Passive micromixers for DNA analysis using CFD modelling

Abstract

Mixing efficiency is an important issue in the design of micromixers, since effective mixing is required between Deoxyribonucleic acid (DNA) sample and restriction enzyme for a fast digestion process. Mixing is improved by chaotic advection through serpentine mixing channels. This leads to the desired reduction in the fluid diffusion path while at the same time increasing the fluid contact areas. The purpose of this research is to evaluate mixing efficiency in microchannel mixers, through a numerical study of different micromixing configuration. To accomplish this, a numerical study is conducted using computational fluid dynamics (CFD) approach using ANSYS Fluent and CFX Software for different geometries designed. Different geometric configuration were proposed and used: bottleneck near the inlet and along the zig zag and curved shaped rectangular zig zag geometry. Mixing analysis is done by different conditions such as Reynold's number, effect of geometry on fluid flow and different diffusion coefficients by evaluating mixing index of the fluid. Results have shown better and faster mixing index around bottleneck region compared to other. This geometry can be used to model passive micromixers and other microfluidic devices with shorter mixing length and for faster mixing between reagents.