Effects of ultrasound frequency and acoustic amplitude on the size of sonochemically active bubbles – Theoretical study
No Thumbnail Available
Date
2013
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Numerical simulation of chemical reactions inside an isolated spherical bubble of oxygen has been performed
for various ambient bubble radii at different frequencies and acousticamplitudes to study the effects
of these two parameters on the range of ambient radius for an active bubble in sonochemical reactions. The
employed model combines the dynamic of bubble collapse with the chemical kinetics of single cavitation
bubble. Results fromthismodel were compared with some experimental results presented in the literature
and good apparent trends between them were observed. The numerical calculations of this study showed
that there always exists an optimal ambient bubble radius at which the production of oxidizing species at
the end of the bubble collapse attained their upper limit. It was shown that the range of ambient radius
for an active bubble increased with increasing acoustic amplitude and decreased with increasing ultrasound
frequency. The optimal ambient radius decreased with increasing frequency. Analysis of curves showing
optimal ambient radius versus acoustic amplitude for different ultrasonic frequencies indicated that for
200 and 300 kHz, the optimal ambient radius increased linearly with increasing acoustic amplitude up to
3 atm.However, slight minima of optimal radius were observed for the curves obtained at 500 and 1000 kHz.