Analysis and Test of a Robust Sector Thrust Bearing for a Cryogenic Turboalternator

Abstract

The miniature turboalternator associated with a reverse-Brayton cryocooler requires geometrically simple, self-acting thrust bearings capable of reliable operation over a large temperature range and insensitive to secondary leakage flows. In order to meet this need, a robust sector thrust bearing has been developed. This thrust bearing is different from a classic stepped sector thrust bearing in that the restoring force at cryogenic temperatures originates primarily from inertial effects while at higher temperatures its restoring force is related primarily to viscous effects. This paper describes the analysis and initial test results for a prototypical robust sector thrust bearing.