论文总字数：20920字

摘 要

锅炉水冷壁管是锅炉的关键部件之一，长期承受着高温、高压及炉气、水蒸气的腐蚀和冲刷，工作环境恶劣。水冷壁管的变形、开裂往往会造成巨大的人身伤亡和财产损失。本文主要用等效建模的有限元方法对锅炉水冷壁的温度场模型及热行为进行研究，得出的出结论为等效建模的方法来研究本课题是可行的，相对误差是在允许的范围之内，并随着温度、载荷和管壁厚度的增加，锅炉水冷壁所受到的温度场、热应力和总变形都是增加的。但是厚度改变对水冷壁温度场、热应力和总变形的影响小于温度和载荷对水冷壁温度场、热应力和总变形的影响。总过程可以分三个部分进行，首先进行锅炉水冷壁的理论推导和计算、其次锅炉水冷壁的有限元模拟，最后进行不同模型的对比分析。主要是用有限元等效建模的方法，并通过和三维模型的对比来分析温度变化、载荷变化和管壁厚度变化时对水冷壁温度、热应力和总变形的影响规律，从而为锅炉的结构设计与安全运行提供参考和建议。

关键词：有限元；等效建模；等效应力；总变形；温度；

Study on Temperature Field Model and Thermal Behavior of Water Wall of Boiler

Abstract

Boiler water-wall tube is one of the key parts of the boiler, which has long been subjected to high temperature, high pressure and corrosion and erosion of furnace gas and steam, and the working environment is bad. Deformation and cracking of water-wall pipe often cause great personal casualties and property losses. In this paper, using the finite element method of equivalent model of boiler water wall temperature field model and to study the thermal behavior of of the conclusion for the method of equivalent modeling to study this subject is feasible, the relative error is in the permitted range, and with the increase of temperature, load and thickness of pipe, boiler water wall's temperature field, thermal stress and total deformation is increased. However, the influence of thickness change on the temperature field, thermal stress and total deformation of water wall is smaller than that of temperature and load. The whole process can be divided into three parts. Firstly, the theoretical derivation and calculation of boiler water-cooled wall are carried out, followed by the finite element simulation of boiler water-cooled wall, and finally, the comparative analysis of different models is carried out. This paper mainly uses the method of finite element equivalent modeling, and analyzes the influence law of temperature change, load change and pipe wall thickness change on water wall temperature, thermal stress and total deformation by comparing with the three-dimensional model, so as to provide reference and suggestion for the structural design and safe operation of boiler.

Key words: finite element;Equivalent modeling;Equivalent stress;The total deformation;Temperature;

目录

摘要 I

Abstract II

第一章 绪论 1

1.1 课题研究的背景与意义 1

1.2 国内外在该领域研究的现状 1

1.3 课题研究方案 2

第二章 水冷壁等效模型的计算 3

2.1 水冷壁的特点和重要性 3

2.2 等效建模水冷壁参数理论推导 3

2.2.1 等效材料参数 3

2.2.2 y方向的抗弯刚度 5

2.2.3 x方向的抗弯刚度及扭转刚度 5

2.2.4 等效厚度与等效密度 6

2.3 等效建模水冷壁参数计算 6

第三章 锅炉水冷壁的有限元分析 8

3.1 软件ANSYS Workbench介绍 8

3.2 基于ANSYS Workbench的水冷壁管板三维模型有限元分析 8

3.2.1 三维实体建模 8

3.2.2 三维模型边界条件赋值 10

3.2.3 三维模型的软件分析 12

3.3 基于ANSYS Workbench的水冷壁管板等效模型有限元分析 13

3.3.1 等效建模 13

3.3.2 等效模型边界条件赋值 14

3.3.3 等效模型的软件分析 16

3.4 不同模型的对比分析 17

3.4.1 压强改变时三维模型和等效模型的对比分析 17

3.4.2 温度改变时三维模型和等效模型的对比分析 21

3.4.3 水冷壁厚改变时三维模型和等效模型的对比分析 22

第四章 总结与展望 23

4.1 总结 23

4.2 展望 23

第五章 致谢 24

参考文献 25

绪论

1.1 课题研究的背景与意义

农作物秸杆作为一种农业生产的副产品，产量大、分布广，同时也是一项重要的生物资源。秸秆锅炉因其高效、低污染、施工快和投资效益高等综合因素，在国内外应用十分广泛。锅炉水冷壁向火侧内、外壁面温差大，应力分布会发生很大变化，而水冷壁温度过高或者应力集中会引起爆管，造成巨大经济损失，并影响锅炉的安全运行。水冷壁管沿炉膛高度的方向的温度变化较大，可能会造成水冷壁管整体向下膨胀，水冷壁向火侧向锅炉内部凸起变形，存在的变形量叠加可能会加剧水冷壁磨损，甚至可能可能发生爆管事故。

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