphology evolution and lubrication characteristics of oil film in hydrostatic thrust bearing

To address the issues of oil film morphology deviation from theoretical design models and lubrication failure in hydrostatic thrust bearings under high-speed and heavy-load conditions caused by temperature rise and structural deformation, this study establishes a bidirectional fluid–structure interaction mechanical model. The model systematically analyzes the fluid-thermal-structural coupling mechanisms of friction pairs under varying rotational speed and loads, as well as their effects on oil film morphology. The results indicate that increased rotational speed and load intensify shear-induced heating and squeeze effects in the oil film, leading to film thinning and enhanced non-uniformity in temperature and pressure fields, particularly at the downstream side of the sealing edge. The oil film morphology, influenced by thermo-mechanical coupling deformation, exhibits a wedge-shaped distribution characterized by a thicker outer region and thinner inner region. Under critical operating conditions, the inner sealing edge film thickness approaches the safety threshold, indicating imminent lubrication failure risks. These findings elucidate the dynamic evolution characteristics of oil film morphology and lubrication characteristics in hydrostatic bearings, providing a theoretical foundation for structural optimization and reliability-oriented design.