鼓泡流化床风帽压力波动信号的小波包分析

Wavelet Packet Analysis on Pressure Fluctuation Signal of Nozzle Button in Bubble Fluidized Bed

提出通过采集、分析流化床风帽压力波动信号的方法,实现对床内气固两相流的状态监测.在冷态鼓泡流化床试验台上,对不同表观气速、不同床料粒径分布条件下的风帽压力波动信号进行采集,并采用小波包变换分析方法计算小波包各分解结点的功率谱密度值,分析了流化风速及粒径变化对鼓泡流化床压力波动特性的影响.结果表明:小波包分解低频结点的压力信号功率谱密度值P30、P31的变化与表观气速和床内物料粒径分布变化密切相关,表明基于流化床风帽压力信号的流化床状态监测方法具有可行性.

A method was presented to realize the condition monitoring of gas-solid two phase flow in the bed by collecting and analyzing of pressure fluctuation signal of nozzle button in fluidizing bed.The pressure fluctuation signals of nozzle button were collected under different superficial gas velocities and different particle size distribution of the bed material on the cold bubble fluidized bed test rig.The effects of fluidizing gas velocity and particle size variation on pressure fluctuation characteristics in the fluidizing bed were analyzed by using the wavelet packet conversion analysis method to calculate the power spectral densities of every wavelet packet decomposition nodes.Results show that the change of power spectral density P_（30）,P_（31） of wavelet packet decomposition node with low frequency are closely related with the change of superficial gas velocity and bed material particle size distribution.So the condition monitoring method for fluidized bed based on the pressure signals of nozzle button in fluidized bed is feasible.