Mixing Performance of the Modified Tesla Micromixer with Tip Clearance

Area of Science:

• Microfluidics
• Fluid Dynamics
• Chemical Engineering

Background:

• Passive micromixers are crucial for efficient fluid manipulation at the microscale.
• Modified Tesla mixing units offer potential for enhanced mixing but require optimization.
• Tip clearance is a novel design feature for modifying flow dynamics in micromixers.

Purpose of the Study:

• To design and simulate a passive micromixer with embedded tip clearance in a modified Tesla mixing unit.
• To evaluate the impact of tip clearance height on mixing performance (Degree of Mixing - DOM) and pressure load across a range of Reynolds numbers (Re = 0.1 to 80).
• To optimize tip clearance height for improved mixing efficiency and reduced pressure drop.

Main Methods:

• Numerical simulations were performed to analyze fluid flow and mixing characteristics.
• The micromixer geometry featured a wedge-shape divider with adjustable tip clearance (40 μm to 80 μm).
• Mixing performance was quantified by the Degree of Mixing (DOM) at the outlet and the pressure load.

Main Results:

• Tip clearance significantly enhances mixing for Reynolds numbers below 50 (Re < 50).
• An optimal tip clearance height of approximately 60 μm (33% of micromixer depth) was identified for maximizing DOM.
• For Re ≥ 50, mixing enhancement from tip clearance diminishes, with vortex formation becoming dominant. Tip clearance reduces pressure load for a given DOM.

Conclusions:

• Embedded tip clearance is an effective strategy for enhancing mixing in modified Tesla micromixers, particularly at low to intermediate Reynolds numbers.
• The study identified an optimal tip clearance height that balances mixing enhancement and pressure drop.
• The findings provide valuable insights for the design of efficient passive micromixers for various microfluidic applications.