Liquid kinematic viscosity

D = the diffusion coefficient of the solute in the liquid phase dp = the particle diameter v = the liquid kinematic viscosity. 

While the actual Reynolds number will be greater than 140 the value Re - 140 is a good initial value to use in the above equation. Using the liquid properties given above, the liquid kinematic viscosity and Prandtl number are. 

Fig. 11. Condition for uniform irrigation in trickle flow. Maximum particle size as a function of liquid kinematic viscosity for different bed lengths and different space velocities.

The use of Fig. 13.36 requires a value of the packing factor i, which may be taken from Table 13.13 or 13.15. The abscissa term is the same as that for tray columns. It is sensible to use a value of about 80% of the maximum curve (equivalent to 1.5 in. H20/ft, or 125 mm Fl20/m) for design purposes. The corresponding ordinate term then allows deduction of the value of Cs, defined as Cs = Us[pg/(pL - Pg)]°, where Us is the allowable superficial velocity of vapor or gas through the column. Also, v = liquid kinematic viscosity = centistokes (centipoises/density, gm/ml). Example 13.16 shows how Fig. 13.36 is used. 

For liquids, kinematic viscosities vary with temperature over a somewhat narrower range than absolute viscosities. For gases, the kinematic viscosity increases more rapidly with temperature than does the absolute viscosity. 

Equation 24.7.vi, derived by Radchffe [70], is a function of the surface tension, liquid kinematic viscosity, hquid mass flow rate and the injection pressure of the liquid. In his experiment though, Radcliffe did not alter the value of surface tension too much. His results were focused primarily to fuel combustion, and thus his equation does not yield good values when used for other liquids like water. Jasuja [8] modified this to 24.7.vii later on, using the same experimental conditions. In his equation, mass flow rate and kinematic viscosity are slightly less significant, while the injection pressure is slightly more significant. 

The glass capillary viscometer is widely used to measure the viscosity of Newtonian fluids. The driving force is usually the hydrostatic head of the test liquid. Kinematic viscosity is measured directly, and most of the viscometers are limited to low viscosity fluids, approx 0.4 16,000 mm /s. However, external pressure can be applied to many glass viscometers to increase the range of measurement and enable the study of non-Newtonian behavior. Glass capillary viscometers are low shear stress instruments 1-15 Pa or 10-150 d5m/cm if operated by gravity only. The rate of shear can be as high as 20,000 s based on a 200-800 s efflux time. 

Appearance Dark brown, viscous liquid Kinematic Viscosity 6 40C, cSt 650 Color, Gardner 8... 

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