Viscosity Bingham

Of the models Hsted in Table 1, the Newtonian is the simplest. It fits water, solvents, and many polymer solutions over a wide strain rate range. The plastic or Bingham body model predicts constant plastic viscosity above a yield stress. This model works for a number of dispersions, including some pigment pastes. Yield stress, Tq, and plastic (Bingham) viscosity, = (t — Tq )/7, may be determined from the intercept and the slope beyond the intercept, respectively, of a shear stress vs shear rate plot. 

The second expression is obtained by neglecting the fourth-power term. The Bingham viscosity pB is the slope of the plot in the laminar region and is found from the terminal points as... 

The study of plastic (Bingham) viscosity (rj ) has shown [34] that it varies in the range from 0.1 to 10 Pa s r strongly falls with the viscosity of the dispersion medium and bubble expansion but weakly increases the expansion ratio. 

To represent the above-named Bingham viscosity in the simulation model the possibility to characterize Non-Newtonian fluids in the CFD-code is necessary. Most commercial CFD-Software allocate a so-called Power-Law-Model whereby (26) may be possibly specified. Otherwise the Bingham model has to be implemented in the actual internal expression language, e.g. an executive Fortran-Routine in ANSYS/FLOTRAN or a definition in the CFX-Expression Language (CEL). In either case it is inevitable for the CFD-code to have dynamic access to the (system-) variable for the shear strain rate y. 

WaU shear rate or rate of shear strain with respect to time Coefficient of rigidity of a non-Newtonian fluid, also called Bingham viscosity... 

The soft high clay taUing from a copper concentrator develops a Bingham viscosity of 400 mPa s at a weight concentration of 45% as well as a yield stress of 5 Pa. The slurry density is 1350 kg/m. The taUings flow rate is 1600 m /hr. If the maximum allowed slope is 1.5%, determine the suitable size for a half-full smooth HDPE pipe (i.e., ignore roughness factor). 

Here the slope of the line, tib, is the tangent or Bingham viscosity and the stress intercept, tb, is the Bingjiam yield stress. 

The Bingham viscosity remains small (few mPa.s). The effect of the solid content in silica-alumina hydrogels is illustrated on figure 9. The value of increases from 2 Pa to 20 Pa if the solid content in-... 

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