Bubble deformation dynamics in asymmetric semicircle pore-throat microchannels

Multi-phase microfluidic transport is a topic of great interest in both academic research and industry. This study focuses on the deformation dynamics of bubbles generated during oil transport in microchannels. We investigate the deformation behavior of bubbles in square microchannels with two semi-cylinders. Our findings show that bubble deformation occurs in two modes: breakup deformation and elastic non-breakup deformation. By evaluating the minimum width of the microchannel neck, we divide both modes into four stages, which exhibit power-law variation. Additionally, we investigate the effects of presetting factors on viscosity in the microchannel. To gain deeper insight into the deformation mechanism of bubbles, we used micro-particle image velocimetry to describe the velocity patterns and dimensional distribution of viscosity in the flow. We successfully summarize a dynamical scaling law that specifies the size of bubbles formed in the pore throat microchannels. It reveals that the fluid characteristic of the continuous phase dominates the deformation of bubbles in such microdevices.