Abstract: In this paper, the volume of fluid-continuum surface force (VOF-CSF) numerical model was used to numerically simulate the generation process of double emulsion droplets in coaxially hedged focusing glass capillaries. The rationality of the numerical model was confirmed by comparing the experimental photos in the literature and calculated results, which could predict the kinetic process of double emulsion droplet formation. The effects of viscosity, interfacial tension and flow rate on droplet size, flow pattern and fracture position were investigated. The results show that the generation of double emulsion droplets will be significantly affected by the low viscosity of the outer phase and the inner phase. The former will generate smaller double emulsion droplets, while the latter will generate multi-nucleated droplets at a suitable flow ratio. The increase of the interfacial tension will inhibit the jet at the relevant interface, so that the fluid pattern changes from the jet state to the drop state, which makes easier generation of the droplets. The outer phase flow rate mainly affects the size of the droplets. The larger the flow rate is, the smaller the size is, while the change of the flow rate of the middle phase and the inner phase mainly affects the core-shell ratio of the droplets.
Keywords: double emulsion droplet; microfluidic method; numerical simulation; co-flowing
合肥工业大学学报自科版