Numbering-up and stability strategies of bubbles in yield stress fluids in asymmetric parallelized microchannel

Preparation of foams within microchannels is a clean and capable of precisely controlled synthesis. In this work, high throughput production of bubbles in Carbopol gels (0.05 wt%, 0.1 wt%, 0.2 wt%) in asymmetric parallel channels is investigated. Bubbles in Carbopol gels are strongly unstable, and the asymmetry of the microchannel makes bubble instability more pronounced. A “slug-slug” flow pattern is observed for only 0.05 wt% Carbopol and microchannels with back cavities, and the bubble train is highly unstable. The strategy proposed in this article solves the challenge of numbering-up of bubbles produced in YSFs by strategically reducing the gas pressure, and the stability of bubble train and activation rate of microchannel are improved, which is of great engineering significance for the high-throughput production of high-quality foam materials.