Drop Generation Using Cross-Flow in Rigid Body Rotation*

Inspired by crossflow membrane droplet generation and microfluidic droplet generation, we propose an easy method to generate monodisperse drops using cross-flow caused by rigid body rotation. In our approach, a dispersed phase liquid was injected through a stationary vertical needle into an immiscible continuous phase liquid which was in rigid body rotation. A dispersed phase drop growing at the end of the needle experienced fluid dynamic forces from the horizontal continuous phase flow, and it was detached from the needle when it had grown to a certain size. This study investigated the relationship between the resultant size and generation frequency of drops and the controllable experimental factors including the flow velocity of the continuous phase at the needle end and the flow rate of the dispersed phase through the needle. As an example of possible application, the method was utilized to generate monodisperse hydrogel beads.