Optimal Design and Experimental Validation of Single- and Dual-Frequency Sonochemical Baths
碩士 === 國立成功大學 === 機械工程學系 === 103 === In a sonochemical reactor, high power ultrasound is introduced into liquid. Once the amplitude of the ultrasound beyond a threshold, nuclei in the liquid become unstable; volumes of the oscillating bubbles fast increase and collapse violently. This phenomenon is...
| Main Authors: | , |
|---|---|
| Other Authors: | |
| Format: | Others |
| Language: | zh-TW |
| Published: |
2015
|
| Online Access: | http://ndltd.ncl.edu.tw/handle/28719388758981511297 |
| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 103 === In a sonochemical reactor, high power ultrasound is introduced into liquid. Once the amplitude of the ultrasound beyond a threshold, nuclei in the liquid become unstable; volumes of the oscillating bubbles fast increase and collapse violently. This phenomenon is called unstable acoustic cavitation. Violent collapses of the cavitation bubbles result in high local pressures and temperatures accompany with extremely rapid cooling, providing a unique environment and means for driving chemical reactions under extreme conditions. In the present study the COMSOL multiphysics analysis software is employed to construct a complete model of the sonochemical bath by coupling the vibrations of piezoelectric ultrasonic transducers and vessel walls with the acoustic field of the liquid. A genetic algorithm is then employed to optimize the geometries of the bath such that a resonant acoustic field and a maximum average sound pressure can be built inside the bath. Two types of sonochemical baths are examined, namely the single-frequency bath and dual-frequency bath. Experimental results show that the distributions of cavitation bubbles qualitatively agree with the simulations. Cavitation yields generated by the single-frequency sonochemical bath is about 5 times greater than those reported in the literature.
|
|---|