大管径直埋热力管道在实际工程中应力分析

发布时间：2018-07-20 14:03

【摘要】：因为供热管道直埋敷设技术具有能耗低、施工快、投资小、对周围环境影响小等优势，因此在我国得到迅速发展，1998年颁布了《城镇直埋供热管道工程技术规程》（CJJ-T81-98）。近年来，由于城市集中供热迅速增长，供热管道向大口径发展，很多供热工程管径已超过DN1000mm。然而，，国内现行的《技术规程》的使用条件限制管径等于或小于DN500mm，因此已不能满足大管径的设计需要，而且大管径应力的相关研究也不多。因此本课题提出针对大口径直埋供热管道的受力特点和应力验算条件进行研究，以指导供热管道的正确设计和安装。设计中，在充分考虑管道安全的基础上，尽可能的充分利用管道自身的强度特点，减少施工造价。本文对直埋热力管道的基础理论进行了分析，指出在小管径管道应力分析时忽略的影响因素，有很多影响因素在大管径管道应力分析时已经成为不能忽略的影响因素，如管道和介质的重量对摩擦力的影响等，并提出修正的计算公式。鉴于目前不少大管径实际工程的设计，由于应力计算和分析的不足，以至影响到固定墩、补偿器的数量，增加了工程的投资。本文针对一个实际工程设计进行了全面的应力分析与计算，做到在满足应力要求的基础上合理布置管道附件，大大减少了固定墩、补偿器的数量，并对其三通利用ANSYS软件进行了有限元分析，支持了三通的优化方案。本文研究的主要成果是把管道和介质重量考虑到摩擦力公式里，并用该公式对实际工程进行计算；过渡段长度计算时，考虑了内压泊松作用和内压不平衡作用的影响；计算固定墩推力时考虑了供回水管应力的不同；在进行环向应力计算时，利用的管壁壁厚是最不利条件下的壁厚，充分考虑了实际运行情况下出现刻蚀、焊接缺陷等因素。本研究发现在大管径直埋热力管道实际工程中，还有许多可以优化的部分。如果能够在设计时引起注意，重视这些部分，那么直埋大管径热力管道工程的造价会有显著的降低；其次随着计算机仿真技术的发展，有必要在设计时对容易破坏的部分，进行有限元分析，以此指导设计。
[Abstract]:Due to its advantages of low energy consumption, fast construction, small investment and little impact on the surrounding environment, the direct buried heating pipeline laying technology has been developed rapidly in China. In 1998, the Technical regulations for Urban Direct buried heating Pipeline Engineering (CJJ-T81-98) were promulgated. In recent years, due to the rapid growth of central heating in cities and the development of heating pipelines to large caliber, many heating engineering pipe diameters have exceeded DN1000mmm. However, the current domestic technical specification limits the diameter of pipe to be equal to or less than DN500mm, so it can not meet the design needs of large diameter, and there is not much research on the stress of large diameter. Therefore, this paper puts forward the research on the stress characteristics and stress checking conditions of large diameter direct buried heating pipeline, in order to guide the correct design and installation of heating pipeline. In the design, on the basis of taking full account of pipeline safety, as far as possible to make full use of the characteristics of the strength of the pipeline itself, reduce the construction cost. In this paper, the basic theory of directly buried thermal pipeline is analyzed, and it is pointed out that the influence factors neglected in the stress analysis of small diameter pipeline have become the influential factors which can not be ignored in the stress analysis of large diameter pipeline. For example, the influence of the weight of pipe and medium on the friction force and so on, and the modified formula is put forward. Due to the shortage of stress calculation and analysis, the number of fixed piers and compensators has been affected and the investment of the project has been increased. In this paper, a comprehensive stress analysis and calculation is carried out for a practical engineering design. The pipe accessories are reasonably arranged on the basis of satisfying the stress requirements, and the number of fixed piers and compensators is greatly reduced. The finite element analysis of the three links is carried out by ANSYS software, which supports the optimization scheme of the three links. The main results of this paper are that the weight of pipeline and medium is taken into account in the friction force formula, and the actual engineering is calculated by the formula, and the influence of the internal pressure Poisson action and the internal pressure imbalance action are considered in the calculation of the length of the transition section. In calculating the thrust of fixed piers, the different stresses of water supply and return pipes are considered, and the wall thickness of the pipe is the most unfavorable when the circumferential stress is calculated, and the factors such as etching and welding defects in actual operation are fully considered. In this study, it is found that there are many parts that can be optimized in the practical engineering of large diameter directly buried thermal pipeline. If attention can be paid to these parts in the design, the cost of directly buried large diameter thermal pipeline projects will be significantly reduced. Secondly, with the development of computer simulation technology, it is necessary to deal with the vulnerable parts in the design. Finite element analysis is carried out to guide the design.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU995.3

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