Coupled dynamics of flow, microstructure, and conductivity in sheared suspensions

Area of Science:

• Physics of complex fluids
• Materials science
• Computational physics

Background:

• Understanding the electrical conductivity of suspensions is crucial for various applications.
• Flowing suspensions exhibit complex microstructural evolution affecting bulk properties.
• Existing models may not fully capture the dynamic interplay between flow, microstructure, and conductivity.

Purpose of the Study:

• To develop and validate a predictive model for the evolution of the electrical conductivity tensor in flowing suspensions.
• To couple discrete particle simulations with continuum mechanics for microstructure evolution.
• To experimentally validate the model using rheo-electrical measurements.

Main Methods:

• Discrete particle numerical simulations to model suspension microstructure.
• Continuum physical framework to derive microstructure evolution laws.
• Rheo-electrical conductivity measurements of carbon black suspensions.
• Parameter fitting using experimental data across a range of shear rates.

Main Results:

• A robust model for the evolution of the conductivity tensor in flowing suspensions was established.
• The model successfully predicted conductivity for steady shearing and unsteady flow experiments.
• Close agreement between model predictions and experimental measurements was achieved.

Conclusions:

• The proposed model accurately captures the relationship between suspension microstructure and electrical conductivity under flow.
• The combined discrete-continuum approach provides a powerful tool for analyzing flowing functional materials.
• The validated model can be used for designing and optimizing systems involving conductive suspensions.