7. キャビテーションバブルの誘導時間と溶存酸素量

抄録

We have studied the efficiency of sonochemistry on the various sound field form. We defined the efficiency of sonochemistry as the amount of chemical reaction / sound energy density. We assume that efficiency is determined by the number and intensity of the cavitation bubbles. We directly measured the number of cavitation bubbles using CCD video camera. Sonochemically active bubbles are invisible therefore we counted visible ones. Although these are inefficient in chemical reactions, we assume that their number is proportional to the active ones. We found that the number of visible bubbles is proportional to sound intensity and the luminescence is also proportional to sound intensity. Thus, the number of bubble has a stronger effect on the sonochemical reaction than the intensity of each bubbles. The nucleus of bubbles is growing sonochemically active ones with sonication time. The growth time of the bubbles was measured by sonochemical luminescence and acoustic emission method. The time difference between measured value of luminescence and acoustic emission was about 0.1msec. The generation time was from 50msec to 1sec. High concentration of O_2 accelerates the growth of bubbles. The luminescence was increasing with the sonication time and reaches its saturation level which is independent of the O_2 concentration.