Flow feature analysis of an eye shaped split and collision (ES-SAC) element based micromixer for lab-on-a-chip application

An eye shaped split and collision micromixer having low-pressure drop is proposed, which works on the concept of unbalanced splits and cross-collisions of fluid streams. The 3-D Navier–Stokes equations in combination with an advection–diffusion model were solved for the analysis with water and ethanol as working fluids. The in-depth analysis of the flow features and the mixing performance parameters viz. mixing index and pressure drop of the micromixer has been carried out. The micromixer model is composed of two sub-channels of equal/unequal widths which repeatedly undergo splitting and collision of fluid streams along the flow direction. The numerical study has been carried out on the micromixer at Reynolds numbers ranging from 0.1 to 45. The difference between the mass flow rates in the two sub-channels creates an unbalanced collision of the two fluid streams. Mixing enhancement is mainly due to the effect of unbalanced collisions of the fluid streams. The micromixers show exciting flow features for different ratios of the widths of the sub-channels. The ratios of a width of subchannels viz. 1, 1.4 and 2 are considered. The highest mixing performance has been observed for the width ratio of 2, whereas poor mixing performance has been observed for the width ratio of 1.