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Ph.D. Dissertation-Arman Boromand.pdf (16.69 MB)

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Computational Studies on Multi-phasic Multi-component Complex Fluids

Boromand, Arman
http://rave.ohiolink.edu/etdc/view?acc_num=case1480500319335545

Abstract Details

2017, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science and Engineering.
Advancement in computational capacity combined with the emergence of efficient algorithms has made the computational studies very powerful and desirable. Despite the great importance of complex fluids such as emulsions, colloidal suspensions, and gels in many applications, some of their physical and mechanical properties remain poorly understood. To understand rheological and mechanical properties of such systems, one needs to understand their properties at different time and length scales through careful multiscale analysis. To answer these questions, we use Dissipative Particle Dynamics as a versatile coarse-grained method to gain a better understanding of different scales and bridge the gap between the microscopic and macroscopic worlds in particulate multicomponent complex fluids. In Chapter 1, briefly, we introduce the DPD mathematical and physical formalism. In Chapter 2, we examine different algorithms to measure the transport properties of a simple DPD fluid and introduce the new computational method to measure the viscosity of DPD liquids under non-equilibrium conditions to account for the numerical instabilities. In Chapter 3, we discuss the properties of multiphasic systems mainly liquids in liquids. We investigate the effect of molecular composition, configuration, and conformability of surface active molecules in stabilizing immiscible mixtures for flat interfaces as well as curved interfaces. The final section of chapter 3 is dedicated to studying the effect of shear deformation on the geometrical evolution of surfactant covered nanodroplets. In chapter 4, we mainly focus on colloidal suspensions and their rheological responses in nonlinear deformation. Through network analysis, we show that the frictional bonds form a percolated network at volume fractions close to jamming while at volume fractions well below jamming the frictional networks are transient and unstable. Measuring viscosity and normal stresses show the discontinuous transition occurs in the viscosity and positive values for the first normal stress which is concomitant with the formation of the percolated network. In Chapter 5, we look at mechanistic behavior of colloidal particles with short-ranged attraction potential. We observe a two-step yielding transition under start-up deformation and explained it through careful analysis of the microstructure. It was shown that hydrodynamic interactions are important to explain this behavior at high deformation rates.
Joao Maia (Committee Chair)
Gary Wnek (Committee Member)
Michael Hore (Committee Member)
Daniel Lacks (Committee Member)
408 p.
Engineering; Molecular Physics; Morphology; Physical Chemistry; Physics
Coarse-grained Computational Studies; Dissipative Particle Dynamics; Fluid Mechanics; Emulsions; Compatibilization efficiency; Suspension Rheology; Frictional Force Network; Colloidal Gels

Recommended Citations

Citations

  • Boromand, A. (2017). Computational Studies on Multi-phasic Multi-component Complex Fluids [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1480500319335545

    APA Style (7th edition)

  • Boromand, Arman. Computational Studies on Multi-phasic Multi-component Complex Fluids. 2017. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1480500319335545.

    MLA Style (8th edition)

  • Boromand, Arman. "Computational Studies on Multi-phasic Multi-component Complex Fluids." Doctoral dissertation, Case Western Reserve University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1480500319335545

    Chicago Manual of Style (17th edition)

case1480500319335545
166
© 2017, some rights reserved.Creative Commons License Computational Studies on Multi-phasic Multi-component Complex Fluids by Arman Boromand is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.