Preparation of microdispersed droplets by phase inversion in gas/liquid/liquid microdispersion system

A simple and effective method was conducted for preparing microdispersed droplets with decreased size and increased uniformity, in which phase inversion in high-phase-ratio liquid/liquid system was combined with addition of microbubbles. Five typical flow patterns were observed, including W/O, O/W/O, transition regime, O/W and G/W/O regimes. Flow regime transition was observed, according to which physical properties of systems and operating conditions for preparing single-oil-droplet-in-water emulsion were determined in different liquid/liquid and gas/liquid/liquid modes. Effects of liquid viscosities as well as interfacial tension on droplet size ( D O ) and its standard deviation (SD) were studied systematically and the most effective gas/liquid/liquid mode was recommended. Mathematical models were established for correlating D O in five different modes, which show relatively good agreement with experimental results. D O decreases by 42% via introducing phase inversion and further reduces to 25% by addition of microbubbles, both under the same operating conditions.