期刊论文详细信息
Brazilian Journal of Chemical Engineering
Time-frequency analysis of Hilbert spectrum of pressure fluctuation time series in a Kenics Static Mixer based on empirical mode decomposition
Huibo Meng1  Zhiqiang Liu1  Yanfang Yu1  Jianhua Wu1 
[1] ,University of Chemical Technology College of Mechanical Engineering Key Laboratory of Liaoning Province for Efficient Chemical Mixing TechnologyShenyang,P.R. China
关键词: Static mixer;    Pressure fluctuation;    Hilbert-Huang transform;    Empirical mode decomposition;   
DOI  :  10.1590/S0104-66322012000100018
来源: SciELO
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【 摘 要 】

The turbulent flow in a Kenics Static Mixer (KSM) was intensified under the mutual-coupling effect between the twisted leaves and the tube-wall. In order to understand the intrinsic features of turbulent flow in KSM, the Hilbert-Huang Transform based on Empirical Mode Decomposition were first introduced to describe the time-frequency features of the pressure fluctuation. The Hilbert spectra of pressure fluctuation time series were quantitatively evaluated under different Reynolds numbers, and different radial and axial positions, respectively. The experimental results showed that: the fluctuation frequencies of pressure signals in a KSM were mainly distributed below 40 Hz, and more than 68% of the energy of signals is concentrated within 10 Hz. Compared with the other IMFs, the pressure component of C6 in the range of 7.82~15.63 Hz has the maximum fluctuation energy ratio. As the flow rate increases, the energy of fluctuation of fluid micelles and the proportion of low-frequency energy increases. The pressure fluctuation with higher energy ratio of low frequency (0~10 Hz) had lower amplitudes at r/R=0.3 because of the core of forced vortex. Nevertheless, the effect of the free vortex was that the pressure fluctuation with lower energy ratio of low frequency had higher amplitudes at r/R=0.8. The higher amplitudes of pressure fluctuation at cross sections of CS3 (z=420 mm) and CS5 (z=620 mm) proved that the transitions between the adjacent mixing element had better mixing performance.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License

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