Development of Novel Triangular Single-Layer Separation and Recombination Inspired Micromixers Integrated with The Minkowski Fractal Principle

Abstract

The present work proposes and numerically investigates a series of novel passive micromixers based on the triangular-shaped separation and recombination (TSAR) configuration. These designs are further integrated with the Minkowski fractal principle into the triangular obstacle geometries to promote enhanced mixing performance. The study begins with three fundamental configurations: converging triangular separation and recombination (TSAR-CC), diverging triangular separation and recombination (TSAR-DD), and a union of converging-diverging triangular separation and recombination (TSAR-CD) micromixers, each designed to induce chaotic advection along the mixing channel. Subsequently, the variants of each base design are introduced inspired by the Minkowski fractal theory, featuring two, four, and eight steps within triangular obstacles. These modifications create distinct flow perturbations and local recirculation zones that further strengthen chaotic advection and improve mixing uniformity. The numerical simulations are carried out in OpenFOAM v24 workbench for mixing of fluids having identical properties, while the Reynolds number range of 1 to 100 is set for the analysis. We evaluate the mixing efficiencies of the micromixers qualitatively and quantitatively through concentration contours, while the streamlines and velocity vectors are also presented to reveal the flow dynamics. Among all the designs, TSAR-CD demonstrates superior results, particularly, in low Reynolds number range (Re < 25). We have further reported the improvement in the mixing quality in the wide range of Reynolds numbers (more than 90%), as the TSAR-CD is modified with the Minkowski fractal.