Suspension rheograms

Shear thinning behavior is commonly observed in emulsions. When solids are added to emulsions, both shear thinning and shear thickening behaviors are observed. Figure 32 shows the rheograms of clay-and-oil in water measured by Yan (private communication), where the clay-free oil volume fraction, j30 = 0.2. Part of Figure 32, y > 10 s"1, was also shown by Yan et al. (195). The systems are shear thinning, which is similar to the pure suspension of clay in water and oil in water emulsion... 

Figure 15. Rheograms of bentonite-water suspensions at various temperatures and in the presence of various additives (1 ppb — 2.85 g/L). (Reproduced with permission from reference 73. Copyright 1967 Society of Petroleum Engineers.)...

The rheograms shown in Figure 4 can be fitted by a power law relation, and the concentrations at which rheological measurements were taken also were those tested in the flow loop. The physical data including suspension density, power law flow behavior index, and material consistency coefficient are given in Table 1. It is noticeable that the suspension displays a consistent movement away from Newtonian behavior as solid concentration increases the flow behaviour index consistently reduces in Table 1. 

Run a test following the procedure described in Section 10.4.1.1. Determine whether the suspension is Newtonian or not. If the suspension is non-Newtonian, derive the rheograms to determine parameters of characterization of the fluid. 

The suspension is highly concentrated, and resulted to be non-Newtonian (shear thickening type) as determined in solution of Example 10.4. The use of Equations 10.82 through 10.84 would be, therefore, most appropriate. The parameters of characterization n and K, from the rheogram of the suspension are 1.39 and 2 X 10"5 kg/m s "", respectively. 

Figure 13 Rheograms of 5% montmdrillohile suspensions of differeni NaCL concentrations pH 5.5 6.0.

Rheograms. The suspensions shear stress (x) as a function of shear rate (y ) is shown in Figure 5 and 6. In the absence of an electric field, the dependence of x on... 

---