서강대학교

초록/요약

Nanobubbles have been widely used in a variety of fields of biology, medicine and industries. Such demand on nanobubbles causes ongoing researches on the invention of bubble generators to produce nanobubbles with a smaller size or a higher concentration. However, the efficiency of bubbles in the applications strongly depends on both its size and concentration. Therefore it is necessary to get a bubble generator controlling both its size and concentration. In general, most of bubble generators have the limit on the production of bubbles with a particular size and concentration. In this study, the experiments on the design factors to affect the size or concentration of nanobubbles are conducted by bubble generator prototypes using low-cost piezoelectric transducers. The design parameters are the height of water, the direction of exciting piezoelectric transducers, the distorted water surface, the excited frequency and the number of transducers. The experiments on the effect of each factor on both size and concentration are conducted and analyzed with the theory about standing wave field. The proposed low-cost ultrasonic method generates nanobubbles with the average size of 80 ~ 200 nm with the maximum concentration of 108 /ml using 1.7 and 3.0 MHz piezoelectric transducers.