Thermally-controlled generation of uniform droplets in an axisymmetric co-flow-focusing device.

Today, droplet generation in microfluidic chips has many applications The monodispersity and uniformity of droplets play a crucial role in most of these applications, ensuring optimal performance and reliable results. The monodispersity is achieved through the dripping regime, while to attain uniformity, precise control of the formation of the droplets is needed. In this numerical study, we used a microfluidic chip with axisymmetric co-flow-focusing geometry. The light mineral oil and water were the continuous and dispersed phases, respectively. At first, we studied how a change in the outer diameter of the chip affects the dripping-jetting transition boundary and found out that decreasing outer diameter results in a larger dripping regime region, therefore we could generate monodisperse droplets in a greater range. Subsequently, in addition to studying the effects of different constant inlet temperatures, our work investigated droplet generation using harmonic fluctuation of inlet temperature such that the frequency of droplet generation matched the frequency of temperature. Hence, we obtained droplets of the same size. Finally, we generated monodisperse uniform droplets using the optimum outer diameter and thermal control. [ABSTRACT FROM AUTHOR]