Experimental characterisation of a novel viscoelastic rectifier design

Area of Science:

• Fluid dynamics
• Rheology
• Microfluidics

Background:

• Viscoelastic effects can induce anisotropic flow resistance in microfluidic systems.
• Understanding these effects is crucial for designing efficient microfluidic devices.

Purpose of the Study:

• To characterize the anisotropic flow resistance in a planar microfluidic system with contractions and obstacles.
• To quantify the diodicity performance of the system and identify optimal operating conditions.

Main Methods:

• Experimental characterization using streak photography to visualize flow dynamics.
• Quantification of diodicity performance through precise pressure drop measurements.
• Two-dimensional (2D) simulations of the FENE-CR differential constitutive model.

Main Results:

• The microfluidic system exhibits anisotropic flow resistance attributed to viscoelastic effects.
• Maximum diodicity performance, around 3.5, was achieved at relatively low elasticity levels.
• Experimental data showed limitations in direct comparison with 2D simulations at low elasticity due to reproducibility and uncertainty.

Conclusions:

• Viscoelasticity significantly influences flow resistance and diodicity in microfluidic systems.
• Optimal performance is achieved at specific, often low, elasticity levels.
• Further research is needed to reconcile experimental findings with numerical simulations, particularly in the low elasticity regime.