Numerical Analysis On The Influence Factors Of Microfluidic Mixing

Microfluidic chips technology is becoming a hotspot study area of analysis science, successfully applied in analytical chemistry, life sciences, etc. Micromixer is its important component and functional mode. As for micro mixing-reaction systems, the reaction efficiency depends on mixing, there is no complete reaction without sufficient mixing, and mixing time becomes a bottleneck for reaction even for the whole system analysis. High efficiency of mixing under micro scale is significant. And how to achieve high efficiency of mixing is one of important research subjects. Now varied micromixers is presented, designed by different theory, such as serial micromixer, chaotic micromicer, etc. But a summarized theory or experience hasn't been made yet for designing and experiment. A lot of factors have influence on microfluidic mixing. As microchannel be concerned, there are three important factors, the shape of cross-section, flow velocity profile, and the shape of mixing microchannel. This paper aims to analyses these factors influence on microfluidic mixing through numerical simulation.1. Influence of cross-section shape on microfluidic mixing. Mainly analyses influence of variant characteristic length under same diffusion distance, and which is the best choice from square, circular, and equilateral triangle. The results show that equilateral triangle is the best.2. Influence of flow velocity profile on micromixing. The mixing effects for three flow velocity profiles, parabola, plug-like and concave, are compared. The results show that the parabola velocity profile produced by pressure driven system is the best choice for micromixing. It is different from traditional thinking.3. Influence of microchannel figure on micromixing. It mainly analyses influence of different angles of turns and the combined turns, and the shape of sinuous channel, such as folded, arc, straight turning.In a word, micromixer is an important study subject. This paper studies on the influence factors of microfluidic mixing from three aspects, cross-section shape of microchannel, flow velocity profile and figure of mixing channel, through numerical simulation, and draws some conclusions for designing of microchannel and operation of experiment.