Highly stable existence of ultra-fine bubble in temperature changes

Abstract

For investigating stability of ultra-fine bubble (UFB) under practical conditions (relatively high and low temperature), we measured particle diameter of UFB in liquid-state and ice-state conditions. In the liquid-state, the number density did not change up to 60°C. The peak diameter did not changed, neither. Although there was a difference in the critical temperature of 50°C, a similar tendancy was obtained in the ice-state. It was found that UFB was highly stable existence up to 50°C when it was boiled in hot water. On the other hand, number density was reduced by approximate an order of magnitude after ice-state. For understanding the experimental results, we discussed comparison with ultrasonic irradiation and dissolved oxygen.