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Determination of kinematic viscosity and density.
Fuel leakage, trouble-free operation of the fuel pump of
high pressure, the operation of precision pairs, the continuous
supply of fuel to the cylinders, the fineness of spraying and the
completeness of combustion of fuel, its consumption, the
composition of the exhaust gases depends to a large extent on
the viscosity of diesel fuels.
Viscosity is called the property of a liquid to resist the
displacement of one layer relative to another under the action of
external forces.
There are dynamic, kinematic and conditional
viscosities. Dynamic viscosity () – is the ratio of the active
tangency to the speed factor.
Units of measurement of dynamic viscosity in SI are
-3
pascal-second (Pa s), in practice are used 1 mPаs=10 Pаs, it
is allowed to use centipoise (1 сP=1 mPаs). The most common
in various technological calculations, as well as in the quality
control of petroleum products is the kinematic viscosity.
Kinematic viscosity () – is the ratio of the dynamic viscosity
of the liquid to its density at the same temperature. Units of
2
kinematic viscosity in SI are square meter per second (m /s), на
2 -6 2
practice is used 1 сSt = 1 mm /s = 10 m /s.
For evaluation of high viscosity petroleum products use
conditional viscosity (VC), which is understood as the ratio of
the time of leakage from a standard viscometer of a certain
volume (200 ml) of the test liquid to the time of leakage of the
same amount of distilled water at 20 С.
Conditional viscosity can also be determined by the
time of leakage (in seconds) of a certain volume of liquid from
the standard viscometer of Seibolt, Redwood. Formulas, tables
and nomograms are used for mutual recalculation of different
viscosity units.

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