A novel micromixer with multimixing mechanisms for high mixing efficiency at low Reynolds number

Abstract

In this paper, we propose a novel passive micromixer structure for high mixing efficiency based on the combination of multimixing principles. With a special structure, our proposed micromixer can create vortices, transversal flows and chaotic advections to provide high mixing efficiency event at low Reynolds number. Moreover, two narrow slits at two ends of each mixing unit remarkably reduce pressure drop, making it easy to be built into micro-devices. We conduct intensive simulation to evaluate the performance of our proposed micromixer by numerically solving the governing Navier-Stokes equation and convection-diffusion equation using COMSOL Multiphysics package. The simulation results indicate that our proposed micromixer may achieve stable mixing efficiency of 80% or above for a wide Reynolds number range from 0.5 to 100. Especially, at Reynolds number (Re) > 30, mixing efficiency is less dependent on Reynolds number. The mixing efficiency of our micromixer is two times higher than mixing efficiency of micromixer based on unbalanced splits and collisions of fluid at the same mixing channel length of 5mm. At Re = 30, our proposed micromixer has high mixing efficiency of 85% with moderate pressure drop ΔP = 12,600Pa.