A small and effective tool for thoroughly mixing fluids at the microscale level is the Mixing In Straight Micromixer. This type is perfect for applications in chemical reactions, biological tests, and pharmaceutical advances where accurate and speedy mixing is vital. This time a reference paper entitled “ Comparative assessment of mixing characteristics and pressure drop in spiral and serpentine micromixers” is targeted. It is a paper validation study in which the mixing index will be investigated.

Simulation Process

Two inlets provide water and ethyl alcohol to the main micromixer with Y joint. The primary portion is 400 μm in depth and 200 μm in length. Then, 2814400 structured cells are utilized to discretize the domain. The flow is determined to be three-dimensional, laminar, steady, isothermal, and incompressible. The Species Transport Module models two fluids (ethyl alcohol and water).

Post-Processing

The mixing index (η) is a crucial parameter for evaluating micromixer performance. The mixing index is calculated to quantify the mixing by determining the variance of species in the plane perpendicular to the fluid flow. The variance of the mass fraction of a given fluid in the mixture at a cross-sectional plane of the micromixer perpendicular to the fluid flow is calculated as:

Where γ is the variance, N is the total number of sampling points, Ck is the mass fraction at sampling point k, and Cm is the average mixing mass fraction. TIt is calculated as:

As given in the plot, mixing index for a straight micromixer at Re=10 equals 0.27, whereas the present CFD simulation reports 0.239. It shows only 11% difference, which proves the validity of our simulation.