有压管道输水系统的瞬变特性及安全防护研究

发布时间：2018-06-05 19:12

本文选题：有压管道 + 水力瞬变　；参考：《太原理工大学》2014年硕士论文

【摘要】：迄今为止,大流量、远距离输水大多采用两种方式—渠道输水和管道输水。渠道输水相对古老,且有较大的水流渗漏与蒸发,对水资源的可持续发展不利,而管道输水作为一种新型输水方式,优势明显,在世界范围内的工业用水和城市生活用水中已被广泛采用。尽管管道输水优势明显,但在有压管道输水过程中,由于阀门的急剧关闭、开启及水泵机组的突然停机等常常造成管中瞬时高压或低压,严重破坏管道输水的安全性,造成重大经济损失和安全事故。因此,研究输水管路的水力瞬变理论,寻找控制及防护水力瞬变的方法措施,对确保工程的安全运行具有重要意义。随着现代大型远距离调水工程的持续发展,输水系统的瞬变特性及安全防护研究更越来越受到重视。本文以有压输水管道系统为背景,重点研究了模拟水力瞬变特性的IAB摩阻模型,提出了模型摩阻项的Simpson积分处理方法,并利用模型试验对提出的非恒定摩阻模型进行验证；研究了多种常用防护措施的适用条件及工作原理,并给出了其边界条件；发现并解决了在模拟实际输水工程中应用瞬变模型存在的问题。本文主要研究工作及成果包括： (1)详细阐述目前国内外关于瞬变摩阻模型及安全防护的研究现状,找出其中存在的问题及不足。 (2)基于对研究管道水力瞬变需要更准确的模型的认识,定性分析了几类瞬变摩阻模型,并给出了IAB摩阻模型中摩阻项的Simpson处理方法及其离散网格；利用模型试验,定量分析了准恒定摩阻模型及IAB非恒定摩阻模型的模拟结果与实测压力值的吻合程度,对比分析模型的优劣。 (3)通过对两个经验公式分别计算出的Brunone摩阻系数κ值进行算例分析,验证了系数κ原经验公式的准确性,并研究了系数κ对IAB模型的影响。 (4)在LAB模型的基础上,通过对不同关阀时间进行模拟,研究了关阀时间与最大间接水锤及其出现时刻间的关系；通过算例研究了Simpson差值网格计算的时间步长zΔt对模拟精度的影响,提出了At的合理取值范围。 (5)详细论述了多种瞬变流安全防护措施的防护机理及工作原理,并给出了相应的边界条件,为安全防护方案的选择提供依据。 (6)结合IAB摩阻模型和安全防护措施的边界条件,开发有压管道输水工程安全运行决策支持系统,并通过工程实例,对工程水力瞬变过程进行计算机仿真,提出输水系统安全合理的运行方式,验证系统软件的有效性。
[Abstract]:Up to now, two ways are used for large flow and long distance water delivery: channel water delivery and pipeline water conveyance. The canal water conveyance is relatively old, and has the bigger water flow leakage and the evaporation, which is unfavorable to the sustainable development of the water resources. As a new type of water conveyance, the pipeline water conveyance has obvious advantages. It has been widely used in industrial and urban water use all over the world. Although the pipeline water conveyance superiority is obvious, but in the pressure pipeline water conveyance process, because of the valve sharp closing, the opening and the pump unit sudden shutdown and so on, often causes the instantaneous high pressure or the low pressure in the pipe, seriously destroys the pipeline water conveyance safety. Cause great economic loss and safety accident. Therefore, it is of great significance to study the hydraulic transient theory of the pipeline and to find the methods and measures to control and protect the hydraulic transient in order to ensure the safe operation of the project. With the continuous development of modern large-scale long-distance water transfer projects, more and more attention has been paid to the transient characteristics and safety protection of water conveyance systems. In this paper, the IAB friction model which simulates the hydraulic transient characteristics is studied, and the Simpson integral treatment method for the friction term of the model is put forward. The model test is used to verify the unsteady friction model. The applicable conditions and working principles of various common protective measures are studied, and the boundary conditions are given, and the problems existing in the application of transient model in simulating actual water conveyance projects are found and solved. The main work and achievements of this paper are as follows: 1) the research status of transient friction model and safety protection at home and abroad are described in detail, and the existing problems and shortcomings are found out. 2) based on the understanding of the need for more accurate models for the study of pipeline hydraulic transients, several kinds of transient friction models are qualitatively analyzed, and the Simpson treatment method of friction term in IAB friction model and its discrete mesh are given. The simulation results of the quasi-constant friction model and the IAB unsteady friction model are quantitatively analyzed and compared with the measured pressure values, and the advantages and disadvantages of the model are compared and analyzed. 3) the accuracy of the original empirical formula of coefficient 魏 is verified by the example analysis of the Brunone friction coefficient 魏 calculated by two empirical formulas, and the influence of coefficient 魏 on the IAB model is studied. 4) on the basis of LAB model, the relationship between the time of closing valve and the maximum indirect water hammer and its appearance time is studied by simulating the different time of closing valve. The influence of the time step size z 螖 t of Simpson difference grid calculation on the simulation accuracy is studied, and the reasonable value range of at is proposed. The protection mechanism and working principle of various kinds of transient current safety protection measures are discussed in detail, and the corresponding boundary conditions are given to provide the basis for the selection of safety protection scheme. Combined with the IAB friction model and the boundary conditions of safety protection measures, a decision support system for safe operation of water conveyance project in pressurized pipeline is developed, and the hydraulic transient process of the project is simulated by computer through an engineering example. The safe and reasonable operation mode of the water conveyance system is put forward to verify the validity of the system software.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV134;TV672

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