Development of Foil Journal Bearing for Small High Speed Cryogenic Turboexpander

Abstract

This chapter develops a simple and high performance selfacting gas journal beating for small cryogenic turboexpander. A new type of gaslubricated and self-acting foil bearing is designed. The effects of the bearing clearance and the foil stiffness on the bearing performance are experimentally studied in detail in the chapter. With the optimum clearance and foil stiffness, the foil bearing presented can achieve sufficiently high stability. The maximum rotational speed obtained is greater than 150,000 rpm. Many times of start-stop test are carried out and the durability of the foil bearing is confirmed. The optimum bearing clearance and bearing stiffness are C=20 μm and n=22 respectively. In addition, the foil bearing has high durability. So, the foil bearing is hopeful as a simple and high performance SA gas bearing for small high speed cryogenic turboexpander.