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UNDERSTANDING AGGLOMERATE DISPERSION: EXPERIMENTS AND SIMULATIONS

Fanelli, Maddalena
http://rave.ohiolink.edu/etdc/view?acc_num=case1119374160

Abstract Details

2005, Doctor of Philosophy, Case Western Reserve University, Chemical Engineering.
The behavior of clusters of particles ranging from the nanometer scale to the micrometer scale impacts a number of important processes. Dispersion of particle clusters is seen in applications involving pharmaceutical tablets, detergent granules, agglomerates of biological cells, and clusters of pigments or fillers for advanced materials. As these clusters are subjected to shearing forces associated with the motion of their host fluid, they can be broken down into smaller fragments. Often, this is the desirable outcome, but in other cases dispersion may be undesirable. Previous research has analyzed and modeled dispersion in simplified and idealized situations: steady, simple flows and agglomerates of uniform structure. The current work aims to improve the level of sophistication for the understanding of dispersion processes by considering the effects of binders in particulate agglomerate systems and the impact of unsteady dispersion conditions, more representative of real dispersion scenarios. Through experimental trials, practical limitations of our testing protocols were clarified. Agglomerates made from compacted powders provided the most control and consistency in response. Multiple testing protocols were deemed key to clarifying the complex interactions that impact particulate agglomerate dispersion. Packing effectiveness and molecular weight were found to impact the characteristics of particulate agglomerates. The development of a flexible and detailed simulation allowed predictions of dispersion and enhanced understanding of the phenomenon. The discrete/distinct element method (DEM) was adopted to study the behavior of single nano-scale spherical agglomerates, immersed in a simple shear flow field, in response to shearing under steady or dynamic/oscillatory flow conditions. Results, in good agreement with reported experimental trends, were used to demonstrate the functionality of the three-dimensional simulation as a predictive and analytical tool. The current model allows probing and prediction of dispersion as a function of processing conditions, agglomerate structure/morphology, and material properties and interaction forces with a level of detail not previously seen. The approach will give insight into the dynamics of particulate break-up in real mixing systems, provide a systematic means of evaluating the relative importance of various forces in dispersion behavior, and clarify the role of modifier and primary particle properties and agglomerate morphology in dispersion.
Donald Feke (Advisor)
256 p.
dispersion; DEM; simulation; discrete element method; agglomerate; particle; aggregate

Recommended Citations

Citations

  • Fanelli, M. (2005). UNDERSTANDING AGGLOMERATE DISPERSION: EXPERIMENTS AND SIMULATIONS [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1119374160

    APA Style (7th edition)

  • Fanelli, Maddalena. UNDERSTANDING AGGLOMERATE DISPERSION: EXPERIMENTS AND SIMULATIONS. 2005. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1119374160.

    MLA Style (8th edition)

  • Fanelli, Maddalena. "UNDERSTANDING AGGLOMERATE DISPERSION: EXPERIMENTS AND SIMULATIONS." Doctoral dissertation, Case Western Reserve University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=case1119374160

    Chicago Manual of Style (17th edition)

case1119374160
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© 2005, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.