Quantitative Prediction of CO₂ Condensations in a SCO₂ Centrifugal Compressor at Various Inlet Temperature and Pressure Conditions

Carbon dioxide near the critical condition has high density but low viscosity. Due to this characteristic a compressor using sCO₂ can achieve a high pressure ratio with small compression work, which makes a cycle more efficient. However when the inlet temperature and pressure get close to the critical point, CO₂ becomes susceptible to condensation in the compressor which can damage compressor blades. This paper aims to quantify the amount of the CO₂ condensation in a compressor with various inlet temperature and pressure conditions. Over 10 inlet conditions are calculated by multiphase CFD considering real gas property of CO₂ and a condensation map in temperature-pressure domain is obtained. The results show that the amount of CO₂ condensation depends on the inlet temperature than the pressure and there is a pressure where the maximum condensation occurs at the given inlet temperature.