基于WebGIS的供水管网爆管事故关阀分析研究

利用WebGIS技术建立了爆管事故关阀分析系统,深入研究了管网要素之间的网络拓扑关系,分析了基于邻接表存储结构的爆管事故关阀分析流程,得出了爆管事故状态下的最优关阀方案和受影响管段.以某供水管网为例,实现了爆管事故时的关阀分析.该系统的建立大大降低了爆管事故造成的经济损失,提高了供水企业的现代化管理水平.     

爆管事故对多水源管网供水分区的影响

基于图论理论,建立了多水源供水管网的供水分区模型,结合EPA管网模拟软件,采用C++平台实现了供水分区算法.通过对爆管事故发生管网前后供水分区的研究,得到了爆管事故对于多水源管网供水分区的影响规律,事故管段的输水能力强弱直接影响到供水分区变化的程度,并在实例管网中得到了很好的验证,为管网在事故发生及关阀抢修时的水量调配提供了技术支持.     

给水管网拓扑结构对供水行为压力波动的影响

城市给水管网在实际运行中,经常通过泵阀启停实现供水量的改变或事故检修,工况的切换不可避免地引发管内正负压力波动。研究不同管网拓扑结构在无其他防护措施的供水行为(如多阀关闭、泵的启停和消防等工况)下的水锤现象。通过对比分析发现,相对于树状管网,环状管网对关阀产生的高压波、消防工况产生的低压波以及因停泵再启产生的水柱分离有较好的消减作用,但对解决停泵后负压没有帮助,必须与空气阀配合使用。该结论可为城市管网运行以及管网的扩建和改造提供参考。     

供水管网阀门分析与统计系统设计与开发

为实现城市供水管网的信息化管理,体现"安全供水、优质服务"的宗旨,在城市供水网络发生事故时,及时制定出切实可行又较优的处理方案,本文以城市供水管网地理信息系统为辅基础进行供水管网阀门分析与统计系统的设计与开发。系统可以实现对供水管网阀门日常维护及事故处理情况下的科学管理,以提高供水管网维护人员的工作效率,实现真正的安全高效供水。     

采用非常规方法抢修管网的实例分析

正管网抢修是供水企业确保安全供水、减少漏损的日常工作,常规的管网抢修一般程序是:找到漏点→关阀止水→开挖→修复漏点→开阀通水。抢修时,供水企业一般会关注以下几个要点:一是根据漏水管道实际情况,现场会采取多种办法进行修复,控制好修复的成本及停水的时间;二是考虑修复时抢修人员的安全施工;三是修复时对周围环境的交通影响等等。从实际的抢修工作来看,由于管网的口径和材质、阀门分布情况、漏点的周边环境较为     

基于MapInfo的小区供水管网故障关阀系统

在MapInfo平台上 ,以MapBasic作为开发工具 ,采用分级搜索的方法建立小区供水管网事故处理关阀搜索系统。     

移动GIS系统在供水管网现场管理中的应用研究

针对供水GIS缺乏现场使用手段的问题,开发完成了移动版GIS。通过应用移动GIS,施工人员能够方便快捷地实现管网及相关附属设施的属性查询、事故现场相关阀门的定位,在缩短抢修时间的同时,快速制定科学合理的关阀和抢修方案,提升服务水平。同时,停水范围分析和事故信息的采集也更加细致准确,有助于提高管网管理的工作效率和规范化水平。     

基于Maplnfo的小区供水管网故障关阀系统

在Maplnfo平台上，以MapBasic作为开发工具，采用分级搜索的方法建立小区供水管网事故处理关阀搜索系统。     

基于城市供水管网地理信息系统的管网维护与巡检

介绍了基于城市供水管网地理信息系统管网维护与巡检系统的建设目标、拓扑结构及应用情况。结果表明,升级后的供水管网地理信息系统能够对供水管网阀门有效管理,通过智能巡检系统能够加强供水管网及设施的管理,增强巡检人员现场处理应急状况的能力,提高城市供水的科学性和应急处置能力,优化供水调度机制,保障供水安全。     

GIS环境下事故管网关阀搜索的应用初探

建立GIS城市供水管网系统,利用关阀搜索的思想,能够准确快速地找出检修时需要关闭的阀门数并打印停水信息提供给相应的用户,但在实际应用中仍存在着关阀数过多等不足。文章主要针对关阀搜索在实际应用中的不足进行了探讨并给出了一些建议和意见。考虑到爆管较强的随机性,探讨了爆管预测及爆管模型的建立,为日后的一些管网工程的改造或是重点监测提供依据,动态模拟和监测将成为该方向的主导。     

Leakage detection and location in water distribution systems using a fuzzy-based methodology

Loss of water due to leakage is a common phenomenon observed practically in all water distribution systems (WDS). However, the leakage volume can be reduced significantly if the occurrence of leakage is detected within minimal time after its occurrence. This paper proposes a novel methodology to detect and diagnose leakage in WDS. In the proposed methodology, a fuzzy-based algorithm has been employed that incorporates various uncertainties into different WDS parameters such as roughness, nodal demands, and water reservoir levels. Monitored pressure in different nodes and flow in different pipes have been used to estimate the degree of membership of leakage and its severity in terms of index of leakage propensity (ILP). Based on the degrees of leakage memberships and the ILPs, the location of the nearest leaky node or leaky pipe has been identified. To demonstrate the effectiveness of the proposed methodology, a small distribution network was investigated which showed very encouraging results. The proposed methodology has a significant potential to help water utility managers to detect and locate leakage in WDS within a minimal time after its occurrence and can help to prioritise leakage management strategies.     

Robust optimization of valve management to improve water quality in WDNs under demand uncertainty

ABSTRACT

Water quality deterioration in water distribution networks can be associated with high water residence time in the network. To this end, some previous studies have proposed optimization procedures for valve management. However, these studies generally come up with operational configurations assuming deterministic user demand patterns that may never occur in reality. In consequence, the proposed solutions may not be effective for improving water quality or do not comply with pressure constraints if different demand patterns are observed. This study proposes a methodology to determine robust configurations of the valves to keep water residence time at acceptable levels regardless of the variability in demand patterns. The methodology is tested on four different distribution systems of varying topology and size. Results show the importance of executing robust – instead of deterministic, optimization to find valve configurations that guarantee the performance of the networks in terms of hydraulics and water quality.     

平衡阀与定流量阀在水系统平衡中的不同应用

通过对平衡阀与定流量阀两种调节阀的工作原理,使用范围以及工程实例的对比分析了,区分了两种阀门的不同作用和功能,认为平衡阀宜用在需要保持阻力平衡（流量平衡）的系统中,定流量阀宜用在需要保持流量不变的系统中,二者有不同的作用。不能完全相互取代。     

On the significance of maximum number of components failures in reliability analysis of water distribution systems

Many factors may influence the results of a reliability analysis for a water distribution system (WDS). These may include (but not limited to) the techniques chosen for reliability assessment, criterion to measure a system's reliability, number of components-failure combinations and failure probabilities and/or frequencies. Among these factors, the maximum number of components-failure scenarios is an important one which has not received sufficient attention in the literature. This study estimated the accuracy in reliability and damage tolerance analysis when an unrealistic and imprecise number of failure scenarios is assumed. Exercising a hypothetical WDS, the modified version of EPANET2 was applied for the hydraulic analysis. The reliability and redundancy or damage tolerance were evaluated based on weighted mean of performance indices of the system. The results indicated that incorporation of maximum acceptable error allow the engineers to estimate the number of failure combinations and ultimately to conduct a more computationally-efficient and realistic reliability assessment. Application of this methodology prevents redundant and unnecessary hydraulic simulations in reliability analysis and reduces computational simulations significantly.     

Segment identification in water distribution systems

This paper presents a new method for identifying the segments that are formed after the installation and closure of isolation valves in a water distribution network. This method is able to identify segments also when one-way devices are installed in the network. Thanks to its short computing times, the method enables the analysis of real networks which always comprise a large number of nodes and pipes.

The numerical examples presented in this paper refer to two real water distribution networks. The first network is a part of a provincial network where two one-way devices are present; the second is a complex urban network without one-way devices. The method was first used to analyse the existing situation in both networks, i.e. the set of segments that are formed as a consequence of the present valve system. The method was subsequently used for the problem of the hypothetic redesign of the isolation valve system in the second urban network, i.e. the search for the optimal positions of the isolation valves in the network; in the redesign phase it provided solutions which are more cost-effective than the configuration of isolation valves currently present, the level of water service reliability being the same.     

给水管网球阀局部阻力系数计算研究

为确定给水管网阀门的局部阻力系数,提出了一种基于几何计算和现场试验的局部阻力系数公式的构建方法。先通过几何计算建立球阀通流面积与阀芯旋转角度的关系,并以某转角下和全开时的通流面积之比作为球阀的面积开度,指出了传统的以阀芯旋转角度与全行程所需旋转角度之比作为球阀开度定义的缺陷。然后以DN20球阀作为试验对象,通过现场试验,采集各开度下的压差和流量值并计算出相应的局部阻力系数,经曲线拟合,建立了面积开度与球阀局部阻力系数之间的关系。另一组面积开度和球阀局部阻力系数的试验数据表明,该计算公式能有效地应用于球阀局部阻力系数计算。     

Incorporation of prior information on parameters in inverse transient analysis for leak detection and roughness calibration

Leak detection and calibration of hydraulic models for water distribution systems (WDS), including the pipe roughness and other parameters, is undoubtedly a critically important issue. This paper first briefly reviews the relevant literature. After addressing some general issues regarding prior information (PI) on calibration parameters, an inverse transient model, capable of detecting leaks and internal pipe roughness in WDS, is presented. The classic objective function of the weighted least squares type is generalized by adding terms accounting for PI on calibration parameters. The methodology presented is general in that it can be applied to any WDS inverse model. It is then shown that PI, when used in a certain way, conditions the inverse problem and thus improves the solution obtained. As a part of the suggested approach, a procedure for careful and effective use of PI on the parameters in inverse transient problems is suggested. Finally, the methodology is applied to three case studies, leading to some general conclusions about the value and use of PI.     

Failure probability minimization of buildings through passive friction dampers

This paper proposes a methodology for robust optimization of the failure probability of buildings subjected to stochastic earthquakes, using a less common type of passive energy dissipation device: the friction dampers. There is a lack of studies on optimal positions and parameters of passive friction dampers, and additionally, the few studies found in the literature consider the problem in a deterministic way. The robust optimization proposed in this paper is carried out through the recently developed backtracking search optimization algorithm, which is able to deal with optimization problems involving mixed discrete (positions) and continuous (friction forces) design variables. In order to take into account uncertainties present in both the system and the dynamic excitation (earthquakes), some parameters are modeled as random variables, and consequently, the structural response becomes stochastic. For illustration purposes, a 10‐story building is analyzed. The results showed that the proposed method was able to reduce the failure probability in approximately 99% with only three friction dampers, installed in their best positions and with their optimized friction forces. The proposed methodology is quite general, and it is believed that it can be recommended as an effective tool for optimum design of friction dampers. Copyright © 2016 John Wiley & Sons, Ltd.     

厨房集中排烟道用止逆阀性能研究及其影响

通过实验方式测定排烟道用止逆阀造成的局部阻力,得到以下结果：所测上开式电磁阀的局部阻力系数随阀片开启角度的增大而减小;排风量增大,阻力系数亦减小,且和其他类型的电磁阀及重力阀相比,该阀门的阻力系数小。针对目前住宅建设发展趋势,可得出以下结论：阻力系数过大的止逆阀不适合用于集中排烟道系统,烟道设计时一定要注意选用对烟道内气流流动影响小(顺流向,如上开式),本身造成阻力小,止逆性能好的阀门,以有利于系统的运行。     

输配水管道设计体会

结合工程实例，分析了城市输配水管道设计中遇到的一些问题，介绍了几种常用管材的性能和使用情况，论述了不同地质条件，管道基础处理的不同方法，并对管道附属设施的阀门、伸缩门、排气阀、泄水阀及支墩的选型及使用情况进行了说明，指出在管位的确定上要考虑多方面因素，进行技术性和经济性的比较。