上海中心给水系统管道水锤消除技术

本文结合超高层建筑工程中给水系统管道水锤现象,通过对高区传输水泵产生水锤现象与其他设备层管线分析对比,采取不同方案进行整改,最终发现产生水锤现象的原因与现场管线走向有密切关系,通过增加水锤消除器,彻底缓解了水击现象造成的管道抖动,经施工实践总结的技术措施对今后高层建筑给水系统安装及调试有借鉴作用。     

水锤波试验系统研究

建立液压水锤波试验台,提出了多参数可调的液压管道水锤波试验系统方案,通过改变增压缸活塞杆质量、调整增压缸活塞杆缓冲阻尼器的阻尼系数,实现对水锤波波形超调量、升压率及振荡的控制.     

中央空调水系统水锤效应对管道固定支架的影响及破坏分析

结合实际案例,本文从流体和空气两方面就水锤产生的原因进行了深刻分析,从气态现象和径向应力等方面就水锤对管道支架的影响及破坏进行了系统解析,从泵的软启动装置、检查及更换失效排气阀等方面就消除水系统管道水锤效应的方法进行了具体论析,试图对于预防中央空调水系统水锤效应带来的影响探索实践路径、提供参考思路。     

基于Bentley Hammer的气囊式空气罐的水锤防护研究

水锤现象在有压管道输水工程中不可避免,气囊式空气罐在高扬程中小流量输水工程中相比其他水锤防护措施体现出较好的可靠性和经济性。基于实际工程,应用商用软件Bentley Hammer对输水管道进行水力过渡过程分析,研究气囊式空气罐与多功能水泵控制阀和空气阀联合使用时的水锤防护效果及罐体的体积和气囊预设压力对水锤防护效果的影响。通过Bentley Hammer软件对无防护措施,加装多功能水泵控制阀和空气阀,多功能水泵控制阀、空气阀与气囊式空气罐联合使用3种情况建立数值模拟模型,在3台水泵同时停机时进行水力过渡过程分析。研究结果表明,在高扬程中小流量输水工程中加装气囊式空气罐能起到良好的水锤防护效果。对输水管道系统整体而言,气囊式空气罐的水锤防护能力随罐体体积和预设压力的增大而增强。合理选择气囊式空气罐的体积与预设压力,能使管道内水锤最大正压和负压得到有效控制,并取得最佳的社会经济效益。     

长距离输水管线水锤分析与数值解法研究

本文主要对长距离输水管线中水锤现象进行分析并对水锤方程的数值解法进行了研究,为更好地求解水锤方程,同时出于解决工程问题的需要,从传统的也是较为成熟的差分解法入手,最后将小波分析求解偏微分方程的思想引入到水锤方程,对水锤方程的数值解进行了探索性的研究。     

安康铁路水厂供水系统水锤危害综合防治

安康铁路水厂自建成投用以来，泵房设备、二级扬水管道长期受到水锤的危害，多次发生设备故障，几年来通过一系列有针对性的改造，消除了水锤的危害，确保了设备的安全运行。本文通过对改造过程实施和效果进行分析和介绍，总结出水厂水锤综合防治的方式和方法，对其它水厂水锤危害的防治有一定的借鉴意义。     

室内蒸汽管道及附属装置安装技术

本文结合工程实例,详细介绍了室内蒸汽管道及其过滤器、疏水阀、汽水分离器等附属装置的安装技术,以解决在施工过程中出现水锤和蒸汽流量减小的问题,可为类似的蒸汽系统施工提供实践参考.     

浅谈高寒地区长输供热管网水锤分析及防护措施

该文分析以应用“零→一→二级”供热管网结构为基础的长距离多级加压供热输水管网水锤危害防护的必要性;并通过模拟8种不同事故工况进行水锤分析,以保障长输供热热水管网安全地运行,免受水锤影响,为高纬度、极寒地区多级长输供热管网设计、施工及应用过程中的水锤防护提供实践经验。     

水锤方程的二次插值有限元解法

为了提高在每个有限元单元上的逼近精确度,一种途径就是提高Lagrange插值基函数的次数。讨论抛物型方程的有限元法,给出水锤方程的二次Lagrange插值基函数的有限元求解过程,为水锤方程的解法开辟一条新的途径和理论依据。     

基于混合模型方法的大型输水隧道水锤冲击响应数值分析

针对大型输水隧道水锤分析响应分析中由于超大计算规模和非线性强流-固耦合计算造成的数值计算困难,该文提出将混合模型方法应用到大型衬砌输水隧道水锤冲击响应的数值模拟中,通过该方法不仅可以得到输水隧道全程水锤压力,也可以得到关键区域衬砌环管片结构响应。模型中流场部分通过FLUENT计算得到流场节点压力和速度,然后通过初始条件或边界信息施加到结构部分进行LS-DYNA计算,水锤计算时流-固耦合通过基于ALE(Arbitrary Lagrangian-Eulerian)描述的罚函数实现。该文对上海某大直径双线输水隧道在水锤作用下的结构响应进行了分析,结果呈现了水锤压力在长距离输水隧道内的传播以及对衬砌结构的影响。     

Water pipeline failure due to water hammer effects

A numerical model has been established in order to simulate the propagation of pressure waves in water networks. The present model formulation is based on a system of partial hyperbolic differential equations. This system has been solved via the characteristics method. The current model provides the necessary data and the necessary damping of water hammer waves, taking into account the structure of the pipe network and the pressure loss. The numerical algorithm estimates the maximum pressure values resulting from the water hammer when closing valves in the network and consequently, the maximum stresses in the pipes have been calculated. In the case of simultaneous closing of several valves, the over pressure can exceed the admissible pressure. In this case, the severity of a defect such as a corrosion crater (pit) has been estimated by computing a safety factor for the stress distribution at the defect tip. This allows the applied notch stress intensity factor to be obtained. To investigate the defect geometry effects, semi‐spherical and semi‐elliptical defects are deemed to exist in up to one‐half of the thickness of the pipe wall. The outcomes have been introduced into the structural integrity assessment procedure (SINTAP) failure diagram assessment (FAD) in order to obtain the safety factor value. Conventionally, it is considered that a failure hazard exists if this safety factor is less than two.     

PLC在饮用水深度净化控制系统中的应用

根据系统工艺,分析饮用水处理过程的特点和对控制系统的要求,采用西门子S7-200 PLC对控制系统的软硬件进行合理配置,利用PLC强大的逻辑控制功能和较多的内部时钟,实现控制系统的净水过滤和正反冲洗定时时间,各加压泵、反冲洗电机及众多阀门间复杂的联锁控制,保证了控制系统的安全可靠运行,并在运行中取得良好效果。     

OPTIMAL OPERATION OF MULTIQUALITY WATER SUPPLY SYSTEMS-III: THE Q-C-H MODEL

A new technique for optimal operation of multiquality water supply systems is proposed. The technique, which is known as a Q-C-H (flow-quality-head) model, combines previously developed Sow-quality (Q-C) and flow-head (Q-H) models for optimal operation of water supply systems. The decision variables in the model are the operation of treatment plants, pumps and valves. The model minimizes the cost of water at sources, treatment, energy, and loss of agricultural yield when water quality is low. The model uses an iterative modified projected gradient method combined with the Complex method. As in the Q-C and Q-H models, the solution method is based on decomposition, dis-aggregation/aggregation approach, involving internal and external optimization. The decision variables of the external model are the flows in the loops of the network and the removal ratios at the treatment plants. The operation of the pumps and valves are the decision variables of the internal model. The method is demonstrated by application to an example problem.     

OPTIMAL OPERATION OF MULTI-QUALITY WATER SUPPLY SYSTEMS-II: THE Q-H MODEL

This paper describes the second in a series of three models for optimal operation of multi-quality water supply systems. This second model, which is termed the Q-H (flow-head) model, seeks to determine the optimal operation of pumps and valves, and does not consider water quality aspects. However, the model belongs to the group of three models Tor multi-quality systems because it is one of the two building blocks (the other is the flow-quality Q-C) of a full-llow-quality-head (Q-C-H) model. This Q-H model is based on continuous representations of the head-flow and power-flow functions of the pumping stations, which in turn results in a continuous non-convex optimization model. For a given flow distribution in the network, Q₀, the Q₀-H model is solved for the optimal operation of pumps and valves. The flow distribution is then modified by changing the circular flows, using a projected gradient method combined with the Complex Method which employs the results of the Q₀-H solution, such that the locally optimal solution at the next point has a better value of the objective function. The process is continued until one of the termination criteria is satisfied. The circular flows thus serve as decision variables in an external problem, while in the internal problem the decisions are the operation of pumps and valves. The method is demonstrated by application to a sample problem.     

有压管道水击波动过程及优化控制的解析研究

为了实现阀调节对有压管道水击过程的精确控制,获得水击波动过程的解析解很有意义。该文在详细分析水击基本微分方程组及初边值条件的基础上,将波动方程在有限区间内的行波解应用于线性水击波动问题中。通过给定阀门处速度变化规律,引入曲线积分与路径无关条件,得到了阀门关闭过程中管道内无因次水击压强的精确解析解。应用Ritz法求解泛函极值,得到了使管道阀门处峰值压强为最小值时所对应的速度变化及相应的关阀规律。以此构建程序控制,就可最大限度地削减水击压强,以求通过阀门来实施对水击过程的主动控制。     

Prediction of residual pipeline resource taking into account the operation loading conditions

An effective energy approach to the evaluation of the residual service life of a pipe of oil pipeline containing a crack on its inner surface for the two-frequency loading mode of biaxial tension-compression has been proposed. The two-frequency variations of pressure in the pipe are caused by the turbulence of the oil flow (high frequency), opening and closing of the gate valves, and the shutdowns of the pumps (low frequency). __________ Translated from Problemy Prochnosti, No. 1, pp. 44–52, January–February, 2009.     

超滤膜处理黄河水工程实例

山东滨化集团超滤系统设计出水每天10 080 t,原水为黄河水,2004年12月投运,至今已稳定运行6年整.报道了超滤膜材料,超滤系统错流量、反洗,化学加强反洗条件以及化学药洗周期等运行条件对超滤系统稳定运行的影响;报道了这些运行参数选择和优化结果.该超滤系统和多介质过滤器合并的运行直接吨水成本约0.24元.该工程运行参数对设计和运行自来水系统具有借鉴意义.     

CRE变频泵在火电厂输煤工业水系统中的应用

通过分析火电厂输煤系统水的应用特点,结合CR／CRE系列泵的应用,阐明了应用一体化变频泵于同类末端恒压供水系统,可起到按需供水、恒压控制、节约能源的目的。     

超滤膜渗透通量法评价水质的研究

提出了一种通过超滤膜水的渗透通量或渗透体积评价水质污染状态的新方法．从我国不同地区取来18种水质,包括井水、河水、海水、湖水,并用固定超滤膜的超滤实验装置进行了测试,水渗透体积和水通量随时间的变化可以表征水样中污染物的含量,以此描述水质的差别．由串联阻力模型推导出的修正污染指数（MFI）数学关系并结合渗透体积和水通量的实验数据拟合出18种不同水质的MFI．结果表明,水渗透体积随时间、渗透通量随时间及操作压力的变化与MFI值是一致的．并且从膜污染的理论上解释了超滤膜的实验结果．     

超滤膜净化水库水试验研究

用中空纤维超滤膜处理哈尔滨附近B水库水,以替代混凝、沉淀、砂滤的传统自来水生产方法,研究生产饮用水的新工艺.研究了原水温度、浊度、操作压力和混凝剂的加入量对膜通量的影响.研究发现超滤膜通量与膜进水浊度的对数成反比,跨膜压力增大、适当加入混凝剂,膜通量增加.超滤出水和传统工艺的出水进行了比较,超滤膜出水浊度小于0.2 NTU,明显好于传统工艺的出水浊度.对超滤处理后的出水水质进行了全分析,超滤对铁、铝、锰、色度、好氧量、总有机碳等均有较好的处理效果,完全满足饮用水水质的标准.