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| Effect of rectifier in the draft tube on flow of hydraulic turbine |
| YANG Lijing1*, YAN Chengming1, ZHANG Jun1, DENG Zhihui2 |
| 1.Guangdong Polytechnic of Water Resources and Electric Engineering, Guangzhou, Guangdong 510635, China; 2.Created Model Design Corporation of Zhongshan City, Zhongshan, Guangdong 528400, China |
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Abstract The internal flow of the draft tube is very complicated. There are various problems with the inside of the draft tube and the turbine because of the asymmetrical pressure distribution of its internal cross-section. A rectifying cylinder having openings at both ends of the front and rear ends is arranged in the channel of the draft tube. The CFD technique is used to simulate the typical working conditions, and the influence of the rectifier on the internal flow of the draft tube is discussed. The results show that under normal operating conditions, the pressure distribution of the outlet section of the draft tube is relatively uniform, and when the diameter of the rectifier cylinder is 1.05D1, the increase of the pressure is most obvious. Under different conditions, the hydrostatic distribution of the center of the inlet cross-section of the draft tube and the pressure distribution of the central axis cross-section are calcula-ted, and the pressure fluctuation of the recording point on the wall surface of the inlet pipe at the inlet is monitored. It is concluded that the rectifier has a positive effect on improving the distribution of the pressure field of the draft tube and inhibiting the effect of cavitation when the diameter of the rectifier cylinder is 1.05D1. The pressure gradient of the axial center is reduced in the draft tube with recti-fier. At the inlet cross-section of the draft tube, the vortex is dispersed and the number is reduced, and the pressure difference between the axial center and the wall surface of draft tube is reduced, and the stability of the flow field of the draft pipe increases.
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Received: 18 September 2017
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| [1]齐继贺. 混流式水轮机尾水管涡带及压力脉动数值模拟[J].水资源与水工程学报,2017(6):168-172. QI Jihe. Numerical simulation of francis turbine draft tube vortex and pressure pulsation[J]. Journal of water resources & water engineering, 2017(6):168-172.(in Chinese)[2]MOTYCAK L, SKOTAK A, OBROVSKY J. Analysis of the Kaplan turbine draft tube effect[J]. Earth and environmental science, 2010,12(1):012038-012047.[3]MADDAHIAN R, CERVANTES M J, SOTOUDEH N. Numerical investigation of the flow structure in a Kaplan draft tube at part load[J]. Earth and environmental science, 2016,49(2):022008-022017.[4]MOHAMED A M, HAMIDOU M K, HAMEL M. Inf-luence of the volute cross-sectional shape on mixed inflow turbine performances[J]. Advances in mechanical engineering, 2017,9(7):1-15. [5]WILHELM S, BALARAC G, METAIS O, et al. Head losses prediction and analysis in a bulb turbine draft tube under different operating conditions using unsteady simulations[J]. IOP comference series:earth environmental science, 2016, 49(2):022010.[6]杨栗晶, 安源, 王幼青,等. 反转双涡轮机械非定常流动与干涉控制[J]. 排灌机械工程学报, 2011, 29(4):307-311. YANG Lijing,AN Yuan,WANG Youqing,et al. Unsteady flow and interaction control of counter-rotating double-rotor turbine [J].Journal of drainage and irrigation machinery engineering,2011,29(4):307-311.(in Chinese)[7]杨栗晶. 双涡轮灯泡贯流式水轮机三维定常流动解析[J]. 水利水电技术, 2012, 43(7):123-126. YANG Lijing.3-D steady flow analysis on double-rotor bulb turbine [J].Water resources and hydropower engineering,2012,43(7):123-126.(in Chinese)[8]HAN Fengqin, YANG Lijing, YAN Shijie,et al.New bulb turbine with counter-rotating tandem-runner[J]. Chinese journal of mechanical engineering, 2012, 25(5):919-925.[9]杨栗晶.一种用于水轮机的尾水管:中国,ZL 2014 2 0291918.1[P].2014-12-26.[10]韩冬冬,于凤荣,张思青. 水泵水轮机水轮机工况全流道三维非定常数值模拟[J].排灌机械工程学报,2017,35(4):325-332. HAN Dongdong,YU Fengrong,ZHANG Siqing.Numerical simulation of unsteady three-dimensional flow in turbine mode of a pump-turbine[J].Journal of drainage and irrigation machinery engineering(JDIME),2017,35(4):325-332.(in Chinese)[11]SOSA J B, URQUIZA G, GARCIA J C,et al. Computational fluid dynamics simulation and geometric design of hydraulic turbine draft tube[J]. Advances in mechanical engineering, 2015,7(10):1-11. |
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