Experiment 9: Viscosity and Refractive Index of Liquid Petroleum Products

1. Measure and calculate the viscosity of petroleum products

2. Study the effect of temperature on the kinematic viscosity of the petroleum products

3. Determine the refractive index of petroleum products

Objectives of the experiment

Viscosity

Meausre of the oil’s flow characteristics with resistance to flow

Kinematic viscosity

Measure of the flow characteristics of a fluid under gravity

Dynamic viscosity to the density, both at the same temperature

Ratio of kinematic viscosity

stoke (St) and has the units of cm² /s

Unit of kinematic viscosity in cgs unit

m² /s, 104 St

SI unit of kinematic viscosity and its equivalent to St

Centistoke (1/100 of a Stoke) = 1 mm² /s

Common unit used in the petroleum industry

1.0039 cSt at 20^o C

Kinematic viscosity of pure water

Absolute or dynamic viscosity

Measure of a material’s resistance to flow

Formula of absolute/dynamic viscosity

Poise (P)

Unit for dynamic viscosity

g/cm·s

Cgs unit of dynamic viscosity

0.1 Newton· second/m²

SI unit equivalent to poise

Specifications of lubricating oils

What dynamic and kinematic viscosity help define

1.002 cP at 20^o C

Absolute viscosity of water

ASTM D445: Kinematic Viscosity of Transparent and Opaque Liquids

Most widely used method for determining the viscosity of lubricating oils

Time required for a volume of liquid to flow under gravity through a calibrated viscometer at a controlled temperature

What the viscosity determination is based on

40^o C and 100^o C

Kinematic values used to calculate the viscosity index of lubricating oils by ASTM method D2270

1. Gasoline

2. Motor oil

3. Diesel fuel

4. Viscometer

5. Viscosity bath

6. Refractometer

Materials used for the experiment