Double emulsion using hierarchical microchannel


   One of the novel and practical phenomena in microfluidic devices is the double emulsion. The double emulsion structure occurs when a droplet contains one or more smaller droplets. The appropriate control is difficult to achieve over the number, size and ratio of the encapsulated droplets in the double emulsion. This research presents a practical way to create three kinds of double emulsions such as double emulsion, double-component double emulsion and viscoelastic double emulsion. A hierarchical T-junction microfluidic device is selected to simulate this phenomenon. A system of the three-phase flows consists of the inner, middle and outer phases were simulated by the Direct Numerical Simulation (DNS) method. The dripping regime is considered for the droplet formation in both T-junctions. The one-step and two-step encapsulation are used to create the double emulsion and the viscoelastic double emulsion, respectively. In both T-junctions, droplets are created by the balance of three parameters which are instability, viscous drag and pressure buildup. The simulated hierarchical microchannel shows some desirable features for creating the complex compounds. The encapsulation process is simulated in microscale that is useful for drug delivery applications. Emerald Publishing. 2015 Int. J. Numer. Method. Heat Fluid Flow. []