供水管网水力模型模拟精度变化的分析研究实例

供水管网水力模型的模拟精度水平是决定模型在管网运行管理中发挥作用大小的关键.模型模拟的精度受多种因素的影响总是处在不断的变化中.通过对实例模型的精度长达13个月的跟踪记录,总结分析模型精度的变化规律,为模型维护策略的确定及建模技术的完善提出建议.     

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。     

供水管网水力模型在管网管理中的应用

针对杭州萧山区全区供水范围内的管网系统,运用"混合节点 环"方法,完成供水管网水力模型的计算.通过该模型模拟评估管网规划、设计、建设、水质等方案,提出相应的决策参考建议,并取得了良好的应用效果.通过部分供水管网水力模型应用的实际案例,证明模型在管网管理中起到了重要的指导作用,对相关工作的决策提供了理论和科学依据,具有一定的实际应用意义.     

城市供水管网局部故障工况下运行状态模拟仿真的研究

本文就城市供水管网局部故障工况下运行状态的模拟仿真进行研究。首先在对现状管网正常运行状态和事故运行状态水力分析、模拟仿真的基础上，分别确定模拟管网供水量、供水压力及管网监测点压力在2种状态下的相关关系；其次，以实际管网正常运行状态宏观模型为基础，结合所求出的模拟管网2种状态的相关关系，建立实际管网事故运行状态宏观模型。对上述各模型，均确定了相应的解法及编程，并结合实例进行了计算、分析，效果令人满意，证明该方法实用可行。     

苏州市某区给水管网微观水力模型的建立与应用

以苏州市某区给水管网为例,介绍了给水管网微观水力模型的建立过程、方法、校核及水力模型构建后对城市供水系统的作用。通过水力模型对给水管网运行工况进行了评估,发现供水管网普遍存在流速偏低、水龄偏大的问题,对由此可能产生的不利情况进行了分析。通过水力模型模拟了供水量从平均日到最高日管网自由水压线、流速变化情况,指出当前管网管径整体偏大是造成流速偏低、水龄偏大的主要原因,是管网水质二次污染的原因之一。     

微观水力模型在优化调度预案方面的应用研究

为了应对供水高峰期,保证城市供水安全,对郑州市第一主力水厂柿园水厂进行清水池和滤池改造工程。在施工改造期间,柿园水厂每天约减少供水量3×104 t,为了减小因施工原因对供水管网造成的影响,利用微观水力模型,对管网中关键阀门的不同组合状态进行方案模拟,分析评价模拟结果并取得最优阀门状态方案,从而制定施工期间的合理调度预案,对供水调度提供数据支持和科学指导。     

供水管网水力计算研究与实现

实现城市给水管网系统科学管理,首先必须对管网系统进行水力分析计算和模式的复核计算,以期获取准确的运行工况数据;在此基础上,进行管网改、扩建优化设计。将水力计算嵌入给水管网信息系统,可以使水力计算中的大部分输入数据直接从GIS数据库中提取,并借助GIS的数据更新手段保持管网计算模型的现势性,还可以利用GIS的表现能力显示输出计算,绘制各种专题图。     

供水管网水力模型在佛山市第二水源工程运行管理中的应用

佛山市水业集团有限公司自2003年开始建立供水管网水力模型。以管网水力模型在佛山市第二水源工程项目中的应用为例,介绍了水力模型在供水管网改扩建方案评估、供水泵房水泵机组改造方案评估、供水系统运行调度方案制定等三个方面的应用。     

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。     

MIKE URBAN在供水管网设计和管理中的应用研究

在介绍MIKEU RBAN软件的基础上,分析了该软件在恒定水力计算、水锤分析、半恒定水力计算、水质模拟中的各种应用的初始条件和边界条件。研究表明:MIKE URBAN软件具有较强的管网水力计算校核和各种工况的模拟功能,以及在水厂生产运行中的优化调度功能,并可应用于供水管网的规划和设计。     

A Life Cycle Oriented Multi‑objective Optimal Maintenance of Water Distribution: Model and Application

Aiming at trading off several conflicting criteria in practical maintenance in a deteriorating water distribution network, a life cycle oriented multi-objective optimization model of water distribution network maintenance is developed, which is composed of seven interrelated sub-models with different functions. This model can provide decision support for preventive maintenance decision, including identifying the pipeline that needs to be maintained, judging the time point for maintenance, determining the type of maintenance technology, calculating the economic cost of maintenance, and presenting the impact under different maintenance strategies. Based on the life cycle of each pipeline, multiple effects in the water distribution can be dynamically evaluated, such as pipeline age, failure rate, hydraulic reliability health level etc. Based on special design of chromosome gene encoding, the algorithm of elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) is incorporated to achieve multi-objective optimization solution effectively. With application of a county in Zhejiang province in China, three strategies including empirical decision single-objective optimization decision and multi-objective optimization decision are evaluated and compared to the baseline systematically. Although the annual maintenance cost of strategy III is not the lowest among those three strategies, the pipeline age, failure rate, hydraulic reliability, and health level of the water distribution network under the strategy are at the best level. With multiple objectives considered simultaneously, the results of strategy III are recommended as the optimal maintenance implementation arrangements. This model can promote to find an optimal maintenance strategy, and provide a technical support for the planning, design and implementation of maintenance arrangements of water distribution network in a long-term period.

     

Optimal pipe replacement strategy based on break rate prediction through genetic programming for water distribution network

Pipe breaks often occur in water distribution networks and result in large water loss and social-economic damage. To reduce the water loss and maintain the conveyance capability of a pipe network, pipes that experienced a severe break history are often necessary to be replaced. However, when to replace a pipe is a difficult problem to the management of water distribution system. This study took part of the water distribution network of Beijing as a case and collected the pipe properties and the pipe breaks data in recent years (2008–2011). A prediction model of pipe beak rate was first developed using genetic programming. Then, an economically optimal pipe replacement model was set up. Finally, the optimal pipe replacement time was determined by the model. The results could help the utility managers to make cost-effective pipe maintenance plans.     

Functional Structure and Data Management of Urban Water Supply Network Based on GIS

This paper presents an urban water supply network system based on GIS technology. The system will adopt three-tier/N-tier architecture as the application logic structure. Thy system can be divided into six subsystems: the analysis subsystem, the aided design subsystem, the installation and maintenance management subsystem and the customer service subsystem serve data management subsystem. The data management of the system will adopt SuperMap. We present the details of the data management, such as basic data collection, structure framework of the basic geographic information bank, the process to construct GIS basic information bank of water supply network, data conversion and input into banks, data vectorization and input into banks, etc. Then the system database is designed in detail. We adopt object oriented analysis and design methods, and utilize Class Diagram of UML to represent the entity tables and their relations against the core data of the network system, that is spatial dictionary database and spatial database. According to Class Diagram, it can be directly mapped as the database structure and an example is given. Finally, the successful application of the system in Yiyang city of China is beneficial for water supply enterprises to utilize the existing water resource in time, rationally and effectively.     

城市给水系统优化调度研究

用水量预测研究和给水管网数学模型研究是优化调度的基础,用水鼍预测模型是在分析城市用水量序列数据模式的基础上,综合利用统计回归的方法建立的数学表达式;给水管网数学模型是建立水厂出厂压力和流量与管网测压点之间的经验数学表达式,它反映了给水系统的运行工况.优化调度模型的建立和求解是优化调度的核心.     

灌溉渠道远程数据采集平台设计

为促进灌区信息化建设,针对灌溉渠道数据信息有线监测系统面临的布线复杂、施工及维护成本高等问题,在分析灌溉渠道数据采集节点分布特点的基础上,结合Zig Bee近距离通信技术和GPRS远距离通信技术各自的优势,设计了一款数据测量终端和用于远程数据传输的遥测终端。测量终端以一定采样频率获取监测区域水位、流量、水质等信息,通过测量终端将传感器数据以无线信号形式向遥测终端传输,遥测终端完成Zig Bee网络数据收集并远程传输至监控中心。利用测量终端和遥测终端构建了渠道数据监测网络,可用于灌溉渠道水位、流量及其它重要参数信息的监测。现场实际测试运行效果表明,该平台采用无线传输方式,实现了渠道流量的数据采集、传输及显示功能,并能够实现渠道多数据信息的采集及远程数据传输。     

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.     

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.     

静力水准系统在水工模型高程测控中的应用

 水工物理模型高程测控的精度是直接影响试验成果可靠程度的关键因素之一,模型高程精度必须满足相关标准和试验任务的要求。采用水准仪法测量大型模型高程操作困难 , 根据连通管原理,利用连通管和辅助器件将模型水位站与高程控制基点连接起来形成静力水准测量系统,按照一定的观测操作程序和计算方法可提高测控精度。经三峡 - 葛洲坝日调节模型应用证明：该系统具有测量精度高、构造简单、操作维护方便的特点。静力水准测量方法可供其他高程精密测控领域借鉴。     

DESIGN OF GROUNDWATER LEVEL MONITORING NETWORK WITH ORDINARY KRIGING

The primary network of groundwater level observation wells aims at realizing a regional groundwater management policy. It may give a regional picture of groundwater level with emphasis on the natural situation. Observation data from the primary network can be used to estimate the actual state of groundwater system. Since the cost of the installation and maintenance of a groundwater monitoring network is extremely high, the assessment of effectiveness of the network becomes very necessary. Groundwater level monitoring networks are the examples of discontinuous sampling on variables presenting spatial continuity and highly skewed frequency distributions. Anywhere in the aquifer, ordinary kriging provides estimates of the variable sampled and a standard error of the estimate. In this article, the average Kriging standard deviation was used as a criterion for the determination of network density,and the GIS-based approach was analysized. A case study of groundwater level network simulation in the Chaiwopu Basin, Xinjiang Uygur Autonomous Region, China, was presented. In the case study, the initial phreatic water observation wells were 18, a comparison of the three variogram parameters of the three defferent variogram models shows that the Gaussian model is the best. Finally, a network with 55 wells was constructed.     

基于图论的城市河网水系连通方案优选——以清潩河许昌段为例

对于复杂河网水系来说,水系连通方案的选择决定了河道是否有效连通以及各种功能能否得以保障。为了优选最佳水系连通方案,本文以清潩河许昌段为研究对象,借助图论法构建了城市水系河网图模型;考虑多闸联合调度以及各节点水量平衡关系,并利用图模型的邻接矩阵和加权邻接矩阵来描述河网水系对水量的分配作用,进而计算整个河网水系各河段和节点的流量值;以水生态景观面积最大为优选目标,结合河网水量分配关系和水力约束建立了多闸联合调度下的水系连通方案优选模型,优选得到在不同工况下的清潩河许昌段最佳水系连通方案。结果显示,在多数连通方案下河网流量可能会超出流量限值,而优选方案下的河网流量不仅可以满足流量约束、保障河网功能需求,还可有效提高水生态景观面积。