Open Access

ARTICLE

Performance Analysis of sCO₂ Centrifugal Compressor under Variable Operating Conditions

Jiangbo Wu¹, Siyi Sun¹, Xiaoze Du^1,2,*

1 School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, 730050, China
2 School of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing, 102206, China

* Corresponding Author: Xiaoze Du. Email:

Fluid Dynamics & Materials Processing 2025, 21(8), 1789-1807. https://doi.org/10.32604/fdmp.2025.064254

Received 10 February 2025; Accepted 21 April 2025; Issue published 12 September 2025

Abstract

This study explores the aerodynamic performance and flow field characteristics of supercritical carbon dioxide (sCO₂) centrifugal compressors under varying operating conditions. In particular, the Sandia main compressor impeller model is used as a reference system. Through three-dimensional numerical simulations, we examine the Mach number distribution, temperature field, blade pressure pulsation spectra, and velocity field evolution, and identify accordingly the operating boundaries ensuring stability and the mechanisms responsible for performance degradation. Findings indicate a stable operating range for mass flow rate between 0.74 and 3.74 kg/s. At the lower limit (0.74 kg/s), the maximum Mach number within the compressor decreases by 28%, while the temperature gradient sharpens, entropy rises notably, and fluid density varies significantly. The maximum pressure near the blades increases by 6%, yet flow velocity near the blades and outlet declines, with a 19% reduction in peak speed. Consequently, isentropic efficiency falls by 13%. Conversely, at 3.74 kg/s, the maximum Mach number increases by 23.7%, with diminished temperature gradients and minor fluid density variations. However, insufficient enthalpy gain and intensified pressure pulsations near the blades result in a 12% pressure drop. Peak velocity within the impeller channel surges by 23%, amplifying velocity gradients, inducing flow separation, and ultimately reducing the pressure ratio from 1.47 to 1.34.

---

Keywords

---