Numerical analysis of electroosmotic mixing in a heterogeneous charged micromixer with obstacles

Abstract The mixing and flow characteristics are numerically investigated for an electroosmotic flow through a heterogeneous charged micromixer with obstacles both at the top and bottom walls arranged in inline and staggered order by varying the obstruction angle (θ). The results are presented by varying the Debye parameter (κ), magnitude of the zeta potential (|ζ|), and obstruction angle in the range of 10 ≤ κ ≤ 100, 1 ≤|ζ| ≤ 4, and 60° ≤ θ ≤ 120°, respectively. Results reveal that the strength of the recirculation zone is the highest for θ = 90° and it enhances with κ and |ζ|, and moreover, the strength is always higher for the staggered arrangement of obstacles as compared to the inline order. For inline arrangement of the obstacles, the value of mixing efficiency (ME) decreases with κ as well as |ζ| and the highest values are seen for θ = 90°. For the staggered arrangement of obstacles, the variation of ME with κ is not monotonic; rather, it strongly depends on |ζ| and θ. The flow rate increases with the increase in κ and it is the lowest for θ = 90° and importantly, the flow rate is always more for inline arrangements of the obstacles.