Abstract

Evaluation of the Number of Cavitation Bubbles with Light Scattering

T.Tuziuti, K.Yasui, H.Mitome (National Institute of Advanced Industrial Science and Technology, Moriyama-ku Nagoya, Japan)

e-mail: tuziuti.ni@aist.go.jp

Evaluation of the number of cavitation bubbles in an ultrasonic standing wave field is studied experimentally with light scattering through the measurements of the intensity from the oscillating bubbles. It is shown that at moderate amplitude of sound pressure the averaged level of a waveform of scattered light from the bubbles at an antinode of sound pressure increases as content of dissolved oxygen (DO) in distilled water increases, and then it decreases after the maximum appears. At higher amplitude of sound pressure, the maximum of the averaged level shifts towards the lower side of DO content. It is also shown that at the case of node of sound pressure the scattered light from the degassing bubbles are measured and the averaged level is intermediate between the level at antinode and the optical background. Accordingly, the difference between the scattered light intensity at the pressure antinode and that at the pressure node corresponds to the amount of bubbles which can contribute to the sonoluminescence and sonochemical reaction. The present method enables the evaluation of relative variation in the number of cavitation bubbles, which is important for accomplishment of high efficiency in sonochemical reaction.

Section : 4