Mixing performance of unbalanced split and recombine micomixers with circular and rhombic sub-channels

Mixing performance has been evaluated for planar split and recombine micromixers with asymmetric sub-channels. The three-dimensional Navier–Stokes equations have been used to analyze fluid flow and mixing in a Reynolds number range from 1 to 80. The widths of the split channels are kept unequal to create unbalanced collisions of the fluid streams. Two shapes of the split channel have been considered; circular and rhombic. In the case of rhombic sub-channels, higher mixing is realized when width of the major sub-channel is either three or four times as wide as the minor sub-channel unlike the case of circular sub-channels. The results show the lowest mixing performance for the case of balanced collisions of fluid streams. The pressure-drop characteristic has been also analyzed at various Reynolds numbers.