Numerical Study of Unsteady Flow in Centrifugal Cold Compressor

Abstract

In helium refrigeration system, high-speed centrifugal cold compressor is utilized to pumped gaseous helium from saturated liquid helium tank at low temperature and low pressure for producing superfluid helium or sub-cooled helium. Stall and surge are common unsteady flow phenomena in centrifugal cold compressors which severely limit operation range and impact efficiency reliability. In order to obtain the installed range of cold compressor, unsteady flow in the case of low mass flow or high pressure ratio is investigated by the CFD. From the results of the numerical analysis, it can be deduced that the pressure ratio increases with the decrease in reduced mass flow. With the decrease of the reduced mass flow, backflow and vortex are intensified near the shroud of impeller. The unsteady flow will not only increase the flow loss, but also damage the compressor. It provided a numerical foundation of analyzing the effect of unsteady flow field and reducing the flow loss, and it is helpful for the further study and able to instruct the designing.

Optimization of mixing parameters for a cold model system by CFD for aluminum matrix composites synthesis process

“…Alfonsi investigated the diffraction of water waves around large‐diameter, surface‐piercing, vertical circular cylinders by numerically solving the system of the Navier‐Stokes equations. Zhang investigated unsteady flow during low mass flow or high pressure ratio using CFD, to obtain the installed range of a centrifugal cold compressor. Their numerical analysis deduced that the pressure ratio increases with the decrease in reduced mass flow.…”