内蒙古科技大学
本科生毕业设计说明书（毕业论文）
题 目：超声波测量气固两相流流体及 其信号分析 学生姓名：冯厚金 学 号：1267106326 专 业：自动化
班 级：自动化2012-3班 指导教师：王月明
内蒙古科技大学毕业设计说明书（毕业论文）
超声波测量气固两相流流体及其信号分析
摘 要
目前，在社会各个行业中还没有能利用超声波准确测量气固两相流浓度的具体方法和设备。而超声波测量气固两相流浓度具有无污染、结构简单、穿透性好等优势。本论文将以超声波为工具对气固两相流的浓度测量进行初步研究。
首先是对超声波特征的研究，学习探究超声波基本特征以及在超声波遇到障碍物时的波形变化和信号衰减的过程。然后，通过一些工业现象和自然现象选取能获得较为接近其状态的气固两相流的实验材料，通过比较本实验采用的是细沙（取材于包头市响沙湾），其细腻程度略大于电厂炉膛中的燃料——煤粉。
第二步，设计气固两相流的发生装置，利用地心引力使得沙子做自由落体运动来实现气固两相流现象。计算得到沙子的流速从而得到所需要的沙流量，来设计气固两相流发生装置的具体参数。学习超声波发生装置的工作原理。
第三步，进行实验，对两个实验变量参数进行控制。首先，改变超声波探头的距离，找到最佳测量距离；在上一步的基础上，改变气固两相流浓度，找到气固两相流浓度和超声波信号的关系，为以后超声波传感器的发明制作做好一定的前期理论准备工作。
对大量实验结果进行分析处理，为以后的超声波浓度测量仪的研究发明，奠定部分理论和实践基础。
关键词：超声波；气固两相流；信号衰减；浓度测量
I
内蒙古科技大学毕业设计说明书（毕业论文）
Abstract
At present, all sectors of society are not able to take advantage of the ultrasonic method and apparatus for accurately measuring the specific gas-solid flow concentration. The ultrasonic measuring the concentration of gas-solid flow has no pollution, simple structure, penetrating good advantage. The papers will be ultrasound as a tool for measuring the concentration of gas-solid flow in a preliminary study.
The first is characterized by ultrasound study, learn and explore the basic characteristics of the ultrasonic signal in the ultrasonic waveform and an obstacle when the decay process. Then, by some industrial phenomena and natural phenomena choose to get closer to their state of experimental material gas-solid flow by comparing the present study is to sand (taken from Baotou Sand Bay), which is slightly larger than the detail of Power furnace fuel - pulverized coal. The second step, the design phase flow generating device, use the force of gravity so that the sand free fall movement to achieve phase flow phenomena. Sand flow rate calculated to give the desired flow of sand to the specific parameters of the design phase flow generating means. Working principle of ultrasonic learning occurs.
The third step is to experiment on two experimental variables parameter control. First, changing the distance between the ultrasonic probe to find the best measure distances; in the previous step, based on the change in the concentration of gas-solid flow, and to find the relationship between the concentration of gas-solid flow ultrasonic signal.
II
内蒙古科技大学毕业设计说明书（毕业论文）
A large number of experimental results analysis and processing for future ultrasonic concentration meter study found that part of the theory and practice laid the foundation.
Keywords: Ultrasound; measurement
phase flow;
III
signal attenuation; concentration 内蒙古科技大学毕业设计说明书（毕业论文）
目录
摘 要 ......................................................................................................................................... I Abstract ...................................................................................................................................... II 第一章 绪论 .............................................................................................................................. 1
1.1气固两相流浓度测量的意义 ...................................................................................... 1 1.2气固两相流浓度测量面对的困难............................................................................... 2 1.3常见的气固两相流测量方法 ...................................................................................... 3
1.3.1差压法 ............................................................................................................... 3 1.3.2光学法 ............................................................................................................... 4 1.3.3热平衡法 ........................................................................................................... 5 1.3.4电学法 ............................................................................................................... 6 1.3.5过程层析成像法 ............................................................................................... 7 1.3.6超声法 ............................................................................................................... 8 1.4本章小结 ...................................................................................................................... 8 第二章 超声波浓度测量的基本原理 ...................................................................................... 9
2.1超声波产生过程及其应用 .......................................................................................... 9 2.2气固两相流基本知识 ................................................................................................ 10 2.3超声在两相介质中的声衰减 .................................................................................... 11 2.4本章小结 .................................................................................................................... 14 第三章 气固两相流浓度测量系统 ........................................................................................ 15
3.1气固两相流发生装置 ................................................................................................ 15 3.2超声波检测装置 ........................................................................................................ 16
3.2.1超声波换能器 ................................................................................................. 17
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