伴有水柱分离的长距离平坦管路停泵水锤综合防护研究

发布时间：2018-06-16 22:31

本文选题：水柱分离 + 长距离平坦管路　；参考：《长安大学》2017年硕士论文

【摘要】：近年来,随着我国社会经济的不断发展和人口的快速增加,人们对水的需求急剧增加。然而,我国水资源的分布受降水的影响,空间分布表现为南多北少、东多西少。为了解决水资源在空间上分布不均匀的问题,长距离输水工程应运而生,而且越来越得到重视。长距离输水工程建设中投入了大量的人力和财力,一旦发生事故,不仅造成巨大的经济损失,更会造成不好的社会影响,因此,保证输水管线安全运行非常重要。在实际工程中,我们需要对输水管线进行详细的水锤计算分析,根据分析结果选择经济合理的水锤防护措施从而保证长距离输水工程的安全运行。本文简要的阐述了长输压力管道气液两相流的流动特性和管道中气囊的升压原理及常用的排气方式。文中详细叙述了水锤数值模拟的特征线法,以特征线法为基础建立了如水泵、水池等特殊边界点在瞬变流过程中的数学模型;同时分析了蒸汽型和空气型两类断流空腔的产生原理及边界控制方程。全面的剖析了各类长距离输水过程中常用水锤防护设备的功能和适用条件,并推导了作为特殊边界点的控制方程;介绍了采用计算机语言编写计算源程序的流程。在长距离平坦管路输水工程中,水泵扬程较低,水泵机组转动惯量较小,管线较长,在停泵过程中水锤升压泵站附近及管线中往往会发生水柱分离和严重的空腔弥合水锤危害,而且管线坡度小,缺乏排气动力,管道中极易存气而产生压力振荡,故对其进行水锤模拟计算具有重要意义。在论文的最后,以湖北应城市城市供水汉江饮用水工程为例,建立了伴有水柱分离的长距离平坦管路的水锤计算模型,模拟计算了在事故停泵时管路的水锤升压情况,进行了普通排气阀、恒速缓冲排气阀、超压泄压阀、空气罐、箱式双向调压塔等多种水锤方案的比较分析,最终得出了选择以恒速缓冲排气阀作为最佳的排气设备,以箱式双向调压塔作为经济有效的稳压设备,采用两者联合的防护方案为最佳防护方案。本文对类似输水工程的水锤防护提供了一定的借鉴意义。
[Abstract]:In recent years, with the development of social economy and the rapid increase of population, people's demand for water has increased sharply. However, the distribution of water resources in China is affected by precipitation. The spatial distribution of water resources in China is as follows: more in the south, less in the north, less in the east and less in the west. In order to solve the problem of uneven distribution of water resources in space, long distance water conveyance projects have emerged as the times require, and more attention has been paid to them. A large amount of manpower and financial resources have been invested in the construction of long-distance water conveyance project. Once an accident occurs, it will not only cause huge economic losses, but also cause bad social impact. Therefore, it is very important to ensure the safe operation of water pipeline. In the actual engineering, we need to calculate and analyze the water hammer in detail, and select the economical and reasonable water hammer protection measures according to the analysis results to ensure the safe operation of the long distance water conveyance project. In this paper, the flow characteristics of gas-liquid two-phase flow in long distance pressure pipeline, the principle of air bag pressure rise and the usual exhaust mode are briefly described. In this paper, the characteristic line method for numerical simulation of water hammer is described in detail. Based on the characteristic line method, the mathematical model of special boundary points such as water pump and pool in transient flow process is established. At the same time, the generation principle and boundary control equation of two types of steam type and air type cutoff cavity are analyzed. In this paper, the functions and applicable conditions of various kinds of water hammer protection equipment used in long distance water conveyance are analyzed, and the control equations as special boundary points are deduced, and the flow chart of calculating source program with computer language is introduced. In the water conveyance project of long distance flat pipeline, the pump head is low, the moment of inertia of pump unit is smaller and the pipeline is longer. In the process of pump stopping, water column separation and serious cavity closing will often occur in the vicinity of water hammer pressure booster pump station and in the pipeline. Because of the small slope of pipeline and the lack of exhaust power, it is easy to store gas in the pipeline and produce pressure oscillation, so it is of great significance to simulate and calculate the water hammer. At the end of the paper, taking the Hanjiang drinking water project of Hubei Yingcheng water supply as an example, the water hammer calculation model of the long distance flat pipe with water column separation is established, and the water hammer pressure rise of the pipeline when the pump is stopped in the accident is simulated and calculated. The comparison and analysis of various water hammer schemes, such as common exhaust valve, constant speed buffer exhaust valve, overpressure relief valve, air tank, and box-type bi-directional pressure regulating tower, are carried out. Finally, it is concluded that the constant speed buffer exhaust valve is chosen as the best exhaust equipment. The box-type bi-directional pressure regulating tower is used as the economical and effective equipment for stabilizing the pressure, and the combined protection scheme is adopted as the best protection scheme. This paper provides some reference for water hammer protection of similar water conveyance projects.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU991.39

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