Dynamics of bubble breakup with partly obstruction in a microfluidic T-junction

• Bubble breakup with partly obstruction in a T-junction is studied.
• The variation of the minimum width of the neck during bubble breakup is studied.
• The bubble breakup process includes squeezing stage and pinch-off stage.
• A tunnel characterizing the bubble breakup with partly obstruction is highlighted.
• The leakage volume for the breakup process is calculated.

The bubble breakup with partly obstruction in a microfluidic T-junction was investigated experimentally in this paper. It was demonstrated that the breakup process could be divided into two stages: squeezing stage and pinch-off stage, according to the evolution of the minimum width of the bubble neck wm. During the squeezing stage, the variation of 1−wm/wc with time t could be scaled by a power law. In the pinch-off stage, the minimum width of the bubble neck wm could also be correlated into a power law function with the remaining time (Tc−t). A tunnel, which characterized the bubble breakup with partly obstruction, appeared between the bubble tip and the microchannel wall in the squeezing stage, and exhibited little effect on the evolution of the bubble neck. However, the evolution of the bubble tip was obviously different before and after tunnel appearance. By means of the analysis on the dynamics of the bubble tip, some important parameters such as the final bubble length and the leakage volume were studied and discussed.

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