基于声发射旋风分离器内颗粒粒度分析

采用声发射技术对旋风分离器内颗粒粒度进行分析,获得了声发射信号结构与分离器内气固两相运动行为的对应关系。选用0.4 mm、0.7 mm、1.5 mm和2 mm的活性炭颗粒进行实验,将采样得到声发射信号进行Daubechies二阶小波的1~9尺度分解,用R/S算法分别求取各个频段的Hurst指数。结果表明,声发射信号具有多尺度特征,依据hurst指数的不同,将其划分为微尺度、介尺度、宏尺度,分别反映颗粒间的无规则运动、主体流相对于系统运动或不同主体流之间的相互运动,整个系统相对于外界环境随时间的变化。在同一质量流量下,计算出各颗粒粒径对应的微尺度,介尺度分别所占总能量的比值。实验发现,固相颗粒粒径与其有很大的相关性;随着粒子尺寸的增大,微尺度信号所占的能量比率减少,介尺度能量所占的比率增加。声发射技术可用于旋风分离器内颗粒粒度的分析。

Based on acoustic emission analysis of particle size in Cyclone

Using the method of acoustic emission to analyze the solid particle size in the cyclone, and gaining the corresponding relationship between acoustic emission signal and behave of solid particle. Using different kinds of activated carbon particles of 0.4mm, 0.7mm, 1.5mm and 2mm to experiment, and decomposing the sampled acoustic emission signals by named Daubechies second order wavelet from scale of 1 to 9, then to strike each band Hurst exponent with R/S algorithm. The result showed that the acoustic emission signal in cyclone has a multi-scale features, based of Hurst index to depend the acoustic emission signals into micro-scale, medium-scale, macro-scale, which reflects that the solid particles move randomly; the movement of the body phase relative to the system or streams between different body phase; the entire system state to the external environment changing with time. Under the same mass flow, calculating the energy of the micro-scale, medium-scale of total energy. The study found that it has much correlation with particle size. With the particle sizes increasing, the energy of micro-scale is declining and the energy of medium-scale is increasing. Acoustic emission technique can be used to analyze the solid particle size in cyclone.