SUBJECT: M.S. Thesis Presentation
BY: Natalie Walsh
TIME: Tuesday, April 23, 2024, 1:00 p.m.
PLACE: Teams, Teams
TITLE: Characterization of Thermal Conductance Between a Ball and Parallel Plates for Spacecraft Bearing Applications
COMMITTEE: Dr. Zhuomin Zhang, Chair (ME)
Dr. Yoshimi Takeuchi (Aerospace Corporation)
Dr. Mostafa Ghiaasiaan (ME)


Bearings are essential to rotational spacecraft components, so a proper understanding of bearing behavior is necessary for reliable spacecraft operation. Characterization of bearing thermal conductance provides accurate temperature predictions, which are important to a successful design so that critical mechanical fit is maintained and lubricant degradation and migration is avoided. This thesis describes a static “Ball-on-Flat” (BoF) test platform that has been developed to simplify bearing conductance testing, specifically for low-speed bearings where dynamic effects are not considered. The test consists of a single, lubricated ball between two plates that use the similar material properties as traditional bearing raceways. The goal of this thesis is to use thermal conductance data from the simplified bearing geometry to validate analytical conductance models for a complete bearing, including Aerospace’s BBTherm tool. The motivation for adding data-driven truth to the BBTherm model with test data is to ensure proper modeling of the effect that the lubricant meniscus has on the bearing conductance. The BoF test data has shown good agreement between theoretical models indicating that the combination of the BoF test and BBTherm tool will allow for ease of testing and quicker thermal characterization of complete bearings for various ball and lubricant combinations.