Effects of the ring clearance on the aerodynamic performance of a CO2 centrifugal compressors annular seal: A numerical study

Computational fluid dynamics simulations are performed on a floating-ring annular seal of a Carbon Dioxide (CO2) centrifugal compressor. The numerical methodology has been validated by comparing the numerical results for the labyrinth function of a stepped-type labyrinth seal with those from experiments. An annular seal of a CO2 compressor is considered and the effects of the rings’ clearances on the seal function are investigated. Results showed that although the leakage rate grows considerably with increasing ring clearance, the leakage function rises marginally with clearance. Furthermore, the leakage function remains almost constant with increasing the inlet total pressure and temperature. Results also showed that the minimum required flow rate of the barrier gas grows substantially with increasing the ring clearance.