A cross-mixing channel 3D-SAR micromixer with high mixing performance

Abstract

Abstract As an important part of laboratory-on-a-chip (LOC) and micro-total analysis system (μTAS), micromixers are widely used in the fields of biological analysis and chemical synthesis. Most of them are used for the pretreatment of the detection and analysis system to realize the full mixing between the sample and the target to improve the accuracy of the inspection system. A new type of 3D-SAR micromixer with cross-channel structures was put forward after the systemic simulation by using CFD software. The mixing performance and mechanism of 3D-SAR micromixer with/without cross-mixing channel has been investigated with different Reynolds numbers (Re). The results show that the 3D-SAR micromixer with or without cross-mixing channel structures are of excellent mixing performance when the Re was high (Re > 50), and the mixing index is close to 1. While the concentration stratification of the two fluids in the cross-mixing channel (CMC) 3D-SAR micromixer is obviously better than that of no-cross-mixing channel (NCMC) 3D-SAR micromixer when Re is low (Re < 10). It is because the two fluids in the cross-mixing channel rotate counterclockwise at the mixing unit, which induces a vortex and increases the contact area between the two fluids. The mixing performance is greatly improved, and the mixing index at the outlet is more than 0.9. Meanwhile, in order to optimize the higher pressure drop of the CMC micromixer, a new 3D-SAR micromixer with the unbalanced-cross-mixing channel (UCMC) is proposed based on the CMC structure. This channel structure can meet the requirements of high mixing index and low-pressure drop at the same time, which is helpful to design and manufacture of new type micromixer.