Windage and Leakage Losses in Impeller Back Gap and Labyrinth Seal Cavities of Supercritical CO<sub>2</sub> Centrifugal Compressors
The windage loss in impeller back gap and labyrinth seal cavities significantly impacts the aerodynamic performances of supercritical carbon dioxide (sCO<sub>2</sub>) compressors. To accurately calculate windage loss, essential factors affecting the skin friction coefficients <i>C&...
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2025-03-01
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| author | Bing Tang Jianxin Liao Zhuobin Zhao Qinghua Deng Jun Li Zhenping Feng |
| author_facet | Bing Tang Jianxin Liao Zhuobin Zhao Qinghua Deng Jun Li Zhenping Feng |
| author_sort | Bing Tang |
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| description | The windage loss in impeller back gap and labyrinth seal cavities significantly impacts the aerodynamic performances of supercritical carbon dioxide (sCO<sub>2</sub>) compressors. To accurately calculate windage loss, essential factors affecting the skin friction coefficients <i>C</i><sub>f,d</sub> (disk-type gap) and <i>C</i><sub>f,s</sub> (shaft-type gap), including Reynolds number <i>Re</i>, pressure ratio <i>π</i>, and radius ratio <i>η</i>, are investigated in this paper. The flow characteristics of the gap are analyzed and prediction models are proposed. The results indicate that both <i>C</i><sub>f,d</sub> and <i>C</i><sub>f,s</sub> decrease with increasing <i>Re</i> and grow with <i>π</i> and <i>η</i>, attributable to expanded high-vorticity regions caused by enhanced flow instability and larger vortices. The leakage flow rate <i>m</i> is unchanged for <i>Re</i> < 10<sup>6</sup> since the fluid can flow into the impeller back gap, and slightly decreases for <i>Re</i> ≥ 10<sup>6</sup> due to the centrifugal force and the inhibition effect of the vortices filling inlet regions. Moreover, the <i>m</i> grows with <i>π</i> and <i>η</i> due to a larger pressure difference and through-flow area. Maximal relative deviations of 6.23% and 6.83% can satisfy the requirements for calculating accurate windage loss in the impeller back gap and labyrinth seal cavities, which help the primary design of sCO<sub>2</sub> compressors. |
| format | Article |
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| language | English |
| publishDate | 2025-03-01 |
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| spelling | doaj-art-718f640da3664bfeb5deaf5c4b1912b52025-08-20T03:08:44ZengMDPI AGApplied Sciences2076-34172025-03-01157367810.3390/app15073678Windage and Leakage Losses in Impeller Back Gap and Labyrinth Seal Cavities of Supercritical CO<sub>2</sub> Centrifugal CompressorsBing Tang0Jianxin Liao1Zhuobin Zhao2Qinghua Deng3Jun Li4Zhenping Feng5Nanjing Engineering Institute of Aircraft Systems, AVIC, Nanjing 211106, ChinaDongfang Turbine Co., Ltd., Dongfang Electric Corporation, Deyang 618000, ChinaSchool of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaSchool of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaSchool of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaSchool of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaThe windage loss in impeller back gap and labyrinth seal cavities significantly impacts the aerodynamic performances of supercritical carbon dioxide (sCO<sub>2</sub>) compressors. To accurately calculate windage loss, essential factors affecting the skin friction coefficients <i>C</i><sub>f,d</sub> (disk-type gap) and <i>C</i><sub>f,s</sub> (shaft-type gap), including Reynolds number <i>Re</i>, pressure ratio <i>π</i>, and radius ratio <i>η</i>, are investigated in this paper. The flow characteristics of the gap are analyzed and prediction models are proposed. The results indicate that both <i>C</i><sub>f,d</sub> and <i>C</i><sub>f,s</sub> decrease with increasing <i>Re</i> and grow with <i>π</i> and <i>η</i>, attributable to expanded high-vorticity regions caused by enhanced flow instability and larger vortices. The leakage flow rate <i>m</i> is unchanged for <i>Re</i> < 10<sup>6</sup> since the fluid can flow into the impeller back gap, and slightly decreases for <i>Re</i> ≥ 10<sup>6</sup> due to the centrifugal force and the inhibition effect of the vortices filling inlet regions. Moreover, the <i>m</i> grows with <i>π</i> and <i>η</i> due to a larger pressure difference and through-flow area. Maximal relative deviations of 6.23% and 6.83% can satisfy the requirements for calculating accurate windage loss in the impeller back gap and labyrinth seal cavities, which help the primary design of sCO<sub>2</sub> compressors.https://www.mdpi.com/2076-3417/15/7/3678skin friction coefficientimpeller back gaplabyrinth sealsupercritical CO<sub>2</sub> compressor |
| spellingShingle | Bing Tang Jianxin Liao Zhuobin Zhao Qinghua Deng Jun Li Zhenping Feng Windage and Leakage Losses in Impeller Back Gap and Labyrinth Seal Cavities of Supercritical CO<sub>2</sub> Centrifugal Compressors Applied Sciences skin friction coefficient impeller back gap labyrinth seal supercritical CO<sub>2</sub> compressor |
| title | Windage and Leakage Losses in Impeller Back Gap and Labyrinth Seal Cavities of Supercritical CO<sub>2</sub> Centrifugal Compressors |
| title_full | Windage and Leakage Losses in Impeller Back Gap and Labyrinth Seal Cavities of Supercritical CO<sub>2</sub> Centrifugal Compressors |
| title_fullStr | Windage and Leakage Losses in Impeller Back Gap and Labyrinth Seal Cavities of Supercritical CO<sub>2</sub> Centrifugal Compressors |
| title_full_unstemmed | Windage and Leakage Losses in Impeller Back Gap and Labyrinth Seal Cavities of Supercritical CO<sub>2</sub> Centrifugal Compressors |
| title_short | Windage and Leakage Losses in Impeller Back Gap and Labyrinth Seal Cavities of Supercritical CO<sub>2</sub> Centrifugal Compressors |
| title_sort | windage and leakage losses in impeller back gap and labyrinth seal cavities of supercritical co sub 2 sub centrifugal compressors |
| topic | skin friction coefficient impeller back gap labyrinth seal supercritical CO<sub>2</sub> compressor |
| url | https://www.mdpi.com/2076-3417/15/7/3678 |
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