Viscosity high temperature data

Figure 12.7 shows values of xy calculated in two different ways as a function of temperature for panicles of dilTerent. size. One set of curves (solid lines) was calculated front the phenomenological relationships (12.5) and (12.6). For the solid particles (low temperature). MD simulations were used to obtain the diffusion coefficient and surface tension that appear in (12.6). For the liquid-like particles (high temperature), data for the viscosity and surface tension that appear in (12.5) were obtained from experimental results reported in the literature. The dashed lines in Fig. 12.7 were calculated directly from MD simulations of the decrease in the moment of inertia of two coalescing spheres. 

By far the best situation is to have oil viscosity versus temperature data for a particular oil to be treated. Alternately, data from other wells in the same field can usually be used without significant error. This viscosity versus temperature data may be plotted on special ASTM graph paper. Such plots are usually straight lines, unless the oil has a high cloud point. The viscosity may then be predicted at any temperature. 

Note the smaller range of temperaaire for SO2 and H2O. This was due to lack of high temperature viscosity data. ... 

Shear viscosity is a measure of the ahihty of one layer of molecules to move over an adjacent layer. Bulk viscosity will be mentioned in Section V.2. Since viscosity usually refers to shear viscosity, the term will he used in this way unless otherwise stated. Recommended techniques for measuring the viscosity of high-temperature melt are given below. Experimental data are available from the database mentioned in Section 1.2. Data on viscosities of slags (7 single component systems, 35 two-component... 

Fig. 3.14. The data is for a very broad range of times and temperatures. The superposition principle is based on the observation that time (rate of change of strain, or strain rate) is inversely proportional to the temperature effect in most polymers. That is, an equivalent viscoelastic response occurs at a high temperature and normal measurement times and at a lower temperature and longer times. The individual responses can be shifted using the WLF equation to produce a modulus-time master curve at a specified temperature, as shown in Fig. 3.15. The WLF equation is as shown by Eq. 3.31 for shifting the viscosity. The method works for semicrystalline polymers. It works for amorphous polymers at temperatures (T) greater than Tg + 100 °C. Shifting the stress relaxation modulus using the shift factor a, works in a similar manner.

Aqueous solutions of magnesium nitrate are appreciably denser and more viscous than water. Table II illustrates data (9) On the densities (in g/ml) of concentrated solutions at high temperatures. Figure 2 illustrates the viscosity variations in concentrated solutions (9). 

Secondly, at high temperatures the molecules of nitrous oxide have more rotational quanta than at low temperatures. Thus the collision area is greater than that calculated from Rankine s viscosity data, which are obtained at ordinary temperatures. 

The Mandelkern-Flory viscosity data for cellulose tributyrate are plotted according to Eq. (58) in Fig. 18. It is seen that the line for the viscosities in the good solvent methyl ethyl ketone at 30° C passes without strain to the same intercept as the lines for the two high-temperature theta solvents. The intercept gives K = (9.7 1.5) 10-4 and a = 1.79 0.10, as listed in Table 9. Although, as discussed in the... 

Figure 4.12 The points give the measured viscosity-temperature relationship for e-terphenyl, while the shaded regions are the viscosities predicted by the Adam-Gibbs equation (4-10) using A5(7 ) measured for o-terphenyl. The two shaded regions represent alternative fits of the Adam-Gibbs parameters, one fit to the high-temperature, and the other to the low-temperature, data. (From Greet and Turnbull, reprinted with permission, from J. Chem. Phys. 47 2185, Copyright 1967, American Institute of Physics.)...

Viscosity is one of the most frequently measured properties of silicate melts. Viscosity data vary in the range 0.1-10 Pa s. To obtain precise and correct viscosity data is experimentally very difficult, especially at high temperatures. Contradictory data frequently found in the literature demonstrate this fact. This can be illustrated by the CaSiOs melt, for which at 1873 K, values of 0.15 to 0.25 Pa s are given. 

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