Multiscale resolution of fluidized‐bed pressure fluctuations
Multiscale resolution of fluidized‐bed pressure fluctuations
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DOI：
10.1002/aic.690490407
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发表时间：
2003-04
期刊：
影响因子：
3.7
通讯作者：
Gui‐Bing Zhao;Yongrong Yang
中科院分区：
文献类型：
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作者：
Gui‐Bing Zhao;Yongrong Yang
采用小波变换、赫斯特分析、多尺度分辨率和时滞嵌入等多种方法对直径 0.3 m、高 3 m 的鼓泡床中四个不同轴向位置测量的压力波动信号进行分析。在使用不同的紧支持 Daubechies 小波检查分解残差后，选择 Daubechies 二阶小波作为分解压力信号的最佳小波。对分解信号的 Hurst 分析表明，测得的压力波动可以解析为三个特征尺度：具有两个不同 Hurst 指数的双分形介观尺度信号；仅具有一个特征赫斯特指数的单分形微观和宏观信号。三个尺度分量的能量分布证实测得的压力信号主要反映介尺度分量。三个尺度信号的时滞嵌入分析表明，微观尺度动力学比介观尺度动力学更复杂，介观尺度动力学比宏观尺度动力学更复杂。仅从赫斯特分析中无法得出这一结果，这表明整合多种方法来表征流化系统复杂性的重要性。
Pressure fluctuation signals measured from four different axial locations in a bubbling bed 0.3 m in diameter and 3 m in height were analyzed using multiple approaches, including wavelet transform, Hurst analysis, multiscale resolution, and time-delay embedding. After examining decomposition residuals using different compact support Daubechies wavelets, the Daubechies second-order wavelet was chosen as an optimal wavelet for decomposing pressure signals. Hurst analysis of the decomposed signals shows that the measured pressure fluctuations can be resolved to three characteristic scales: bifractal mesoscale signals with two distinct Hurst exponents; monofractal micro- and macroscale signals with only one characteristic Hurst exponent. Energy profiles of the three scale components confirm that the measured pressure signals mainly reflect the mesoscale component. Time-delay embedding analysis of three scale signals demonstrates that the microscale dynamics is more complex than the mesoscale dynamics, and the mesoscale dynamics is more complex than the macroscale dynamics. That this result cannot be found solely from Hurst analysis shows the importance of integrating multiple approaches for characterizing the complexity of fluidized systems.