Application of River Network Hydrodynamic Model in Determining Water Distribution Scale of Haishu Plain

The water distribution network is an important part of the plain water environment improvement system. To make efficient use of the regional water diversion source, scientifically distribute the water diversion flow and improve the water environment carrying capacity of Haishu Plain, the river network hydrodynamic model is used in this paper to simulate the water intake location, reasonable water quantity and influence range of water transfer in Haishu Plain. The simulation results have high accuracy, which can provide a scientific basis for the scale, water transfer mechanism and project layout of water transfer construction in Haishu Plain and show a strong reference value for the study of water diversion and distribution scheme of coastal plain river network.

STUDY ON OPTIMAL CONTROL OF MUNICIPAL WATER DISTRIBUTION NETWORK

A systematic investigation is made on the problems which are related to the optimal control of the municipal water distribution network.A mathematical model of forecasting the water short term demand is proposed using the time series trigonometric function analysis method;the service discharge based macroscopic model of network performance is established using the network structuring method;a relatively satisfactory mathematical model for the optimal control of water distribution network is put forward in view of security and economy,and solved by the constrained mixed discrete variable complex arithmetic.The model is applied in many examples and the results are satisfactory.

Joint optimization scheduling for water conservancy projects incomplex river networks

In this study, we simulated water flow in a water conservancy project consisting of various hydraulic structures, such as sluices, pumping stations, hydropower stations, ship locks, and culverts, and developed a multi-period and multi-variable joint optimization scheduling model for flood control, drainage, and irrigation. In this model, the number of sluice holes, pump units, and hydropower station units to be opened were used as decision variables, and different optimization objectives and constraints were considered. This model was solved with improved genetic algorithms and verified using the Huaian Water Conservancy Project as an example. The results show that the use of the joint optimization scheduling led to a 10% increase in the power generation capacity and a 15% reduction in the total energy consumption. The change in the water level was reduced by 0.25 m upstream of the Yundong Sluice, and by 50% downstream of pumping stations No. 1, No. 2, and No. 4. It is clear that the joint optimization scheduling proposed in this study can effectively improve power generation capacity of the project, minimize operating costs and energy consumption, and enable more stable operation of various hydraulic structures. The results may provide references for the management of water conservancy projects in complex river networks.

Optimal operation of water distribution networks under local pipe failures

The optimal operation of water distribution networks under local pipe failures, such as water main breaks, was proposed. Based on a hydraulic analysis and a simulation of water distribution networks, a macroscopic model for a network under a local pipe failure was established by the statistical regression. After the operation objectives under a local pipe failure were determined, the optimal operation model was developed and solved by the genetic algorithm. The program was developed and examined by a city distribution network. The optimal operation alternative shows that the electricity cost is saved approximately 11%, the income of the water corporation is increased approximately 5%, and the pressure in the water distribution network is distributed evenly to ensure the network safe operation. Therefore, the proposed method for optimal operation under local pipe failure is feasible and cost-effective.

Seismic reliability analysis of urban water distribution network

An approach to analyze the seismic reliability of water distribution networks by combining a hydraulic analysis with a first-order reliability method （FORM）, is proposed in this paper. The hydraulic analysis method for normal conditions is modified to accommodate the special conditions necessary to perform a seismic hydraulic analysis. In order to calculate the leakage area and leaking flow of the pipelines in the hydraulic analysis method, a new leakage model established from the seismic response analysis of buried pipelines is presented. To validate the proposed approach, a network with 17 nodes and 24 pipelines is investigated in detail. The approach is also applied to an actual project consisting of 463 nodes and 767 pipelines. The results show that the proposed approach achieves satisfactory results in analyzing the seismic reliability of large-scale water distribution networks.

Calculation of the Water Distribution Networks Based on the Theory of Slow Transient Flow

Urban water supply network is a modern urban survival and development of the infrastructure of a city,and its normal running conditions have important significance. The actual hydraulic process in the variableload water distribution networks can be treated as the slow transient flow which belongs to the unsteady flow. This paper analyzes the multi-loops network slow transient model based on graph theory,and the link flow matrix is treated as the variables of the discrete solution model to simulate the process of the slow transient flow in the network. With the simulation of hydraulic regime in an actual pipe network,the changing laws of the flow in the pipes,nodal hydraulic heads and other hydraulic factors with the passage of time are obtained. Since the transient processes offer much more information than a steady process,the slow transient theory is not only practical on analyzing the hydraulic condition of the network,but also on identifying hydraulic resistance coefficients of pipes and detecting the leakage in networks.

Seismic Reliability and Rehabilitation Decision of Water Distribution System

In order to evaluate the seismic reliability of water distribution system and make rehabilitation decisions correspondingly, it is necessary to assess pipelines damage states and conduct functional analysis based on pipe leakage model. When an earthquake occurred, the water distribution system kept serving with leakage. By adding a virtual node at the centre of the pipeline with leakage, an efficient approach to pressure-driven analysis was developed for simulating a variety of low relative scenarios, and a hydraulic leakage model was also built to perform hydraulic analysis of the water supply network with seismic damage. Then the mean-first-order-second-moment method was used to analyse the seismic serviceability of the water distribution system. According to the assessment analysis, pipes that were destroyed or in heavy leakage were isolated and repaired emergently, which improved the water supply capability of the network and would constitute the basis for enhancing seismic reliability of the system. The proposed approach to seismic reliability and rehabilitation decision analysis on water distribution system is demonstrated effective through a case study.

Effectiveness of urban distributed runoff model for discharge and water depth calculation in urban drainage pipe networks

Effective urban land-use re-planning and the strategic arrangement of drainage pipe networks can significantly enhance urban flood defense capacity.Aimed at reducing the potential risks of urban flooding,this paper presents a straightforward and efficient approach to an urban distributed runoff model(UDRM).The model is developed to quantify the discharge and water depth within urban drainage pipe networks under varying rainfall intensities and land-use scenarios.The Nash efficiency coefficient of UDRM exceeds 0.9,which indicates its high computational efficiency and potential benefit in predicting urban flooding.The prediction of drainage conditions under both current and re-planned land-use types is achieved by adopting different flood recurrence intervals.The findings reveal that the re-planned land-use strategies could effectively diminish flood risk upstream of the drainage pipe network across 20-year and 50-year flood recurrence intervals.However,in the case of extreme rainfall events(a 100-year flood recurrence),the re-planned land-use approach fell short of fulfilling the requirements necessary for flood disaster mitigation.In these instances,the adoption of larger-diameter drainage pipes becomes an essential requisite to satisfy drainage needs.Accordingly,the proposed UDRM effectively combines land-use information with pipeline data to give practical suggestions for pipeline modification and land-use optimization to combat urban floods.Therefore,this methodology warrants further promotion in the field of urban re-planning.

Hydraulic model for multi-sources reclaimed water pipe network based on EPANET and its applications in Beijing, China

Water shortage is one of the major water related problems for many cities in the world.The planning for utilization of reclaimed water has been or would be drafted in these cities.For using the reclaimed water soundly,Beijing planned to build a large scale reclaimed water pipe networks with multi-sources.In order to support the plan,the integrated hydraulic model of planning pipe network was developed based on EPANET supported by geographic information system(GIS).The complicated pipe network was divided into four weak conjunction subzones according to the distribution of reclaimed water plants and the elevation.It could provide a better solution for the problem of overhigh pressure in several regions of the network.Through the scenarios analy-sis in different subzones,some of the initial diameter of pipes in the network was adjusted.At last the pipe network planning scheme of reclaimed water was proposed.The proposed planning scheme could reach the balances between reclaimed water requirements and reclaimed water supplies,and provided a scientific basis for the reclaimed water utilization in Beijing.Now the scheme had been adopted by Beijing municipal government.

基于Model Online给水管网水力模型的分析与应用

为了更好地模拟和优化西南H镇城乡供水管网的设计,应用Model Online给水管网平差软件,综合考虑供水安全性与经济性对管网进行优化和模拟,得出最佳供水效果,以指导设计施工,为供水技术进入互联网时代探寻新的道路。

考虑水质因素的供水管网抗震韧性评估

城市基础设施系统抗震韧性分析模型是评估城市防震减灾能力并指导震后恢复工作的重要依据。提出了耦合水力与水质模拟的供水管网抗震韧性评估模型。根据管道地震易损性模型和Monte Carlo模拟生成管网地震破坏场景,并采用动态重要度方法模拟管网震后修复过程。通过管网中余氯浓度的降低表示地震破坏对管网水质的负面影响,震后管网余氯浓度的变化取决于管道破坏引起的供水路径和水量的变化。采用震后余氯浓度未下降的用户节点供水量,作为管网系统水质性能评估指标。所提出的模型应用于2个不同布局的Benchmark案例管网。研究结果表明:管道破损处的水量漏失导致其上游管道的水流量增加、余氯浓度增大,下游管道的供水路径延长、余氯浓度减小。管网的水质韧性值往往低于水力韧性值,水力和水质韧性相对差异程度受到管网布局和运行规则的影响,文中案例管网水质和水力指标计算的抗震韧性损失指标的相对差异在17%~286%之间;运行规则复杂且含有调节水箱的管网,其水力和水质韧性的差异较大。

基于空间聚类的供水管线优化改造

在城市供水管线更新维护实践中,若按照管材、直径和建设年代等物理属性划分改造管线组,相同管线组内通常包括许多在空间上分散、长短不一的孤立管线,更换这些管线需要频繁的服务中断和额外的资源维修成本。为了减少更换方案中分散的孤立管线数,提出一种基于空间聚类划分管线组的管线优化改造框架。该框架根据管线破损点的空间自相关分析划分空间网格,然后将网格内的管线进一步按管径分组,构成待更换的候选管线组;利用基因表达式编程方法,以及管径、管龄和管长属性参数建立管线破损数失效模型,预测管线组未来的破损数;以最小化破损数为目标函数,年度预算为约束条件,建立管线优化改造的数学模型。将该方法应用于实例管网,对比了空间聚类、属性聚类、基于风险排序3种不同方法得到的管线更换方案;结果表明,与其他2种方法相比,基于空间聚类的方法将空间分散的孤立管线数分别减少36.7%和64.6%。该框架可为制定更具成本效益的供水管线改造方案提供参考。

给水管网爆管水力水质综合影响分析方法的研究

给水管网爆管事故严重威胁着城市供水的安全性,建立一套完善的事故影响分析体系,对于降低事故损失和提高供水安全具有重要意义。围绕给水管网爆管事故造成的水力和水质影响,建立了爆管失效的压力驱动水力模型与水质模型,针对全局梯度算法迭代初值的敏感性问题,提出了基于拟牛顿和粒子群的混合优化算法,即先利用智能算法找到较优的迭代初值,再利用拟牛顿法进行局部精细搜索获取最优解,实现了管网失效状态的仿真模拟。实际应用结果显示,爆管造成管网节点压力最大降幅达到82%,余氯质量浓度最大降幅为39%,事故对压力影响更为显著;爆管关阀后停水区域的下游节点,压力和余氯质量浓度分别平均降低了77%和27%。

基于压力估计的供水管网水力模型校核

供水管网水力模型校核过程中,由于监测点个数较少而校核的参数过多,校核结果往往与实际不符。为使校核结果较为符合实际,提出一种基于压力估计的水力模型校核方法,根据实测监测点压力和入口流量数据估计非监测点的压力,并将估计的节点压力作为校核问题中的已知条件。以管道海曾威廉系数为校核参数,使用多层感知器(Multilayer perceptron,MLP)估计节点压力,使用遗传算法(Genetic algorithm,GA)优化目标函数。案例分析表明,提出的MLP-GA比GA校核效果更好,3个监测点压力绝对误差之和从37.81 m减小到33.65 m,降幅达11.0%;管道海曾威廉系数的绝对误差之和从933.5降低到847.0,降幅达9.27%。

基于深度聚类的供水管网分区构建方法研究

在供水系统管理中,分区管理是进行管网运营、压力管理和漏损控制的有效工具,其构建方法直接影响分区效能的发挥程度。然而,大多数分区方法通常未能充分考虑管网的拓扑结构与水力状态之间的复杂相互作用,所得分区方案无法充分利用现有分区设施,在实际工程应用中面临困难。鉴于此,提出了一种基于结构性深度聚类网络(Structural Deep Clustering Network,SDCN)的供水管网分区构建方法。使用SDCN有机融合管网拓扑结构和水力状态信息进行聚类分析,根据聚类结果以及管网计量设施实际情况,对孤立节点进行归类分析,提出聚类边界调整的有效计算方法,以形成最终分区方案。与两种经典的管网聚类方法相比,该方法具有更好的管网节点聚类精度,分区结果面向工程实际需求,可以为管网分区规划与建设提供有效的技术支撑。

基于模型驱动的供水自适应调度应用研究

随着供水企业精细化管理需求的日益增长,对供水调度的要求也随之提升。研究了基于水力模型的供水管网自适应优化调度方法,通过建立水力模型及水量预测模型,基于遗传退火模拟搜索算法,建立了优化调度的数学模型,同时结合工况聚类分析,大大降低搜索算法运算量,提升优化调度方案生成效率,实现供水管网自适应调度系统。此外,该系统与厂站控制系统对接完成自动调度控制,实现了系统自动厂站、管网优化调度。基于深圳市FY水司实际生产工况,实现区域内供水压力平稳,整体配电能耗下降约3%,系统调度方案生成时间不超过40 s,调度指令自动执行时间优于30 s,运行效果显著,有效提升了调度效率,实现供水调度的提质增效。

基于供水管网水力模型的市政管网消防供水能力研究

为提高城市消防安全水平和火场救援的效率和质量,基于供水管网水力模型,对市政管网消防供水能力进行研究,利用算法分析计算应急状态下满足消防取水需求的市政管网最大消防给水量,得出市政给水设施在火灾条件下的实际给水能力。填补城市消防给水设施管理部门和消防实战应用单位之间的真空地带,解决各信息之间的“信息断层”和应用系统之间的“信息孤岛”问题,充分发挥城市消防给水设施效能,保障消防安全。

水量调度对平原河网能量影响分析

平原河网水动力条件相对较差,水质问题较为突出,为改善平原河网地区水环境状况,选取江苏省无锡市滨湖河网2018年洪季和枯季19个断面水文水质监测数据,基于MIKE21滨湖河网水动力-水质模型及Python能量计算模型,探究能量耗散规律以及能量、水质间的关系,并确定最佳调水流量区间。结果表明:滨湖河网水质浓度与河流能量显著负相关;一定调水流量的增加使得河流总能量随之上升,能量到达阈值后,随调水流量的上升,河流总能量呈降低趋势;在能量目标层面上优选引调水方案,能有效协调引调水过程中存在的异质性因素,确定逐日最佳调水流量区间及河网总能量最佳区间,提供流量优化调控方案,保障平原河网水动力与水环境条件。

县域供水管网水力模型建设与应用实践

与大中城市相比,县域城镇供水管网具有独特的地形特征、管网覆盖密度等特点。以安吉县供水管网为例,总结近年来水力模型在降本增效、动态评估、联合调度等场景中的建设与应用实践,为其他县域城镇供水管网水力模型应用提供参考。

AFT Fathom在某大型化工厂循环水系统水力学计算中的应用

应用AFT Fathom软件对某大型化工厂循环水系统管网进行水力学分析计算,得出循环水系统管网的流量、压力分配情况。与传统手算方法相比,该方法能够优化设计,提高设计准确性,减少工程运行成本,对于同类型给水排水系统的设计优化具有指导意义。