气液固三相移动床中流型的声发射检测

Acoustic Emission Detection of Flow Patterns in a Gas-liquid-solid Three-phase Moving Bed

本文采用声发射检测分析了气液固三相移动床中的各相运动信息,实现了三相移动床中涓流-脉冲流的识别,并进一步分析了不同条件下脉冲流的演变规律。结果表明,滴流床中气液流型为脉冲流时,声信号在时域上会形成能量包,可据此实现涓流-脉冲流的准确识别,且该识别准则对于三相移动床同样适用。固相移动导致的床层空隙率增大会使三相移动床中脉冲流形成的条件变得更加苛刻。气液达到稳定脉冲后,固相颗粒对于气液的带出作用会在一定程度上增大三相移动床中的气液脉冲频率。

In this work,acoustic emission detection was used to analyze the motion information of each phase in the gas-liquid-solid three-phase moving bed,realize the identification of trickle-pulse flow in the three-phase moving bed,and further analyze the evolution law of pulse flow under different conditions.The results showed that when the gas-liquid flow pattern in the trickle bed was pulse flow,the acoustic signals would form energy packets in the time domain,which could be used to accurately identify the trickle-pulse flow,and the identification criterion was also applicable to three-phase moving bed.The increase of bed porosity caused by solid phase movement would make it more difficult to form the pulse flow in three-phase moving bed.After the gas-liquid reached the stable pulse,the entrainment effect of solid particles on the gas-liquid would increase the gas-liquid pulse frequency in the three-phase moving bed to a certain extent.