Cluster Collapse in a Cylindrical Cell: Correlating Multibubble Sonoluminescence, Acoustic Pressure, and Erosion

Abstract

A cylindrical ultrasonic reactor was driven at eight discrete frequencies in the range 20-150 kHz. Imaging of multibubble sonoluminescence (MBSL) within this cell showed discrete modes of activity throughout this frequency range. This modal activity was compared to the pressure distribution through the cell and also to the erosion/corrosion activity. The erosion/corrosion was detected using an electrochemical method employing a passivated aluminum electrode (250 µm diameter). Each erosion/corrosion event was counted over a fixed time period (specifically 30 s) and used to map this phenomenon throughout a region of the cell. A strong spatial correlation was shown between the MBSL imaging, the acoustic pressure, and the erosion mapping at relatively low ultrasonic frequencies (here <50 kHz). However, at higher frequencies, although MBSL activity and relatively high acoustic amplitudes were detected, the rate of the erosion/corrosion activity of the system decreased. High-speed imaging (>100000 fps) of a bubble cloud near the electrode surface showed a region of bubble activity, the dynamics of which were correlated to the erosion/corrosion transients produced. These observations contribute to the growing body of knowledge which will allow the development of ultrasonic cleaning systems optimized for particular scenarios.

Cavitation clusters in lipid systems – surface effects, local heating and streamer formation

“…For example, the piston like emitter (PLE) is a common sound source employed in HIU applications. The PLE system has been shown to produce a complex environment where hot spots 11,12 , bubbles, bubble clusters [13][14][15] , inertial 16,17 cavitation and non-inertial [18][19][20] cavitation exist and where different processes may be driven (for example surface erosion 21,22 , chemical changes [23][24][25][26][27] and mass transfer [28][29][30] effects). While many experimental studies of these effects in water environments exist, oils, and in particular lipids 31 have received little fundamental investigation.…”

Prediction of far-field acoustic emissions from cavitation clouds during shock wave lithotripsy for development of a clinical device

“…All of the work in the first and second stages simulated single bubbles. This third paper extends those methods to multiple bubbles because, in most practical cases, the erosive effect and the far-field emission will depend on the response of a cloud that can not only generate a summation of single-bubble effects, but can also generate important effects through the interactions between bubbles (such as cooperative bubble effects in the generation of erosion) [22][23][24]. The degree of influence of a bubble on its neighbours is dependent on their separation distance, size, composition clustering, the incident pressure field and the location and composition of any boundaries present (such as a kidney stone might represent) [25][26][27][28][29][30][31][32][33].…”

The collapse of single bubbles and approximation of the far-field acoustic emissions for cavitation induced by shock wave lithotripsy

“…It is believed that high-speed jets of this type play a primary role in cavitation erosion (Benjamin & Ellis 1966) as well as formation of circular pits and indentation on metal foils (Coleman et al 1987). The development of real-time techniques for monitoring the formation of damage (Birkin, Offin & Leighton 2004a,b), and their correlation with high-speed photography (Vian, Birkin & Leighton 2010), should enable crucial tests in this area to be conducted. The initial collapse and all the bubble motion shown in figure 9 are driven solely by the compressive wave of the lithotripter shock as the bubble does not encounter the tensile wave of the shock before the primary collapse is complete.…”

“…The maximum pressure recorded varies from nearly 7 GPa for ζ = 1.0625 to a mere 0.5 GPa for ζ = 2.125. It would be a likely candidate to assess for the generation of at least surface damage on a nearby surface, although full assessment of all possible contributions to damage is beyond the scope of this article (Philipp & Lauterborn 1998;Tong et al 1999;Eisenmenger 2001;Zhong et al 2001;Zhu et al 2002;Birkin et al 2005a;Calvisi et al 2007Calvisi et al , 2008Klaseboer et al 2007;Sapozhnikov et al 2007;Iloreta et al 2008;Lauterborn & Kurz 2010;Vian et al 2010).…”