Transient tribo-dynamic behavior of bi-directional misaligned water-lubricated bearings coupled with journal axial motion

The novelty of this study is that the mechanism of the impact of axial motion on the nonlinear tribo-dynamic behavior of bi-directional misaligned water-lubricated bearings (WLBs) is systematically discussed. A novel model that incorporates journal axial motion and bi-directional misalignment is introduced to evaluate the complex transient performance of WLBs under dynamic loads. Based on the mass conservation cavitation algorithm, the average Reynolds equation is modified to account for the impact of axial motion on Couette and unsteady flow, and the time-varying water film thickness equation is modified to achieve the complicated coupling effect of multi-factorial and multi-physical fields. The accuracy of the model and methodology proposed in this study is evaluated by existing experimental and numerical data. The impact of axial motion, misalignment type, misalignment angle, axial velocity, rotational speed, load, and radius clearance on the transient tribo-dynamic behaviors is systematically investigated. The results show that an appropriate misalignment angle positively affects the enhancement of hydrodynamic performance and diminishes rotor vibration response. Nonetheless, the impact of axial motion varies significantly across different misalignment types. The impact of axial motion becomes more significant with increasing load, decreasing rotational speed, or decreasing radius clearance. The results of this study present a helpful reference for misaligned WLB theoretical analysis and optimal design.