An analysis of the forces acting on acoustic cavitation- oriented bubbles in a formation of a spherically flocculated particle swarm

摘要

Recently, an innovative solid-liquid separation technique using kHz-band ultrasound was proposed (1). It flocculates solid particles dispersed in liquid, using acoustic cavitation-oriented bubbles (ACOBs) which gather at the pressure antinode (2). This technique possesses the potential for many industrial applications due to its non- contact operation. However, deeper understanding about this technique is required for its actualization. In the present study, the formation of a spherically flocculated particle swarm (SFPS) in this technique will be discussed. The ACOB activity was estimated by pointwise sonoluminescence (SL) measurement using an optical fiber probe (OFP). Next, the motion of ACOBs was observed using high-speed videography, and force analysis was performed using numerical method. Finally, the contribution of primary and secondary Bjerknes force (FB1 and FB2) on the formation of an SFPS was discussed.