Coupled thermo-elastohydrodynamic analysis of a bump-type compliant foil journal bearing

Official URL: http://risc01.sabanciuniv.edu/record=b1589546 (Table of Contents)

This work presents a fully coupled thermo-elastohydrodynamic analysis of a bump-type compliant foil journal bearing. The operational characteristics of compliant foil bearings have been evaluated under different operating conditions. Even though some experimental research data are available in literature, extended thermo-hydrodynamic analysis is required to better understand and optimize the system performance at the design level. The presented comprehensive model benchmarked to experiment data will help enable the widespread usage in novel turbomachinery applications. The proposed model predicts three-dimensional thermal, structural and hydrodynamic performance of a bump-type compliant foil bearing. The model couples finite element analysis of the structural deformation and hyrodynamic pressure to a finite difference code for film temperature. The Augmented-Lagrangian contact model and advanced thermal contact modeling is applied. The model involves complete bearing mechanism as well as the interacting section of the shaft with the bearing. Nickel-based superalloys are used as bearing material and temperature dependent thermo-mechanical properties are defined in the solver. The thermal growth of the shaft, foil structure, bearing sleeve, and centrifugal growth of the shaft are considered. The model captures the physics very well and could be utilized to design more advanced bearings. The predictions of the proposed model are benchmarked to published experimental data and a reasonable correlation is obtained. Parametric study is conducted for various shaft speeds and loading conditions to predict thermal and structural performance. Derivation of governing momentum and energy equations, mechanical and thermal contact models, finite element and finite difference formulations are given in detail.