论文总字数：23097字

摘 要

关键词：六分螺旋折流板；螺旋折流板换热器；热力设计；Visual Studio 2010

Thermal Design and Programming of Water-to-water

Sextant Helical Baffle Heat Exchangers

03312507 Zhang Hongyuan

Supervised by Chen Yaping

Abstract: Basic information and background of sextant helical baffle heat exchangers have been introduced in this article. The calculation method and formulae of sextant helical baffle heat exchangers were summarized and selected based on the shell and tube heat exchangers from the relevant literatures. The most widely used supporting component in conventional heat exchanger is segmental baffle, due to higher pressure drop, considerable stagnant dead zones, easy to scale, easy to vibration and other defects it has gradually been replaced by the helical baffle in recent years. The helical baffles form a continuous spiral channel. Such helical baffles can reduce the pressure drop by about 45% and increase the overall heat transfer coefficient by 20% to 30%, compared to the segmental baffle in the same conditions. Under the same thermal load, it can also greatly reduce the heat exchanger size. These features are especially promising for water-to-water heat exchangers of expensive Titanium material used in power plants. The equilateral triangle tube layout was eventually adopted because of its features of more compact and higher heat transfer efficiency than those of the square one. Both trisection and sextant helical baffle schemes can fit the nature interval of the equilateral triangle tube layout. The formal has less parts while the latter has smaller size more suitable for large to medium heat exchangers. The circumferential overlap helical baffles were adopted with rod holes located at the outermost periphery of the overlap zone of adjacent baffles for least rod and spacing tube assemblies. The row of tubes at overlap zone can damper the leakage at the conjunction of adjacent baffles and improve the heat transfer coefficient.

The calculation model was established for programming sextant helical baffle heat exchanger thermal design with Visual Studio 2010. The program including sextant helical baffle heat exchanger thermal and structural design calculations with a friendly user interface. The output results of the program can be directly used to draw the drawings. Based on the helical baffle angle and the tube layout, the cutting program of the sextant helical baffles can be converted. Finally, an example case was presented and draw the sixth helical baffle heat exchanger overall view of the spiral baffle rod bundle sets of plans and baffles figure.

Key words：sextant helical baffles; helix heat exchangers; thermal design; Visual Studio 2010

目 录

第一章 绪论 1

1.1研究背景 1

1.2螺旋折流板换热器简介 2

1.3六分螺旋折流板换热器简介 4

1.4软件环境简介 5

1.5本文的研究目的和主要研究内容 5

第二章 六分螺旋折流板换热器程序编制设计方法 6

2.1热力设计基本方法 6

2.2结构设计基本方法 6

2.3.1 计算有效温差 9

2.3.2 估算传热系数、传热面积 9

2.3.3 确定换热管系列 9

2.3.4 拉杆和定距管的确定 10

2.3.5 折流板尺寸计算 11

2.3.6 计算管内、管外传热膜系数 12

2.3.7 计算设计传热系数 14

2.3.8 校核传热系数 14

2.3.9 计算管内、管外阻力损失 14

2.3.10管内外流体介质随温度的物性方程 15

第三章 程序操作界面展示 17

第四章 实例试算 21

4.1 计算实例 21

4.2 计算结果 21

第五章 总 结 26

5.1 总结与讨论 26

5.2 问题和展望 26

致 谢 27

参考文献(References) 28

六分螺旋折流板闭式冷却器的热力设计

与程序编制

第一章 绪论

1.1研究背景

换热器是将热流体的部分热量传递给冷流体的设备，又称热交换器^[1,2]。换热器是能源动力、石油化工、食品安全及其它许多工业部门的必要设备，在生产工作过程中占有重要地位。在化工生产中热换热器可作为一个加热器、冷却器、冷凝器、蒸发器或者再沸器等，应用非常广泛。换热器种类很多，但根据不同流体（冷、热流体）热量交换原理和方式基本上可分三大类即：间壁式、混合式和蓄热式。换热器不仅在生产、工程应用中需要保证生产设备的正常运转，而且在动力消耗和投资建设等方面都占有重要份额，在生产工程中是必不可少的一部分。换热器是化工生产中重要的单元设备，根据统计，热交换器的吨位约占整个工艺设备的20%有的甚至高达30%，其重要性可想而知。同时，换热器的换热效率与能源的使用消耗尤其是可控制的浪费有着紧密的联系，所以在全球能源消耗日渐增多能源储备日趋减少、国家政策鼓励节约能源减少排放的背景下，合理的设计与使用换热器与能源的节约和再生使用有着紧密联系。国内在节能增效等方面改进换热器性能，提高传热效率，减少传热面积降低压降，提高装置热强度等方面的研究皆取得了显著成绩。换热器的大量使用有效的提高了能源的利用率，使企业成本降低，效益提高。

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