Analysis of flow field in draft tube of pump-turbine during load increasing period
Li Rennian1, Jiang Lei1, Li Qifei1, Han Wei1, Liu Baofu2
1.School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; 2.Qinghai Engineering Construction Branch Office, Yellow River Upstream Hydropower Development Co. Ltd., Xining, Qinhai 810008, China
Abstract:To study the internal transient flow characteristics of the draft tube in a pump-turbine during its load increasing period, the unsteady fluid flow in the pump-turbine is simulated based on the dynamic mesh method in Fluent. According to the simulated results, the transient evolution of flow structure in the draft tube is analyzed extensively. The results show that the relationships of pressure with time are basically similar in the cone and elbow during the period. A sudden increase and remarked fluctuation in static pressure just occurs at the first period of time(0-0.9 s)during the wicket gate opening starting to change. After 0.9 s, the averaged fluctuation in the static pressure is not beyond 9.76 kPa, showing the static pressure remains constant roughly. Besides, a notable vortex rope and a reverse flow structure exist in the draft tube in smaller wicket gate openings, which can easily lead to the instability in operation of the pump-turbine. With the increasing wicket gate opening, the flow in the draft tube becomes steady gradually, suggesting the increase of flow rate can make the flow in the draft tube smoother.
李仁年, 蒋雷, 李琪飞, 韩伟, 刘保福. 水泵水轮机增负荷过程尾水管内流场分析[J]. 排灌机械工程学报, 2015, 33(1): 49-54.
Li Rennian, Jiang Lei, Li Qifei, Han Wei, Liu Baofu. Analysis of flow field in draft tube of pump-turbine during load increasing period. Journal of Drainage and Irrigation Machinery Engin, 2015, 33(1): 49-54.
[1]梅祖彦. 抽水蓄能发电技术[M]. 北京:机械工业出版社,2000.[2]黄涛. 论水电站水力机械过渡过程[J]. 企业科技与发展,2012(15):116-117,120. Huang Tao. On hydraulic mechanical transitional process of hydropower station[J]. Enterprise Science and Technology & Development[J]. 2012(15):116-117,120.(in Chinese)[3]Wang Leqin, Yin Junlian, Jiao Lei, et al. Numerical investigation on the "S" characteristics of a reduced pump turbine model[J]. Science China: Technological Sciences, 2011,54(5):1259-1266.[4]Yin Junlian, Liu Jintao, Wang Leqin, el at. Performance prediction and flow analysis in the vaned distributor of a pump turbine under low flow rate in pump mode[J]. Science China: Technological Sciences, 2010,53(12):3302-3309.[5]李君,王磊,廖伟丽. 可逆式水泵水轮机“S”形区域内部流场特性分析[J]. 农业工程学报,2014,30(15):106-113. Li Jun, Wang Lei, Liao Weili. Internal flow characteristics analysis on S-shaped region of reversible pump-turbine[J]. Transactions of the CSAE, 2014,30(15):106-113.(in Chinese)[6]Ran Hongjuan, Luo Xianwu, Zhu Lei, et al. Experimental study of the pressure fluctuations in a pump turbine at large partial flow conditions[J]. Chinese Journal of Mechanical Engineering, 2012,25(6):1205-1209.[7]王乐勤,刘迎圆,刘万江,等. 水泵水轮机泵工况的压力脉动特性[J]. 排灌机械工程学报, 2013,31(1):7-10,35. Wang Leqin, Liu Yingyuan, Liu Wanjiang, et al. Pressure fluctuation characteristics of pump-turbine at pump mode[J]. Journal of Drainage and Irrigation Machinery Engineering, 2013,31(1):7-10,35.(in Chinese)[8]王乐勤,刘锦涛,张乐福, 等. 水泵水轮机泵工况小流量波动特性[J]. 浙江大学学报:工学版,2011,45(7):1239-1243. Wang Leqin, Liu Jintao, Zhang Lefu, et al. Low flow′s fluctuation characteristics in pump-turbine′s pump mode[J]. Journal of Zhejiang University: Engineering Science, 2011,45(7):1239-1243.(in Chinese)[9]Yin Junlian, Wang Dezhong, Walters D K, et al. Investigation of the unstable flow phenomenon in a pump turbine[J]. Science China Physics, Mechanics & Astronomy, 2014,57(6):1119-1127.[10]Liu Jintao, Liu Shuhong, Sun Yuekun, et al. Three-dimensional flow simulation of transient power interruption process of a prototype pump-turbine at pump mode[J]. Journal of Mechanical Science and Technology, 2013,27(5):1305-1312.[11]李仁年,刘殿兴,董志强,等. 水泵水轮机“S”形区全流道数值模拟[J]. 排灌机械工程学报,2013,31(5):401-405. Li Rennian, Liu Dianxing, Dong Zhiqiang, et al. Numerical analysis of flow in pump-turbine operating in S-shape region[J]. Journal of Drainage and Irrigation Machinery Engineering, 2013,31(5):401-405.(in Chinese)[12]李金伟,刘树红,吴玉林,等. 混流式水轮机飞逸过渡过程的试验与数值模拟[J]. 大电机技术, 2010(6):44-49. Li Jinwei, Liu Shuhong, Wu Yulin, et al. 3D unsteady turbulence simulation of the runaway transients of the francis turbine[J]. Large Electric Machine and Hydraulic Turbine, 2010(6):44-49.(in Chinese)[13]周大庆,钟淋涓,郑源,等. 轴流泵装置模型断电飞逸过程三维湍流数值模拟[J]. 排灌机械工程学报, 2012,30(4):401-406. Zhou Daqing, Zhong Linjuan, Zheng Yuan, et al. Numerical simulation of transient flow in axial-flow pump unit model during runaway caused from power failure[J]. Journal of Drainage and Irrigation Machinery Engineering, 2012,30(4):401-406.(in Chinese)[14]周大庆,张蓝国. 抽水蓄能电站泵工况断电过渡过程数值试验[J]. 华中科技大学学报: 自然科学版, 2014,42(2):16-20. Zhou Daqing, Zhang Languo. Numerical experiments in power-off transient process of pumped storage power station under pump condition[J]. J Huazhong Univ of Sci & Tech: Natural Science Edition, 2014,42(2):16-20.(in Chinese)[15]Hellström J G I, Marjavaara B D, Lundström T S. Parallel CFD simulations of an original and redesigned hydraulic turbine draft tube[J]. Advances in Engineering Software, 2007,38(5):338-344.[16]王正伟,周凌九,黄源芳. 尾水管涡带引起的不稳定流动计算与分析[J]. 清华大学学报: 自然科学版, 2002,42(12):1647-1650. Wang Zhengwei, Zhou Lingjiu, Huang Yuanfang. Simulation of unsteady flow induced by in vortices the draft tube of a Francis turbine[J]. Journal of Tsinghua University: Science and Technology, 2002,42(12):1647-1650.(in Chinese)[17]郑源,汪宝罗,屈波. 混流式水轮机尾水管压力脉动研究综述[J]. 水力发电, 2007,33(2):66-69. Zheng Yuan, Wang Baoluo, Qu Bo. Study on the pressure pulse in the draft tube of francis turbine[J]. Water Power, 2007,33(2):66-69.(in Chinese)