Improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids
Biomicrofluidics
|August 21, 2009
Summary
Viscoelastic fluids enhance rectification in microfluidic diffusernozzle structures. This enables efficient low Reynolds number pumping for lab-on-a-chip applications, overcoming limitations of traditional Newtonian fluid micropumps.
Area of Science:
- Microfluidics
- Fluid Dynamics
- Materials Science
Background:
- Rectification in diffusernozzle structures typically relies on inertial effects, requiring high Reynolds numbers and frequencies for Newtonian fluids.
- Low Reynolds number applications face challenges with traditional micropump designs.
Purpose of the Study:
- To investigate the improvement of rectification effects in diffusernozzle structures using viscoelastic fluids.
- To explore the potential of viscoelasticity for low Reynolds number micro-pumping.
Main Methods:
- Fabrication of a silicon microfluidic device using deep reactive ion etching.
- Utilizing a dilute polyethylene oxide solution as the viscoelastic fluid.
- Experimental measurements of flow visualization, pressure drop, and diodicity across varying diffusernozzle angles (15-60 degrees).
Main Results:
- Viscoelastic fluids demonstrate anisotropic behavior at low Reynolds numbers.
- Significant improvement in diodicity was observed with the viscoelastic fluid compared to de-ionized water.
- The study compared performance across different diffusernozzle opening angles.
Conclusions:
- Viscoelastic effects can achieve anisotropic behavior in diffusernozzle structures at low Reynolds numbers.
- The improved diodicity offers a promising, simple pumping concept for lab-on-a-chip systems.
- This approach overcomes the limitations of inertial effects in Newtonian fluid-based micropumps.
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