An Integrated Pumping and Mixing Device

Abstract

The present work numerically characterizes a microfluidic device with pumping and mixing functions for lab-on-a-chip applications. The planar fluidic network of the device consists of two inlet channels, a pump chamber, a neck channel, and an outlet channel, all of which connect at a junction. The pump chamber is enclosed by a soft polymeric diaphragm. Pump performance is based on a new valveless principle. Mixing enhancement relies on the unsteady flow obtained from the pumping function. Numerical simulations are performed on two different floor structures in the neck channel: with and without an oblique ridge. The pumping result achieved shows that the flow rate increases notably with increasing deflection of the diaphragm and that the ridge has a negligible effect on the pump performance of the device. The results also demonstrate that the fluidic network of the device rectified flow better than its conventional nozzle/diffuser counterpart. For the measurement of the mixing, the intersection map, mixing variance coefficient, and mixing efficiency are analyzed. Analysis shows that mixing is substantially improved with the ridge and the device can suitably perform mixing for a wide range of flow rates. Without the ridge, mixing relies only on pure diffusion processes; thus, it is very poor. With the integrated pumping and mixing functions, the device serves as a promising step toward the realization of lab-on-a-chip or microfluidic systems.