Analysis and test of a robust sector thrust bearing for a cryogenic turboalternator

The miniature turboalternator associated with a reverse-Brayton cryocooler requires geometrically simple, self-acting thrust bearings capable of relia ble operation over a large temperature range and insensitive to secondary l eakage flows. In order to meet this need, a robust sector thrust bearing ha s been developed. This thrust bearing is different from a classic stepped s ector 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 descri bes the analysis and initial test results for a protypical robust sector th rust bearing.