水力机组变负荷过渡过程流体分析及安全评估研究

发布时间：2018-01-13 16:37

本文关键词：水力机组变负荷过渡过程流体分析及安全评估研究　出处：《浙江大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着国民经济的快速发展,水电作为一种最经济的高质量无污染的清洁能源,必将在我国电力系统组成中占据重要的地位,水电行业的发展将会保持持续增长的势头。水力机组在水电站运行中,难免会遇到变负荷过渡过程工况,这将造成机组转速上升和引水系统压力上升,引起机组振动,危及厂房安全。因此,水力机组变负荷过渡过程精确的流体分析及安全评估对于电站的安全稳定运行具有重要的意义。但是这一过程的试验具有危险性高、周期性长和可靠性低等特点,处理不当将会出现机组故障,发生危及人身安全的重大事故。因此,目前广为采用数值模拟安全评估的方法分析过渡过程诸动态工况参数的变化规律,为电站的安全评估提供参考依据。本文以混流式水力机组为研究对象,提出了一种基于静态效率的SE-ICNA内特性数值算法进行变负荷过渡过程安全评估研究。针对变负荷过渡过程工况,通过流体分析建立安全评估的数学模型,包括三大组成部分：管道流动特性线微分方程、水轮机特性方程和转速瞬变规律解析方程。通过不同水位范围实例电站的计算,研究过渡过程动态工况参数变化规律。最后,采用数值模拟方法进行流体分析,分别进行全流道稳态与非稳态的仿真研究,并对尾水管进行了压力脉动分析,完成水力机组全流道安全性评估。通过本文的研究发现SE-ICNA评估方法在中低水位、甩较大负荷的低水头工况小机组范围下表现出良好的计算性能。该方法实现了水力机组变负荷过渡过程安全评估计算,具有良好的工程实践意义。
[Abstract]:With the rapid development of national economy, hydropower, as the most economical clean energy with high quality and no pollution, will play an important role in the composition of power system in China. The development of hydropower industry will maintain the momentum of sustained growth, hydraulic units in the operation of hydropower stations, will inevitably encounter variable load transition process conditions, which will lead to the increase of unit speed and the pressure of the water diversion system. Therefore, the accurate fluid analysis and safety evaluation of hydraulic units during load transition is of great significance to the safe and stable operation of power plants. However, the test of this process has the characteristics of high risk, long periodicity and low reliability. Improper handling will lead to the failure of the unit and the occurrence of serious accidents endangering the personal safety. At present, the method of numerical simulation safety assessment is widely used to analyze the variation law of the dynamic operating conditions parameters during the transition process, which provides a reference for the safety assessment of the power station. This paper takes the Francis hydraulic unit as the research object. This paper presents a numerical algorithm of SE-ICNA internal characteristics based on static efficiency to evaluate the safety of variable load transition process. The mathematical model of safety assessment is established by fluid analysis, which includes three parts: differential equation of pipeline flow characteristic line. The characteristic equation of hydraulic turbine and the analytic equation of transient law of rotational speed. Through the calculation of power station in different range of water level, the variation law of dynamic working condition parameters of transient process is studied. Finally, the fluid analysis is carried out by numerical simulation method. The simulation of steady and unsteady flow channel is carried out, and the pressure pulsation of draft tube is analyzed to evaluate the safety of hydraulic unit. Through the study of this paper, it is found that the SE-ICNA evaluation method is in the low and middle water level. The method has good calculation performance in the range of small units with large load rejection and low head working conditions. This method can realize the safety evaluation calculation of hydraulic units during load transition, which has good engineering practice significance.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TV734

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