【作者】 谢善斌；

【导师】 周玉文；

【作者基本信息】 北京工业大学 ， 市政工程， 2009， 博士

【摘要】 现阶段,给水管网运行状态的分析方法主要是以EPANET软件模型为代表的管网延时分析模型,分析的水力时间尺度一般为小时,所分析的状态为该时段的特征状态,并非实时状态,只是统计意义上的“期望”状态,不能满足管网机械设备控制动作及管网节点用水量变化的实时表达,不能更“真实”的描述管网状态变化。管网的状态变化本质上是组成管网的各个管网物理构件的状态变化及其对管网其它构件状态的影响,若能够知道管网构件状态的变化过程以及构件状态变化对管网状态的影响,就能够建立管网的在线模型,能够描述管网状态的实时变化过程。管网构件状态的变化过程一般是应用SCADA系统及相关算法对构件状态进行估计。对于构件状态变化的描述及其对管网状态的影响,本文引入一个新概念:事件模型加以描述和表达。给水管网的事件模型抽象、封装了管网构件状态变化触发的管网瞬变流动分析逻辑,本论文基于给水管网事件模型的分析主要作了以下各项创新性工作:(1)架构了给水管网框架模型系统。基于面向对象的分析与设计原理,分析了管网模型设计的要求以及将来模型应用的需要。基于模型设计的要求以及软件工程学的方法论,构建了给水管网基础模型框架。并对管网的主要构成构件进行具体分析,给出了管网及管网构件的模型具体表述及类型表达,它是管网事件模型的表达基础及重要组成部份。(2)设计了给水管网模型系统的数据库表结构。主要包括:构件静态数据表,动态数据表,模型选项配置表,流体特性表,单位表等。(3)给水管网系统用水量分析。用水量的准确估算是给水管网模型运行的重要条件,也是给水管网事件分析模型得以建立并运行的必要条件。本文对用水量的时序特征,空间分布及运行时管网节点用水量的计算都进行了分析。(4)推导了瞬变流动的动力方程与连续性方程,应用特征线法,将运动方程与连续性方程两个偏微分方程转化为在两条特征线上的常微分方程,通过对常微分方程积分的方法来求解流体的流量与水头等运动参量的时序变化;推导了管网中各类边界条件的处理方法(包括管线与连接点、水泵、阀门、水库、水箱等构件的连接),对在管网瞬变流动计算中的管系分段与网格剖分问题的多种方法作了探讨(包括刚化法、波速调整法、内插法、重分阻尼系数法等),最后对瞬变流动管壁阻力模型的发展做了回顾。(5)提出了管网的事件及事件分析模型的概念,讲述了事件原型的结构及构成对象,对于多事件的模拟应采用事件池的结构来解决,同时对于事件的触发机制及事件类型进行了分析,引进控制理论相关知识来表征流体瞬变的特性(如:延迟时间、上升时间、峰值时间、最大超调量、调节时间或过渡时间、振荡次数等)。(6)对管网构件的状态变化对管网的状态影响进行了分析,并对示例管网进行了案例分析,主要有:水泵停车影响分析,水泵启动影响分析,水泵调速影响分析,用水点异常突发用水影响分析,阀门的开启、关闭影响分析等。更多还原

【Abstract】 At this phase, the primary method of water distribution system analysis is extended period analysis such as Epanet software model. The time scale of this method is general hours, and the state of pipelines analyzed is characteristic status of that period time, not real-time status, it is only "expectations" state, and can not satisfy requirements of the analysis for network mechanical equipment control movements and junction water demand variation. Changes in the status of the network are essentially according to variation of the state of network components. If variation process of components states and its impacts on network state are known, the real-time model of pipelines can be built to describe real-time variation of pipelines status. Variation of component status is commonly detected by using SCADA system and estimated by some algorithms. The new conception: event-driven model is introduced to describe variation process of components’states and its’ impacts on network states.The event-driven model for water distribution system abstracts and encapsulates logics of analysis of transient flow induced by components’status variations. This paper completes several innovative works listed below based on event-derived model analysis for water distribution system.(1) The framework for water distribution system model is constructed based on object-oriented analysis and design principle and also based on requirement of model design and software engineering methodology.The most category components of the network are in detailed analyzed and related classes are designed, these are basic and important part for constructing event-driven model.(2) The database tables are designed for water distribution model system, it mostly include:static data tables of model elements,dynamic data tables of model elements,data tables of physical units, analysis options and fluid characteristics, etc.(3) Water consumptions and demand categories are analyzed for water distribution system. It is important to accurately estimate water demand and it is the basic prerequisite to construct the events-driven model. Water demands temporal and spatial distributions are analyzed, and the related methods are presented of junction demand computation.(4) Continuity equation and motion equation are deduced. using characteristic method, the two partial differential equations can be converted to two ordinary differential equations along two characteristic lines, and these two ordinary differential equations can be integrated along characteristic lines to get time series for fluid flow rate and head .The methods for treatment of different boundary conditions are given (including pipe connection with junction, pump, valve, reservoir, tank etc.). Methods of sectioning for pipelines are discussed (including rigid method, wave velocity adjustment, interpolation method, etc). Finally, history of research of wall shear stress models is briefly reviewed.(5) The conceptions of event and event-driven model are presented, events prototype and structure are given. Multi-event model can be simulated using event pool structure, the mechanism for firing events and event types are analyzed. Related conceptions in modern control theory are induced to reflect fluid transient flow characteristics (delay time, rise-time, peak value time, maximum amplitude value, transition time, surge time etc.)(6) The impacts are analyzed on pipelines system of events triggered by variation of component status. Several cases listed for demonstration pipelines system are studied: pump shut off analysis, pump restart up analysis, pump speed adjustment analysis, junction abnormal demand analysis, and valve open (close) analysis, etc.更多还原