Effect of Seal Locations of Pump-Turbine on Axial Hydraulic Trust
Axial hydraulic thrust is an important factor that affects safety and stability of pump turbine operation. Research and analysis of axial hydraulic thrust is of a great significance for guiding the safe and stable operation of a pumped storage power station. Since the runner shape of the pump turbin...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-06-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/9/6/623 |
| _version_ | 1797531478170533888 |
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| author | Huifang Sun Yue Lv Jinbing Ni Xianyu Jiang Zhengwei Wang |
| author_facet | Huifang Sun Yue Lv Jinbing Ni Xianyu Jiang Zhengwei Wang |
| author_sort | Huifang Sun |
| collection | DOAJ |
| description | Axial hydraulic thrust is an important factor that affects safety and stability of pump turbine operation. Research and analysis of axial hydraulic thrust is of a great significance for guiding the safe and stable operation of a pumped storage power station. Since the runner shape of the pump turbine is flat and its radial dimension is large, an increase of leakage can happen easily. In order to reduce the leakage and improve the efficiency of the unit, a labyrinth ring seal is usually used in the upper crown and lower ring of the runner because the inner clearance of the seal has a great influence on the axial thrust. In order to study the influence of the change of labyrinth seal position on axial hydraulic thrust, a fluid domain model with a pressure balance pipe, upper crown clearance, and lower ring clearance is established for a pump turbine of a power station. The distribution position of labyrinth ring in the upper crown clearance is changed. The CFD numerical simulations are carried out under both 100% working load and 75% working load of turbine conditions, considering the flow in clearance areas. The research results of this paper have found that the axial hydraulic thrust of the 100% load condition is consistent with the change of the gap position compared with the 75% load condition. The amplitude of the change of the water thrust under the 100% load condition is greater. As the sealing position of the labyrinth ring in the upper crown gap moves away from the central axis, the resultant vertical and upward water thrust increases, and the operating efficiency of the unit first increases and then decreases. As the position of the labyrinth ring seal in the upper ring clearance moves away from the central axis, the resultant vertical and upward water thrust increases, and the operating efficiency of the unit first increases and then decreases. Defining the radial dimension ratio δ between the front clearance area and the total area of labyrinth ring, the closer δ is to 0.5, the unit efficiency is higher; the smaller that δ is, then the high pressure area in the upper crown clearance is smaller, and the hydraulic thrust force increases vertically. Considering a variety of factors, the clearance seal position has the optimal value. In the practical application of the project, the condition of excessive upward hydraulic thrust leading to the lifting of the unit can be avoided, and the phenomenon of excessive downward hydraulic thrust leading to the excessive load-bearing of the frame is evitable. |
| first_indexed | 2024-03-10T10:44:22Z |
| format | Article |
| id | doaj.art-de54094806cb47ef8a710e53c1e58ee8 |
| institution | Directory Open Access Journal |
| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-10T10:44:22Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-de54094806cb47ef8a710e53c1e58ee82023-11-21T22:44:41ZengMDPI AGJournal of Marine Science and Engineering2077-13122021-06-019662310.3390/jmse9060623Effect of Seal Locations of Pump-Turbine on Axial Hydraulic TrustHuifang Sun0Yue Lv1Jinbing Ni2Xianyu Jiang3Zhengwei Wang4Pumped-Storage Technological & Economic Research Institute, State Grid Xin Yuan Company Ltd., Beijing 100761, ChinaCollege of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, ChinaPumped-Storage Technological & Economic Research Institute, State Grid Xin Yuan Company Ltd., Beijing 100761, ChinaPumped-Storage Technological & Economic Research Institute, State Grid Xin Yuan Company Ltd., Beijing 100761, ChinaDepartment of Energy and Power Engineering, Tsinghua University, Beijing 100084, ChinaAxial hydraulic thrust is an important factor that affects safety and stability of pump turbine operation. Research and analysis of axial hydraulic thrust is of a great significance for guiding the safe and stable operation of a pumped storage power station. Since the runner shape of the pump turbine is flat and its radial dimension is large, an increase of leakage can happen easily. In order to reduce the leakage and improve the efficiency of the unit, a labyrinth ring seal is usually used in the upper crown and lower ring of the runner because the inner clearance of the seal has a great influence on the axial thrust. In order to study the influence of the change of labyrinth seal position on axial hydraulic thrust, a fluid domain model with a pressure balance pipe, upper crown clearance, and lower ring clearance is established for a pump turbine of a power station. The distribution position of labyrinth ring in the upper crown clearance is changed. The CFD numerical simulations are carried out under both 100% working load and 75% working load of turbine conditions, considering the flow in clearance areas. The research results of this paper have found that the axial hydraulic thrust of the 100% load condition is consistent with the change of the gap position compared with the 75% load condition. The amplitude of the change of the water thrust under the 100% load condition is greater. As the sealing position of the labyrinth ring in the upper crown gap moves away from the central axis, the resultant vertical and upward water thrust increases, and the operating efficiency of the unit first increases and then decreases. As the position of the labyrinth ring seal in the upper ring clearance moves away from the central axis, the resultant vertical and upward water thrust increases, and the operating efficiency of the unit first increases and then decreases. Defining the radial dimension ratio δ between the front clearance area and the total area of labyrinth ring, the closer δ is to 0.5, the unit efficiency is higher; the smaller that δ is, then the high pressure area in the upper crown clearance is smaller, and the hydraulic thrust force increases vertically. Considering a variety of factors, the clearance seal position has the optimal value. In the practical application of the project, the condition of excessive upward hydraulic thrust leading to the lifting of the unit can be avoided, and the phenomenon of excessive downward hydraulic thrust leading to the excessive load-bearing of the frame is evitable.https://www.mdpi.com/2077-1312/9/6/623pump turbineclearance seal positionhydraulic efficiency changeaxial hydraulic thrust |
| spellingShingle | Huifang Sun Yue Lv Jinbing Ni Xianyu Jiang Zhengwei Wang Effect of Seal Locations of Pump-Turbine on Axial Hydraulic Trust Journal of Marine Science and Engineering pump turbine clearance seal position hydraulic efficiency change axial hydraulic thrust |
| title | Effect of Seal Locations of Pump-Turbine on Axial Hydraulic Trust |
| title_full | Effect of Seal Locations of Pump-Turbine on Axial Hydraulic Trust |
| title_fullStr | Effect of Seal Locations of Pump-Turbine on Axial Hydraulic Trust |
| title_full_unstemmed | Effect of Seal Locations of Pump-Turbine on Axial Hydraulic Trust |
| title_short | Effect of Seal Locations of Pump-Turbine on Axial Hydraulic Trust |
| title_sort | effect of seal locations of pump turbine on axial hydraulic trust |
| topic | pump turbine clearance seal position hydraulic efficiency change axial hydraulic thrust |
| url | https://www.mdpi.com/2077-1312/9/6/623 |
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