An optimized rotating helium-recondensing system using roebuck refrigerators

摘要

This paper describes an optimized design of thehelium-recondensing system utilizing cascade Roebuckrefrigerators. A supercon-ducting generator or motor has asuperconducting field winding in its rotor that should becontinuously cooled by cryogen. Liquid helium transfer from thestationary system to the rotor of the LTS (Low TemperatureSuperconductor) superconducting generator has been problematic,cumbersome, and inefficient. The novel concept of a rotatinghelium-recondensing system is contrived. The vaporized coldhelium inside the rotor is isothermally compressed by centrifugalforce and recondensed to 4.2 K reservoir through the expansionprocess. There is no helium coupling between the rotor and thestationary liquid helium storage. Thermodynamic analysis of thecascade refrigeration system is performed to determine theoptimum key design parameters. The loss mechanisms are alsodescribed to point out the sources that might reduce the system performance.