Remarkable reduction of microbubble size by constructing a flexible interaction region in a T‐junction microchannel

Abstract High‐efficiency reduction of the microbubble size is important for bubble‐based microflow processes but has hitherto required high‐energy‐consumption methods. This study designed a new T‐junction microchannel with a flexible interaction region exhibiting apparent superiority in producing smaller bubbles with high energy‐utilization efficiency, and for the first time breaks the limitation of the flow pattern in the ordinary T‐junction microchannel. The results indicate that under the given two‐phase working conditions, the microbubble size was greatly reduced in the new T‐junction microchannel compared to that in the ordinary one. The microbubble formation mechanism in the new microdevice is analyzed via a simulated liquid velocity field. Importantly, the bubbly flow pattern appeared rapidly under a higher gas flow rate, which is totally opposite to the expectations in the ordinary T‐junction. Finally, via interface analysis, the importance of the gas velocity on the viscous shearing force was clarified, and a new bubble size‐prediction model was developed.