城市输配水管网水质变化的动态模拟

【作者】 李斌；

【导师】 许仕荣；

【作者基本信息】 湖南大学 ， 市政工程， 2002， 硕士

【摘要】 经给水水质净化厂处理后的合格的生活饮用水，在经过复杂的城市输配水管网，输送到用户时，可能会有明显的水质恶化，从而使水质不合格。为了改善管网的水质，加强对管网水质的运行管理，有必要充分了解水质在管网中的时空分布情况。 论文首先论述了两种在输配水管网中选择水质监测采样点的优化方法。一种方法是基于DC(监测水量)的优化；另一种是基于DD(有效监测范围)的优化。利用优化选址的方法所选择的水质监测点，对整个管网水质的时空分布将更具有代表性，有利于对管网水质数据可靠性的定量分析。 论文的第二部分，对水质在输配水管网中变化的数学模型作了讨论。详细论述了余氯和总三卤甲烷两种主要水质指标物质的在管网中变化的机理模型。其中，余氯的机理模型是余氯在水体中衰减和与管壁发生反应两个消耗管网中余氯的主要途径的组合。余氯在水体中的衰减分别用一阶和二阶的形式作了描述。 在论文的第三部分，论述了动态模拟管网水质变化模拟算法的实现。论文采用的是适用于离散动态系统的事件驱动模拟算法。事件驱动模拟算法通过对管网水力水质变化的离散产生事件，然后用事件的发生来驱动动态模拟过程的自动推进。事件驱动算法便于用计算机实现，相对传统的算法，体现出较好的计算时间效率。 最后，论文给出了一个计算实例。运用论文中介绍的各水质变化流态模型、机理模型和模拟算法，实现了对实例管网的水质变化动态模拟，其模拟结果与实测值体现出良好的吻合性。更多还原

【Abstract】 Water quality although acceptable when it leaves the treatment plant may deteriorate before it reaches the users through drinking water distribution netwok. In the planning and control of water quality in distribution systems, it is useful to know the time history and eventual spatial distribution of water quality substances in the network.Firstly, two methodologies for finding the optimal layout of a detection system in a municipal water network is formulated and demonstrated. One is based on the concept of DC (demand coverage), the other is based on DD(detected domain). Water quality data collected from these monitoring stations can be more representative in indicating the characteristic of water quality in the distribution network.Then models of flow modality and deterioration kinetics of waterborne substances in distribution network are discussed. Models of chlorine residual kinetics characterize chlorine decay as a combination of first-order or second-order decay in the bulk liquid and first-order decay reactions at the pipe wall. This paper also presented a model that predicts total trihalomethanes(TTHMs) based on the consumption of chlorine.To model the contaminant transport problem in drinking water distribution systems, an event-driven method is proposed in the third part of the thesis. The solution of the time varying water quality problem is obtained in an event-oriented system simulation framwork that determines the optimal pipe segmentation scheme with the smallest number of segments necessary to carry out the simulation process. It is predicated on the material mass balance accounting for transport and kinetics reaction process. Perfect advective one-dimensional displacement with complete mixing of material at the network nodes is assumed.finally, the performance of the methods presented above is demonstrated by application to an example water distribution network. The modeling outcome shows good correspondence with observed field data.更多还原