Experimental study on breakup mechanism of microbubble in 2D channel

Abstract

The breakup mechanism of a microbubble in a 2D channel, was studied through visualization experiments. A venturi-shaped nozzle made with a 3D printer in a 2D channel was employed, and the pressure data and visualization images were analyzed. It is compared that he bubble behavior and size distribution according to the change in the rear-end exit angle of the venturi-shaped nozzle. As the exit angle increased, the bubble size decreased. However, it was confirmed that wake flow was formed in the venturi channel with an exit angle above 20°. By analyzing the visualization, we confirmed that the air bubbles interacted with the central flow and split into pieces. To maximize this process, a flare-shaped diffuser was designed and evaluated. The bubble breakup performance of the flared diffuser was better than that of the linear exit angle, in terms of the bubble size. It was a flared diffuser that satisfied the conditions for maximizing the bubble breakup process in a water flow rate of (35 L/min) and an air flow rate (0.1 L/MIN) experiments. Based on the results, it is expected that the limitations of the venturi-shaped microbubble generator can be overcome. © 2021 The Authors