Structure of Thixotropic Suspensions in Shear Flow. III. Time-Dependent Behavior

Mercer, H. A.; Weymann, Helmut D.

doi:10.1122/1.549356

Cited by 25 publications

(3 citation statements)

References 2 publications

(2 reference statements)

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“…It is equally commonly acknowledged that the relationship is unique for any given fluid (and temperature, etc). More recent results supporting this conclusion include those of Jones and Brodkey (1970), Lee and Brodkey (1971), Joye and Peohlein (1971), Godfrey (1973), Cheng (1973a, b), Weymann et aZ(l973) and Mercer and Weymann (1974). The materials involved were a proprietary colloidal suspension, polymer solutions, waxy fuel oils, a negative thixotropic perbunan latex dispersion, and water-bentonite suspensions.…”

Section: L156mentioning

confidence: 86%

“…This is to investigate the microscopic and molecular nature of materials. In this respect the theory of Cheng et al, in common with other research, is open to criticism (Mercer and Weymann 1974) because the structure of a thixotropic fluid is assumed to be characterized by the use of only one structural parameter, whereas, in reality, the structure consists of a distribution of different types and grades of microscopic and molecular species. In order to assess the implication of this criticism on the engineering and technological applications of thixotropic theory, I have studied the degree of approximation involved in treating fluids with a multitude of structures (hereafter referred to as 'multistructured') by the use of one structural parameter (hereafter referred to as 'single-structured').…”

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confidence: 99%

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On the behaviour of thixotropic fluids with a distribution of structure

Cheng¹

1974

J. Phys. D: Appl. Phys.

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This letter discusses the criticism - based on the fact that real fluids are multistructured - that has been made of theoretical studies on thixotropy that employ only one structural parameter. The kinds of experimental observations that could be obtained on multistructured fluids are suggested, but a review of recent results indicates that there is no evidence that multistructured behaviour is significant. There are, of course, many experimental difficulties associated with the study of thixotropy, resulting in much scatter in data. It is concluded that at the present state of knowledge the first approximation in the description of thixotropy in the form of the single-structured theory is adequate, particularly for engineering and technological purposes. In case multistructured behaviour should become apparent, the way in which a second approximation can be set up is summarized, with reference being made to the report in which details are given.

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Section: L156mentioning

confidence: 86%

mentioning

confidence: 99%

On the behaviour of thixotropic fluids with a distribution of structure

Cheng¹

1974

J. Phys. D: Appl. Phys.

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“…A full characterisation of the fluid requires the determination of both this 'equilibrium' curve and the time dependence of shear stress r(t) for all arbitrary changes in shear rate i'i ~ i'i [19). The results of these thixotropic studies will be reported in due course.…”

Section: Fluid Preparationmentioning

confidence: 99%

High-Temperature, High-Pressure Rheology of Water-Based Muds

Alderman¹,

Gavignet²,

Guillot³

et al. 1988

Proceedings of SPE Annual Technical Conference and Exhibition

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This paper reports measurements of the rheology of a range of water-based drilling muds at temperatures up to 130°C and pressures up to 1000 bar. The fluids are highly thixotropic; decoupling of temperature/pressure effects from those due to time-dependent structural changes was achieved by developing a sample preparation and handling procedure which ensures that all samples experience identical shear histories prior to study in the rheometer. This enabled essentially equilibrium flow curves to be determined over a shear rate range of 0 -1200 s-1 with a reproducibility of better than ±1 Pain stress.

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Stress relaxation behaviour of liquid crystalline solutions of ethyl celluloses with different molecular weight in m‐cresol

Suto

Sasaki

Tateyama

1990

Angew. Makromol. Chem.

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The stress relaxation behaviour of liquid crystal‐forming ethyl celllulose (EC) solutions in m‐cresol was determined by means of a cone‐plate type viscometer at 30°C. The effect of molecular weight (MW) on the behaviour was also determined. The relaxation behaviour could be fitted with the following equation: where σi and σf are steady‐state shear stresses at shear rate \documentclass{article}\pagestyle{empty}\begin{document}$\dot \gamma _{\rm i}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$\dot \gamma _{\rm f}$\end{document}, σ(t) is time‐ dependent stress, A1 and A2 are constants, τ1 and τ2 are relaxation times, t is time, and tc is a characteristic time. When log σ* was plotted against time, one straight line was obtained for isotropic solutions, whereas anisotropic solutions yielded two straight lines. This suggests that the liquid crystalline solutions have two separate relaxation processes: Process 1 has a relatively short relaxation time, and process 2 has a long one. The parameters τ1, τ2, and A2 were greatly dependent on polymer concentration, combination of \documentclass{article}\pagestyle{empty}\begin{document}$\dot \gamma _{\rm i}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$\dot \gamma _{\rm f}$\end{document}, and MW, whereas A1 was independent thereof and was close to unity. The process 1 was supposed to be valid for individual molecules, and process 2 for liquid crystalline domains or randomly aggregated or entangled molecules.

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Structure of Thixotropic Suspensions in Shear Flow. III. Time-Dependent Behavior

Cited by 25 publications

References 2 publications

On the behaviour of thixotropic fluids with a distribution of structure

On the behaviour of thixotropic fluids with a distribution of structure

High-Temperature, High-Pressure Rheology of Water-Based Muds

Stress relaxation behaviour of liquid crystalline solutions of ethyl celluloses with different molecular weight in m‐cresol

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