Session: 23-07 Gas Foil Thrust Bearings

Paper Number: 154008

Performance Evaluation and Comparison of Hybrid Rigid and Hybrid Foil Thrust Bearings 

Foil thrust bearings have demonstrated significant potential as oil-free alternatives for use in high-speed turbomachinery, largely due to their adaptability to a wide range of environmental conditions. However, increasing the load capacity of foil bearings while maintaining high rotational speeds and minimizing wear remains a critical challenge. To address this limitation, hybridization of foil bearings has been explored by introducing externally pressurized air to maintain adequate bearing clearance. In this study, a performance comparison is conducted between a hybrid rigid thrust bearing (HRTB) and a hybrid thrust foil bearing (HFTB). Both bearings share an outer diameter of 82 mm, along with identical taper angles, orifice locations, and sizes. The performance evaluation was carried out at 40,000 rpm under a hydrostatic pressure of 5 bar absolute. Key metrics such as mass flow rate, film thickness, and zero-speed performance were assessed. Additionally, power loss and load capacity were compared at both zero speed and higher rotational speeds. The HFTB demonstrated a load capacity of 400 N at 40,000 rpm with a limiting criterion of a 5-micron average film thickness. In contrast, the HRTB exhibited pneumatic air hammering during dynamic testing, with the onset of this instability occurring earlier as speed increased, accompanied by corresponding surges in torque measurements.

Presenting Author: EHIREMEN EBEWELE UNIVERSITY OF TEXAS ARLINGTON

Presenting Author Biography: Ehiremen Ebewele is a PhD graduate in Aerospace Engineering from the University of Texas at Arlington. His research focuses on the design, testing and analysis of foil thrust bearings, where he has worked over the past four years under tutelage of Dr. Daejong Kim. He obtained his bachelor's and master's degrees in Aerospace engineering from the University of Maryland at College Park.

Authors:

EHIREMEN EBEWELE UNIVERSITY OF TEXAS ARLINGTON
Woongeon Lee University of Texas at Arlington
Daejong Kim University of Texas at Arlington