| 抽水蓄能机组低水头起动过渡过程压力脉动分析 |
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| 引用本文： | 陈会向,刘汉中,王胤淞,周大庆,徐辉,阚阚.抽水蓄能机组低水头起动过渡过程压力脉动分析[J].农业工程学报,2023,39(6):63-72. |
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| 作者姓名： | 陈会向 刘汉中 王胤淞 周大庆 徐辉 阚阚 |
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| 作者单位： | 1. 河海大学 农业科学与工程学院，南京 211100；2. 河海大学 水利水电学院，南京，210024；;3. 河海大学 能源与电气学院，南京 211100;2. 河海大学 水利水电学院，南京，210024；3. 河海大学 能源与电气学院，南京 211100 |
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| 基金项目： | 国家自然科学基金资助项目（52006053）；江苏省自然科学基金资助项目（BK20200508）；中央高校基本科研业务费资助项目（B220202069）；中国博士后科学基金（2021M690876）；江苏省博士后科研资助计划（2021K498C）。 |
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| 摘 要： | 抽蓄机组在低水头起动时易进入其全特性曲线的反S不稳定区，从而导致机组并网失败，严重影响机组的安全稳定运行。其中机组内部复杂流动演变导致的剧烈压力脉动是影响机组动态特性的关键。该研究基于计算流体动力学（computational fluid dynamics,CFD）数值模拟方法对水泵水轮机低水头起动过程进行研究，重点分析了导叶与尾水管区域的压力脉动特性及产生原因。结果表明：机组起动过程中，无叶区时均压力幅值是固定导叶与活动导叶间的6倍，且时均压力幅值在无叶区沿周向分布不均。动静干涉主导了无叶区时均压力和脉动压力的变化，而在上游固定导叶与活动导叶间的动静干涉作用主要影响的是压力脉动幅值。尾水管直锥段压力脉动在机组起动过程不同阶段表现出不同的波动特征，PID(proportion integration differentiation)调节阶段压力波动较为明显。通过内部流动对比发现，活动导叶开启会引起无叶区水流速度的分布变化和波动，活动导叶小开度下转轮进口和无叶区存在明显的大尺度旋涡，这些和动静干涉联合作用是导致无叶区时均压力和脉动压力波动幅值高的原因。尾水管涡带在起动过程经历了从边条状涡...
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| 关 键 词： | 压力脉动 数值模拟 抽水蓄能机组 过渡过程 低水头起动 |
| 收稿时间： | 2022/10/27 0:00:00 |
| 修稿时间： | 2023/2/24 0:00:00 |
Pressure pulsation during low head start-up transient in a pumped-storage hydropower unit |
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| CHEN Huixiang,LIU Hanzhong,WANG Yinsong,ZHOU Daqing,XU Hui,KAN Kan.Pressure pulsation during low head start-up transient in a pumped-storage hydropower unit[J].Transactions of the Chinese Society of Agricultural Engineering,2023,39(6):63-72. |
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| Authors: | CHEN Huixiang LIU Hanzhong WANG Yinsong ZHOU Daqing XU Hui KAN Kan |
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| Institution: | 1. College of Agricultural Science and Engineering, Hohai University, Nanjing 211100, China; 2. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210024, China;;3. College of Energy and Electrical Engineering, Hohai University, Nanjing 211100, China; 2. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210024, China; 3. College of Energy and Electrical Engineering, Hohai University, Nanjing 211100, China |
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| Abstract: | Abstract: Pumped storage hydropower (PSH) can be focused on the transient stability in the field of energy sources in the world. A great challenge can be the hydraulic instability characteristics of PSH units in the anti-S instability zone. The PSH units are prone to enter the anti-S instability zone during low head start, leading to the failure of the grid connection. There was a serious threat to the safe and stable operation of the units. The severe pressure pulsations can be caused by the complex flow evolution in the dynamic characteristics of the unit. In this study, a computational fluid dynamics (CFD) numerical simulation was introduced to explore the start-up process of a pump turbine at low-head in PSH. Experimental verification was also made on the accuracy of the numerical simulation. A dynamic mesh was used to realize the dynamic opening of the guide vanes. A proportional-integral-differentiation (PID) regulation was also introduced. A closed-loop feedback model was established to regulate the opening of the guide vane using rotational speed fluctuations, in order to realize the simulation of the low-head star-up process of a PSH whole flow system. The numerical simulation was focused on the pressure pulsation characteristics in the area of the guide vane and draft tube. The results show that the numerical simulation was in an excellent agreement with the experimental, and the maximum error does not exceed 10%. The PID regulation model was added to simulate the variation pattern of the active guide vane opening. The strong dynamic and static interaction was caused by the speed of the unit. There were the significant mean pressure changes in the vaneless zone, followed by the speed of the unit. The stator-rotor interaction was dominated the variation of the time-averaged pressure dimensionless amplitude and pulsating pressure dimensionless amplitude in the vaneless zone. By contrast, there were the effects of dynamic and static interference on the pulsation amplitude of the pressure in the upstream. The pressure pulsation signal was evenly distributed over the circumference in the area between the stay vane and the guide vane, whereas, there was the uneven distribution along the circumference in the vaneless area. The vortex near the rotor area first appeared in the center of the blade, and then progressed upstream, eventually forming a stable vortex ring structure at the mid-plane position in the vaneless zone. There were the different fluctuation characteristics in the pressure pulsation in the straight cone section of the draft tube in different stages of the start-up process. The pressure fluctuation was more significant in the PID regulation. The comparison of internal flow revealed that the guide vane opening was caused some changes in the distribution and fluctuations of the velocity in the vaneless zone. Significant large-scale vortices were found in the runner inlet and the vaneless zone at the small guide vane opening. The stator-rotor interaction was combined to be responsible for the high amplitude of the time-averaged pressure and pulsation pressure fluctuations in the vaneless zone. The draft tube vortex rope was ever changing from a side strip vortex rope to a spiral vortex rope, and then to a curtain vortex rope during the start-up process. The persistence and dynamics of the vortex rope were induced the uneven pressure radial distribution. The main reasons were attributed to the drastic pressure fluctuations. The findings can provide a strong reference to improve the success rate of the starting pump-turbine at the low head and connecting to the grid. |
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| Keywords: | pressure pulsation numerical simulation pumped storage hydropower unit transient process low-head start-up process |
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