Clearance flow patterns and pressure distribution of a pump-turbine: Measurement and simulation of a rotating disk flow
The clearance flow patterns and pressure distribution determine the clearance axial hydraulic thrust of a pump turbine, which has a substantial impact on the unit axial imbalance. However, due to the tiny size and complex shape of the clearance flow channel, there is no detailed description of the f...
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| Format: | Article |
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Frontiers Media S.A.
2022-08-01
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| Series: | Frontiers in Energy Research |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fenrg.2022.910834/full |
| _version_ | 1818515068564799488 |
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| author | Xiaoxia Hou Herui Liu Yongguang Cheng Ke Liu Demin Liu Hongyu Chen |
| author_facet | Xiaoxia Hou Herui Liu Yongguang Cheng Ke Liu Demin Liu Hongyu Chen |
| author_sort | Xiaoxia Hou |
| collection | DOAJ |
| description | The clearance flow patterns and pressure distribution determine the clearance axial hydraulic thrust of a pump turbine, which has a substantial impact on the unit axial imbalance. However, due to the tiny size and complex shape of the clearance flow channel, there is no detailed description of the flow patterns and pressure characteristics. In this study, we conducted a model test with particle image velocimetry (PIV) measurements and CFD simulation of a rotating disk flow that was a simplified model of the pump-turbine clearance flow. It is shown that a typical Batchelor flow is formed in the clearance region, demonstrating a “core region + double-boundary layers” distribution for the circumferential velocity along the clearance height direction; the core region rotates at a speed of only around 41–42% of the rotating disk speed and is independent of the clearance inlet pressure and clearance height. Driven by centrifugal force, the flow is radially outward around the rotating disk, while inward around the stationary disk in the meridian section, showing secondary flow vortices. The pressure in the clearance region has a circumferentially symmetric and radially quadratic distribution. Based on the liquid differential equilibrium equation and core region circumferential velocity, the pressure and clearance axial hydraulic thrust in the clearance region can be expressed as a function of the clearance inlet pressure and the square of the runner rotating speed. These findings can be used to investigate axial force imbalance issues of the pump-turbine unit. |
| first_indexed | 2024-12-11T00:24:12Z |
| format | Article |
| id | doaj.art-6fe47173e678418b8b3ad52b32eae0b2 |
| institution | Directory Open Access Journal |
| issn | 2296-598X |
| language | English |
| last_indexed | 2024-12-11T00:24:12Z |
| publishDate | 2022-08-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Energy Research |
| spelling | doaj.art-6fe47173e678418b8b3ad52b32eae0b22022-12-22T01:27:37ZengFrontiers Media S.A.Frontiers in Energy Research2296-598X2022-08-011010.3389/fenrg.2022.910834910834Clearance flow patterns and pressure distribution of a pump-turbine: Measurement and simulation of a rotating disk flowXiaoxia Hou0Herui Liu1Yongguang Cheng2Ke Liu3Demin Liu4Hongyu Chen5State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, ChinaState Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, ChinaState Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, ChinaState Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, ChinaDongfang Electric Machinery Co., Ltd, Deyang, ChinaCSG Power Generation Co., Ltd., Guangzhou, ChinaThe clearance flow patterns and pressure distribution determine the clearance axial hydraulic thrust of a pump turbine, which has a substantial impact on the unit axial imbalance. However, due to the tiny size and complex shape of the clearance flow channel, there is no detailed description of the flow patterns and pressure characteristics. In this study, we conducted a model test with particle image velocimetry (PIV) measurements and CFD simulation of a rotating disk flow that was a simplified model of the pump-turbine clearance flow. It is shown that a typical Batchelor flow is formed in the clearance region, demonstrating a “core region + double-boundary layers” distribution for the circumferential velocity along the clearance height direction; the core region rotates at a speed of only around 41–42% of the rotating disk speed and is independent of the clearance inlet pressure and clearance height. Driven by centrifugal force, the flow is radially outward around the rotating disk, while inward around the stationary disk in the meridian section, showing secondary flow vortices. The pressure in the clearance region has a circumferentially symmetric and radially quadratic distribution. Based on the liquid differential equilibrium equation and core region circumferential velocity, the pressure and clearance axial hydraulic thrust in the clearance region can be expressed as a function of the clearance inlet pressure and the square of the runner rotating speed. These findings can be used to investigate axial force imbalance issues of the pump-turbine unit.https://www.frontiersin.org/articles/10.3389/fenrg.2022.910834/fullpump turbineclearance axial hydraulic forceclearance pressure distributionclearance flow patternscircumferential velocity core regionrotating disk flow |
| spellingShingle | Xiaoxia Hou Herui Liu Yongguang Cheng Ke Liu Demin Liu Hongyu Chen Clearance flow patterns and pressure distribution of a pump-turbine: Measurement and simulation of a rotating disk flow Frontiers in Energy Research pump turbine clearance axial hydraulic force clearance pressure distribution clearance flow patterns circumferential velocity core region rotating disk flow |
| title | Clearance flow patterns and pressure distribution of a pump-turbine: Measurement and simulation of a rotating disk flow |
| title_full | Clearance flow patterns and pressure distribution of a pump-turbine: Measurement and simulation of a rotating disk flow |
| title_fullStr | Clearance flow patterns and pressure distribution of a pump-turbine: Measurement and simulation of a rotating disk flow |
| title_full_unstemmed | Clearance flow patterns and pressure distribution of a pump-turbine: Measurement and simulation of a rotating disk flow |
| title_short | Clearance flow patterns and pressure distribution of a pump-turbine: Measurement and simulation of a rotating disk flow |
| title_sort | clearance flow patterns and pressure distribution of a pump turbine measurement and simulation of a rotating disk flow |
| topic | pump turbine clearance axial hydraulic force clearance pressure distribution clearance flow patterns circumferential velocity core region rotating disk flow |
| url | https://www.frontiersin.org/articles/10.3389/fenrg.2022.910834/full |
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