混响场中超声化学效应的研究

本文借助荧光光谱分析法,使用815kHz超声波对小尺度混响场中声化学产额进行了研究。研究发现混响场中的声化学效应有两个特点:一是声空化的阈值声强下降到约0.3W/cm²(行波场为0.7W/cm²);二是声强大于阈值时,声化学产额随声强而增加,随后(声强约为1.69—2.13w/cm²)出现陡然上升的拐点(行波场则趋向饱和)。理论分析表明,阈值下降是由于混响场的声能密度增大;声化学产额随声强变化的拐点则来自于声波辐射压力对液体表面的干扰.为此,本文从实验与理论上证明,为使声化学获得尽可能高的产额应在声化学反应器内建立混响声场。

Sonochemical effect of ultrasound in reverberation field

The sonochemical yield of 815kHz ul rasound in a reverberation field of small scale was investigated with fluorescence spectrophotometer. It has been shown that the sonochemical effect in a reverberation field is of two characters: 1, Cavitation threshold sound intensity decreases and apears to be 0.3W/cm² (while it is aboul 0.7 W/cm² in progressive field); 2, Sonochemical yield increases with rise of sound intensity following the threshold at first, and then it suddenly increases (while it tends to a saturation value in field of prograssive wave). Theoretical analysis performed in this paper shows that the decrease of threshold is caused by increase of sound energy density in the reverberation field, and the steep point in the curve of sonochemical yield as sound intensity resullts from the liquid surface disturbance of the sound radiation pressure. This paper therfore, has experimentally and theoretically shown that in order to get easily and more sonochemical yield a reverberation sound field in teactor must be established.