Uniformity and stability of droplet formation at T-junctions in symmetrical microchannels

Abstract

The numbering-up strategy of microchannels is an important method to improve the production capacity of microchemical technology, but it sometimes leads to the deterioration of the uniformity and stability of droplet formation. In this paper, the flow patterns distribution is introduced, and the predicted formula for droplet volume is fitted. The reason for the difference in droplet formation between symmetrical microchannels is explained. The uniformity of droplet formation is characterized by the relative deviation of average microdroplet volume between microchannels E(V), which determined by flow distribution depends on the resistance distribution in the microchannel device, and a prediction model of E(V) is proposed. The stability of droplet formation is characterized by the coefficient of variation CV for the volume of microdroplets in each single microchannel, which determined by the pressure fluctuations in the single microchannel, and a prediction model of CV is proposed. It shows that the crossing-shearing method of two-phase flow in dripping regime is the optimal way to produce microdroplets in symmetrical microchannels.