ORCID Identifier(s)

0000-0002-6116-5162

Graduation Semester and Year

2018

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Mechanical Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Daejong Kim

Abstract

Gas foil thrust bearing is one of few axial bearing options for high speed turbomachinery systems. Its advantages include low cost, light weight, generous allowance for component mis-alignment and runout. However, the bearing has low load carrying capacity comparing to other types such as rigid gas bearing and magnetic bearing. This work explores two non-traditional design aspects to improve gas foil thrust bearing’s static performance. The bearing bump foil is redesigned to tailor to the bearing pressure profile; hence induces a more uniform gas film thickness. Simulation using independent elastic foundation model predicts the new tailored bump foil thrust bearing can achieve bump deflection uniformity within 0.3 micron difference. A pocket groove pattern is etched onto the bearing top foil as a secondary pressure boosting mechanism in addition to the traditional taper-flat configuration. FEA simulation of a fluid structure interaction model validates that the compliancy of the foil thrust bearing structure does not compromise the benefits of the pocket grooves. Experimental data shows that the tailored stiffness bump has small positive effect on the bearing performance, while the pocket grooves show more significant gain. The combined benefits of the proposed features improve the bearing static performance by almost 18 percent bringing the bearing specific load capacity from 1.2 bar to 1.7 bar.

Keywords

Thrust bearing, Foil, Compliance, Performance, Surface grooves, Load capacity

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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