论文总字数：21600字

摘 要

作为热量传递中的过程设备，换热器在工业以及生活各个方面都有着极为广泛的应用。因为现今各种能源的短缺，所以换热器的合理设计、运转和改进对于节省资金、材料、能源和空间而言相当重要。翅片管换热器作为一种紧凑式换热器，并且拥有很高的换热效率，因此在生活中应用十分普遍，例如干衣机。而叉排倾斜圆翅片热管换热器传热效率到底如何是本文研究的宗旨。

本文利用流体计算软件Icepak，通过改变翅片间距、翅片高度、翅片厚度、管间距、以及迎面风速，分析其对换热器的传热系数h、传热热阻R的影响。其中选取不同翅片间距3mm、4mm、5mm、6mm，不同翅片高度6mm、8mm、10mm、12mm，不同翅片厚度0.4mm、0.6mm、0.8mm、1mm,不同管间距30mm、34mm、38mm、40mm以及迎面风速3m/s、4m/s、5m/s、6m/s。计算结束后，对模型的温度场、速度矢量场、速度标量场以及压力场进行分析，以了解传热与流动情况。之后处理Re数、Nu数、传热系数h、传热热阻等数据与各变量参数整理为折线图，以定性分析其影响。

数值模拟结果表明：随着迎面风速的增加，表面传热系数和流动阻力显著增加，传热热阻减小；随着翅片间距的增加，Nu减小，流动阻力减小；表面传热系数和流动阻力随翅片厚度的增加呈单调增加的趋势；而随着翅片高度的增加换热系数增加，热阻减小，但增幅范围很小。本文数值模拟可为换热器的设计与实验提供参考。

关键词：圆翅片、传热系数、流动阻力、数值模拟

Analysis on heat transfer on cross arrangement of tilt circular fin heat pipe exchanger for clothes dryer

ABSTRACT

The heat pipe exchanger, a process equipment of heat transfer, is widely used in the industry. Due to the shortage of energy, so the reasonable design,and improve the operation for saving money, materials, energy and space of heat pipe exchanger is quite important. As a kind of compact heat exchanger, and has high thermal efficiency, so has been widely used in the life, for example a clothes dryer.And my topic about heat transfer efficiency of the heat pipe exchanger is the aim of this article.

With changing one of the three variations, fin pitch, fin thickness and fin height, numerical simulation were performed with the help of the fluid calculation software, Icepak, to analyze the effects to the heat exchanger on the heat transfer coefficient, the heat transfer resistance and pressure drop, In the actual simulation process, the wind speed was set to 3m/s、4m/s、5m/s、6m/s. The three variations were considered separately with fin pitch (3mm、4mm、5mm、6mm) and fin height（6mm、8mm、10mm、12mm）. After the calculation, some distribution maps, such as temperature field, the velocity vector field and the pressure field, were read to analyze the performs of the heat transfer and flow. After all the simulation was done, drafting the Re number, Nu number, heat transfer coefficient h and heat transfer resistance R with the variable parameters into line graph forms made it convenient to analyze the three specific factors’ influencing trend on finned tube exchanger.

Numerical simulation results showed that both heat transfer coefficient and pressure drop increased with the increase of head wind air velocity, while the thermal resistance of R decreased.With the increasing of fin pitch, the Nu number and flow resistance both experience a decreasing process. The heat transfer coefficient and pressure drop increased with the increase of fin thickness. With the increasing of fin height, the heat transfer coefficient have increased, the thermal resistance reduced. The results will provide a reference to the design and experiment of the clothes dryer.

Key words:circular fin; heat transfer coefficient; numerical simulation

目 录

摘要…………………………………………………………………………………I

ABSTRACT………………………………………………………………………II

符号表 ……………………………………………………………………………III

第一章 绪论

1.1热管换热器简介……………………………………………………………1

1.2热管换热器研究现状………………………………………………………1

1.3课题研究意义及方法 ……………………………………………………4

第二章 热管换热器模型建立

2.1Icepak软件介绍 …………………………………………………………5

2.2物理模型 …………………………………………………………………6

2.3几何模型 …………………………………………………………………6

2.4边界条件 …………………………………………………………………8

2.5网格划分 …………………………………………………………………9

第三章 数据处理及分析

3.1对流传热问题完整的数学描述 …………………………………………13

3.2理论计算 …………………………………………………………………13

3.3模拟结果后处理 …………………………………………………………15

3.4模拟结果后处理与理论结果对比 ………………………………………17

3.5模拟结果云图分析 ………………………………………………………17

3.6模拟数据汇总及分析 ……………………………………………………24

第四章 换热器的设计

4.1给定数据及物性参数 ……………………………………………………31

4.2计算传热量Q ……………………………………………………………31

4.3冷空气出口温度t₂^C及对数平均温差_m ………………………………32

4.4 确定迎风面积及迎风面管排数 ……………………………………33

4.5 求总传热系数 ………………………………………………………33

4.6求加热侧总传热面积 ………………………………………………35

4.7 求所需热管数n …………………………………………………………36

4.8 求换热器纵深排数 m……………………………………………………36

4.9 求通过热管换热管的压力降 …………………………………………36

参考文献…………………………………………………………………………38

致谢………………………………………………………………………………40

符号表

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