An analytical study of micro-droplet generation in microfluidic double T-junction devices under effects of channel depth ratio using VOF method

This paper describes a numerical study on micro-droplet generation in a microfluidic double T-junction device under the effects of channel depth using the Volume-Of-Fluid method. The effects of various parameters such as capillary number (Ca), water fraction (wf), viscosity ratio \((\beta )\) $(\beta )$ , and particularly the channel depth ratio \((\varepsilon )\) $(\epsilon )$ were examined. Consequently, the numerical results match well with the experimental data obtained in the literature. Additionally, the micro-droplet size increases with increasing the channel depth ratio. A phase diagram with four main micro-droplet generation regimes is provided. Particularly, the alternating mode is narrowed in both Ca and wf ranges when increasing \(\varepsilon \) $\epsilon$ . Moreover, four regimes of micro-droplet generation with the presence of channel depth were first discovered in the present study, and the stable micro-droplet generation regime can be gained within an effective range of both \(\varepsilon \) $\epsilon$ and \(\beta \) $\beta$ . These results are very useful and valuable for many applications in emulsion production, hydrogel particle generation, and drug delivery synthesis in biomedical treatment.