Session: Student Poster Competition

Submission Number: 187188

Experimental Identification of Dynamic Force Coefficients in Compliant Foil Bearings Lubricated With Liquid Nitrogen 

With the active development of technologies related to reusable launch vehicles, the importance of reliable cryogenic turbopumps has steadily increased. These turbopumps operate using extremely low-temperature fluids, such as liquid methane, liquid hydrogen, and liquid oxygen. Therefore, the experimental performance measurement and demonstration of shaft support bearing components are critical requirements for system development. Conventional rolling element bearings face limitations in operational lifespan and reliability when applied to the demanding cryogenic environments. Foil bearings, as hydrodynamic fluid film bearings, enable high-speed operation while providing enhanced damping characteristics to the rotor-bearing system. However, for stable operation under cryogenic conditions, it is essential to understand how the structural and dynamic characteristics of these bearings change under high-speed rotation. This study describes high-speed, component-level experiments conducted on a bump-type foil bearing lubricated with liquid nitrogen. The experiments identify the structural stiffness and damping characteristics of the test foil bearing. The test bearing is fabricated using Inconel X-750 foils with a thickness of approximately 0.13 mm and a nominal diameter of 60 mm. Rotating tests are performed at speeds up to 30 krpm to evaluate the bearing dynamic force coefficients. The measurement data indicate that, under cryogenic conditions, the stiffness and damping characteristics exhibit distinct differences compared to performance under ambient air conditions. These variations are primarily attributed to temperature-induced changes in the bearing clearance of the foil assembly. This study provides valuable experimental data for the design and analysis of cryogenic turbopumps and demonstrates the potential of foil bearings for next-generation cryogenic turbomachinery applications.

Presenting Author: Yueun Jeon Hanyang University

Presenting Author Biography: Graduate Research Assistant

Authors:

Yueun Jeon Hanyang University
Kyuman Kim Hanyang University
Hyunsung Jung Hanyang University
Keun Ryu Hanyang University