气固流化床中静电信号的多尺度分形特征与流型  

Multi-Scale and Multi-Fractal Analysis of Electrostatic Potential Signal in a Gas-Solid Fluidized Bed and Recognition of Fluidization Pattern

作　　者：虞贤波[1] 姜坤[1] 徐怡[1] 王芳[1] 王靖岱[1] 阳永荣[1] 

机构地区：[1]浙江大学化学工程与生物工程学系,浙江杭州310027

出　　处：《北京理工大学学报》2010年第10期1235-1239,共5页Transactions of Beijing Institute of Technology

基　　金：国家自然科学基金重大资助项目(20490205)

摘　　要：通过小波分析和R/S分形分析方法,对气固流化床内静电势波动信号进行多尺度分解,研究了信号的分形特征,建立了静电波动信号的尺度划分标准.实验结果表明,在鼓泡流化状态下,静电信号中介尺度的能量分率最高,且介尺度能量分率沿径向由内而外逐渐减小,与床内空隙率的径向变化规律一致.证实介尺度信号与气泡运动有直接的对应关系,各尺度能量分率的变化能够灵敏地指示出流化床内的流型转变,据此可对颗粒的起始流化速度以及起始湍动速度作出较准确的判断.The criterion of dividing the electrostatic potential signal in three characteristic scales is established by Hurst analysis of the wavelet decomposed signals.For bubbling fluidization,energy percent of meso-scale component is highest,which confirms that the electrostatic signals mainly reflect the action of bubbles.Furthermore,energy profiles of three components vary with the radial distance of the bed.It is also found that micro-scale and meso-scale components are sensitive to the flow regime transition.

关 键 词：气固流化床 静电 R/S分析 起始流化速度 起始湍动速度 

分 类 号：TQ021.8[化学工程]