Development of Externally Pressurized Thrust Bearing for High-Expansion-Ratio Helium Expander.

Abstract

The authors developed an expander for a helium liquefier of 100 1/h liquefaction capacity used for a superconducting generator. This paper focuses on the development of the shaft-bearing system, which uses a thrust bearing exerting significant influence on the reliability of the turbine. An externally pressurized thrust bearing was used to support the high thrust load resulting from the high expansion ratio of the turbine. The characteristics of the bearing were estimated based on analytical solution of the theory of complex velocity potential. Good agreement was found between theoretical and experimental results and the practicality of the design method was verified.