论文总字数：17300字

摘 要

随着迅猛的高精细科学技术的发展态势,微液滴因为有着独特的流体力学特性和尺度优势已被广泛应用于医学、化工、石油、采矿、核能、动力、环境、冶金等领域。微液滴生成的尺寸的大小、过程的稳定性、以及分布的均匀度都不同程度的影响其应用效果。近些年来，微型流体技术研究得到了较大的发展，以单相流以及多相流的技术研究和实际应用为基础，成为国内外学者开始关注的对象。本文研究了T型微道内气液两相流流动。

为了观测采用不同质量比的气液两相流流过T型矩形微通道内形成的流型，采用了激光摄影技术进行观测。以气液两相流的流速为坐标绘制了流型图，进一步得出流型转换图。将所得的结果与相关的文献进行了比较。

利用高速摄影仪观测并采集图片从而研究T型微通道内液滴形成的过程和机理以及不同的气液质量比对流型的影响。研究了微通道的截面形状（矩形）以及尺寸、气液（空气和水）两相流的流速、流体的物理性质（粘度、界面张力）等对液滴形成的影响。其中滴状流的液滴的形成与破裂受界面张力以及剪切力的影响，且小液滴形成的的尺寸大小与毛细管数呈指数的关系；弹状流液滴的形成受到进出口压力差的影响，且小液滴形成的尺寸与微通道的进出口压差呈正比关系。由于进出口压差和剪切力的作用机理相同，将不同的气液质量比φ（流量比）与T型微通道内小液滴形成的尺寸大小关联起来并进行了预测与实验验证，最后的预测值与实验结果基本一致。

关键词：微通道 微液滴 两相流 流型

ABSTRACT

With the rapid development of high-precision science and technology, micro-droplet has been widely used in medical, chemical, petroleum, mining, nuclear energy, power, environment, metallurgy and other fields because of its unique fluid mechanics characteristics and scale advantages. The size of the droplets generated, the stability of the process, and the uniformity of the distribution all affect the application effect to varying degrees. In recent years, the research on microfluidic technology has been greatly developed. Based on the technical research and practical application of single-phase flow and multiphase flow, it has become the object that domestic and foreign scholars have begun to pay attention to. This paper studies the flow of gas-liquid two-phase flow in T-junction microchannels.

In order to observe flow patterns formed in the T-junction microchannels using gas-liquid two-phase flow with different mass ratios, laser photographic techniques were used for observation. The flow pattern was plotted with the flow rate of gas-liquid two-phase flow as the coordinates, and the flow pattern conversion chart was further obtained. The results obtained were compared with the relevant literature.

The process and mechanism of droplet formation in the T-junction microchannels and the effect of different gas-liquid mass ratios on the flow pattern were investigated using a high-speed camera to observe and collect images. The effects of the cross-sectional shape (rectangular shape) and size of the microchannel, the flow velocity of the gas-liquid (air and water) two-phase flow, and the physical properties of the fluid (viscosity, interfacial tension) on the droplet formation were investigated. The formation and breakage of droplets in droplet flow are affected by interfacial tension and shear force, and the size of small droplets is exponentially related to the number of capillaries; the formation of slug flow droplets is subject to pressure difference between inlet and outlet. The impact, and the size of the formation of small

droplets and the microchannel inlet and outlet pressure difference is proportional to the relationship. Since the differential mechanism of inlet and outlet pressure difference and shear force is the same, different gas-liquid mass ratio φ (flow ratio) are associated with the size of small droplets formed in the T-type microchannel, and predictions are made. Experimental verification shows that the final predicted values are basically consistent with the experimental results.

Key words: microchannel；micro-droplets；two-phase flow；flow pattern

目 录

第一章 绪论 1

1.1 引言 1

1.2 T型微通道内气液两相流 1

1.2.1 简介 1

1.2.2 微通道内气液两相流研究现状 2

1.2.3 微通道气液两相流发展前景与趋势 2

1.3 T型微通道气泡形成机理 3

1.4 背景意义与研究内容 4

1.4.1 背景意义 4

1.4.2 研究内容 4

第二章 实验装置及流程 5

2.1 实验台介绍 5

2.2 实验仪器和样品 5

2.2.1 微通道尺寸及形状 5

2.2.2 实验仪器介绍 6

2.3 实验原理 10

2.4 实验步骤 10

第三章 实验数据与分析 13

3.1 无量纲数简介 13

3.1.1 雷诺数Re 13

3.1.2 两相流量比φ 13

3.1.3压降△P 13

3.2 实验数据 14

3.2.1 实验现象 14

3.2.2数据整理与计算 17

3.3 实验分析与结论 18

3.3.1 数据处理 18

3.3.2 实验现象与数据的分析 18

3.4 经济分析与评价 20

3.4.1 实验筹备预算 20

3.4.2 经济评价 20

3.4.3 环境影响评价 20

3.4.4 可行性评价 20

第四章 总结与展望 21

4.1 总结 21

4.2 展望 21

参考文献 23

致谢 25

第一章 绪论

引言

微通道技术是最近十年以来渐渐走进人们的视野，随着人类高新技术的飞快发展，人类对微化工技术的不断探索研究，微通道技术也正被国内外学者广泛地研究与应用。由于微化工有着高效性、精细性、智能性、稳定性以及清洁性等优良的特点，目前微化工技术已经登上工业大规模化的舞台，逐渐担当起化解当下阻挡化工行业继续前行的诸多拦路石与实现工业智能制造化的重要角色。

基于这种背景与态势，国内外学者开始广泛地关注起微化工技术，对于微通道的技术研究也就应运而生，其中微通道内两相流的理论研究是实验研究与实际应用的主要对象。

1.2 T型微通道内气液两相流

1.2.1 简介

微通道内气液两相流流型是研究传热传质的基础，由于会形成会随着时间和空间不断发生大小和位置改变的两相界面，而两相存在相对速度的影响，使得微通道内流量占比不同导致了气液两相流流动结构繁多，流型复杂多变。查阅国内外的相关文献，得出一些认识一致且比较常见的流型，主要有：气泡流、液环流、弹状流、翻腾流和弹状-液环流。如图(1-1)

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