Mixing Analysis of Passive Micromixer with Unbalanced Three-Split Rhombic Sub-Channels

A micromixer with unbalanced three-split rhombic sub-channels was proposed, and analyses of the mixing and flow characteristics of this micromixer were performed in this work. Three-dimensional Navier-Stokes equations in combination with an advection-diffusion model with two working fluids (water and ethanol) were solved for the analysis. The mixing index and pressure drop were evaluated and compared to those of a two-split micromixer for a range of Reynolds numbers from 0.1-120. The results indicate that the proposed three-split micromixer is efficient in mixing for a range of Reynolds numbers from 30-80. A parametric study was performed to determine the effects of the rhombic angle and sub-channel width ratio on mixing and pressure drop. Except at the lowest Reynolds number, a rhombic angle of 90 degrees gave the best mixing performance. The three-split micromixer with minimum minor sub-channel widths provided the best mixing performance.