The smooth operation of the power transmission systems found in many transport vehicles and energy production systems is often limited by the reliability of the bearings which support their rotating shafts. Under high shaft speeds and applied loads, hydrodynamic journal bearings may constitute the only acceptable option for the designer.
When predicting the performance of journal bearings submitted to severe operating conditions it is crucial to account for the local variation of the temperature and the viscosity field. Furthermore, the lubricant supply conditions such as lubricant feeding pressure and temperature and the actual groove geometry should be treated realistically in the theoretical analysis.
The presentation will highlight the work carried out during the speaker's recently finished PhD, a work that was made within the Tribology team of the CT2M research group (Mechanical Engineering Department, Minho University). It has been focused on the theoretical and experimental study of the performance of twin groove journal bearings operating under steady state. A particular emphasis was put on the analysis of the influence of lubricant supply conditions.
The work included the development of a Thermohydrodynamic (THD) model for the analysis of the performance of twin groove journal bearings. The model has been based on the simultaneous numerical solution of the Generalized Reynolds and Energy equations within the lubricant film and the heat transfer within the bush body. Special care was taken in the treatment of the phenomena taking place in the vicinity of feeding grooves and the modeling of the ruptured film region (solid+gaseous phase).
The theoretical model was extensively validated and refined with experimental results obtained at the Laboratory of Tribology and Machine Elements of the University of Minho (LOMT), at the Laboratory of Solid Mechanics of the University of Poitiers (LMS), and with experimental results from the literature. |