循环流化床压力波动信号的局部奇异性检测

压力波动现象是研究气固流态化机理的重要线索。该文应用小波局部极大模方法分析循环流化床中的压力波动信号。通过对压力波动信号进行连续小波变换，提取小波局部极大模线，计算每条局部极大模线对应的Lipschitz指数α。可以采用负α均值表征循环流化床的动力学特征。文中深入讨论了信号获取和处理系统中诸因素(如数据点选取、测点高度、引压管长度等)的影响，同时分析了循环流化床运行状态(如表观气速、静床高、单组分系统和双组分系统)的影响。分析结果有助于深入理解循环流化床流动机理。

WAVELET ANALYSIS OF PRESSURE FLUCTUATIONS IN CIRCULATING FLUIDIZED BEDS

The pressure fluctuations in gas-solid fluidized beds are an important phenomena to investigate the fluidization mechanism. In this study, continuous wavelet transform is put on the pressure fluctuation signals in lab-scale circulating fluidized bed, then, maxima lines are extracted by means of wavelet modulus maxima method and lipschitz exponent a of every maximum line is calculated by non-linear least square method. The mean of the negative a is adopted to describe the hydrodynamic characteristics in circulating fluidized bed. The effects of the signal sampling and processing system factors including the selection of data, measurement height and pressure ducts length are discussed in detail. The effects of the operation states including the superficial gas velocity, static bed height and bed materials are also investigated. The experimental results are helpful to understand the gas-solid flow mechanism in circulating fluidized bed.