Analysis of a Two‐Layer Nozzle‐and‐Diffuser Electroosmotic Micromixer

An electroosmotic micromixer with two‐layer microchannels of a nozzle‐and‐diffuser structure was proposed. Numerical analysis of the flow and mixing was performed using the three‐dimensional Poisson‐Boltzmann and Navier‐Stokes equations with a diffusion‐convection model for the species concentration. A parametric analysis of the microchannels was performed using three geometric parameters, i.e., length of the nozzle section, length of the diffusion section, and width of the nozzle end, to investigate the impact of each parameter on the mixing performance, which was quantified by a quantitative measure based on the mass variance. The numerical results were used to improve the design of the proposed micromixer, leading to a far better mixing performance with a much shorter channel length compared to an existing electroosmotic micromixer. A novel electroosmotic micromixer is proposed with two‐layer microchannels of nozzle‐and‐diffuser structure, which improves the mixing performance by more than 50 % with a much shorter channel length compared to the previous one. This result will greatly contribute to the development of micromixers as a key element of lab‐on‐a‐chip devices, and thus, finally to public health.