Viscosities of water

Horn R, Smith D T and Haller W 1989 Surface forces and viscosity of water measured between silica sheets Chem. Rhys. Lett. 162 404-8... 

At 37°C the viscosity of water is about 0.69 X 10"3 kg m" sec" the difference between this figure and the viscosity of blood is due to the dissolved solutes in the serum and the suspended cells in the blood. The latter are roughly oblate ellipsoids of revolution in shape. 

Viscosity. Sedimentation rate increases with decreased viscosity, )J., and viscosity is dependent on temperature. Often mineral oils, which are highly viscous at room temperature, have a viscosity that is reduced by a factor of 10 at 70—80°C. Tar, soHd at room temperature, is a low viscosity Hquid at 150—200°C and can be clarified of inorganic soHds at high flow rates. Even the viscosity of water changes significantly when the temperature changes between 10 and 35°C (10). 

Fig. 8. Viscosity of water and steam as a function of temperature. Values given correspond to pressures in MPa. To convert MPa to psi, multiply by 145.

HPC is available in a number of viscosity grades, ranging from about 3000 mPa-s(=cP) at 1% total soHds in water to 150 mPa-s(=cP) at 10% total sohds. HPC solutions are pseudoplastic and exceptionally smooth, exhibiting Htde or no stmcture or thixotropy. The viscosity of water solutions is not affected by changes in pH over the range of 2 to 11. Viscosities decrease as temperature is increased. HPC precipitates from water at temperatures between 40 and 45°C. Dissolved salts and other compounds can profoundly influence the precipitation temperature (50,81). 

Component 1 is the solute, while component 2 is water. The molar volume of the solute in mVkmole is at the solute normal boiling point, while the viscosity of water in Pa sec is at the temperature of the system resulting in a diffusivity in mVsec. The average error is about 9 percent when tested on 36 experimental systems. 

IABLE 10 1 Density/ Viscosity/ and Kinematic Viscosity of Water and Air in Terms of Temperature... 

The exponential dependencies in Eq. (14-195) represent averages of values reported by a number of studies with particular weight given to Lefebvre [Atomization and Sprays, Hemisphere, New York, (1989)]. Since viscosity can vary over a much broader range than surface tension, it has much more leverage on drop size. For example, it is common to find an oil with 1000 times the viscosity of water, while most liquids fall within a factor of 3 of its surface tension. Liquid density is generally even closer to that of water, and since the data are not clear mat a liquid density correction is needed, none is shown in Eq. 

The flux equation assumes constant temperature. As T rises, H rises slowly, but around 25°C the viscosity of water drops enough to produce about a 3 percent rise in flux per °C. 

At what rate will a process fluid with approximately the viscosity of water discharge through a 2 in. i.d. pipe 100 ft. long under a differential pressure of 100 psi ... 

Several factors can contribute to the difference in retention times for PEO in different mobile phases the viscosity of a mobile phase, the hydrodynamic volume of a PEO, and the swelling or void volume of a column. Shodex and TSK columns should swell more in water than in water/methanol, and PEO should therefore come out later in water than in water/methanol. PEO should also elute later in water than in water/methanol because water/methanol is a better solvent for PEO than water. The viscosity of the 50 50 water/methanol mobile phase is higher than the viscosity of water. PEO should therefore elute later in water/methanol than in water due to the difference in viscosity. The results in Table 17.9 indicate that the difference in retention time for PEO in water and in water/methanol depends more on the swelling of columns and the hydrodynamic volumes of PEO than the viscosities of mobile phases. 

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. 

Since the expression (41) is deduced for a sphere whose radius is large compared with the molecules of the liquid, it is not known to what extent the behavior of atomic and small molecular ions should be in accordance with (41). It is clear that, if (41) were applicable, the value of the mobility should vary inversely with the viscosity. If for any ion the K on the left-hand side of (41) is set equal to the constant force acting on the ion in a field of unit intensity, the v on the right-hand side of (41) becomes equal to the mobility u. Since K is independent of temperature the product of u and ij should be independent of temperature. From Table 42 it will be seen that at 25°C the viscosity of water is almost exactly half the viscosity at 0°C thus, according to (41) the mobility u of each ion should be double. 

Microbial cells are separated from a culture broth at a flow rate of 3.35 X 10 3m3/s. Assume the cells are spherical with average diameter of 1 pm. Select a centrifuge that can perforin this separation. Given data pcell =1.1 pwatcr, pwalcl. = 997kg-m-1 at 25 °C pbroth = 3Pwatee an(J the viscosity of water is 0.9 X 10 3N-s/m2. 

The property of the fluid which appears in the Reynolds number is the kinematic viscosity pfp. The kinematic viscosity of water at 294 K and atmospheric pressure is 10 6 m2/s compared with 15.5 x 10 6 nr/s for air. Thus, gases typically have higher kinematic viscosities than liquids at atmospheric pressure. 

Water flows in a 50 mm pipe, 100 m long, whose roughness e is equal to 0.013 mm. If the pressure drop across this length of pipe is not to exceed 50 kN/m2, what is the maximum allowable water velocity The density and viscosity of water may be taken as 1000 kg/m3 and 1.0 mN s/m2 respectively. 

A cylindrical tank, 5 m in diameter, discharges water through a horizontal mild steel pipe, 100 nj long and 225 mm in diameter, connected to the base. What is the time taken for the water level in the tank to drop from 3 m to 0.3 m above the bottom The viscosity of water may be taken as 1 mN s/m2. 

Water flows through an orifice of 25 mm diameter situated in a 75 mm diameter pipe, at a rate of 300 em /s. What will be the difference in level on a water manometer connected across the meter The viscosity of water... 

Density of water 1000 kg/m3 Viscosity of water 1 mN s/m2 Assume pipes to be smooth walled... 

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