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Updated: Jul 6, 2025
08:42
Challenges in Rheological Characterization of Highly Concentrated Suspensions — A Case Study for Screen-printing Silver Pastes
Published on: April 10, 2017
20.0K
Rheology of bi-disperse dense fiber suspensions
Monsurul Khan1, Ria D Corder1, Kendra A Erk2
1School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA. ardekani@purdue.edu.
Soft Matter
|January 3, 2024
Summary
This study validates models for concentrated fiber suspensions with varying fiber sizes. Numerical simulations and experiments show that fiber size ratio and composition significantly impact suspension viscosity by affecting the jamming volume fraction.
Area of Science:
- Rheology
- Fluid Dynamics
- Materials Science
Background:
- Modeling uniform fiber suspensions is established, but validation for concentrated, multi-aspect ratio systems is lacking.
- Industrially relevant suspensions often contain fibers of varying lengths and aspect ratios, complicating rheological predictions.
Purpose of the Study:
- To validate direct numerical simulations (DNS) against experimental measurements for bi-disperse fiber suspensions.
- To investigate the influence of fiber aspect ratio distribution and composition on the rheological behavior of concentrated suspensions.
Main Methods:
- Direct numerical simulations (DNS) of bi-disperse suspensions in steady shear flow.
- Experimental measurements of suspension viscosity using controlled bidisperse nylon fibers in a Newtonian fluid.
Main Results:
- Good agreement was found between numerically predicted and experimentally measured viscosities.
- The rheological behavior is strongly influenced by the size ratio of large to small fibers and the volume fraction of large fibers.
- Increased relative viscosity correlates with a decreased jamming volume fraction.
Conclusions:
- The study provides a validated model for predicting the rheology of concentrated bi-disperse fiber suspensions.
- Jamming volume fraction is a critical parameter controlling the rheological behavior of these complex fluids.
- Findings are crucial for optimizing industrial processes involving fiber suspensions.
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