煤自燃实验过程中温度场的数值模拟研究 - 图文

太原理工大学硕士研究生学位论文

STUDY ON NUMERICAL SIMULATION OF TEMPERATURE FIELD OF COAL

SPONTANEOUS COMBUSTION EXPERIMENT PROCESS

ABSTRACT

Spontaneous combustion of coal is one of the main disasters in the coal industry, and brings great safety troubles to coalmine. As we know that the occurrence and development of coal spontaneous combustion is a very complicated, physical and chemical process, which fills dynamic changes and auto-acceleration, but it presents the temperature rises gradually macroscopically. So studies on the change of the temperature field of coal self-ignition process are helpful to clarify the occurrence and development of spontaneous combustion of coal.

Therefore, after some investigations and tests, the paper based on referring the foreign and domestic literatures and systematically generalizing the former research results analyses the form of temperature field and influencing factors with the collaboration of theoretical analysis, experiment simulation and computer simulation. Because of great deal of influencing factors and difficulty to follow, the experiment unit of coal spontaneous combustion was designed and built to simulate storing heat, air leak, granularity and thickness of locale

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太原理工大学硕士研究生学位论文

instance depending on the oxidation of coal giving out heat and run after the change of temperature and gas. After studies and analysis of the temperature field of samples from Kangjiatan, it was discovered that the hottest point appears around the axis, which moves to the enter side of the wind by the development of spontaneous combustion. The mathematical model was set up based on the theory of heat and mass transfer, which can be solved by numeric calculation methods, sequentially, to reducing the experimental quantity and saving cost. Finally, 3-D real time dynamic simulation of coal experiment unit was taken with the finite element analysis software MSC.NASTRAN, from which it is gained that the temperature of each coal point in the inner oven at a certain time and the temperature change of any point during the spontaneous combustion process. The result of simulation is identical to the experiment, which showed the dependability of the model.

Due to the marginal nature of coal heat characteristic research and the complexity of coal spontaneous combustion, the study on temperature field of coal spontaneous combustion is little. The paper preliminary discusses the temperature field of experiment units by ways of experimental and numerical simulation, in order to offer reference to study the occurrence and development of coal spontaneous combustion in practice circumstances.

KEY WORDS: coal spontaneous, temperature field, experiment, finite element method, numerical simulation, MSC.NASTRAN

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太原理工大学硕士研究生学位论文

目 录

第一章 绪 论 ............................................................. 1 1.1 问题的提出及解决方法 ................................................ 2 1.2 国内外研究成果综述 .................................................. 3 1.2.1 煤自燃机理研究现状 .............................................. 3 1.2.2 煤自燃火灾防治研究现状 .......................................... 5 1.2.3 煤自燃过程实验模拟研究现状 ...................................... 7 1.2.4 煤自燃数学模型和数值模拟研究现状 ................................ 8 1.2.5 有限元法、有限元软件的研究现状 .................................. 8 1.3 主要研究内容 ....................................................... 10 1.4 技术路线 ........................................................... 10 第二章 煤自燃过程中温度场的形成 ......................................... 12 2.1 煤自燃过程简介 ..................................................... 12 2.2 煤自燃升温的充要条件 ............................................... 13 2.3 煤自燃过程中温度场的形成及其影响因素 ............................... 14 2.4 煤自燃过程温度场研究的意义 ......................................... 17 2.5 本章小结 ........................................................... 18 第三章 煤自然发火温度场的实验研究 ....................................... 19 3.1 煤自然发火与测氡实验台简介 ......................................... 19 3.1.1 实验台炉体 ..................................................... 19 3.1.2 检测和控制系统 ................................................. 21 3.1.3 实验台特点 ..................................................... 23 3.2 康家滩煤样自然发火实验研究 ......................................... 23 3.2.1 实验条件 ....................................................... 24 3.2.2 实验过程及原始数据 ............................................. 24 3.2.3 实验结果分析 ................................................... 27 3.3 本章小结 ........................................................... 36 第四章 煤自燃实验台温度场数学模型及求解的基本理论 ....................... 37 4.1 求解温度场的传热学理论 ............................................. 37 4.1.1 温度梯度 ....................................................... 37 4.1.2 傅立叶定律 ..................................................... 37 4.1.3 热传递的基本方式 ............................................... 38 4.2 煤自燃实验台温度场的数学模型 ....................................... 39 4.2.1 温度场控制方程 ................................................. 39 4.2.2 初始条件和边界条件 ............................................. 41 4.3 煤自燃实验台温度场有限元求解的基本理论 ............................. 43

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太原理工大学硕士研究生学位论文

4.3.1 有限元法的基本思想 ............................................. 43 4.3.2 有限元法的基本特点 ............................................. 44 4.3.3 有限元分析的主要步骤 ........................................... 44 4.3.4 有限元法在煤自燃过程温度场研究中的适用性分析 ................... 46 4.4 本章小结........................................................... 46 第五章 煤自燃实验台温度场的数值模拟 ..................................... 47 5.1 MSC.NASTRAN基本介绍 ............................................... 47

5.1.1 软件构成 ....................................................... 48 5.1.2 热分析计算步骤 ................................................. 50 5.2 煤自燃实验过程的有限元模拟......................................... 50 5.2.1 建立有限元模型 ................................................. 50 5.2.2 计算结果及分析 ................................................. 54 5.3 本章结论........................................................... 59 第六章 结 论 ............................................................ 60 6.1 全文结论........................................................... 60 6.2 不足与展望......................................................... 61 参考文献 ................................................................ 62 致 谢 ................................................................... 66 攻读硕士学位期间发表的论文 .............................................. 67

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