Effect of side channel configuration of a T-junction on droplet generation: A computational study

Microfluidics has significantly advanced various fields, particularly in biological and medical applications. Droplet generation within a T-junction configuration is a fundamental technique, where channel geometry plays a critical role in determining droplet size, frequency, and uniformity. This study employs computational fluid dynamics (CFD) simulations using COMSOL Multiphysics ${ }^{\circledR}$ to systematically investigate the impact of different side channel geometries on droplet formation in a T-junction. Our findings indicate that variations in channel geometry, such as narrowing and curving the side channel, result in smaller droplet sizes just in one set of configurations (“H. curved tapered” with respect to “H. tapered”) while no major variations in droplet diameter for other two sets of configurations (“Hourglass” with respect to “Simple straight” and “Curved” with respect to “Tapered”) were observed. In general, the “Tapered” and “Curved” configurations yielded slightly higher generation frequencies than other configurations, indicating an inverse relationship between generation frequency and droplet size. These insights contribute to the optimization of microfluidic devices for specific bio-applications, such as single-cell analysis and drug delivery, by offering a detailed understanding of the relationship between channel geometry and droplet characteristics.