气固流化床压力脉动信号的Hilbert-Huang变换与流型识别

The Hilbert-Huang Transform and Flow Regimes Identification for Pressure Fluctuation of Gas-Solid Fluidized Beds

采用Hilbert-Huang变换(HHT),提取出气固流化床压力脉动信号的各阶内禀模态函数(IMFs),进一步证明了压力脉动信号是由复杂的不同波间和波内频率调制成分所组成,具有气固两相运动相互调制的非线性特征。分析各阶内禀模态函数的能量分布及其转换,发现不同频段IMF的能量与流型状态之间有着很好的对应关系,能够从整体上反映流化床的流化状态,从而提出了应用IMF中频段能量进行流化床流型识别的新方法。该方法只需一个压力脉动信号,算法简单、实用,没有需要主观决定的参数,具有较好的工业应用前景。HHT分析比现有的分析方法更能深入地揭示流化床内的非线性流体动力学特征。

By using Hilbert-Huang Transform(HHT), the Intrinsic Mode Functions (IMFs) were extracted from the pressure fluctuation in gas-fluidized beds. The nonlinear characteristics of the intermodulation between complex particle movement and bubble movement in the pressure fluctuation signals were demonstrated. Analyzing the energy distribution and its transfer within different IMFs, the relationship between the flow regimes in gas-solid fluidized beds and the energy distribution of IMFs is found. Based on it, a new method was proposed for the flow regime identification. Since no other signals are needed except the pressure fluctuation signal only and no parameters are needed to be determined subjectively, this method is simple, practical and has good prospect for its application to engineering. The results show that the Hilbert-Huang Transform can provide more useful information and show the nonlinear fluid dynamics features in gas-fluidized beds more clearly than other conventional analysis methods.