论文总字数：21375字

摘 要

热管一直是现代工业发展必不可少的一个组成部分。而随着科技的迅速更新迭代，工业上对热管的功能与更高的传热性能提出了要求，单管热管换热器应运而生。单管热管换热器是一种最简单的换热器，将研发的资源全部投入到最小的一个单元。然而麻雀虽小五脏俱全，单管热管对于整个热管发展甚至传热学有着举重若轻的影响。因此本文利用ANSYS中的Fluent组件进行建模，试图通过数值模拟研究找出最佳的单管热管换热器所要具备的条件。

此篇文章详细叙述了热管传热的相关原理、传热特性及数值模拟的相关技术，并通过改变热管换热过程中的各项参数来探究如何使得热管在最优条件下进行稳定的换热过程。众所周知，热管的传热性能优劣受着许多因素的影响，比如热管长度、热管直径、工作流体、冷水进口温度、热管材料、热管是否内外表面处理等等。故本文通过建立数个单管热管换热系统的数值模型，在初始冷水温度（10℃）、热管长度（360mm）、工作流体(水)、热管材料（不锈钢）、热管长度(360mm）确定的情况下建立一个单管热管换热器模型。建立模型后经过模型验证和网格划分后，算出翔实的数据，再分别单独改变工作流体（石蜡，水，月桂酸）得出不同模拟的结果，并根据数值模拟结果画出折线图对该系统的换热过程进行分析。得出最优的换热状态结论。

关键词：单管热管换热器 数值模拟 传热影响因素 工作流体

Numerical simulation of single-tube heat pipe heat exchanger

Abstract

Heat pipe has always been an indispensable part of modern industrial development. With the rapid update and iteration of science and technology, the industrial heat pipe function and higher heat transfer performance requirements, single-tube heat pipe heat exchanger came into being. As a heat exchanger with excellent heat transfer performance, single-tube heat exchanger is widely used in chemical industry, energy, refrigeration and other fields. Coupled with the increase in the price of heat exchanger materials, the single-tube heat exchanger with high efficiency has become a big hit. Therefore, Fluent component in ANSYS was used for modeling in this paper to try to find out the conditions for the optimal single-tube heat pipe heat exchanger through numerical simulation.

This paper describes in detail the relevant principles of heat pipe heat transfer, heat transfer characteristics and related technologies of numerical simulation, and explores how to make the heat pipe heat transfer process stable under optimal conditions by changing various parameters in the heat pipe heat transfer process. As we all know, the heat transfer performance of the heat pipe is affected by many factors, such as the length of the heat pipe, the diameter of the heat pipe, the working fluid, the temperature of cold water inlet, the material of the heat pipe, whether the heat pipe is treated with internal and external surface, and so on. Therefore, this article through the establishment of a number of numerical model of single tube heat pipe heat exchanger system, during the initial cold water temperature (10 ℃), the length of the heat pipe (360 mm), the working fluid (water), heat pipe material (stainless steel), under the condition of heat pipe length (360 mm) to determine a single tube model of heat pipe heat exchanger. Model after the model validation and meshing, full and calculate the data, then change separately the working fluid (water, lauric acid, paraffin) different simulation results, and draw a line chart according to the results of the numerical simulation of the heat transfer process of the system are analyzed. The conclusion of optimal heat transfer state is obtained.

Keywords: single-tube heat pipe heat exchanger; Numerical simulation; Influencing factors of heat transfer; Working fluid

目录

摘 要 Ⅰ

Abstract Ⅱ

符号表 Ⅳ

第一章 绪论 1

1.1课题背景 1

1.2热管的工作原理 2

1.3换热器的发展与热管换热器的结构和特点 3

1.4数值模拟技术介绍 6

1.5数值模拟在本课题中的应用 7

1.6本课题的意义 7

第二章 换热器内流体的流动与传热模型的建立 8

2.1几何模型 8

2.2模型假设 10

2.2.1 ANSYS Fluent中物理模型概述 10

2.2.2在运动的参考系中流动 11

2.3网格的划分 11

2.3.1网格的划分介绍 11

2.3.2控制方程 13

2.3.3湍流模型方程 13

2.4边界条件 14

2.5网格独立性验证 15

2.4相关蓄热参数 16

2.6模型验证 17

第三章 结果与讨论 19

3.1温度、速度云图与换热效率折线图 19

3.2结论 22

3.3不足与未来的改进 22

参考文献 24

致谢 26

1. 绪论

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