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INTER-PARTICLE LIQUID BRIDGES: A BUILDING BLOCK TO MODEL COMPLEX MIXING PHENOMENA

Gopalkrishnan, Prasad
http://rave.ohiolink.edu/etdc/view?acc_num=case1085169849

Abstract Details

2004, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science.
Previous research, on the size scale of macroscopic agglomerates dispersing in controlled hydrodynamic flow fields, lead to the observation of some new dispersion mechanisms, differing from the conventional cohesive mechanism of failure. Erosion and rupture, the most common failure modes observed in powder agglomerates, correspond to sustained removal of small surface fragments and instantaneous shatter of the agglomerate respectively. These are both classified under a cohesive mechanism due to failure initiating at a dry-dry or a wet-wet interface. However, recent work identified an alternate mechanism of wet-dry failure in partially infiltrated sparse agglomerates. The occurrence of this mechanism was attributed to fluid-induced rearrangement at the advancing end of the liquid interface within the agglomerate. To probe such an interfacial phenomenon with sufficient resolution on the scale of the units comprising the interface, a more fundamental approach is necessary. To this end, we outline an experimental and modeling methodology to characterize the basic units that comprise a partially infiltrated agglomerate, i.e. the dry contacts in the core and the interstitial fluid contacts in the outer infiltrated portions of the agglomerate. Dry contacts having been dealt with extensively by workers in the past, we concern ourselves more specifically with characterization of the wet contacts. We treat the wet contacts in terms of two-particle interactions through liquid bridges of viscous fluid. Solving the bridge profile for the capillary contributions as well as the dynamics of the interaction, starting from a lubrication regime approximation appropriate for contacts at the micro/nano scale of interacting particles, we develop an analytical solution of each single wet contact interaction. Using these fundamental wet and dry interactions, we build and simulate real agglomerates, monitoring them vis-à-vis a failure criterion at potential failure loci, each representative of a characteristic experimentally observed dispersion behavior. Incorporation of agglomerate distortion dynamics enables more accurate estimation of agglomerate strengths, when subjected to dispersive flow fields. This approach is used to probe phenomena ranging from infiltration-induced rearrangement in development of a weak failure locus to agglomerate strengthening by introduction of liquid bridges within the porous structure.
Ica Manas-Zloczower (Advisor)
177 p.
Pendular liquid bridges; Viscous force; Glass PDMS; Distinct Element Modeling (DEM); Dispersion/Aggregation mechanisms; Cohesive or Adhesive failure; Erosion or Rupture modes

Recommended Citations

Citations

  • Gopalkrishnan, P. (2004). INTER-PARTICLE LIQUID BRIDGES: A BUILDING BLOCK TO MODEL COMPLEX MIXING PHENOMENA [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1085169849

    APA Style (7th edition)

  • Gopalkrishnan, Prasad. INTER-PARTICLE LIQUID BRIDGES: A BUILDING BLOCK TO MODEL COMPLEX MIXING PHENOMENA. 2004. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1085169849.

    MLA Style (8th edition)

  • Gopalkrishnan, Prasad. "INTER-PARTICLE LIQUID BRIDGES: A BUILDING BLOCK TO MODEL COMPLEX MIXING PHENOMENA." Doctoral dissertation, Case Western Reserve University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1085169849

    Chicago Manual of Style (17th edition)

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© 2004, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.