中文摘要：

通过数值模拟和实验分别研究了点聚焦超声换能器在液体中直接辐照和间接辐照时产生的声场和声化学场分布。研究结果表明，在直接辐照时，数值模拟得到的液体中声压较大位置与声化学反应场位置相一致：在聚焦超声焦点处及液体表面附近。当使用间接辐照时，焦点处声压减小，在试管底与超声换能器之间形成驻波。为了增加间接辐照时容器内的声压，实验使用底端贴有薄膜的双通试管，通过计算机模拟和实验证明在该情况下，容器内声压，特别是容器焦点处声压和声化学反应场有所增强。

英文摘要：

In this work, numerical simulation and experimental studies are carried out to investigate the distribution of ultrasonic and sonochemical fields in a liquid induced by the direct or indirect irradiation of a point-focusing ultrasound transducer. Results indicate that the sonochemical reaction fields are consistent with the high amplitude acoustical fields by direct irradiation. High amplitude acoustical fields are observed at the focused point and near the liquid surface. The amplitude of acoustical field is decreased at the focused point when indirect irradiation is used. Standing waves are formed between the bottom glass of tube and the transducer. To enhance the pressure amplitude at the focused point,a film is pasted on the bottom of a double-passing tube. In this case, simulation and experiment results indicate that the acoustical pressure in the tube is increased.