A novel design for passive misscromixers based on topology optimization method.

Area of Science:

• Fluid dynamics
• Microfluidics
• Chemical engineering

Background:

• Passive micromixers are crucial for efficient fluid mixing in microchannels.
• Existing designs like serpentine micromixers have limitations in mixing performance and fabrication.
• Chaotic advection is a key mechanism for enhancing mixing efficiency.

Purpose of the Study:

• To propose and investigate novel passive micromixers, termed topological micromixers with reversed flow (TMRFX).
• To optimize micromixer design using topology optimization, focusing on maximizing reversed flow.
• To evaluate the mixing performance and pressure drop of TMRFX compared to traditional designs.

Main Methods:

• Topology optimization was employed to design micromixers based on a square-wave unit.
• Numerical simulations were conducted to analyze fluid flow and mixing characteristics.
• The performance was evaluated across various Reynolds numbers (Re).

Main Results:

• The proposed TMRFX series, including TMRF, TMRF0.75, TMRF0.5, and TMRF0.25, demonstrated improved mixing over the square-wave micromixer.
• TMRF and TMRF0.75 showed significant advantages in mixing performance at various Re.
• TMRF0.75 achieved over 95% mixing efficiency for Re ≤ 0.1 and Re ≥ 10, and over 85% for 0.1 < Re < 10, with lower pressure drop than TMRF.

Conclusions:

• TMRFX, particularly TMRF0.75, offer enhanced mixing efficiency through reversed flow and chaotic advection.
• TMRF0.75 presents a favorable balance between high mixing performance and acceptable energy consumption (pressure drop).
• The developed TMRFX are promising for applications requiring efficient mixing in microfluidic devices.