Shear thinning in non-Brownian suspensions.
Guillaume Chatté1, Jean Comtet2, Antoine Niguès2
1ESPCI Paris, PSL Research University, Sciences et Ingénierie de la Matière Molle, CNRS UMR 7615, 10 rue Vauquelin, F-75231 Paris Cedex 05, France. annie.colin@espci.fr.
Soft Matter
|December 8, 2017
Summary
This study reveals two shear-thinning behaviors in particle suspensions, separated by shear thickening. Particle interactions and friction dictate these flow regimes, impacting suspension rheology.
Area of Science:
- Fluid dynamics
- Materials science
- Colloid science
Background:
- Understanding the rheology of non-Brownian particle suspensions is crucial for various industrial applications.
- The interplay between particle interactions and macroscopic flow behavior remains a complex area of study.
Purpose of the Study:
- To investigate the complex flow behavior of non-Brownian particle suspensions.
- To elucidate the mechanisms behind observed shear-thinning and shear-thickening regimes.
- To correlate microscopic particle interactions with macroscopic rheological properties.
Main Methods:
- Capillary and conventional rheometry to measure flow properties.
- X-ray radiography to observe particle distribution and flow homogeneity.
- Atomic force microscopy to quantify inter-particle forces and friction.
Main Results:
- Observed a sequence of two shear-thinning regimes with an intermediate shear-thickening regime.
- Confirmed homogeneous flow without particle migration across all observed regimes.
- Measured repulsive forces and friction coefficients between particles as a function of normal load.
Conclusions:
- The initial shear-thinning regime is attributed to lubricated rheology and decreasing effective volume fraction due to repulsive forces.
- The second shear-thinning regime is linked to frictional rheology and a decrease in microscopic friction at higher loads.
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