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Spatial statistics as a means of characterizing mixing and segregation

  • Author / Creator
    Kukukova, Alena
  • Although a number of definitions of mixing have been proposed in the literature, no single definition accurately and clearly describes the full range of problems in the field of industrial mixing. Based on the review of mixing and segregation characterization techniques in chemical engineering, spatial statistics and population studies, a definition of industrial mixing is proposed in this thesis, based on three separate dimensions of segregation. The first dimension is the intensity of segregation which quantifies the uniformity of concentration; the second dimension is the scale of segregation or clustering; and the last dimension is the exposure or the potential to reduce segregation. The first dimension focuses on the instantaneous concentration variance; the second on the instantaneous length scales in the mixing field; and the third on the driving force for change, i.e. the mixing time scale, or the instantaneous rate of reduction in segregation. The definition is introduced using concepts, theory and mathematical equations. This definition provides a theoretical framework for the rigorous analysis of mixing problems, encompassing all industrial mixing processes and allowing a clear evaluation of experimental methods. In this work, the three dimensions of segregation are presented and defined in the context of previous definitions of mixing, and then applied to a range of industrial mixing problems to test their accuracy and robustness. Suitable quantities for direct measurement of the dimensions of segregation are then investigated in detail. The result is a toolkit of ready-to-use methods for the measurement of the intensity (CoV) and the scale of segregation (maximum striation thickness on a transect, point-to-nearest neighbour distributions and variogram), provided as Matlab codes. The chosen methods are thoroughly investigated by testing their applicability, limitations, sampling strategies and meaningfulness of the results using selected sets of mixing data, resulting in creation of guidelines for the use of each of the provided methods. The developed definition of mixing, together with tools and guidelines for measurement of mixing will help researches to further develop the field of mixing, engineers to solve practical industrial mixing problems, and instructors of chemical engineering courses to introduce mixing concepts more easily.

  • Subjects / Keywords
  • Graduation date
    2011-06
  • Type of Item
    Thesis
  • Degree
    Doctor of Philosophy
  • DOI
    https://doi.org/10.7939/R3BW5T
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Doctoral
  • Department
    • Department of Chemical and Materials Engineering
  • Supervisor / co-supervisor and their department(s)
    • Kresta, Suzanne (Chemical and Materials Engineering)
    • Aubin, Joelle (Chemical and Materials Engineering)
  • Examining committee members and their departments
    • Deutsch, Clayton (Civil and Environmental Engineering)
    • Gilchrist, James (Lehigh University, PA)
    • Derksen, Jos (Chemical and Materials Engineering)
    • Semagina, Natalia (Chemical and Materials Engineering)