A Thermal Hydrodynamic Lubrication Model of Pivoted Plane-Pad Thrust Bearings
Open Access
- Author:
- Yan, Yan
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- July 06, 2011
- Committee Members:
- Liming Chang, Thesis Advisor/Co-Advisor
Liming Chang, Thesis Advisor/Co-Advisor - Keywords:
- thermal
hydrodynamic lubrication
pivoted slider bearing - Abstract:
- This thesis develops an analytical model for the study of oil-lubricated plane-pad slider bearings with thermal effect. The effects of viscosity changes in the lubricant with temperature are taken into account. The performance of the slider bearing system can be determined by reference to three dimensionless design parameters: length-to-width ratio (B/L), bearing load parameter (w_th) and the pivot location (X_C) of the bearing pad. The relationships between the performance variables and the design parameters are analyzed. The analysis suggests that centrally pivoted bearings can develop significant hydrodynamic lubrication load capacity when the bearing pad is sufficiently wide such as a length-to-width ratio (B/L) of 1 or less. The results show that the load capacity is reduced as the bearing pad narrows and the reduction becomes steep for bearings of B/L>1. At B/L=2, the reduction has become pronounced and the load capacity of the bearing is diminished. In addition, the analysis reveals that the lubricant film thickness in the bearing is relatively insensitive to the applied load when the bearing pad is sufficiently wide such as B/L<1. As the bearing pad narrows, however, the film thickness becomes increasingly sensitive and the sensitivity becomes large at B/L=2, making it very difficult to design centrally pivoted narrow bearings. The model is then used to study off-centrally pivoted bearings, and design charts are given for such bearings. The relationships between film thickness, friction coefficient, and pivot location are studied under various combinations of load parameters and length-to-width ratios. The results obtained from the model are compared to numerical results in the published literature. The validity and accuracy of the model may be evaluated by numerical analysis and by performing experiments on actual slider bearings in future work.