Droplet generation at T-junctions in parallelized microchannels

Microchemical technology is an advanced chemical production technology and the large-scale production for industrial applications is realized by parallelization of microchannels. In this paper, the emulsification process and numbering-up of droplets in asymmetric parallelized microchannels with T-junction are investigated, and the effects of fluid properties and operating conditions on droplet size are analyzed. The droplet generation process is divided into waiting stage, filling stage, necking stage, and pinch-off stage, according to the variation of the characteristic length scale during droplet generation. The flow patterns of droplet swarm in cavities and their influence on fluid distribution are analyzed. The droplet size prediction equation and fluid distribution model in asymmetric parallelized microchannel are constructed. The phenomenon of droplet asynchronous generation due to the coupling of parallelized microchannels during the numbering-up process is analyzed. The effect of asynchronous generation on droplet monodispersity is investigated and the mothod for the prevention of this effect is proposed. Graphical abstract