Kinematic viscosity tables

The heavy fuel should be heated systematically before use to improve its operation and atomization in the burner. The change in kinematic viscosity with temperature is indispensable information for calculating pressure drop and setting tbe preheating temperature. Table 5.20 gives examples of viscosity required for burners as a function of their technical design. 

A number of arbitrary viscosity units have also been used. The most common has been the Saybolt Universal second (SUs) which is simply the time in seconds required for 60 mL of oil to empty out of the cup in a Saybolt viscometer through a carefully specified opening. Detailed conversion tables appear in ASTM D2161, approximation of kinematic viscosity V in mm /s(= cSt) can be made from the relation shown in equation 8 ... 

If it is necessary to calculate kinematic viscosities from efflux times, such as in a caUbration procedure, equation 20 should be used, where /is the efflux time and k and K are constants characteristic of the particular viscosity cup (see Table 5) (158,159). 

In most cases it is sufficient to be able to convert from one viscometer value to another or to approximate kinematic viscosities with the help of charts or tables Hterature from manufacturers is useful. 

Rheology. PVP solubihty in water is limited only by the viscosity of the resulting solution. The heat of solution is — 16.61 kJ/mol (—3.97 kcal/mol) (79) aqueous solutions are slightly acidic (pH 4—5). Figure 2 illustrates the kinematic viscosity of PVP in aqueous solution. The kinematic viscosity of PVP K-30 in various organic solvents is given in Table 13. 

Rizzuti et al. [Chem. Eng. Sci, 36, 973 (1981)] examined the influence of solvent viscosity upon the effective interfacial area in packed columns and concluded that for the systems studied the effective interfacial area a was proportional to the kinematic viscosity raised to the 0.7 power. Thus, the hydrodynamic behavior of a packed absorber is strongly affected by viscosity effects. Surface-tension effects also are important, as expressed in the work of Onda et al. (see Table 5-28-D). 

This formula gives accurate values only when the kinematic viscosity of the liquid is about 1.1 centistokes or 31..5 SSU, which is the case with water at about OOF. But the viscosity of water varies with the temperature from 1.8 at 32F to. 29 centistoke.s at 212F. The tables are therefore subject to this error which may increa.se the friction loss as much as 20% at 32F and decrease it as much as 20% at 212F. Note that the tables may be used for any liquid having a viscosity of the. same order as indicated above. 

The kinematic viscosity of MEM containing aqueous electrolytes at different concentrations of MEM and ZnBr2 and at different temperatures has been studied [68] (see Table 8). 

Table 8. Kinematic viscosity (m2sH ) of aqueous electrolyte containing MEM and 3 mol L l ZnBr2 (taken from Ref. [68])...

Experimental values of diffusivities are given in Table 10.2 for a number of gases and vapours in air at 298K and atmospheric pressure. The table also includes values of the Schmidt number Sc, the ratio of the kinematic viscosity (fx/p) to the diffusivity (D) for very low concentrations of the diffusing gas or vapour. The importance of the Schmidt number in problems involving mass transfer is discussed in Chapter 12. 

By using a liquid with a known kinematic viscosity such as distilled water, the values of Ci and Cj can be determined. Ejima et al. have measured the viscosity of alkali chloride melts. The equations obtained, both the quadratic temperature equation and the Arrhenius equation, are given in Table 12, which shows that the equation of the Arrhenius type fits better than the quadratic equation. 

The physical and chemical properties of hazardous dense solvent compounds are given in Tables 18.8 and 18.9, in which the absolute viscosity and kinematic viscosity are expressed in cen-tipoises and centistokes, respectively. 

As mentioned before in Eq. (3), the most common source of SGS phenomena is turbulence due to the Reynolds number of the flow. It is thus important to understand what the principal length and time scales in turbulent flow are, and how they depend on Reynolds number. In a CFD code, a turbulence model will provide the local values of the turbulent kinetic energy k and the turbulent dissipation rate s. These quantities, combined with the kinematic viscosity of the fluid v, define the length and time scales given in Table I. Moreover, they define the local turbulent Reynolds number ReL also given in the table. 

The kinematic viscosity v is of more fundamental importance than the dynamic viscosity fi and it is appropriate to consider typical values of both these quantities, as shown in Table 1.2. 

Various correlations for mean droplet size generated by plain-jet, prefilming, and miscellaneous air-blast atomizers using air as atomization gas are listed in Tables 4.7, 4.8, 4.9, and 4.10, respectively. In these correlations, ALR is the mass flow rate ratio of air to liquid, ALR = mAlmL, Dp is the prefilmer diameter, Dh is the hydraulic mean diameter of air exit duct, vr is the kinematic viscosity ratio relative to water, a is the radial distance from cup lip, DL is the diameter of cup at lip, Up is the cup peripheral velocity, Ur is the air to liquid velocity ratio defined as U=UAIUp, Lw is the diameter of wetted periphery between air and liquid streams, Aa is the flow area of atomizing air stream, m is a power index, PA is the pressure of air, and B is a composite numerical factor. The important parameters influencing the mean droplet size include relative velocity between atomization air/gas and liquid, mass flow rate ratio of air to liquid, physical properties of liquid (viscosity, density, surface tension) and air (density), and atomizer geometry as described by nozzle diameter, prefilmer diameter, etc. 

Table 2.1. The principal length and time scales, and Reynolds numbers characterizing a fully developed turbulent flow defined in terms of the turbulent kinetic energy k, turbulent dissipation rate e, and the kinematic viscosity v. 

For concentrated solutions, the kinematic viscosity v may differ from values in (standard) tables, so we may need to determine its value for ourselves by using a viscometer (which is an easy process). Note, however, that the exponent of -1/6 on v in equation (7.1) means that most errors are likely to be extremely small. 

TABLE 10-1 Density, Viscosity, and Kinematic Viscosity of Water and Air in Terms of Temperature... 

An experimentally based rule-of-thumb is that laminar flow often occurs when the pipe Reynolds number, Vdjv, is less than 2,000, or when an open channel Reynolds number, Vhjv, is less than 500, where V is the cross-sectional mean velocity, d is the pipe diameter, v is the kinematic viscosity of the fluid, and h is the channel depth. The diameter or depth that would not be exceeded to have laminar flow by these experimental criteria is given in Table 5.1. 

Table 20.3 Molecular Diffusivities, Kinematic Viscosities, and Schmidt Numbers (ScJW) in Water for Selected Chemicals... 

A. Relative temperature dependence of kinematic viscosity vw (see Fig. 20.6 and Appendix B, Table B.3)... 

Calculate the kinematic viscosity (T ) of the sample in centistokes (cSt with units of cm2/sec) by multiplying the efflux time in seconds by the viscometer constant (Table HI.3.1). Repeat measurements as necessary. 

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