Numerical investigation on the efficient mixing of overbridged split-and-recombine micromixer at low Reynolds number

  • Muchuan He
  • Wei Li
  • MinQing Zhang
  • Jinli ZhangEmail author
Technical Paper


It is promising to design a novel structured micromixer that can be easily processed but also exhibit high mixing efficiency as well as low pressure drop at a wide range of Reynolds numbers. The overbridged structure was introduced into the planner E-shape micromixers for the first time to construct a novel kind of bridge-street structure micromixer, in order to improve the mixing efficiency in the wide range of Reynolds number. We investigated numerically the mixing performance of six overbridged E-shape split-and-recombine micromixers via solving 3D Navier–Stokes equations and adopting species transfer model. It is indicated that at lower Reynolds number the tilted interface in the overbridged channel increases the interfacial area and improves the mass transfer efficiency, while at higher Reynolds number the overbridged channels tend to induce vortices and promote the convective diffusion. The results show that the optimal overbridged micromixer DBEM-3 has excellent mixing efficiency exceeding 95% in the range of Re = 0.5–100. The optimal structure of overbridged micromixer was studied further with different viscosity ratio and power law fluid. In addition, the pressure drop under various Reynolds number was calculated, and the pressure drop of the power law fluid was represented by Euler number to reflect the magnitude of the momentum loss rate. It is illustrated that DBEM-3 has excellent mixing efficiency in wide Reynolds number for three different fluid systems, which has promising applications in the biochemistry analysis or mixing systems.



Double-bridge E-shape micromixer


User defining function


Mixing efficiency



List of symbols


Inlet length, μm


Outlet length, μm


Total length, μm


The width of E-shape sub channel, μm


The width of E-shape unit, μm


The height of overbridged channel, μm


The distance of adjoining units, μm


Mass fraction of a component at a sample point i


Mean mass fraction of a component at a certain cross section


Diffusion coefficient of a component, m2/s

\(\Delta {\text{P}}\)

Pressure drop, Pa


Fluid velocity of main channel, m/s


Consistency index, Pa s–n


Rheological index


Euler number


Reynolds number

Greek letters


Fluid viscosity of species i, kg/m s


Fluid density, kg/m3


Standard deviation

\(\sigma_{\hbox{max} }\)

Maximum standard deviation


The fluid shear rate in the direction j on plane i, Pa


The local shear rate, Pa


The average shear rate, Pa



This work was financially supported by the National Natural Science Foundation of China (Nos. 21776179, 21621004), and Program for Chang Jiang Scholars and Innovative Research Team in University (No. IRT_15R46).


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.School of Chemical Engineering and TechnologyTianjin UniversityTianjinPeople’s Republic of China
  2. 2.School of Chemistry and Chemical EngineeringShihezi UniversityShiheziPeople’s Republic of China

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