基于供水管网建模的管网改造方案研究

针对吉林省某市江北供水管网,论述了基于供水管网建模制定改造方案的方法和步骤。结果表明,在最高日最高时工况下,节点压力不低于20mH_2O的节点数占72.1%,基本能够满足用水压力要求,但管网北部末端存在压力小于10mH_2O的低压区。分析发现,该区管网靠近水厂处有3段管共长1.47km,水头损失达15mH_2O,严重制约了供水压力。鉴于这些管段敷设年代久远,建议更换为管径更大的新管。水力模拟表明,改造以后这三段管的总水头损失为5.5mH_2O,降低到改造前的36.7%,97%的管网节点压力达到了20mH_2O以上。     

基于遗传算法参数优化的供水管网模型研究

提出一种基于遗传算法参数优化的管网模型建立方法,将现代控制方法与传统力学模型相结合计算管网的局部水头损失和沿程水头损失。分别运用BP算法模型和基于遗传算法优化的海澄威廉模型对结构简单的供水管道网络实例进行管道仿真和比较,结果证实基于遗传算法优化管道模型参数方法既保证了模型的稳定性,又能提高模型的精度,同时降低了模型建立的复杂度。     

供水管网系统微观模型综合工况分析

在分析微观模型基本理论及其对供水管网系统进行模拟的基础上,为便于计算机对供水管网系统进行水力模拟,提出将供水管网系统中几大特殊系统组件包括供水泵站、加压泵、蓄水池、阀门等的工况特性描述为节点和管段工况特性模式的供水管网图。建立了连续性方程的一般形式,给出了节点水压法求解工况模型的思路。最后对管网系统进行工况分析,为管网运行调度及研究水质模型打下良好的基础。     

南方丘陵地区城乡一体化供水管网规划研究

针对丘陵地区城镇供水管网的特点,提出了管网规划中控制点和最小服务水头的选取方法,应用EPANET建立管网规划模型,分析了管网的分区供水及增压方式选择等问题,通过模拟计算对管网进行优化调整,确定城乡间联络管直径,并分析了城乡间调水的可行性。     

天津市给水管网动态水质模拟系统

通过实验室试验和现场测试,建立了生长环作用下的实际管网水质数学模型,在水力模拟的基础上,进行模型求解与分组校核,实现了天津市给水管网水质动态模拟,模拟参数包括水龄、余氯和三卤甲烷。针对管网中可能发生的污染事件,实现了水质路径诊断。     

基于枝干模型的喷灌管网水力计算分析

喷灌管网水力学计算是喷灌管网水力学设计的关键环节,针对逐级迭代法在求解管网水头损失时,存在计算过程复杂、计算量大的问题,该文提出了基于优化喷灌管网布置和管道工程计算的枝干模型。模型利用节点矩阵的方法,分析单一管元系统的管元阻力系数K_i;结合节点连续性方程、管元方程及辅助方程,简化管网水力计算,精准求解管网水头损失。运用枝干模型算法对喷灌机组进行水力计算,并进行验证。结果表明：模型计算系统水头损失与实际值的相对误差绝对值为2.7%,计算值与实际值吻合,验证了模型的准确性。枝干模型为解决喷灌管网水力计算提供参考。     

北京市某区供水管网水质变化研究及模拟

管网水质稳定性是安全供水的一个重要问题,因此需要研究管网中水质变化规律。由于管道的封闭性,通常很难进行大面积管网水质监测。管网水力与水质模型为研究管网水质变化提供有力支持。通过实际监测和实验室内管段模拟试验分析了北京市某区供水管网中水质变化的规律,建立了供水管网水力水质模型,并应用建立的模型模拟了该区管网水质的变化过程。     

EPANET 模型在再生水管网规划设计中的应用

在北京市再生水管网规划设计中,通过GIS建立规划管网的EPANET水力模型,消除了管网多水源供水、回用范围大、环状支状管网混合、结构复杂对水力计算的不利影响.并且针对水力计算结果--节点压力、管段流速和水力坡降(水头损失)进行分析,通过调整初始设计管径不合理的管段管径以及根据北京市地形分布将再生水管网划分为4个弱连接的供水分区,解决了再生水厂多数集中在地形较低的东部地区和大范围回用高程变化所带来的管网压力过高的问题,提高了管网设计的合理性,降低了管网的投资和运行成本.研究中应用的方法和过程具有通用性,可以用于有压给水、再生水管网系统的模拟.     

上海市自来水市北公司供水管网信息化建设与展望

上海自来水市北有限公司建立了管网GIS综合应用系统、水力动态模拟系统及SCADA在线监测系统.针对目前供水管网信息化建设中存在的实际问题,进行了供水管网信息化的发展规划.提出了完善SCADA系统,整合GIS资源和管网水力模拟系统,发展管网水质模拟系统及资产管理系统,健全各部门信息化资源共享制度的规划方案.     

基于物联网监测的供水管网分区建模技术研究

供水管网水力模型已经成为供水企业科学化管理不可缺少的工具,常规的模型建设思路都是针对整个供水管网系统进行建立,建模过程繁琐、周期长、更新维护困难,在实际运用中效果并不理想。结合日趋完善的物联网技术,提出了基于物联网监测的城市供水系统分区建模技术,并以实际供水企业的城区供水管网为研究对象,系统地阐述了供水管网"分区建模"的设计理念与实施方法,然后建立管网水力模型,不仅保证模型的精度,也提升了模型后期更新维护的效率。基于物联网监测的"分区建模"方法已应用于北方某水司管网日常调度和管理中,并取得了良好的效果,可为其他城市供水管网系统模型建立和管理提供技术借鉴。     

小流域产流汇流模型试验的应用研究

在降雨１：１相似的小流域产汇流模型试验中，不仅产流发生畸变，而且汇流畸变作用更大。本文旨在通过对降雨径流形成及土壤入渗动态方程的推导，分析，实际产流方式与模型产流方式的异同，引入模型产流畸变系数，导出模型试验结果的应用转换函数。在此基础上，又从线性汇流理论出发，依据推理公式，求得实际与模型试验最大洪峰流量及汇流时间之间的畸变关系。该研究使模型试验结果与原型趋于吻合，为小流域治理和水土保持工程设计提供了依据。     

Noniterative Implementation of Pressure-Dependent Demands Using the Hydraulic Analysis Engine of EPANET 2

To analyze water distribution networks under pressure-deficient conditions, most of the available hydraulic simulators, including EPANET 2, must be either modified by embedding pressure-dependent demands in the governing network equations or run repeatedly with successive adjustments made to specific parameters until a sufficient hydraulic consistency is obtained. This paper presents and discusses a simple technique that implements the square root relationship between the nodal demand and the nodal pressure using EPANET 2 tools and allows a water distribution network with pressure-dependent demands to be solved in a single run of the unmodified snapshot hydraulic analysis engine of EPANET 2. In this technique, artificial strings made up of a flow control valve, a pipe with a check valve, and a reservoir are connected to the demand nodes before running the engine, and the pressure-dependent demands are determined as the flows in the strings. The resistance of the artificial pipes is chosen such that the demands are satisfied in full at a desired nodal pressure. The proposed technique shows reasonable convergence as evidenced by its testing on example networks.     

Evolving Effective Hydraulic Model for Municipal Water Systems

Constructing a robust hydraulic network model is vitally important, but a time-consuming task. Over last two decades, several approaches using optimization techniques have been developed for identifying model parameters. Although most of the methods can make the model agree with field observations, few are able to achieve a good level of accuracy in terms of determining the correct model parameters for a water distribution system. The previously developed methods appear to be lacking versatility for users to specify calibration tasks given real data for a real system. This paper proposes a comprehensive framework for evolving a hydraulic network model. Calibration tasks can be specified according to data availability and model application requirements. It allows an engineer to (1) flexibly choose any combination of the model parameters such as pipe roughness, junction demand and link (pipes, valves and pumps) operational status; (2) easily aggregate model parameters to reduce the problem dimension for expeditious calculation and (3) consistently specify boundary conditions and junction demand loadings that are corresponding to field data collection. A model calibration is then defined as an implicit nonlinear optimization problem, which is solved by employing a competent evolutionary algorithm. With this methodology, a modeler can be fully assisted to carry out not only a single parameter optimization run, but also a variety of calibration tasks in a progressive manner according to practical system conditions, thus it is possible to achieve a good model calibration with high level of confidence. The method has been applied to the model of a municipal water system to demonstrate the efficacy and robustness of the evolutionary modeling practices.     

Three-dimensional stochastic seepage field for embankment engineering

Owing to the complexity of get-engineering seepage problems influenced by different random factors, three-dimensional simulation and analysis of the stochastic seepage field plays an important role in engineering applications. A three-dimensional anisotropic heterogeneous steady random seepage model was developed on the basis of the finite element method. A statistical analysis of the distribution characteristics of soil parameters sampled from the main embankment of the Yangtze River in the Southern Jingzhou zone of China was conducted. The Kolomogorov-Smimov test verified the statistical hypothesis that the permeability coefficient tensor has a Gaussian distribution. With the help of numerical analysis of the stochastic seepage field using the developed model, various statistical and random characteristics of the stochastic seepage field of the main embankment of the Yangtze River in the Southern Jingzhou zone of China were investigated. The model was also examined with statistical testing. Through the introduction of random variation of the upstream and downstream water levels into the model, the effects of the boundary randomness due to variation of the downstream and upstream water levels on the variation of simulated results presented with a vector series of the random seepage field were analyzed. Furthermore, the combined influence of the variation of the soil permeability coefficient and such seepage resistance measures as the cut-off wall and relief ditch on the hydraulic head distribution was analyzed and compared with the results obtained by determinate analysis. Meanwhile, sensitivities of the hydraulic gradient and downstream exit height to the variation of boundary water level were studied. The validity of the simulated results was verified by stochastic testing and measured data. The developed model provides more detail and a full stochastic algorithm to characterize and analyze three-dimensional stochastic seepage field problems.     

冷却塔中配水的试验研究

本文给出了一个冷却塔的配水模型试验结果。我国过去多采用槽式配水，现在多采用管式配水。此试验为槽、管结合型，试验结果与原体很一致。由于配水网的复杂性，水力计算很难算准，本文可作为设计计算的参考。     

小湾水电站泄洪洞窄缝挑坎数值模拟研究

窄缝挑坎在水利工程中应用广泛,但尚无成熟的设计方法,工程设计中窄缝主要参照类似工程初拟体型,并经模型试验优化后最终定型。但模型试验存在耗时长、费用高、常规仪器测量精度较低的不足。采用RNG k-ε紊流模型,利用Flow 3D独特的FAVOR网格技术,对小湾水电站泄洪洞窄缝挑坎进行三维数值模拟研究。模拟结果表明窄缝挑坎内水深、水舌形态、水舌前后入水点、水舌最高点及起跳角度等计算结果与模型试验、原型观测值基本一致。表明Flow 3D数值模拟研究方法可作为窄缝挑坎设计的一种方法,并可节省时间和工程费用,优势显著。     

南水北调东线淮安二站泵装置模型试验研究

泵装置模型试验是检验和优化泵装置水力性能的重要手段。根据南水北调东线工程淮安第二抽水站的改造需要,为了进一步检验预测泵装置的水力性能,在河海大学水力机械多功能试验台上对淮安第二抽水站立式全调节轴流泵装置进行了能量、空化以及飞逸转速等方面的试验研究。试验结果表明,装置在水泵工况和飞逸工况下均能够安全、稳定地运行,而且也能够满足淮安第二抽水站改造的设计要求。对研究背景、该泵站的主要技术参数、试验的主要内容及其不确定度分析,装置模型的主要参数和试验条件、水泵工况模型的试验结果、原型装置的飞逸转速、原型的换算条件及结果等情况进行了介绍。     

混凝土渠道糙率原型观测

糙率是渠道水力设计的关键技术参数之一，其值的准确选取决于已建工程原型观测成果的类比。选择3条不同衬砌特性的混凝土渠道进行糙率原型观测，对观测方法及步骤做了较详细描述；计算出了3条渠道的糙率，对其存在误差进行了分析探讨，可为今后进一步开展相关课题研究积累经验并供同行参考。     

水工定床模型相似度的研究

对水工定床模型相似性的分析可量化为模型相似度的比较。模型系统与原型系统之间的相似在于二者之间有若干个相似元。各相似元的相似值等于特征值比例系数和相应的特征权数的乘积。相似元的相似值总和为二者之间的相似度，即二者之间相似性的度量。水工定床模型系统与原型系统之间的相似性由十个相似元构成。根据这一理论，本文分析了模型的几何变形对流速、压强和相应场产生的变态效应，并以算例分析了变态率和几何比尺对水工定床模型相似度的影响。结果表明相似度量化评估有利于提高模型的相似性，水工定床模型宜多采用大比尺。     

Pressure Management Model for Urban Water Distribution Networks

A technique for leakage reduction is pressure management, which considers the direct relationship between leakage and pressure. To control the hydraulic pressure in a water distribution system, water levels in the storage tanks should be maintained as much as the variations in the water demand allows. The problem is bounded by minimum and maximum allowable pressure at the demand nodes. In this study, a Genetic Algorithm (GA) based optimization model is used to develop the optimal hourly water level variations in a storage tank in different seasons in order to minimize the leakage level. Resiliency and failure indices of the system have been considered as constraints in the optimization model to achieve the minimum required performance. In the proposed model, the results of a water distribution simulation model are used to train an Artificial Neural Network (ANN) model. Outputs of the ANN model as a hydraulic pressure function is then linked to a GA based optimization model to simulate hydraulic pressure and leakage at each node of the water distribution network based on the water level in the storage tank, water consumption and elevation of each node. The proposed model is applied for pressure management of a major pressure zone with an integrated storage facility in the northwest part of Tehran Metropolitan area. The results show that network leakage can be reduced more than 30% during a year when tank water level is optimized by the proposed model.