Computational Fluid Dynamics study of heavily loaded fixed-pad thrust bearings operating under thermoelastohydrodynamic regime

Abstract

The present Thesis investigates the effects of thermal deformations on the performance of fixed-pad thrust bearings operating under high loads and temperatures. The presented work consists of two main parts. First, in order to identify the mechanisms of pressure build-up in parallel surface thrust bearings, the different theories proposed in the scientific literature have been evaluated. To this end, a CFD-based thermoelastohydrodynamic (TEHD) model has been generated, accounting for all the physical phenomena of the lubricant, of the solid domains and their interaction, which have been suggested in the literature as phenomena contributing to the pressure build-up mechanism of the parallel thrust bearing. The importance of each theory has been quantified and a final modelling approach has been proposed, for accurately evaluating the performance of a parallel surface thrust bearing. Furthermore, the generated model has been validated against experimental results of the literature. The second part of the Thesis utilises the previously proposed modelling approach to evaluate contemporary designs of thrust bearings, such as textured, coated, pocket and tapered-land bearings. In conclusion, the thermal deformations of the bearing pad are established as the main pressure build-up mechanism in parallel thrust bearings. Moreover, they contribute significantly to the performance of textured and coated bearings. Contrariwise, on pocket and tapered-land bearings, the thermal deformations are of negligible importance, even at high loads and operating temperatures.