Shear flow thinning

The polymer melt used in this example has a density of 1000 kg/m3. The following initially assumes a Newtonian flow behavior with a viscosity of 1000 Pa-s. In later computations, a more realistic shear thinning flow behavior is assumed, which can be described using the power law equation. The flow exponent n ranges between 0.4 and 0.9 and the consistency... 

Flow of hexagonal liquid crystalline systems is presumably a function of the alignment of the rod-like aggregates along their long axis in the direction of flow.f " The shear thinning flow process can be accompanied by an apparent yield stress. Viscoelastic behavior has also been reported. ... 

Rubart, L. and Bohme, G. (1991) Numerical simulation of shear thinning flow problems in mixing vessels. Theoret. Comp. Fluid Dynamics, 3,95-115. 

To differentiate a cubic phase from an ME, D Antona et al. compared the viscosity of the samples over an increasing shear rate [63]. The samples consisted of 70% glycerol monooleate, 2% ethanol, 28% water for the cubic phase, and 70% glycerol monooleate, 20% ethanol and 10% water for the ME sample. As expected, the ME did show Newtonian flow and the viscosity was not influenced by the increasing shear rate. On the other hand, the sample contaiiflng a cubic phase showed a decrease in viscosity upon increasing shear rate, i.e., displayed a typical non-Newtonian shear thinning flow. 

Power-law shear-thinning flow Newtonian flow... 

Shear Thinning Flow. Dispersions showing a decrease in viscosity with shear rate (or shear stress) are described as shear thinning or pseudoplastic. Shear thinning behavior is generally produced by the reversible breakdown of suspension structures or alignment of anisotropic particles due to shear. 

We also find fluids that appear to have a yield stress but once that is reached will then show shear-thinning flow behavior, and these we call x/ield pseudoplastic. These fluids are also sometimes known as Herschel-Bulkley fluids and for these we can write ... 

In order to investigate the collision of shear-thinning droplets, FS3D has been extended for the simulation of shear-thinning flow. This extension has been verified by comparison with analytical solutions of a shear-thinning two-phase gap flow and the shear-thinning Bretherton problem [13]. Experimental results by Motzigemba... 

Derive a relationship to predict the injection rate of a shearthinning fluid in radial flow using the coirelation of Cannela et (Eqs. 5.29 through 5.31) to estimate the apparent viscosity of the polymer solution as a function of the Darcy velocity. The pressure drop, Ap, is known between the injection well and the effective radius of the pattern, r, . Assume piston-like displacement of the resident brine by the polymer. Limit your relationship to the shear-thinning flow regime. 

Theoretically, in shear-thickening and shear-thinning flows, there is not a characteristic viscosity since t] = T/y is not a constant. Therefore, the term apparent viscosity (t]J is introduced and it is deflned as the shear stress divided by shear rate ... 

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