Computational study of the dynamics of two interacting bubbles in a megasonic field

Abstract

Clarification of the mechanism of particle removal by megasonic cleaning and control of cavitation bubbles in the megasonic field are essential for cleaning of nanodevices without pattern damage. Multiple bubble interactions complicate the mechanism of particle removal. Therefore, it is important to understand multiple bubble dynamics to clarify the mechanism of particle removal by megasonic cleaning. In the present study, the dynamics of two bubbles in a megasonic field with several initial radii and initial separation distances were simulated by numerical analysis using a compressible locally homogeneous model of a gas-liquid two-phase medium. The present numerical method simulated the various complex behaviors of two bubbles, which are repulsive motion, coalescence, periodic and stable motion of the separation distance, and bubble breakup. The initial separation distance strongly affected the behavior of the two bubbles because the effect of the secondary pressure induced by the oscillation of one bubble on the other bubble depends on the separation distance. In particular, when the equilibrium radii are larger than the resonant radius and the radius of one or both bubbles is close to the resonant radius, the bubbles can show characteristic behaviors, such as periodic and stable motion of the separation distance.

Effect of the ultrasonic standing wave frequency on the attractive mineralization for fine coal particle flotation

“…The secondary acoustic radiation force could be an attraction force or a repulsion force, which would depend on the distance between bubbles or the vibration of bubbles. If the attractive effect of secondary acoustic radiation force could be controlled, this powerful attraction might promote the flotation of fine particles [26] . In general, the experimental outcomes showed that the formation of carriers was related to the frequency of ultrasound, and the carriers could hardly be generated in the low-frequency USW field.…”

Lithium ion battery recycling using high-intensity ultrasonication

“…The cone-like bubble structure formation is a combined effect of acoustic radiation and attraction forces between the bubbles, a so-called secondary Bjerknes force. 15,16 At this low power intensity, the bubbles are seen moving towards the sonotrode. Bubble quantity decreases with distance from the sonotrode, indicating a radial gradient of acoustic pressure.…”

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