Analysis of internal temperature distribution and its total parasitic heat leak for a cryogenic cold Compressor

Abstract

Cold compressors are the core component needed for the development of a facility for large-capacity refrigeration at superfluid helium temperatures. The compressor impeller is operated at extremely low temperature and low pressure which involves technical issues including material properties at low temperature, heat transfer, failures of the actuating motor resulting from overheating and performance penalty due to heat transfer from the warm side of the machine to the cold side. To address these issues, it is important to understand the temperature distribution inside the housing of the machine. To analyze the temperature distribution, an integrated numerical model is created on the basis of the model of the cold compressor structure and then simulated through computational fluid dynamics. The actual temperature rise of the cold compressor is measured at two temperature measuring points and compared with the temperatures predicted by the simulation to validate the accuracy of the model. The results show that the internal flow field around the motor and bearings of the cold compressor is completely turbulent and the total parasitic heat transfer to the cold gas stream is closely related to the rotating speed of the high-speed motor.