CFD analysis and experimental validation of a stepped early discharge port for over-compression control in a CO₂ scroll compressor.
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| Title: | CFD analysis and experimental validation of a stepped early discharge port for over-compression control in a CO₂ scroll compressor. |
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| Authors: | Zhou, Youxin1 (AUTHOR), Peng, Bin1 (AUTHOR) pengb2000@lut.edu.cn, Liao, Zhixiang1 (AUTHOR), Wei, Mingtong1 (AUTHOR) |
| Source: | International Journal of Refrigeration. Apr2026, Vol. 184, p135-147. 13p. |
| Subjects: | Pressure control, Compressor performance, Computational aerodynamics, Thermodynamics, Flow instability, Mechanical efficiency |
| Abstract: | • A stepped early discharge port (EDP) is proposed for over-compression control. • A coupled thermodynamic-geometric design method determines the EDP location. • It achieves a smoother pressure rise and lowers peak chamber pressure by 0.22 MPa. • It ensures stable flow and temperature uniformity across operating conditions. • It improves both volumetric and isentropic efficiency across operating conditions. Over-compression in transcritical CO₂ scroll compressors leads to considerable energy losses, lower efficiency, and higher thermal loads, thereby compromising both performance and reliability. To address this issue, a novel stepped early discharge port (EDP) is proposed, along with a coupled thermodynamic and geometric design method for determining its location. Using an integrated CFD-experimental approach, the performance of the stepped EDP is evaluated and compared with that of a conventional cylindrical EDP under typical over-compression conditions. Furthermore, its influence on the compressor's flow field and performance is analyzed across conditions ranging from near-design to severe over-compression pressure ratios. Results indicate that the stepped design yields more stable internal flow and better over-compression mitigation than the cylindrical EDP. Analysis of pressure and mass flow rate at the early discharge port reveals that, compared to the circular EDP, the average early discharge pressure decreases by about 4.2%, while the mass flow rate increases by 41.2%. Moreover, the stepped EDP reduces the peak chamber pressure by 0.22 MPa, significantly exceeding the 0.04 MPa reduction achieved by the cylindrical EDP. The variable-condition study confirms that the over-compression mitigation effect of the stepped EDP is maintained across all investigated conditions, consistently lowering working chamber pressure and promoting a more uniform temperature distribution. Under severe over-compression, volumetric efficiency improves by up to 5.99%, and isentropic efficiency shows a maximum increase of 27.02%. Owing to the optimized flow field structure, leakage mass flow rate decreases by approximately 0.8% under severe over-compression. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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