Passive Single-Chamber Micromixer with High Throughput and Low-Pressure Drop

Passive micromixers play a vital role in microfluidic chemical engineering; however, enhancing their throughput while maintaining low energy consumption, specifically low-pressure drop, remains a significant challenge due to the constraints imposed by their narrow microchannels. In this study, a passive single-chamber micromixer (SCM) was designed to achieve high throughput and efficient mixing at low-pressure drop. The novel micromixer has a simple and streamlined mixing chamber, in which a strong oscillating flow is generated based on the Coanda effect. Consequently, intensive chaotic convection is induced to achieve efficient mixing at low-pressure drop. A mixing effectiveness index (MEI), including the mixing index, global energy dissipation rate, residence time, and fluid properties, was proposed to assess the comprehensive performance of the proposed micromixer and others. The flow patterns, mixing performance, and pressure drop of the SCM were investigated using CFD simulations and dye tracer experiments. The results show that the SCM generates a periodic oscillation at a high throughput of 7.2∼21.6 mL/min (Re = 100∼600), achieving the maximum mixing index of 0.81 and a reduction of 5–9% in the pressure drop. The MEI of the SCM is significantly higher than that of existing passive chaotic convection micromixers. The SCM provides a way to significantly increase throughput at low-pressure drop and can advance the application of passive micromixers in large-scale production.