Paper Number
FE6 

Session
Foams, Emulsions & Interfacial Rheology

Title
Field-induced control of magnetic emulsions rheology

Presentation Date and Time
October 17, 2018 (Wednesday) 10:15

Track / Room
Track 6 / Tanglewood

Authors (Click on name to view author profile)

  1. Hildebrand Pires da Cunha, Lucas (University of Brasília, Department of Mechanical Engineering)
  2. Rosa de Siqueira, Ivan (Rice University, Department of Chemical and Biomolecular Engineering)
  3. Felamingo de Oliveira, Taygoara (University of Brasília, Department of Mechanical Engineering)

Author and Affiliation Lines (in printed abstract book)
Lucas Hildebrand Pires da Cunha1, Ivan Rosa de Siqueira2, and Taygoara Felamingo de Oliveira1
1Department of Mechanical Engineering, University of Brasília, Brasília, DF 70910-900, Brazil; 2Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005

Speaker / Presenter 
Hildebrand Pires da Cunha, Lucas

Text of Abstract
It is studied the possibility of controlling the rheology of magnetic emulsions by the application of magnetic fields. For this purpose, numerical simulations in a two-dimensional perspective for a ferrofluid droplet suspended in a non-magnetic liquid under the effect of a shear flow and external magnetic fields are done. The absence of electrical fields and magnetic field variation in time possibility the reduction of the Maxwell equations to the magnetostatic limit. Also, it is considered the hypothesis of superparamagnetism for the magnetizable droplet. The Projection method is applied, decoupling the velocity and pressure solutions, while the Level-Set method is used to capture and compute the droplet geometry. The droplet inclination and emulsion viscosity are measured in function of the magnetic field, varying it in intensity and direction. We found a strong influence of the magnetic field on the droplet inclination and consequently on the emulsion viscosity. The droplet tends to get aligned with the field. The great alignment between the droplet and the flow reduces the emulsion viscosity, while the misalignment increases it. Therefore, the emulsion viscosity can be, indeed, increased and reduced by the application of external fields.