![]() The viscosity of water decreases smoothly from the freezing point while the density remains essentially constant except for the small maximum in density near 4☌. In cgs units the unit is called the centistoke. Expert Answer 1st step All steps Final answer Step 1/2 Given data: The specific gravity of water at 70 o c is 0. The kinematic viscosity is the dynamic viscosity divided by the density of the fluid. If the viscosity of water at 70 C is at 0.00402 poise and its specific gravity is 0.978 determine the absolute viscosity in Pa-s and its kinematic viscosity in m/s and in stokes. ![]() The unit centiPoise = 0.001 Pa s and is is sometimes written mPa s. These viscosities are at 20☌ except for the blood and blood plasma which are at body temperature, 37☌, and for steam which is at 100☌. The Poise is used in the table because of its more common usage. More commonly used is the dyne sec/cm 2 which is called Poise. Viscosity has the SI units Pascal seconds (Pa s) which is called the Poiseuille. Substituting the kinematic viscosity and density of standard water from Table 1.6 into the. ![]() Whether the laboratory experiments used to develop this correlation can be accurately compared to the mixing action that occurs in turbulent flow is certainly open to question.įigure 3-12 can be used to estimate the viscosity of a hydrocarbon gas at various conditions of temperature and pressure if the specific gravity of the gas at standard conditions is known.Viscosity of Liquids and Gases Viscosity of Liquids and Gases Liquids The drag force, D FD, is given by the following equation. specific gravity ( relative density S ) of one liter of a liquid which weighs 7 N. The laboratory data plotted in Figure 3-11 agree closely with a modified Vand’s equation assuming a 70% breakover point. Thus, at approximately 70% water cut, it appears as if oil ceases to be the continuous phase and water For 70% water cut, the emulsion began to break before viscosity readings could be made, and for water cuts greater than this, the oil and water began to separate as soon as the mixing was stopped. Produced oil and water were mixed vigorously by hand, and viscosity was measured for various percentages of water. The following thermodynamic properties are calculated: density water, dynamic viscosity water, kinematic viscosity water, specific inner energy water. Figure 3-11 shows some experimental data for a mixture of produced oil and water taken from a south Louisiana field. ![]() When an emulsion of oil and water is formed, the viscosity of the mixture may be substantially higher than either the viscosity of the oil or that of the water taken by themselves. The viscosity of produced water depends on the amount of dissolved solids in water as well as the temperature, but for most practical situations it varies from 1.5 to 2 centipoise at 50☏, 0.7 to 1 centipoise at 100☏, and 0.4 to 0.6 centipoise at 150☏. Figure 3-10 is a graphical representation of another correlation. The data set from which this relationship was obtained included a range of between 16° and 58° API and 70☏ to 295°R It has been the author’s experience that the correlation tends to overstate the viscosity of the crude oil when dealing in temperature ranges below 100 to 150☏. The following equation relating viscosity, gravity, and temperature was developed by Beggs and Robinson after observing 460 oil systems: In the absence of any laboratory data, correlations exist that relate viscosity and temperature, given the oil gravity.
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