正八棱形套管连续式超声反应器声强分布研究

Study on the Distribution of Sound Intensity in Octangular Double-Tube Continuous Sonochemical Reactor

在大尺寸正八棱形套管连续式超声场污水处理装置内采用无限大障板上活塞形振动元为模型分析了其声场分布特性,采用声强测量仪测量了该反应室轴向和径向的声强分布。结果表明:反应器内声场由各换能器近声场部分叠加而成,轴向和径向的声强分布具有相似的分布结果;多频组合的声强分布均匀性优于单频平行辐射声场,正交辐射声场各频率组合都表现出较好的声强分布均匀性,其中以30-30-30-30kHz的频率组合最佳,声强变化幅度轴向小于5%,径向小于10%;混响声场轴向和径向的声强变化幅度均小于10%,且具有较高的声强强度,平均声强约为0.95W·cm-2,大大减少了由于反应器形状而产生的空化死角,有利于超声空化效应的发生。

The distribution characteristics of sound field in the reaction chamber of a continuous sonochemical reactor with an octangular double-tube construction were studied with the model of using a vibration element of a circular piston on an infinite plate.A small hydrophone was used to measure the distribution characteristics of sound intensity in axial and radial direction in the reaction chamber.The results show that the sound intensity in the reaction chamber is a resultant of the near sound fields of different transducers,and the distribution of sound intensity in axial direction is similar to that in radial direction.The sound intensity of multi-frequency combination has a more uniform distribution than that of single frequency;and the sound intensity of the orthogonal radiation sound field formed by various combinations of frequencies shows better distribution uniformity.Among them,the frequency combination of 30-30-30-30 kHz was proved to be the best one,using this combination,the variation percentage of the sound intensity is below 5% in axial direction distribution and 10% in radial direction distribution.The variation percentage of sound intensity distribution in the reverberant sound field is below 10% in axial or radial direction,and the average sound intensity has a higher value of about 0.95 W·cm-2,which greatly diminishes the inactive cavitational zone of the reaction chamber and subsequently favors the occurrence of violent cavitations in the reaction chamber.