Design of a Supercritical CO₂ Compressor for Use in a 1 MWe Power Cycle

Supercritical CO₂ power cycles are considered to be a more effective means to replace the steam Rankine cycle in power generation by power coal in the future. However, CO₂ compressors for this application have not been well developed. A conceptual design of the compressor for a 1 MWe cycle has been summarized and a calculation method of the axial force of a supercritical CO₂ compressor has been introduced. The influences of inlet temperature and pressure near the critical point on compressor performance, the rotor dynamics analysis for this compressor, and the influence of the rotation factor C ₀ on compressor axial force were also investigated. The results show that the changes in inlet temperature and pressure near the critical point have great influences on compressor performance and the axial force of the compressor is closely related to the selection of the rotation factor C ₀. The pressure ratio and power decrease with the increase of inlet temperature; when the inlet temperature increases by 2 °C, the pressure ratio decreases by 7-24% and the power decreases by 1-9%. With the increase of inlet temperature, the maximum efficiency of the compressor decreases, and the maximum pressure ratio of the compressor decreases with the increase of inlet pressure. When the rotation factor C ₀ is equal to 0 and 0.2, the axial force of the compressor decreases with the increase of rotating speed. When the rotation factor C ₀ is equal to 0.4, the curves of the compressor with the flow rate at different speeds begin to produce intersections. When the rotation factor C ₀ is equal to 0.6, 0.8, and 1, the axial force of the compressor increases with the increase of rotating speed.