长有压引水系统水电站水力过渡过程研究

发布时间：2018-05-04 15:09

本文选题：过渡过程 + 特征线法　；参考：《西安理工大学》2017年硕士论文

【摘要】：水电站在运行过程中,由于事故或其它多种原因造成机组甩负荷,导致机组导叶开度迅速变化,进而引发蜗壳内水压力、调压室水位、机组转速等参数的强烈波动,对电站的安全运行造成严重影响。因此,开展水电站水力过渡过程的研究是十分必要的。本文根据过渡过程数值计算的基本原理和实用计算方法,结合工程实际,进行了长引水式水电站水力过渡过程研究,主要内容包括:(1)利用特征线法,建立了水电有压引水系统水力过渡过程的数学分析模型,及多种边界条件,包括进口边界、阻抗式调压室边界、分岔管边界以及水轮机边界等,实现了电站引水系统中水击压力波动与调压室内水位波动的联合计算。(2)从某一长引水式水电站实例出发,对导叶的关闭规律进行了优化,确定了最佳的导叶折线关闭规律;并通过改变导叶的有效关闭时间,探讨了在长引水式水电站中,导叶关闭时间与蜗壳末端最大压力的关系。(3)对水电站的大波动过渡过程进行了计算,得出了机组转速与蜗壳未端压力的变化过程、调压室内水位的波动过程以及隧洞沿线的压力分布。其计算结果表明:在长引水式水电站的大波动过渡过程程中,由于其管道内水流惯性较大,导致调压室内的水位波动周期长且振幅大,蜗壳末端的压力波动出现了明显的主波与尾波之分。(4)对水电站水力干扰过渡过程进行了计算,结果表明:在长引水式水电站中,当同一水力单元的部分机组丢全部负荷后,调压室内的水位波动将在很长时间内对其它运行中的机组产生影响。但是即便如此,调压室水位波动的衰减趋势还是十分明显的,证明该引水发电系统在选取的计算工况下是稳定的。
[Abstract]:During the operation of the hydropower station, the load shedding of the unit is caused by accident or many other reasons, which leads to the rapid change of the guide vane opening degree of the unit, which leads to the strong fluctuation of the parameters such as the water pressure in the volute, the water level of the regulating chamber, the rotational speed of the unit, and so on. It has a serious effect on the safe operation of the power station. Therefore, it is necessary to study the hydraulic transition process of hydropower station. In this paper, according to the basic principle and practical calculation method of numerical calculation of transition process, combined with engineering practice, the hydraulic transition process of long diversion hydropower station is studied. The main content includes the use of characteristic line method. The mathematical analysis model of hydraulic transition process of hydropower pressurized water diversion system is established, and a variety of boundary conditions, including inlet boundary, impedance surge chamber boundary, bifurcation tube boundary and turbine boundary, are established. The combined calculation of surge of water hammer pressure and fluctuation of water level in regulating chamber in water diversion system of power station is realized. Based on an example of a long diversion hydropower station, the closure law of guide vane is optimized, and the best closing law of broken line of guide vane is determined. By changing the effective closing time of the guide vane, the relationship between the guide vane closing time and the maximum pressure at the end of the volute is discussed. The variation process of rotating speed and unend pressure of volute, the fluctuation process of water level in the surge chamber and the pressure distribution along the tunnel are obtained. The calculation results show that in the large wave transition process of long diversion hydropower station, because of the large inertia of water flow in the pipeline, the fluctuation period of water level in the surge chamber is long and the amplitude is large. The pressure fluctuation at the end of the volute case appears obvious main wave and coda wave. The transient process of hydraulic disturbance of hydropower station is calculated. The results show that in the long diversion type hydropower station, when part of the unit of the same hydraulic unit loses its full load, The fluctuation of water level in the surge chamber will affect other units in operation for a long time. But even so, the attenuation trend of water level fluctuation in the surge chamber is very obvious, which proves that the system is stable under the selected calculation conditions.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV732

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