Numerical Simulation of the Influence of Tip Clearance on the Performance of Centrifugal Cold Compressor

Abstract

To improve the efficiency of the Experimental Advanced Superconducting Tokamak (EAST) subcooled helium cryogenic system, a centrifugal cold compressor (CC) was investigated as an alternative to the oil ring pump. A numerical simulation method was applied to analyse variations in CC performance parameters, pressure ratio and polytropic efficiency. Results indicated that the performance curve of the CC and warm compressor (WC) were similar. The tip clearance at the design point was 0.2 mm and increased to 0.231 mm when the CC was operated at 4 K. This increase in tip clearance resulted in a 0.86% drop in the pressure ratio and a 0.54% drop in polytropic efficiency. To verify the simulation model, experiments were done using cold nitrogen.