Applying Resilient Foil Air Bearings to Turbomachinery - Techniques and Challenges

A review is presented of the features which make the resilient foil air bearing attractive in high temperature and high-speed turbomachinery. Turbomachinery requirements are considered with emphasis on automotive gas turbines in which sometimes both air and oil lubricated rotor bearings are used.

Techniques used in designing and matching foil bearings to the gas turbine and economically developing them under simulated operating conditions are discussed together with some developmental experiences.

The construction of foil bearings, their materials and coatings, manufacture and accuracy is reviewed.

A look is taken at the future challenges of anticipated higher cycle temperatures and speeds where 1400°F bearing soakback temperatures may exist and the all foil bearing rotor system will be required. The possibility of ceramic foil bearings is considered and an example of some new technology work is used to illustrate the continuing development work which will be required.