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Solids shear viscosity

Several different expressions have been derived for solids pressure, solids shear viscosity and solids bulk viscosity, employing different approximations and assumptions while applying the kinetic theory of granular flows. Some of the commonly used equations are described below (see Gidaspow, 1994 and a review given by Peirano, 1998) Solids pressure ... [Pg.105]

Solids shear viscosity also comprises a kinetic contribution and collisional contributions. Commonly used expressions for viscosity are ... [Pg.106]

Figure 10 plots the solids shear viscosity and its comparison with literature results. Different sources of data are scale by the Enskog factor to be viewed in the same figure. Unlike Rahaman s result where the viscosity has a minimum at 9 = 9y our result shows that the are stiU mainly determined by 9 and the maximum of viscosity appears at the maximum of 9, which demonstrates that the dilute viscosity increases with the increase of the granular temperature. [Pg.234]

In a fluid under stress, the ratio of the shear stress, r. to the rate of strain, y, is called the shear viscosity, rj, and is analogous to the modulus of a solid. In an ideal (Newtonian) fluid the viscosity is a material constant. However, for plastics the viscosity varies depending on the stress, strain rate, temperature etc. A typical relationship between shear stress and shear rate for a plastic is shown in Fig. 5.1. [Pg.344]

The viscosity of a fluid is an important property in the analysis of liquid behavior and fluid motion near solid boundaries. Viscosity is the fluid resistance to shear or flow and is a measure of the adhesive/cohesive or frictional fluid property. The resistance is caused by intermolecular friction exerted when layers of fluids attempt to slide by one another. [Pg.751]

Galgali and his colleagues [46] have also shown that the typical rheological response in nanocomposites arises from frictional interactions between the silicate layers and not from the immobilization of confined polymer chains between the silicate layers. They have also shown a dramatic decrease in the creep compliance for the PP-based nanocomposite with 9 wt% MMT. They showed a dramatic three orders of magnitude drop in the zero shear viscosity beyond the apparent yield stress, suggesting that the solid-like behavior in the quiescent state is a result of the percolated structure of the layered silicate. [Pg.288]

The results of Equation (3.56) are plotted in Figure 3.14. It can be seen that shear thinning will become apparent experimentally at (p > 0.3 and that at values of q> > 0.5 no zero shear viscosity will be accessible. This means that solid-like behaviour should be observed with shear melting of the structure once the yield stress has been exceeded with a stress controlled instrument, or a critical strain if the instrumentation is a controlled strain rheometer. The most recent data24,25 on model systems of nearly hard spheres gives values of maximum packing close to those used in Equation (3.56). [Pg.87]

Figure 6.6 The limiting high shear viscosity for quasi-hard sphere for PMMA particles in dodecane. (The particle has a different effective radii, HK3 = 419nm, HK4 = 281 nm, HK5 = 184 nm, HK7 = 120nm, HK8 = 162 nm.) The solid line is given by the Krieger equation (6.6) for a packing of (pm( oo) = 0.605... Figure 6.6 The limiting high shear viscosity for quasi-hard sphere for PMMA particles in dodecane. (The particle has a different effective radii, HK3 = 419nm, HK4 = 281 nm, HK5 = 184 nm, HK7 = 120nm, HK8 = 162 nm.) The solid line is given by the Krieger equation (6.6) for a packing of (pm( oo) = 0.605...
An LDPE resin was used for this study. The resin had a melt index of 2.0 dg/min (2.16 kg, 190 °C) and a solid density of 0.922 g/cmT The shear viscosity was reported previously [37] thermal properties are provided in Chapter 4 bulk density as a function of temperature and pressure is provided in Fig. 4.4 and the coefficients of dynamic friction are provided in Appendix A5. The lateral stress ratio was measured at 0.7 [38] using the device shown in Fig. 4.8. [Pg.160]

Figure 6.18 Melt thicknesses for Zones C, D, and E around a solid bed for the melting simulation using a shear viscosity of 220 Pa-s. Melting started at the entry to the transition section at 6 diameters from the start of the screws and was completed at 13.7 diameters... Figure 6.18 Melt thicknesses for Zones C, D, and E around a solid bed for the melting simulation using a shear viscosity of 220 Pa-s. Melting started at the entry to the transition section at 6 diameters from the start of the screws and was completed at 13.7 diameters...
A simulation was carried out with the melting model using the simulation conditions described earlier for the PE resin with a Newtonian shear viscosity of 220 Pa-s. For this simulation, the pressure at the end of the solids-conveying section... [Pg.215]

The Rheometric Scientific RDAII dynamic analyzer is designed for characterization of polymer melts and solids in the form of rectangular bars. It makes computer-controlled measurements of dynamic shear viscosity, elastic modulus, loss modulus, tan 8, and linear thermal expansion coefficient over a temperature range of ambient to 600°C (—150°C optional) at frequencies 10-5 —500 rad/s. It is particularly useful for the characterization of materials that experience considerable changes in properties because of thermal transitions or chemical reactions. [Pg.201]

A typical evolution of equilibrium mechanical properties during reaction is shown in Fig. 6.1. The initial reactive system has a steady shear viscosity that grows with reaction time as the mass-average molar mass, Mw, increases and it reaches to infinity at the gel point. Elastic properties, characterized by nonzero values of the equilibrium modulus, appear beyond the gel point. These quantities describe only either the liquid (pregel) or the solid (postgel) state of the material. Determination of the gel point requires extrapolation of viscosity to infinity or of the equilibrium modulus to zero. [Pg.198]

Figure 6.1 Schematic evolution of steady-state mechanical properties of a thermoset as a function of reaction time or conversion. Representative properties are the steady shear viscosity for the liquid state and the equilibrium modulus for the solid state. Figure 6.1 Schematic evolution of steady-state mechanical properties of a thermoset as a function of reaction time or conversion. Representative properties are the steady shear viscosity for the liquid state and the equilibrium modulus for the solid state.
Asphalt is a semi-solid variety of bitumen having a (low shear) viscosity of about... [Pg.287]

Figure 19. The ratio of elongational to shear viscosities The theoretical dependence of the ratio of elongational to shear viscosity coefficients on the invariant of the additional stress tensor is calculated according to equation (9.71) and depicted by the dashed curve. The solid curves represent experimental data for systems listed in Table 3. Adapted from the paper of Pokrovskii and Kruchinin (1980). Figure 19. The ratio of elongational to shear viscosities The theoretical dependence of the ratio of elongational to shear viscosity coefficients on the invariant of the additional stress tensor is calculated according to equation (9.71) and depicted by the dashed curve. The solid curves represent experimental data for systems listed in Table 3. Adapted from the paper of Pokrovskii and Kruchinin (1980).
In the case of fluids without yield stress, viscous and viscoelastic fluids can be distinguished. The properties of viscoelastic fluids lie between those of elastic solids and those of Newtonian fluids. There are some viscous fluids whose viscosity does not change in relation to the stress (Newtonian fluids) and some whose shear viscosity T] depends on the shear rate y (non-Newtonian fluids). If the viscosity increases when a deformation is imposed, we define the material as a shear-thickening (dilatant) fluid. If viscosity decreases, we define it as a shear-thinning fluid. [Pg.37]


See other pages where Solids shear viscosity is mentioned: [Pg.105]    [Pg.27]    [Pg.105]    [Pg.27]    [Pg.171]    [Pg.2]    [Pg.796]    [Pg.312]    [Pg.406]    [Pg.187]    [Pg.81]    [Pg.117]    [Pg.119]    [Pg.144]    [Pg.38]    [Pg.95]    [Pg.103]    [Pg.452]    [Pg.121]    [Pg.207]    [Pg.211]    [Pg.214]    [Pg.227]    [Pg.232]    [Pg.181]    [Pg.126]    [Pg.134]    [Pg.77]    [Pg.273]    [Pg.335]    [Pg.176]    [Pg.216]    [Pg.298]    [Pg.320]   
See also in sourсe #XX -- [ Pg.106 ]




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