真实气体效应对 SCO₂ 离心压气机气动性能的影响

By utilizing similitude theory and numerical simulation，the coupling effects of real-gas aerodynamics and thermophysical properties on the performance of compressors were decoupled. The characteristics and internal flow fields of a supercritical carbon dioxide centrifugal compressor were investigated under different inlet conditions，and the real-gas effects on the enthalpy increase，efficiency，and choke margin of the compressor were explored. The results showed that real-gas effects on the compressor performance can be divided into two categories: thermodynamic effects inherent in the thermodynamic definitions of the performance parameters and aerodynamic effects within the compressor's internal flow field. Among them，aerodynamic effects played a dominant role. By leveraging similitude parameters， the thermodynamic effects can be eliminated. When the real-gas effects were intensified， the reduction in fluid compressibility decreased the impeller’s Euler work， leading to a reduction in enthalpy increase. The alleviation of the blade loading reduced load-related aerodynamic losses，thereby improving the efficiency. The presence of two-phase flow and the onset of choking at the throat led to the reduction of choke margin.