Session: 23-02: Gas Foil Bearings I

Submission Number: 176240

Static and Dynamic Characteristics of a Multi-Pad Bump Foil Gas Bearing Under Repeated Start-Stop Cycle Wear 

Significant wear grooves develop on the top foil surface of gas foil bearing after repeated start-up and shutdown. These grooves alter the gas film thickness distribution, consequently degrading the bearing's static and dynamic performance. Existing research on foil wear effects, however, has primarily focused on one-pad bump foil gas foil bearings. This study develops a three-dimensional finite element model of a multi-pad gas foil bearing. Three distinct bump foil stiffness distributions are investigated: high stiffness at the ends with low stiffness in the middle, the reverse pattern, and a uniform distribution. Using a fully coupled model that predicts foil wear during start-up and shutdown of the bearing-rotor system, this study employed a linear cumulative wear law. The top foil wear was calculated at intervals of twenty cycles. This approach enabled us to obtain the top foil surface wear morphology after 500 start-up and shutdown cycles.

The study compares the cumulative wear after 500 start-up and shutdown cycles among three multi-pad gas foil bearing designs and a conventional single-pad bearing. The results indicate that appropriately designed bump-foil architectures and stiffness distributions can effectively reduce top foil wear, enhancing gas foil bearing life and reliability. In addition, the static and dynamic characteristics of the above bearings before and after 500 start–-up and shutdown are computed, quantifying changes in load capacity as well as stiffness and damping coefficients. Comparison of these performance parameters allows for the identification of the optimal foil structure and stiffness distribution.

Presenting Author: Dake Sun Xi'an Jiaotong University

Presenting Author Biography: Dake Sun is a Ph.D. Student from Institute of Turbomachinery, Xi’an Jiaotong University of China. His research focus on the nonlinear rotordynamic characteristics of rotor-gas bearing system.

Authors:

Dake Sun Xi'an Jiaotong University
Zhuocong Li Xi'an Jiaotong University
Ying Zhong China Aero-Polytechnology Establishment
Zhigang Li Xi'an Jiaotong University
Jun Li Xi'an Jiaotong University