Viscosity
- • The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress
- • liquid viscosity tends to decrease (or, alternatively, its fluidity tends to increase) as its temperature increases
- • oil viscosity is usually measured at 30~100 ℃
Viscosity index
- • Viscosity index (VI) is an arbitrary measure for the change of viscosity with variations in temperature. The lower the VI, the greater the change of viscosity of the oil with temperature and vice versa
Pour point
- • The pour point of a liquid is the temperature at which it becomes semi solid and loses its flow characteristics
Flash point
- • The flash point of a volatile material is the lowest temperature at which vapors of a fluid will ignite. Measuring a flash point requires an ignition source. At the flash point, the vapor may cease to burn when the ignition source is removed.
- • The flash point is not to be confused with the auto ignition temperature (which does not require an ignition source) or with the fire point
Fire point
- • The fire point of a fuel is the temperature at which the vapour produced by that given fuel will continue to burn for at least 5 seconds after ignition by an open flame. Most tables of material properties will only list material flash points, but in general the fire points can be assumed to be about 10 °C higher than the flash points.
Dansity
- • The density of oil is its mass per unit volume (at 15.6 ℃), the IS unit is kilogram per cubic meter.
- • One of its application is to transfer weight to volume and vice versa ( for calculation of oil production transportation)
- • Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance with that of water, at a particular temperature (60 ℉).