论文总字数：28924字

摘 要

如今流体的流动传热在能源、石油、动力、航空、化工、医学等各个领域得到了广泛的应用。为了提高能源利用率，减小在传热过程中的热阻以及流体流动阻力，必须要开发强化传热技术。基于此背景，本文进行单相流体流动传热实验，来揭示影响通道表面传热系数的因素以及摩擦阻力系数和雷诺数之间关系。

实验分为两部分，流动实验和传热实验。首先，以水和无水乙醇为工质进行流动实验，实验结果表明，随着雷诺数的增加，摩擦阻力系数随之下降，并且通道内的两种工质在层流范围内摩擦阻力系数均大于常规尺度经验公式计算值。这表明，摩擦阻力系数与通道结构尺寸、流量、工质物性均相关。

其次，以水、无水乙醇、乙二醇为工质，在不同加热功率、不同流量下进行传热实验。通过求解计算，得到传热系数的值，分析其传热特性发现，通道表面传热系数随着雷诺数的增加而急剧增大，但是加热功率影响较小。此外，还发现不同流体与壁面间的传热系数也截然不同，流体物性也影响着传热系数的大小。

关键词：单相流体；传热系数；矩形微通道；摩擦阻力系数；雷诺数

Experiments about flow and heat transmission of single-phase fluid

Abstract

Nowadays, the flow and heat transmission of single-phase fluid has been widely used in various fields, such as energy, petroleum, power, aviation, chemical industry, medicine and so on. In order to improve the energy efficiency, reduce the heat resistance and lower the fluid flow resistance in heat transmission process, technology must be developed to enhance the heat transmission. Based on this background, experiments about flow and heat transmission of single-phase fluid have been conducted to reveal the influence factors of heat transmission on the surface of the channel and find out the relationship between the friction coefficient and Reynolds number.

The experiment is divided into two sections, the heat transmission experiment and the flow experiment. Firstly, we conduct the flow experiment with anhydrous ethanol and water as working fluids. The result shows that, when the Reynolds number increases, the friction coefficient decreases. Both working fluids’ value of the friction coefficient in the channel is larger than that of conventional scale empirical formula. It indicates that the friction coefficient is related to the size and the structure of the channel, quantity of flow, and physical properties of the fluid.

Then, we conduct heat transmission experiment with water, ethanol and ethylene glycol as working fluids under the condition of different heating power and different quantity of flow. We get heat transmission coefficient by calculating. It can be found that the heat transmission coefficient of the channel increases sharply as the Reynolds number increases, but it almost has nothing to do with the heating power. In addition, it can be found that the heat transmission coefficient of different fluid varies widely. Fluid properties also affect the value of the heat transmission coefficient.

Keywords: Single-phase fluid; Heat transfer coefficient; rectangular micro-channel; frictional resistance coefficient; Reynolds number

目 录

摘 要 I

Abstract II

符号说明 VI

第一章 绪论 1

1.1 课题研究背景及其意义 1

1.2 国内外的研究现状 1

1.2.1 传热技术的发展 1

1.2.2 流体流动特性及其传热研究 3

1.2.3流体流动传热的发展趋势 4

1.3本文主要内容 5

第二章 实验原理和实验装置 6

2.1实验原理 6

2.2实验平台 7

2.3实验设备 8

2.3.1实验段 8

2.3.2加热系统 10

2.3.3动力及流量系统 10

2.3.4压力及温度测量设备 12

2.3.5实验工质 13

2.4实验误差 13

2.5 本章小结 14

第三章 单相流体流动实验及其结果分析 15

3.1实验过程与方法 15

3.1.1实验前准备工作 15

3.1.2.实验方法及步骤 15

3.1.3流动实验注意事项 15

3.2流动实验结果及其分析 16

3.2.1流动特性计算 16

3.2.2实验数据处理 17

3.2.3实验结果分析 20

3.3本章小结 22

第四章 单相流体传热实验及其结果分析 23

4.1实验过程与方法 23

4.1.1实验前准备工作 23

4.1.2实验方法及步骤 23

4.2传热实验结果及其分析 24

4.2.1传热特性计算 24

4.2.2实验数据处理 26

4.2.3实验结果分析 28

4.3本章小结 31

第五章 结论与展望 32

5.1实验结论 32

5.2对未来的展望 33

参考文献 34

致 谢 37

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