A constitutive equation for thixotropic suspensions with yield stress by coarse-graining a population balance model

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• 作者：Paul M. Mwasame ; Antony N. Beris ; R. Betrum Diemer and Norman J. Wagner
• 刊名：AIChE Journal
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：63
• 期：2
• 页码：517-531
• 全文大小：869K
• ISSN：1547-5905

文摘

A population balance model appropriate for the shear flow of thixotropic colloidal suspensions with yield stress is derived and tested against experimental data on a model system available in the literature. Modifications are made to account for dynamic arrest at the onset of the yield stress, in addition to enforcing a minimum particle size below which breakage is not feasible. The resulting constitutive model also incorporates a structural based relaxation time, unlike existing phenomenological models that use the inverse of the material shear rate as the relaxation time. The model provides a reasonable representation of experimental data for a model thixotropic suspension in the literature, capturing the important thixotropic timescales. When compared to prevalent structure kinetics models, the coarse-grained population balance equation is shown to be distinct, emphasizing the novelty of utilizing population balances as a basis for thixotropic suspension modeling.