Asymmetrical breakup of bubbles at a microfluidic T-junction divergence: feedback effect of bubble collision
Résumé
This paper aims at studying the asymmetrical breakup of bubbles at a microfluidic T-junction divergence stemming from the feedback effect of bubble behaviors at the T-junction convergence in a loop with the symmetrical branches by a high-speed digital camera. The experiments were performed under gas/liquid flow rates ratio ranging from 0.084 to 4.333. The microfluidic channels have uniform square cross-section with 400 mu m wide and 400 mu m deep. Four bubble behaviors (bubble pair asymmetrical collision, bubble pair staggered flow, single bubble flow and dynamic transformation flow) were observed at the T-junction convergence in different gas and liquid flow rates. The feedback effects of asymmetrical collision and staggered flow of bubble pairs at the T-junction convergence on bubble behavior at the T-junction divergence were mainly investigated. The result showed that the feedback effect is negligible at relatively low flow rates when no collision of bubble pairs occurs. And the bubble pair asymmetrical collision at T-junction convergence or an amplified effect of structured blemish of microchannel at relatively high flow rates is primarily responsible for the asymmetric breakup of bubbles at the T-junction divergence.