ISSN:
1435-1536
Keywords:
Key words Links-nodes-blobs model
;
Suspension rheology
;
Fractal scaling
;
Percolation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract A new model based on fractal and percolation concepts is proposed to explain the rheological behavior of shear-thinning yield-stress fluids. Suspension particles of the fluids are described in terms of the links-nodes-blobs (L-N-B) model. The complex suspension rheology can be interpreted via the similarity of the L-N-B model to the Rouse chain model. Consequently, the empirically universal relationship between the dimensionless shear stress, T, and the dimensionless shear rate, Γ, which was recently suggested by Coussot as T = 1+KΓ n at Γ〈0.3 and approaches Newtonian behavior at Γ〉50, can be derived in terms of microscopic properties of a suspension of the force-free particles, fractal dimensions of the percolation system, and the critical lengths of the percolation system. According to our study, a more precise and more general universal relationship, which fits experimental data well over a wide range from Γ = 10−7103, is proposed as T = 1+Γ+KΓ n . The parameter K in the universal equation can be expressed as a function of the dimensionless cross-section of the blobs, the distribution of links, and fractal dimensions of the percolation system, while the exponent n in the universal equation is a function of the fractal dimensions only. The transition point of a shear-thinning yield-stress fluid from shear-thinning to Newtonian behavior was explicitly interpreted.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003960050485
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