Tailoring bubble size through acoustic-assisted microbubble generation

Various bubble generation methods have been developed to produce microbubbles, but current techniques are inadequate for meeting industrial demands for controlling the size of microbubbles accurately. This study aimed to investigate acoustic bubble generation as a potential solution to the demand. Initially, a capillary tube was exposed to a continuous standing wave to control the bubble generation, which resulted in a relatively large bubble size and number. However, the extent of bubble coalescence was high due to the attractive secondary acoustic radiation force (ARF) between vibrating bubbles. Alternatively, a pulsed wave could reduce attractive ARF, thereby simultaneously reducing bubble coalescence and controlling the bubble generation frequency and size. However, this approach compromised the quantity of bubbles generated. The research contributes to the mass production of microbubbles and the strategic control of bubble size to optimize process efficiency.