During the operation of turbomachinery, alternating loads caused by external impacts or internal fluid excitation pose a serious threat to the stability of bearing-rotor systems. As a key supporting component, the reliability of tilting-pad journal bearings (TPJBs) directly affects the machine safety. However, conventional models based on static forces and fixed misalignment angle assumptions are unable to accurately capture the dynamic responses of TPJBs under practical operating conditions. In this study, a novel dynamic model is developed, which comprehensively incorporates time-varying misalignment angle and alternating loads. By comparing with the traditional fixed-value misalignment and aligned models, the effect of dynamic misalignment on the lubricant performance of TPJBs is investigated. The results demonstrate that dynamic misalignment plays a significant role in determining TPJBs performance under alternating loads. In particular, under heavy-load conditions, the use of fixed-misalignment models introduces obvious deviations in performance prediction. However, time-varying misalignment models effectively address this issue. Compared with fixed-value misalignment, bearing parameters, such as preload, markedly alter the influence of time-varying misalignment on lubrication behavior. The conclusions provide a theoretical support for the optimization of TPJBs in turbomachinery.
Ji et al. (Sun,) studied this question.