Journal ArticleDOI
Flow Properties of Time‐Dependent Foodstuffs
D. De Kee,R. K. Code,G. Turcotte +2 more
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TLDR
In this paper, a new model for viscosity decay at constant shear rate is tested and the thixotropic behavior of representative food products is experimentally analyzed, which is well represented by the Herschel-Bulkley model and by an exponential model in which a maximum of two terms of an infinite series are required.Abstract:
In this work, a new model for viscosity decay at constant shear rate is tested and the thixotropic behavior of representative food products is experimentally analyzed. The equilibrium viscosity (or steady‐state viscosity) of some food products, obtained after a sufficiently long time of shear at a constant shear rate, is found to be well represented by the Herschel‐Bulkley model and by an exponential model in which a maximum of two terms of an infinite series are required. The model for viscosity decay, that is, the decrease in viscosity with time at constant shear rate, assumes nth order kinetics for the decay of a structural parameter λ. The rate constant k, for the decay of λ, is found to be a power law function of the shear rate. The equation for structure decay is combined with a scalar constitutive equation for the shear stress and the resulting model represents adequately the data for viscosity decay of foodstuffs in the range of shear rates 50<γ<5420 s−1. Data for suspensions such as tomato juice...read more
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Journal ArticleDOI
Thixotropy—a review
TL;DR: A history of thixotropy is given in this article, together with a description of how it is understood today in various parts of the scientific community, and a mechanistic description of the thixotropic system is presented.
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Proposal to assess printability of bioinks for extrusion-based bioprinting and evaluation of rheological properties governing bioprintability
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Journal ArticleDOI
Yield stress and thixotropy: on the difficulty of measuring yield stresses in practice
TL;DR: It is argued here that most of the difficulties in determining yield stress disappear when taking the thixotropy of yield stress fluids into account, and an experimental protocol is demonstrated that allows reproducible data to be obtained for the critical stress necessary for flow of these fluids.
Journal Article
Yield stress and thixotropy : on the difficulty of measuring yield stresses in practice
TL;DR: In this paper, the authors argue that most of the difficulties disappear when taking the thixotropy of yield stress fluids into account, and demonstrate an experimental protocol that allows reproducible data to be obtained for the critical stress necessary for flow of these fluids.
Journal ArticleDOI
Transient phenomena in thixotropic systems
TL;DR: In this paper, a nonlinear rheological model which accounts for the time-dependent elastic, viscous and yielding phenomena is developed in order to describe the flow behavior of thixotropic materials which exhibit yield stress.