Ultrasound Induced Cavitation and Sonochemical Yields

The introduction of a strong acoustic field to an aqueous solution results in the generation of cavitation microbubbles. The growth and collapse of these microbubbles focuses and transfers energy from the macro-scale (acoustic wave) to the micro-scale (vapor inside the bubbles) producing extremely high localized pressures and temperatures. This unique energy focussing process generates highly reactive free radicals that have been observed to significantly enhance chemical processing. This paper presents a model that combines the dynamics of bubble collapse with the chemical kinetics of a single cavitation event. The effects on sonochemical yields and bubble dynamics of gas composition and heat transfer are assessed and compared with previous theoretical and experimental studies. Results from this model are used to explain unusual experimentally observed sonochemical phenomena. PACS numbers: 43.25Yw, 43.35E, 82.30cf