摘要此文旨在研究宏观不稳定现象在搅拌容器时的重要作用。宏观不稳定性是搅拌槽内流体运动能量耗散与流场大涡运移的综合表现。控制流体的宏观不稳定性有助于提高流体的混合效率，降低操作能耗，从而减少搅拌成本。实验以 LabVIEW软件连接液位变送器采集搅拌槽反应器某点压力脉动信号，数据经过小波分析处理后得到流体的宏观不稳定频率。实验对比研究了液相流体宏观不稳定频率变化趋势。结果表明，LabVIEW和MATLAB配合能够很好的分析搅拌槽中的数据，液体混合的宏观不稳定频率随着搅拌桨转速上升而增加。并且对于单桨来说，安装高度越低，宏观不稳定现象出现越频繁。62994

毕业论文关键词  宏观不稳定现象  搅拌槽  压力

毕业设计说明书（论文）外文摘要

Title  The stirred tank pressure signal acquisition and analysis based on LabVIEW                    

Abstract In this work,a simplified analysis of the features of Macro-instabilites in stirred tanks is proposed.To adjust Marco-instability can improve mixing performance and reduce energy consumption and Mixing costs.Pressure variation signal data were collected with the software LabVIEW connected with Liquid level transmitter,and MI frequency was obtained by wavelet analysis.MI difference between liquid was omparatively investigated. Results showed that with MATLAB,LabVIEW can analyse the data from stirred tanks very well,and in liquid mixing system,MI frequency rises as  agitation speed increases.And for single-blade,the lower it mounts,the more MI appears. 

Keywords  Macro instability  stirred tank  Pressure

1.引言 2

1.1课题研究背景 2

1.2 LabVIEW概述 4

1.2.1 LabVIEW起源及介绍 4

1.2.2 LabVIEW特点 4

1.2.3 LabVIEW工程应用 4

1.3 MATLAB概述 5

1.3.1 MATLAB介绍 5

1.3.2 MATLAB特色及应用 5

1.4 选题意义 6

2数据分析方法 6

2.1 功率谱估计法 6

2.2小波包分析法 7

2.2.1 小波包介绍 7

2.2.2 小波变换在信号处理中的应用 9

2.2.3 小波包 11

3实验设备与软件 11

3.1 实验设备 11

3.2 数据采集设备 13

3.3 数据采集软件 15

3.3.1 LabVIEW 15

3.3.2 Matlab 16

4实验结果与讨论 17

4.1 实时信号测试 17

4.2 转速对宏观不稳定现象的影响 17

4.3单双桨对宏观不稳定现象的影响 19

4.4 功率谱估计法分析桨叶安装高度对MI频率的影响 21

结  论 24

致  谢 25

参考文献 26