Mixing performance of split-and-recombine micromixer with offset inlets

This study proposes a novel 3D split-and-recombine passive micromixer with offset-inlets. The micromixer is composed of non-aligned inlets and spatially repeating mixing units with mixing chambers and sub-channels. Each repeating unit has a chamber and two sub-channels with a number of alternate bends to create chaos in the flow. The non-aligned inlets provide inlet swirl while split-and-recombine mixing units stretch interfacial area, which eventually enhance mixing efficiency of the micromixer. The numerical modeling was conducted by solving three-dimensional steady state flow equations along with the diffusion equation for several flow conditions to evaluate the parametric mixing performance. A variance-based mixing index was used to compute the degree of mixing. A characterization methodology was employed to demonstrate the effect of several design parameters, i.e., width and depth of the mixing channel, pitch, length and height of the mixing chamber on the performance. The proposed micromixer exhibited excellent performance over a wide range of Reynolds numbers covered in the present study. At low and medium Re, proposed micromixer performed much better than 3D serpentine and 3D serpentine SAR micromixers reported in the recent literature.