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| Analysis of internal flow characteristics of pump-turbine under different openings of misaligned guide vanes |
| LI Qifei1,2, LONG Shican1*, ZHOU Feng1, ZHAO Chaoben1, WEI Xianzhu3 |
| 1. School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; 2. Key Laboratory of Fluid Machinery and Systems, Gansu Province, Lanzhou, Gansu 730050, China; 3. Harbin Institute of Large Electric Machinery, Harbin, Heilongjiang 150040, China |
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Abstract In order to obtain the internal flow characteristics of misaligned guide vanes at different openings, a model of pump-turbine in a turbine storage power station was taken as the research object. Based on SST k-ω turbulence model, the numerical simulation was carried out for fully-three-dimensional unsteady flow field with different openings of guide vanes and compared with the experiment results. The vortex structure between the guide vanes and the runner and inside the runner was discussed, and the force on runner and the pressure fluctuation in draft tube was quantitatively analyzed. The results show that the flow rate of the over current component will increase when the number of pre-opening guide vanes increases, and the high-speed water ring existing in the guide vane and runner area will also follow. The number of pre-opening guide vanes increases and is destroyed, forming a di-sordered turbulence. From the perspective of the runner area, different vortex structures are formed in the liquid passage of the blade. The distribution of these vortex structures is uneven, which directly affects the force of the runner. This situation is more obvious when the number of pre-opening guide vanes increases. As the number of pre-opening guide vanes increases, the amplitude of the radial force of the runner gradually increases. Further analysis of the pressure fluctuation of the draft tube found that the change of the pressure fluctuation of the draft tube was also the same. As the number of pre-opening guide vanes increased, the increase of the pulsation caused the vibration of the unit to intensify, resulting in unstable operation of the unit.
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Received: 17 July 2018
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