5 Conclusion
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Some suggestions for further researches on passive micromixers are: (1) one of
the major goal in micromixing is to develop efficient micromixers, and therefore,
novel micromixer designs need to be developed to achieve higher mixing performance over a shorter micromixer length, (2) a significant portion of the studies on
micromixers assumed fluids to be Newtonian. However, in many practical microfluidic applications, the fluids are non-Newtonian such as bio-fluids, blood samples, and
polymer solutions. Proper models for non-Newtonian fluid need to be incorporated in
governing equations, and analysis can be done with respect to the different operating
conditions encountered in microfluidic devices, (3) affordable computational grid
is key requirement for mixing analysis in micromixers, and to reduce discretization
error (i.e., numerical diffusion), numerical schemes for advection terms need to be
further studied, (4) although optimizations of micromixer designs have been successfully performed by many researchers, the performance parameters were limited to
mixing index and pressure drop. It would be interesting to test other performance
parameters such as mixing time and energy dissipation. Also, the multi-objective
optimization method can be extended to handle three- or more objectives, which
would be useful for more robust design of microfluidic systems.