输配水管线水锤数值模拟与防护措施研究

发布时间：2018-03-12 22:49

本文选题：输配水管线　切入点：水锤　出处：《重庆大学》2013年硕士论文　论文类型：学位论文

【摘要】：供水管线是城市基础设施的重要组成部分，它的运行状况的好坏，与城市居民生活、工矿企业生产密切相关。然而，在输配水管线系统中，突然断电停泵、阀门误操作等原因引起管内流速的突然变化，导致破坏性水锤的发生，因此，选用合适的水锤防护措施，对水锤进行理论分析和预测控制研究，是优化工程设计，保障输配水管线的安全运行的重要前提，具有重要的理论意义和实用价值。论文基于HAMMER水锤分析软件对输配水管线水锤进行数值模拟及防护措施研究。首先介绍了水锤基本理论和计算方法，阐述了HAMMER软件的建模功能、建模原理、建模数据及建模步骤，并对中试装置HAMMER软件数值模拟结果进行实验验证；其次，采用响应曲面法设计模拟方案对简单管路关阀水锤影响因素进行了分析，并基于风险矩阵对水锤风险进行评估。最后，以某高扬程加压供水管线水锤防护为例，分析了空气阀、两阶段关闭蝶阀、水泵转动惯量、单向调压塔、双向调压塔、空气罐、二级止回阀、沿线节点出流的水锤防护特点及影响其防护效果的各个因素，提出了各防护措施的适用范围，以某长距离大流量输水管线水锤防护为例，提出了此类工程水锤防护的解决方案，以某区域供水管网水锤计算为例，分析了突然断电停泵、水泵转速变化、阀门快速关闭、节点流量变化四种水锤工况的特点，提出了管网局部管线水锤防护的措施。主要得到如下结论： ①中试装置水锤数值模拟结果实验结果基本一致，HAMMER软件所采用的数学模型和求解算法是比较合适的，用于实际工程可得到较为准确的结果。 ②管路系统流量越大、高差越大、管线越长、波速越大、关阀历时越短，阀前最大水锤压力就越大，并且各因素对阀前最大压力的影响显著。某高扬程加压供水管线和某长距离大流量输水管线水锤风险等级属于高危险级，因此需采取水锤防护措施，以消减风险。 ③空气罐宜在流量较小、扬程较高的情况下使用，空气罐最佳设置位置为泵出口止回阀附近，选择合适的连接管管径、罐内初始压力、空气罐容积，其水锤防护效果较好；而两阶段关闭蝶阀与空气阀方案、单向调压塔方案在坡度较陡的高扬程系统中，其消除负压作用有限；采用转动惯量较大的水泵，有助于水锤防护，可作为辅助措施；单、双向调压塔分别宜设置在易发生断流弥合水锤的节点、泵出口附近，双向调压塔因其设置高度和引起水质“二次污染”等问题，，不适合在高扬程供水管线中使用；如果供水管线有沿线节点出流，优先考虑易发生断流弥合水锤的点出流，以削弱水锤升压；二级止回阀方案能降低泵前止回阀压力，保护泵站附近管线，当与空气阀或调压塔联用时，能降低二级止回阀前的压力，但对负压的防护作用有限。 ④通过合理设置空气阀和水击泄放阀，能有效消除大流量长距离重力流输水管线阀门误操作引起的正压和负压水锤，并且能满足不同流量下的关阀水锤防护要求；其解决方案可为同类型工程水锤防护提供参考与借鉴。 ⑤管网中停泵水锤对管网压力的影响与用水量有关；当管网采用调速泵供水时，水泵转速的变化对管网中节点压力波动有影响；管网中阀门快速关闭对管网中压力变化与阀门的位置有关；管网中某节点流量突然增大时，会对管网中其它节点压力有影响，其影响与节点距离有关；断电停泵事故对整个管网压力有影响，应作为水锤防护最不利工况考虑，对管网局部管线水锤防护时，可考虑采用空气阀、水击泄压阀等水锤防护措施。
[Abstract]:The water supply pipeline is an important part of city infrastructure, its running status is good or bad, and city residents, industrial and mining enterprises production are closely related. However, in the pipe line system, the sudden shutdown of pump valve misoperation caused by sudden change of flow velocity in the tube, resulting in destructive water hammer occurrence therefore, selection of appropriate water hammer protection measures, to analyze and predict the control theory of water hammer, optimizing engineering design, an important prerequisite for ensuring the safe operation of the pipe line, and has important theoretical significance and practical value.
Based on the HAMMER analysis software for numerical simulation of water hammer and protective measures of water hammer water distribution pipe line transmission. This paper first introduces the basic theories of water hammer and the calculation method, expounds the modeling function of HAMMER software, the modeling principle, data modeling and modeling steps, and the pilot experiments are carried out to verify the numerical simulation results of device HAMMER software; secondly, using the the surface is used to design simulation programs off valve water hammer effect on simple pipeline was analyzed based on the risk response and risk assessment matrix of water hammer. Finally, taking a high lift pressure water supply pipeline water hammer protection as an example, analyzes the two stages close air valve, butterfly valve, pump inertia, one-way pressure regulating tower, two-way Surge Tower, air tank, two level check valve, each node along the flow characteristics of water hammer protection and the effects of its protective effect, put forward their applicable scope of protection measures, to a certain Long distance and large flow water pipeline water hammer protection as an example, proposed solutions to this kind of project of water hammer protection, a regional water supply pipeline water hammer calculation as an example, analyzes the sudden shutdown of the pump, the pump speed changes, quick closing valves, characteristics of node flow changes of four kinds of water hammer conditions, put forward the network local pipeline water hammer protection the main conclusions are as follows:
(1) the experimental results of the water hammer numerical simulation results of the pilot plant are basically the same. The mathematical models and solving algorithms adopted by HAMMER software are relatively suitable, which can get more accurate results for practical engineering.
The pipeline system flow is larger, the greater the elevation, the pipeline is longer, the wave velocity, the shorter the duration of closing valve, the valve before the maximum water hammer pressure is bigger, and the influence of various factors on the maximum pressure valve before significant. A high lift water supply pipelineand a long distance and large flow water pipeline water hammer risk level belong to the high risk level, therefore need to adopt water hammer protection measures, to reduce the risk.
The air tank should be in the flow of small, the use of lift is high, the best position for the air tank near the pump outlet check valve, select the appropriate connection pipe diameter, initial pressure tank, air tank volume, the better the effect of water hammer protection; and the two stage closed butterfly valve and air valve, one-way pressure regulating tower in high lift system in a steep slope, the negative pressure limited elimination; with larger rotational inertia of pump, help water hammer protection, can be used as auxiliary measures; single, two-way pressure regulating tower should be separately set in susceptible nodes the drying up of the water hammer pump near the exit, two-way pressure due to its set height and the water quality caused by the "two pollution" and other issues, not suitable for use in high lift water supply pipeline; if the water supply pipeline along the flow priority node, prone to collapsing water hammer out flow, to reduce water hammer pressure The two level check valve scheme can reduce the pressure of the pump check valve and protect the pipeline near the pump station. When combined with the air valve or surge tank, it can reduce the pressure of the two level check valve, but it has a limited protective effect on the negative pressure.
Through the reasonable setting of air valve and water hammer relief valve, can effectively eliminate the large flow and long distance gravity flow water transfer pipeline valve caused by misuse of positive and negative pressure of water hammer, and can satisfy the closing valve water hammer protection under different flow requirements; the solution can provide reference for the same type of engineering water hammer protection.
The network of water hammer effect on pipeline pressure and water; when the pipeline by variable speed pump water supply, pump speed changes have a significant effect on the pressure fluctuation in the network nodes in the network; quick closing valves on the change of pipe network pressure and valve position; increasing network node flow when a sudden, there will be the impact on other nodes in the network and the influence of pressure, the pump power node distance; accident impact on the whole network pressure, should be the most unfavorable condition of water hammer, water hammer of network local pipeline protection, may adopt the air valve, water hammer pressure relief valve and water hammer protection measures.

【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU991.39

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