Session: 23-07 Gas Foil Thrust Bearings

Paper Number: 153334

Design, Commissioning and Testing of a 230 mm Gas Foil Thrust Bearing Test Rig 

A major growth market has been based around  sub-500 kW turbomachinery with direct drive motors and power electronics, operating at high speeds.  Not just eliminating gearboxes, these machines enable very high speeds and a next-generation aero-performance cycle.  Along with the development of these high speed direct drive motors, oil-free gas foil bearings have evolved from limited commercial use in the 1970’s to many new applications in turbomachinery sizes from a few kW's to hundreds of kW's.  This ideal match of technologies enable meaningful efficiency increases with mass production of thousands of air blowers, microturbines, and HVAC compressors operating in Freon, among other applications.  On the forefront of this technology, a family of Gas Foil Journal Bearings (GFJB) ranging from 15.5 mm to 80 mm journals, and matched Gas Foil Thrust Bearings (GFTB) from 26 mm to 160 mm, has grown with a new customer application. 

 

A much larger 230 mm GFTB matched with a 130 mm GFJB have been designed and manufactured.  This is the largest size foil bearing set known in the literature.   This GFTB retains the mass production features of the smaller bearings, including a no-weld assembly, and only a single, simple, manual forming step.  The GFTB consists of a 360° top foil or loaded surface with a spring support structure of 15 pads.  The 230 mm GFTB can be applied in a high temperature environment up to 500°C or a cryogenic environment and maintain a near-infinite fatigue life.  An existing test rig that was previously used to validate the 160 mm GFTB, has been repurposed for evaluating the 230 mm GFTB.  The thrust bearing test rig will provide a Load-Loss curve that provides real and useful design data for subsequent integration with the turbomachinery.  The test rig design will be reviewed, along with gas foil thrust bearing features, and the resulting test experience.  

Presenting Author: Daniel Lubell Oil-Free Machinery, LLC

Presenting Author Biography: Daniel Lubell, the developer of Oil-Free Machinery™ , specializes in oil-free turbomachinery with over 25 years of related experience, including over 10 years with Oil-Free Machinery, LLC. Daniel's previous experience includes several years at Calnetix Technologies as the Manager of Rotating Machinery and +12 years with Capstone Turbine with diverse roles that included Manager of Turbomachinery Rotating Systems and Principal Engineer of Oil-Free Bearing Technology. His responsibilities included bearing and rotordynamic design integration and testing for all Capstone products as well technical and commercial lead for all outside foil bearing programs. Prior small turbomachinery experience includes APU’s and small thrust jets with Sundstrand Aerospace (now part of Pratt and Whitney) and air cycle machines with Honeywell Aerospace. Daniel has a Master of Science degree in Mechanical Engineering which he earned at the Texas A&M University Turbo Lab in College Station, Texas. Prior to that, he earned a Bachelor of Engineering Science degree from Trinity University in San Antonio, Texas. Daniel is an ASME member and active participant in conferences and journals and has published papers on squeeze film dampers and foil bearing developments for micro gas turbines.

Authors:

Daniel Lubell Oil-Free Machinery, LLC
Dennis Weissert Oil-Free Machinery, LLC
Navjot Chauhan Oil-Free Machinery, LLC