Design and Simulation of an Interdigital-Chaotic Advection Micromixer for Lab-on-a-chip Applications

Dessin et simulation d'un micro mélangeur à advection interdigitale cahotique pour les applications de laboratoire sur puce

Khashayar Khoshmanesh¹, Abbas Z. Kouzani¹, Saeid Nahavandi¹, Sara Baratchi² and Jagat Kanwar²

¹ School of Engineering and IT, Deakin University, Waurn ponds VIC 3217, Australia
² Institute of Biotechnology (BioDeakin), Deakin University, Waurn ponds VIC 3217, Australia

Corresponding authors: kkho@deakin.edu.au kouzani@deakin.edu.au nahavand@deakin.edu.au sbara@deakin.edu.au jagat.kanwar@deakin.edu.au

Abstract

This paper presents the design and simulation of a novel passive micromixer. The micromixer consists of two inlet tanks, one mixing channel and two outlet channels. In order to maximise the mixing efficiency, the following considerations are made: (i) The inlet tanks are followed by a series of microchannels, in which the flow is split. The microchannels are arranged in an interdigital manner to maximise the contact area between the two flows. (ii) The microchannels attached to the lower inlet tank have an upward slope while those attached to the upper tank have a downward slope. The higher-density flow is fed to the lower inlet tank and gets an upward velocity before entering the mixing channel. (iii) Two triangular barriers are placed within the mixing channel to impose chaotic advection and perturb the less-mixed flow along the top and bottom surfaces of the channel. (iv) Finally, two outlet channels are incorporated to discard the less-mixed flow. Three-dimensional simulations are carried out to evaluate the performance of the micromixer. Simulations are performed in the absence and presence of the gravitational force to analyse the influence of gravity on the micromixer. Mixing efficiencies of greater than 92 % are achieved using water and a low-density biological solvent as the mixing fluids.