论文标题:直埋管道温度场计算与分析
Game Model and Throughput Forecast Based on Neural Network of Container Port
论文作者 程艳
论文导师 沈胜强,论文学位 硕士,论文专业 热能工程
论文单位 大连理工大学,点击次数 204,论文页数 60页File Size3088k
2004-05-01论文网 http://www.lw23.com/lunwen_1392892/ 直埋技术,直埋管道,边界元方法,复合保温结构,格林函数基本解
directly buried technology; directly buried pipe; boundary element method; multi-layer insulation; Green"s function fundamental solution.
直埋敷设技术较之架空敷设和地沟敷设有许多优点，诸如占地面积小、施工快、保温性能好、使用年限长、工程造价低、节省建筑材料、节省土方及人力等特点，具有明显的经济效益和社会效益。热水管道无补偿直埋技术己趋于成熟，在城市热力管网建设中得到了广泛的应用，人们正试图将直埋管道技术应用于输送蒸汽。由于介质温度高，保温结构多采用多层复合形式。但目前在各层的结构、厚度等参数确定方面缺乏依据，保温材料未能有效发挥作用，也引发了一些安全事故。开发科学的复合保温设计方法，是保证多层复合保温直埋管道技术得以发展的关键所在。 设计科学合理的复合保温结构，必须解决保温结构中，尤其是各层界面的温度、热流率的计算。本文介绍了一种用边界元方法分析复合保温结构中温度场的方法，并编制出相应的计算程序。 第一章阐明了课题的研究意义和应用价值，简单介绍了本文所用的数值计算方法一边界元方法的发展历史和优点，同时介绍了本文的主要工作。 第二章首先说明了加权余量法的原理，并由此推出了势问题的边界元积分方程，还介绍了无限域中格林函数的基本解的求法，以及多介质域和第三类边界条件的处理方法，最后说明了边界积分方程的数值解法。 本文的主要工作是第三章。在这一章中，讲述了具有复合保温结构的单根埋管和多根埋管问题的数学模型的建立和编制程序的方法。本章还介绍了绝热层经济厚度的概念和编写绝热层经济厚度优化计算程序的方法。该章还给出了程序的各个界面图形和两个子程序框图，还说明了程序的使用方法。 第四章是本文的重点，首先通过对有分析解的具有单层保温结构的单根直埋管道导热问题的计算，证明了所编制的程序是可信的，结果比较精确。然后计算了有复合保温结构的直埋管道的导热问题和各种给定条件下的保温层厚度，对多个算例结果的比较，总结分析出了一些规律。 最后在第五章中对本文的工作进行了总结，归纳了研究结论。
The directly buried technology has manifest economical and social benefit for small area, quickly built, good performance of heat preservation, long service life, low cost, saving construction material and manpower, environmental factors and so on. Technologies of directly buried hot water pipes have been mature and are widely used in thermal pipe network of a city. Now people are trying to apply those technologies to steam transportation. For its high temperature, multi-layer insulation is used. But as a result of lacking parameters about the form of layers and thickness of layers, insulation layers aren"t used effectively and some accidents are caused as well. Developing a method of designing insulation layers is key to advance technologies of multi-layer insulation pipes.Effective forms of multi-layer insulation can"t be gotten unless the temperature and the rate of heat flow in insulation layers, especially in the boundary of insulation layers can be calculated. In this paper, the heat transfer problem in directly buried pipes with multi-layer insulation was solved by boundary element method and the corresponding computer program was designed.The first chapter presents the significance and its values in the practice of the task. It briefly introduces the development history of BEM and its advantage. The main task of this paper is presented in the chapter.In the second chapter the theory of weighted residual technique is illustrated and the boundary integral function of the potential problem is deduced by it. Method of obtaining Green"s function fundamental solution is presented. It also illustrates how to deal with inhomogeneous regions and the third boundary condition. At last the numerical solution of boundary integral function is presented.The third chapter is the major work of the paper. It deals with mathematic model construction of the problem and ideas of designing the computer program. It also introduce the concept of economical thickness of insulation layer and how to design the computing program to optimize the thickness of insulation layer. It also presents interface of the program, the frame figure of a subprogram and explains how to use the program.The fourth chapter is the emphasis of the paper. At first, the program calculates an instance that can be solved by analytical method. By comparing the results obtained by the two methods it demonstrates that the program is credible and its result is precise. Then some rules are achieved by analyzing the results of many different cases.Finally in the fifth chapter an overview of the thesis is made and the research in future is foreseen.
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