Paper Number
SC25 

Session
Suspensions and Colloids

Title
Micromechanics of dense suspensions: Microscopic interactions to macroscopic rheology

Presentation Date and Time
October 11, 2022 (Tuesday) 11:30

Track / Room
Track 1 / Sheraton 4

Authors (Click on name to view author profile)

  1. More, Rishabh V. (MIT, Mechanical Engineering)
  2. Ardekani, Arezoo (Purdue University, School of Mechanical Engineering)

Author and Affiliation Lines (in printed abstract book)
Rishabh V. More1 and Arezoo Ardekani2
1Mechanical Engineering, MIT, Cambridge, MA 02138; 2School of Mechanical Engineering, Purdue University, West Lafayette, IN 47906

Speaker / Presenter 
More, Rishabh V.

Keywords
theoretical methods; computational methods; colloids; suspensions

Text of Abstract
Particulate suspensions, especially dense suspensions, are routinely encountered in nature and in industries, such as manufacturing, food, pharmaceutical, and bio-fuel plants, to name a few. Hence, it is essential to understand the physics governing the rheological properties of these materials so that we can predict and design their flow better. To this end, we perform discrete particle dynamics simulation to simulate the dynamics of dense particulate suspensions and investigate their rheological properties. Using pair-wise lubrication forces for the hydrodynamic interactions and modeling various non-hydrodynamic micro-scale interactions from experimentally measured profiles between particles, we present 1) the first physical explanation of the experimentally observed rise in the suspension viscosity with particle roughness, 2) accurate predictions of the effects of roughness on various critical parameters in shear thickening (ST), 3) a constitutive model to quantify the roughness effects on the rheology of dense suspensions, and 4) the first explanation of the intermediate Newtonian plateau, and the second shear thinning regime to achieve a quantitative unification of the four disparate rate-dependent regimes, i.e., shear thinning - Newtonian plateau - shear thickening - shear thinning with increasing shear rate, observed in dense non-Brownian suspensions. This talk will discuss these findings and the importance of accurately modeling microscopic inter-particle interactions to predict the macroscopic rheological properties of suspensions.