Paper Number
CR6 

Session
Computational Rheology

Title
Three-dimensional Eulerian-Lagrangian solver for suspensions of solid spherical particles with a viscoelastic matrix fluid

Presentation Date and Time
October 9, 2017 (Monday) 1:30

Track / Room
Track 6 / Aspen

Authors (Click on name to view author profile)

1. Faroughi, Salah Aldin (Massachusetts Institute of Technology, Mechanical Engineering)
2. Robisson, Agathe (2Schlumbeger-Doll Research Center)
3. McKinley, Gareth H. (Massachusetts Institute of Technology, Department of Mechanical Engineering)

Author and Affiliation Lines (in printed abstract book)
Salah Aldin Faroughi¹, Agathe Robisson², and Gareth H. McKinley^1
1Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139; ²2Schlumbeger-Doll Research Center, Boston, MA

Speaker / Presenter 
Faroughi, Salah Aldin

Text of Abstract
Many industrial operations are involved with processing concentrated particle-laden complex fluids, in which the bulk rheological behavior of these fluids are of critical interest. When high volume fractions of particles are suspended in a viscoelastic matrix fluid (e.g. in polymer-based fracturing fluids that transport ‘proppant’), simulating the dynamical response of the system becomes challenging not only due to non-linear interaction of the constituents, but also due to nonlinear rheology of the viscoelastic matrix fluid and the effects of elasticity on the extra stress arising from the particle. In this work, we present a 3D numerical model to analyze the transient dynamics of isothermal flow of viscoelastic-based-fluid suspensions based on the Eulerian-Lagrangian approach. The transport of an individual spherical particle is integrated using the Discrete Element Model from the direct calculation of collision (using damped-linear-spring model) and hydrodynamic forces accounting for four-way coupling. For the viscoelastic fluid, which is treated as a continuum phase, the continuity, momentum and constitutive rheology equations (e.g. Oldroyd-B, Giesekus, PTT) are solved. A momentum-exchange model is required to close the formulation and couple the constituent phases. To provide this closure, we first studied the steady-state translation of a single particle and randomly positioned multiple particles to determine the effect of fluid elasticity on the drag and hindrance coefficients. We then adopted approximate models validated for inertia-less regimes to be integrated into our solver. The drag model, for example, captures the reduction in drag coefficient of a particle at low Deborah number, whereas at high De it is enhanced due to the large elastic extra stresses developing in the wake of the particle where the fluid undergoes a sudden change from shearing-dominant to extensional flow. The results obtained using the proposed solver are validated against settling experiments at low Reynolds numbers flow.