钱塘江饮用水源地盐水入侵及数值模拟

发布时间：2018-01-03 01:28

本文关键词：钱塘江饮用水源地盐水入侵及数值模拟　出处：《浙江大学》2013年硕士论文　论文类型：学位论文

【摘要】：钱塘江为我国典型的强潮河流,拥有举世闻名的钱塘江涌潮,强劲的潮流作用使咸水向上游入侵甚远。水源地受到盐水入侵的影响频繁,氯度超标严重,原水水质难以保证。尤其在枯水大潮期,盐水入侵不同程度地影响着钱塘江饮用水源地的自来水厂及诸多取水口的水质。因此,通过实测资料的分析和数值模拟相结合的方法研究钱塘江河口饮用水源地的盐水入侵问题,不仅有助于改善杭州市的水环境质量,同时对于提高居民健康水平、构建和谐社会、促进社会经济可持续发展具有十分重要的意义。本文利用钱塘江河口沿岸8个测站2012年实时监测的氯度资料,分析氯度随时间和空间的变化规律及其影响因素,结果表明潮汐和径流对水源地的氯度值、氯度的时间变化率、日潮不等现象、日超标时间、氯度峰谷值滞后潮位峰谷值的时间等都有着巨大的影响。闸口站氯度是否超标主要由潮差、径流以及初始氯度三方面因素共同决定,当澉浦潮差大于7.5m,上游富春江下泄流量为枯水径流量,初始氯度值大于100mg/L时,饮用水源地可能发生氯度超标的情况。每年的8-11月饮用水源地盐水入侵较为严重。本文基于Navier-Stokes方程和盐度输移方程,采用有限体积法进行离散,建立了二维水动力盐度数学模型,对闻家堰至仓前河段的潮流及盐度输移进行数值模拟,研究在不同径潮流组合下盐水入侵的程度。研究结果显示,大潮-平水径流、大潮-枯水径流以及小潮-枯水径流组合都有可能发生水源地盐度超标的现象。当枯水径流时,通过增加径流量对盐水入侵的抑制作用非常明显,当流量大于500m3/s时,增加相同的流量对盐水入侵的抑制作用逐渐减弱,丰水径流时可忽略盐水入侵对水源地的影响作用。在一个潮周期中七堡涨憩时刻和落急时刻之间的时间段是水源地盐水入侵最严重的。本文的研究成果可为饮用水源地取水口的设置以及取水方案的选择提供理论依据。
[Abstract]:Qiantang River is a typical strong tidal river in our country. It has the world-famous Qiantang River tidal current. The strong tidal current causes the salt water to invade upstream far away. The water source area is frequently affected by salt water intrusion, and the chlorine degree exceeds the standard seriously. It is difficult to guarantee the raw water quality. Especially in the low tide period, the salt water intrusion affects the water quality of the drinking water plant and many water intake in the Qiantang River drinking water source to varying degrees. Through the analysis of the measured data and numerical simulation, the study of saline intrusion in the drinking water source of Qiantang River estuary is not only helpful to improve the quality of water environment in Hangzhou, but also to improve the health level of residents. It is of great significance to build a harmonious society and promote the sustainable development of social economy. In this paper, the variation of chlorine with time and space and its influencing factors are analyzed by using the chlorine data of 8 stations in the Qiantang River estuary on 2012. The results show that the chlorine value of the water source, the time variation rate of the chlorine degree, the phenomenon of diurnal tide inequality, and the daily exceeding standard time of the tide and runoff. The time of chlorinity peak and valley value lags behind tide level peak and valley value has a great influence. Whether the chlorine degree of gate station exceeds the standard is mainly determined by three factors: tidal range, runoff and initial chlorine degree, when the tidal difference is greater than 7.5 m. The discharge of the upstream Fuchun River is dry water runoff, when the initial chlorine value is more than 100 mg / L. The drinking water source may have the situation that the chlorine content exceeds the standard. The salt water intrusion of drinking water source is more serious in August and November of each year. In this paper, based on Navier-Stokes equation and salinity transport equation, a two-dimensional hydrodynamic salinity mathematical model is established by using finite volume method. Numerical simulation of tidal current and salinity transport in Wenjiayan-Cangqian reach is carried out to study the degree of salt water intrusion under different diameters of tidal current combination. The combination of spring tide and low water runoff and the combination of low tide and low water runoff may occur the phenomenon that the salinity of the water source exceeds the standard. When the runoff is low, the inhibition effect on salt water intrusion is very obvious by increasing the runoff volume. When the flow rate was greater than 500 m3 / s, the inhibitory effect of increasing the same flow rate on salt water intrusion was gradually weakened. The influence of brine intrusion on water source can be neglected during high water runoff. The time period between the rising and resting time and falling time in a tidal cycle is the most serious in the water source area. The results of this paper can be used as drinking water. The setting of water intake and the selection of water intake plan provide theoretical basis.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU991.11

【参考文献】