气固流化床压力脉动信号的多重分形分析

Analysis on Multi-fractal of Pressure Fluctuation Signal of Gas-solid Fluidized Bed

针对气固流化床床内气泡非常复杂的非线性运动,提出了利用多重分形来表征气固流化床压力脉动信号的新方法。运用多重分形理论对流化床各种流型进行分析,计算各流型的多重分形谱参数,并分析了流型的变化趋势与多重分形谱之间的关系。计算结果表明,随着风速的增大,多重分形参数(Δa)和流型波动变化趋势均为先增大后减小。因此,多重分形谱可作为监测流化床流型变化的一个特征量。

In accordance with the feature of the non-linear movement of the bubbles inside gas-solid fluidized bed,the new method of describing the pressure fluctuation signals of gas-solid fluidized bed by adopting multi-fractal is proposed.Applying multi-fractal theory,various flow patterns of the fluidized bed are analyzed,the parameters of multi-fractal spectrum with various flow patterns are calculated,and the relationship between flow pattern changing trend and multi-fractal spectrum is analyzed.The result of calculation indicates that following wind speed increases,the multi-fractal parameter（Δa）and the changing trend of pattern fluctuation are both increase first,and then decrease.Thus,multi-fractal spectrum is an eigen-value to be used for monitoring flow pattern change of fluidized bed.