Vortex generation and control in a microfluidic chamber with actuations

In this paper, we present a novel method forvortex generation and control in a resonator-shaped microfluidic chamber with actuations. By varying the actuation conditions, including the working transducers, frequency, and voltage, two regimes ofvortices, clockwisevortex (CWvortex) and counter-clockwisevortex (CCWvortex), are generated in the chamber. We show that the direction of thevortex can be conveniently shifted from clockwise to counterclockwise by switching the working transducers without interrupting theflow, and the intensity of thevortex can be regulated by the actuation frequency and voltage. It is proposed that thevortex generation in the present case is due to theinstability of the actuation-induced pulsatileflow through the sudden expansion part at the outlet of the chamber, while thevortex control is realized through the asymmetricflows in the chamber induced by the upper or lower transducers. The reported method ofvortex generation and control can be applied in microfluidic operations for mixing enhancement of multiple reagents and distribution of microparticles and nanoparticles.

Source: Physics of Fluids - December 2, 2016 Category: Physics Authors: Xiaopeng Shang, Xiaoyang Huang and Chun Yang Source Type: research