Numerical Simulation Study on Influence of Equation of State on Internal Flow Field and Performance of S-CO2 Compressor

• Published in: Journal of thermal science Vol. 33; no. 3; pp. 888 - 898
• Main Authors: Zhang, Lei, Yang, Zhenyu, Sun, Enhui, Zhang, Qian, An, Guangyao, Yuan, Wei
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2024; Springer Nature B.V
• Subjects: Brayton cycle; Carbon dioxide; Classical and Continuum Physics; Compressors; Critical point; Engineering Fluid Dynamics; Engineering Thermodynamics; Equations of state; Heat and Mass Transfer; Internal flow; Numerical stability; Physical properties; Physics; Physics and Astronomy; Power consumption; Pressure ratio; Simulation; Thermophysical properties; condensation; supercritical carbon dioxide; equation of state; centrifugal compressor; numerical simulation
• ISSN: 1003-2169; 1993-033X
• DOI: 10.1007/s11630-024-1944-x

The low power consumption of the near-critical compressor is the key factor for the high efficiency of supercritical CO 2 Brayton cycle. In the numerical simulation of the compressor, the rapid changes in the thermophysical properties of the CO 2 near the critical point make it difficult to capture the condensation phenomenon. This paper investigates the influence of fluid physical properties on the condensation phenomenon. Firstly, the differences in the physical properties of CO 2 in the SRK EOS (equation of state), PR EOS, and SW EOS are compared. Then, the simulation of nozzles and compressors were carried out and discussed. Results show that the condensation positions predicted by the three EOSs are basically the same. Compared with SW EOS, the disparities between the maximum condensation mass fraction predicted by the PR and SRK EOSs is 5.7% and 11.5%, and that of total pressure ratio is 0.3% and 3.8%, respectively. The results show that PR EOS can be considered for numerical simulation in engineering practice. Since its physical property calculation results are closer to the actual physical properties while the physical properties change more gently, it has considerable accuracy and numerical stability.