单根H型翅片椭圆管的传热与流动分析毕业论文
2022-07-13 22:03:21
论文总字数:31501字
摘 要
管翅式换热器是一种常见的换热器,在工业和民用设施中有着广泛的应用。
文中分为三个部分:首先,文章对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,分别就不同翅片间距、翅片厚度、翅片高度等个因素对翅片管换热器的传热系数、范宁摩擦系数、传热热阻这三个流动及传热特性参数的影响进行数值模拟分析。其中,选取不同迎面风速2.3,2.8,3.3,3.8,4.3,不同翅片间距6,7,8,9,10,不同翅片厚度0.6,0.8,1,1.2,1.4,不同翅片长23,25,27,29,31,不同翅片宽9,10,11,12,13。
通过模拟计算并比较数据得出结果:随着迎面风速增大,数增大,数增大,摩擦系数减小,传热热阻也减小;随着翅片间距增大,数减小,摩擦系数减小,对传热热阻的影响较小;随着翅片厚度增大,数增大,摩擦系数明显减小,传热热阻也显著减小。
关键词:H型翅片椭圆管 数值模拟 传热特性 流动特性
Analysis of flow and heat transfer in single H-type fin tube
Abstract
Fin and tube heat exchanger is one of the common heat exchanger ,it is widely used in industrial and civil facilities.
From the global view, the paper will be departed into three stages. Firstly, a roughly review of the definition, structure, domestic and foreign research and the current development conditions about finned tube heat exchanger was given. Secondly, in order to form a more comprehensive understanding of the heat exchanger, an air-cooler through traditional theoretical calculation methods was designed. Finally, the numerical simulation analysis was carried out about how the following five factors(fin spacing, fin thickness,fin long half shaft,fin short half shaft ) impact the flow and heat transfer characteristics of finned tube heat exchanger with the fluid calculation software-Icepak.
In the part of establishing numerical model, three steps have to be accomplished. changing one of the five assumed factors (fin spacing, fin thickness, fin height,fin long half shaft,fin short half shaft ) alone and collecting enough useful dates for some more analysis in detail helped to find the specific influence mechanism on the heat transfer coefficient, the fanning friction factor and the heat transfer resistance of finned tube heat exchanger. Additionally, in the actual simulation process, the wind speed was set to 2.3,2.8,3.3,3.8,4.3,,The factors were considered separately: fin Spacing(6,7,8,9,10),fin thickness(0.6,0.8,1,1.2,1.4),fin long half shaft(23,25,27,29,31),fin short half shaft (9,10,11,12,13).
At last, after the numerical simulation and comparative analysis, the following results can be achieved: with the increasing of wind speed, thenumber, and number are both enhanced, while the fanning friction factorand the thermal resistance of decrease; with the increasing of fin spacing, thenumber and the fanning friction factor both experience a decreasing process, but the heat transfer resistance remains basically unchanged; with the increasing of fin thickness, the number increase which means that the heat transfer is enhanced remarkably, but on the contrary, the fanning friction factorand the thermal resistance ofreduce significantly; With the increasing of fin height, thenumber and the fanning friction factor both ascend, while the heat transfer resistance go through a decreasing process.
Keywords: H finned elliptical tube;numerical simulation;heat transfer characteristic;flow charact- eristic
目 录
第一章 绪论......................................................1
1.1 引言....................................................1
1.2 H型翅片椭圆管的简介..................................1
1.3 国内外对椭圆翅片管的研究.............................2
1.4 椭圆翅片管的应用......................................3
1.5 结语....................................................3第二章 翅片管模型建立.........................................4
2.1 翅片管物理模型及介绍...................................4
2.1.1管束...............................................4
2.1.2翅片...............................................5
2.1.3 风机.............................................. 5
2.2 翅片管几何模型..........................................6
2.4 软件模拟结果与理论计算结果对比......................12
2.5 小结....................................................13
- 数值模型建立...........................................14
3.1 边界条件................................................14
3.2 数值参数设定及模型建立................................14
3.2.1 模型建立............................................15
3.2.2 网格划分............................................16
3.2.3 网格质量检查........................................16
3.2.4 网格划分展示........................................17
3.2.5 网格无关性检查......................................18
3.3 小结....................................................19
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......................................24
4.5 模拟数据汇总及分析................................... 32
4.5.1 翅片间距对换热器流动和传热性能的影响...............32
4.5.2 翅片厚度对换热器流动和传热性能的影响...............35
4.5.3 翅片长轴对换热器流动和传热性能的影响...............36
4.6 小结....................................................38
第五章 结果与展望............................................. 39
5.1 模拟结论...............................................39
5.2 未来展望...............................................39
参考文献.........................................................40
致谢..............................................................42
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