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毕业论文网 > 毕业论文 > 理工学类 > 热能与动力工程 > 正文

单根矩形翅片圆管的传热与流动分析毕业论文

 2022-07-13 10:07  

论文总字数:24808字

摘 要

翅片管热交换器是一种带翅片的管式热交换器,它可以有壳体也可以没有。翅片管热交换器在动力、化工、制冷等工业中有广泛的应用。随着工业的不断发展,工业缺水以及工业用水的环境污染问题越来越严重,空气冷却器的应用更引起人们的重视,致使在许多化工厂中有90%以上冷却负荷都由空冷器负担。与此同时,传热强化方面研究的进展,使得翅片管换热器在蒸发、冷凝方面的相变换热器得到广泛的应用。

本文分为三个部分:首先,对于翅片管式热交换器的定义、结构、国内外研究和发展现状进行综述。其次,本文通过理论计算设计了一台空气冷却器,以对其形成完整的全面的了解。最后,文中采用流体计算软件Icepak 对影响翅片管式换热器流动和传热性能的因素进行数值模拟分析。

在数值模拟中,本文先建立一个基本模型,通过尝试不同的算法参数、精确度参数、 网格参数等设置,对具有相同边界条件的同一模型进行数值模拟,并将模拟结果处理后与手工计算结果进行对比,选取结果最接近的一组作为后续模拟计算的参照组。然后文中将后处理的Re数、Nu 数、传热系数 h、范宁摩擦系数 f 、传热热阻 R 等数据与变量参数(翅片间距 S、翅片 厚度δ 、翅片高度 a)整理成折线图的形式,以定性分析各因素的具体影响趋势。

通过模拟计算并比较数据得出结果:随着迎面风速增大,Re数增大,Nu数增大,摩擦系数 f 减小,传热热阻R也减小;随着翅片间距增大,Nu数减小,摩擦系数 f 减小,对传热热阻R的影响较小;随着翅片厚度增大,Nu数增大,摩擦系数 f 明显减小,传热热阻R也显著减小;随着翅片高度增加,Nu数增加,摩擦系数 f 也增加,传热热阻R减小。所以在翅片管设计时应当把翅片间距、翅片厚度及翅片高度都作为主要的考虑因素。

关键词:矩形翅片管 数值模拟 传热特性 流动特性

Heat transfer and flow analysis of a single

Single rectangular fin tube

Abstract

Finned tube heat exchanger is a finned tube heat exchanger, it can not have to be the case. Finned tube heat exchanger is widely used in the power, chemical, refrigeration and other industries. With the continuous development of industry, environmental pollution problems of industrial water and industrial water and more serious, air cooler and more people pay attention to the application, resulting in more than 90% of the cooling load by air cooler burden in many chemical plants . At the same time, progress in terms of heat transfer enhancement research, making finned tube heat exchanger in the evaporator, condenser aspects phase change heat has been widely used.

This paper is divided into three parts: First, the definition of finned-tube heat exchanger, structure, research and development status at home and abroad are reviewed. Secondly, by theoretical calculation designed an air cooler to complete its comprehensive understanding of the formation. Finally, the paper uses computational fluid dynamics software Icepak factors affecting the finned tube heat exchanger flow and heat transfer performance of the numerical simulation analysis.

In the numerical simulation, this paper first create a basic model, by trying different algorithm parameters, the accuracy of the parameters, the grid parameters set for the same model with the same boundary conditions are simulated, and the simulation results with manual post-processing computing The results were compared to select a group as a result of the closest simulation of subsequent reference group. Then later in the number of Re deal, Nu number, heat transfer coefficient h, Fanning friction factor f, thermal resistance R and other data with variable parameters (fin spacing S, fin thickness δ, fin height a) finishing in the form of a line graph to qualitative analysis of the specific impact of each factor trends.

Calculate and compare data by simulating the outcome: With the head wind speed increases, Re number increases, Nu number increases, the friction coefficient f decreases, the thermal resistance R is also reduced; With the fin spacing increases, Nu number decreases, the friction coefficient f decreases, less impact on the thermal resistance of R; with the fin thickness increases, Nu number increases, the friction coefficient f significantly reduced thermal resistance R was also significantly reduced small; with the fin height increases, Nu number increases, the friction coefficient f increases, thermal resistance R decreases. Therefore, the fin pitch should be designed in a finned tube, fin thickness and fin height of a major consideration.

Keywords: Single rectangular fin tube ; numerical simulation; heat transfer characteristic; flow characteristic

目 录

摘 要 II

Abstract IV

符号说明 VII

第一章 绪论 1

1.1 引言 1

1.2翅片管的特点 1

1.3 翅片管 2

1.3.1翅片管简介 2

1.3.2翅片管国内外研究现状 2

1.3.3.矩形翅片管研究现状 3

1.4.结语 4

第二章 翅片管模型的建立 5

2.1 翅片管物理模型介绍 5

2.2翅片管几何模型 7

2.3 典型翅片管换热器—空冷器设计 9

2.4 小结 13

第三章 数值模型建立 14

3.1 Icepak软件介绍 14

3.2边界条件 15

3.3数值参数设定及模型建立 16

3.3.1 模型建立 17

3.3.2 网格划分 17

3.3.3 网格质量检查 18

3.3.4 网格划分展示 19

3.3.5 网格无关性检查 20

3.3 小结 20

第四章 数据处理及分析 21

4.1 传统理论计算方法 21

4.2 相关控制方程 23

4.3 模拟结果后处理计算 23

4.4 模拟结果云图分析 25

4.4.1温度场: 28

4.4.2速度矢量场: 30

4.4.3速度标量场 32

4.4.4压力场 33

4.5 模拟数据汇总及分析 33

4.5.3 翅片管高度对换热器流动和传热性能的影响 39

4.6 小结 42

第五章 结果与展望 43

5.1 结论 43

5.2 展望 43

致 谢 45

参考文献 46

符号说明

A0 表面或横截面面积 (m2 ) u,v, w x, y, z方向的速率 (m/s)

f 范宁摩擦系数 K0 平均换热系数 (W/m)

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