离散颗粒相浓度和粒度的超声非接触式测量研究

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3.0 赵德峰 2024-11-11 8 4 3.04MB 84 页 15积分
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摘 要
在工业生产中，涉及颗粒两相流中颗粒粒径及其分布的测量如气力输送、水
煤浆的管道输送、化工和制药业中各种悬浮液和乳剂制备中的颗粒在线测量，正
日益引起人们的重视。这类测量问题的一个显著特点是颗粒的浓度高而粒径较小，
需要进行在线测量，光散射法因为透射能力弱不宜采用。而其它一些方法，如电
容法则不能测量颗粒的粒径。超声法在这类高浓度颗粒两相流的测量中具有明显
的优点，体现在非侵入、快速、无需对样品进行稀释等，适合工业现场测量。
超声衰减谱法正发展成为一种应用范围比较广的粒度表征技术。本文作者基
于此方法搭建了一套超声在线非接触式液固两相高浓度纳米颗粒悬浮液的粒度分
布和浓度测量系统，通过分析在线非接触式测量系统信号可以同时得到被测样品
的声速、声衰减、浓度、粒度等信息，并可讨论液固两相流中浓度、温度、团聚
对超声测量高浓度纳米颗粒粒度的影响。根据实验结果，超声衰减谱测量纳米 ITO
铟锡金属氧化物和纳米二氧化钛 TiO2悬浮液颗粒粒度与 TEM 和CPS 高速离心沉
降仪结果非常吻合，其密度和浓度的测量值与配置值存在很好的相关性。比较 5
个不同温度下样品的超声衰减系数和粒径分布，发现随着温度升高，超声衰减系
数增大，粒径的测量结果增大，粒径分布出现向大颗粒偏移的趋势，并通过线性
拟合，得到粒径关于温度的关系，估算温度对超声法测量纳米颗粒悬浮液粒径的
影响，并可用于结果修正。
搭建了一套超声气液两相气泡的尺寸分布和含气率的测量系统，进行了实验
研究，测量该气液两相流中的含气率和气泡尺寸，同时分析了流量、加热功率对
气泡尺寸分布和含气率的影响。气液两相流中气泡粒径分布测量实验结果表明：
质量流量一定，随着加热功率的升高，气泡中位径 D50 增大，气泡粒径分布增宽，
气液两相流含气率增大；在工况大致相当（主要从出口温度 T2和出口绝对压力 p1
判断）的条件下，随着质量流量的增大，气泡中位径 D50 减小，粒径分布变窄，含
气率减小。将超声法所测含气率与气液分离法比较，相对误差最大为 4.1%, 说明
实验测量结果基本可靠。
此外，作者还在用超声法对于纳米级石墨烯的表征，基于超声方法的悬浮液
测量探针设计等方面进行了一些初步的探索。本研究从理论模型研究出发并结合
实验验证证实了超声衰减谱法在高浓度纳米颗粒悬浮液颗粒粒度分布测量中的适
用性和可靠性。同时，该方法也可以为气液两相流中的含气率测量提供一种有效
的手段。
关键字：粒度分布，浓度，超声衰减谱，在线，非接触
ABSTRACT
In industrial production, relates to the particulate two-phase flow of particle size
and its distribution of the measurement pipe pneumatic conveying, coal water slurry
transportation, chemical and pharmaceutical industry in a variety of suspension and
emulsion preparation of particle on-line measurement, are increasingly attracted
people's attention.A remarkable characteristic of this kind of measurement is the
problem of the particle concentration and particle size, the need for online measurement,
light scattering method for transmission ability should not be used.While some other
methods, such as capacitor rule cannot measure the particle size.Ultrasonic method has
obvious advantages in such high concentrations of particulate two-phase flow
measurement, reflected in the non-invasive, rapid, without dilution of sample, suitable
for industrial field measurement.
Ultrasonic attenuation spectrum method is becoming a particle characterization
technique is a relatively wide range of application.In this paper, the author based on this
method, a set of ultrasonic on-line non-contact liquid-solid two-phase high
concentration of nanoparticle suspension particle size distribution and concentration
measuring system, through the analysis of online non-contact signal measurement
system can also be measured sample the sound velocity, attenuation, concentration,
particle size and other information, and discuss the liquid-solid two-phase flow
concentration, temperature, effect of agglomeration on ultrasonic measurement of high
concentration of nanoparticles size.According to the experimental results, the ultrasonic
attenuation spectrum measurement nanometer indium tin oxides (ITO) and nano TiO2
suspensions of TiO2 particles with the size of TEM and CPS high-speed centrifugal
sedimentation instrument results very well, measuring the density and concentration of
value had good correlation with the configuration values.Comparison of 5 different
ultrasonic temperature sample attenuation coefficient and the particle size distribution,
found that with the increase of temperature, ultrasonic attenuation coefficient, particle
size measurement results of particle size distribution appears to increase, large particle
migration trends, and through linear fitting, relationship between the particle size on the
temperature effect of temperature on ultrasonic method, estimation of measurement
nanoparticle suspension particle size, and can be used to revise the result.
A set of ultrasonic gas-liquid two-phase bubble size distribution and gas holdup
measurement system, experiments were conducted to study the measurement of bubble
size, gas flow rate and the content of the gas-liquid two-phase flow, at the same time,
analyzed the effect of heating power on the gas holdup and bubble size
distribution.Gas-liquid two-phase flow in bubble size distribution measurement results
show that: with the increase of mass flow rate, the heating power, the bubble diameter
D50 increases, the bubble size distribution widened, gas-liquid two-phase flow rate
increases gas; roughly equivalent in the condition (mainly from the outlet temperature
T2 and the outlet of the absolute pressure of P1 judgment) conditions, with the increase
of mass flow, bubble diameter D50 decreases, the particle size distribution becomes
narrow, gas rate.The ultrasonic method to measure comparative gas holdup and
gas-liquid separation method, the maximum relative error is 4.1%, shows that the
experimental measurement result is reliable.
In addition, the author also by ultrasonic method for nano graphene
characterization, ultrasonic method measuring probe based on the suspension design
carried out some preliminary exploration.Started from the research of the theoretical
model and the experimental validation confirms the applicability and reliability of
ultrasonic attenuation spectrum method in high concentration of nano particle size
distribution of particles in suspension measurement.At the same time, the method can
also provides an effective means of gas-liquid two-phase flow of gas holdup
measurement.
Key Words: Particle Size Distribution, Concentration, Ultrasonic
Attenuation Spectra, On-line, Non-contact
目录
第一章 绪论 ................................................................................................................................ 1
§ 1.1 课题研究的背景与意义 ................................................................................................ 1
§ 1.2 离散相浓度和粒度测量方法综述 ................................................................................ 4
§ 1.2.1 离散相浓度测量方法综述 ..................................................................................... 4
§ 1.2.2 离散相粒度测量方法综述 ..................................................................................... 6
§ 1.3 本课题研究的主要内容 .............................................................................................. 10
第二章 超声测粒理论 .............................................................................................................. 12
§ 2.1 超声检测基础 .............................................................................................................. 12
§ 2.1.1 超声波的特征量 ................................................................................................... 12
§ 2.1.2 超声衰减机制 ....................................................................................................... 15
§ 2.2 离散相浓度测量理论 .................................................................................................. 16
§ 2.3 离散相粒度测量理论 .................................................................................................. 19
§ 2.3.1 ECAH模型 ............................................................................................................. 19
§ 2.3.2 Coupled-phase模型 ................................................................................................ 20
§ 2.3.3 Core-Shell模型 ....................................................................................................... 21
§ 2.3.4 McClements & BLBL模型 .................................................................................... 23
§ 2.4 离散相颗粒粒度的反演算法 ...................................................................................... 24
§ 2.4.1 ORT算法 ................................................................................................................ 24
§ 2.4.2 Chahine算法 .......................................................................................................... 25
§ 2.5 本章小结 ...................................................................................................................... 28
第三章 在线非接触式超声测粒系统的搭建及测量方法 ...................................................... 29
§ 3.1 液固两相实验系统 ...................................................................................................... 29
§ 3.1.1 超声测量系统 ....................................................................................................... 29
§ 3.1.2 数据采集系统 ....................................................................................................... 34
§ 3.1.3 信号处理系统 ....................................................................................................... 36
§ 3.2 气液两相实验系统 ...................................................................................................... 37
§ 3.2.1 气液两相流循环系统 ........................................................................................... 37
§ 3.2.2 超声测量系统 ....................................................................................................... 40
§ 3.3 声速、声衰减测量方法 .............................................................................................. 41
§ 3.3.1 声速测量方法 ....................................................................................................... 41
§ 3.3.2 声衰减测量方法 ................................................................................................... 41
§ 3.4 本章小结 ...................................................................................................................... 42
第四章 高浓度纳米颗粒浓度和粒度测量实验结果及分析 ................................................... 43
§ 4.1 浓度和粒度测量结果 .................................................................................................. 43
§ 4.1.1 样品制备 ............................................................................................................... 43
§ 4.1.2 样品测量结果 ....................................................................................................... 44
§ 4.1.3 纳米ITO测量结果及分析 .................................................................................... 45
§ 4.1.4 纳米TiO2测量结果及分析 ................................................................................... 48
§ 4.2 浓度的影响 .................................................................................................................. 49
§ 4.2.1 超声幅度谱 ........................................................................................................... 49
§ 4.2.2 超声衰减谱 ........................................................................................................... 49
§ 4.2.3 颗粒粒度分布 ....................................................................................................... 49
§ 4.3 温度的影响 .................................................................................................................. 50
§ 4.3.1 超声幅度谱 ........................................................................................................... 50
§ 4.3.2 超声衰减谱 ........................................................................................................... 51
§ 4.3.3 颗粒粒度分布 ....................................................................................................... 52
§ 4.4 团聚的影响 .................................................................................................................. 53
§ 4.5 本章小结 ...................................................................................................................... 55
第五章 矩形窄通道内气液两相流含气率的实验结果及分析 ............................................... 56
§ 5.1 含气率的测量结果 ...................................................................................................... 56
§ 5.1.1 实验参数 ............................................................................................................... 56
§ 5.1.2 超声幅度谱 ........................................................................................................... 57
§ 5.1.3 超声衰减谱 ........................................................................................................... 57
§ 5.2 流量的影响 .................................................................................................................. 58
§ 5.3 加热功率的影响 .......................................................................................................... 59
§ 5.4 本章小结 ...................................................................................................................... 61
第六章 其他相关工作的初步研究 .......................................................................................... 62
§ 6.1 超声探针的设计以及实验研究 .................................................................................. 62
§ 6.1.1 超声探针的设计 ................................................................................................... 62
§ 6.1.2 超声探针的实验 ................................................................................................... 62
§ 6.2 100MHz高频换能器的实验研究 ................................................................................. 63
§ 6.2.1 实验台的搭建 ....................................................................................................... 63
§ 6.2.2 实验结果 ............................................................................................................... 64
§ 6.3 基于超声衰减谱法表征石墨烯的尺寸研究 .............................................................. 65
§ 6.4 本章小结 ...................................................................................................................... 66
第七章 总结与展望 .................................................................................................................. 68
§ 7.1 本文总结 ...................................................................................................................... 68
§ 7.1.1 理论研究部分 ....................................................................................................... 68
§ 7.1.2 实验研究部分 ....................................................................................................... 68
§ 7.2 本文展望 ...................................................................................................................... 69
附录一： ..................................................................................................................................... 70
主要符号表 ................................................................................................................................ 71
参考文献 .................................................................................................................................... 72
在读期间公开发表的论文和承担科研项目及取得成果 ........................................................ 79
后记 ............................................................................................................................................ 80
摘要：

摘要在工业生产中，涉及颗粒两相流中颗粒粒径及其分布的测量如气力输送、水煤浆的管道输送、化工和制药业中各种悬浮液和乳剂制备中的颗粒在线测量，正日益引起人们的重视。这类测量问题的一个显著特点是颗粒的浓度高而粒径较小，需要进行在线测量，光散射法因为透射能力弱不宜采用。而其它一些方法，如电容法则不能测量颗粒的粒径。超声法在这类高浓度颗粒两相流的测量中具有明显的优点，体现在非侵入、快速、无需对样品进行稀释等，适合工业现场测量。超声衰减谱法正发展成为一种应用范围比较广的粒度表征技术。本文作者基于此方法搭建了一套超声在线非接触式液固两相高浓度纳米颗粒悬浮液的粒度分布和浓度测量系统，通过分析在线非接触式测量系...

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作者：赵德峰 分类：高等教育资料 价格：15积分 属性：84 页 大小：3.04MB 格式：PDF 时间：2024-11-11

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