The roles of acoustic cavitations in the ultrasonic cleansing of fouled micro-membranes
Tan, Soon Keat
Date of Issue2013
International Congress on Acoustics (21st : 2013 : Montreal, Canada)
School of Civil and Environmental Engineering
Nanyang Environment and Water Research Institute
This paper described the experimental studies on the de-fouling mechanism of acoustic cavitation bubbles near the fouled micro-membranes. The presence of the membrane created asymmetry in the flow field, which forced the cavitation bubble to oscillate non-spherically and finally brought forth the jet impact directed to the membrane. The oscillations and micro-jets of the cavitation bubbles enhanced the nearfield dynamic features of the fluid and improved the performance of de-fouling. The acoustic multi-bubble system is complex. In this study, the authors first focused on the individual bubble dynamics near a solid boundary. A succession of individual cavitation bubbles were created by using Q-switched Nd: YAG laser pulses. The evolutions of the bubble dynamics were observed using a high-speed camera (up to 100,000 frames per second). The pressure impulses induced by the jet impact were detected by using the hydrophone system. The pressure impulse was quite intensive as compared with the hydrostatic pressure and was strong enough to dislodge the adherent fouling elements. The authors studied the cavitation bubble dynamics for different laser energies and stand-off distances from the boundary and tried to evaluate the influence of cavitations in the ultrasonic cleaning of micro-membranes.
Proceedings of meetings on acoustics
© 2013 Acoustical Society of America. This paper was published in Proceedings of Meetings on Acoustics and is made available as an electronic reprint (preprint) with permission of Acoustical Society of America. The paper can be found at the following official DOI: [http://dx.doi.org/10.1121/1.4798756]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.