P12 超音波照射法による水中からのウルトラファインバブル生成

抄録

By ISO, “ultrafine bubbles (UFBs)” are defined as bubbles which diameter is less than 1 μm. UFBs are usually produced with a few kinds of special techniques which use continuous liquid flow by a mechanical pump. To compact or to produce small amount of UFB containing water, however, it is difficult by those UFB generation methods. Therefore, in this study, a novel generation technology of UFBs was developed. UFBs were produced batchwise by using ultrasonic irradiation into a bottled water. The number density of UFBs in water depended on dissolved gas concentration, ultrasonic irradiation time, stationary wave and height of liquid. By a correlation of experimental results, a semi-theoretical equation was proposed. The generation of UFBs in water was promoted by solubility change by pressure fluctuation due to ultrasonic wave. Moreover, it was confirmed that no contamination derived from cavitation erosion of an ultrasonic transducer.