Viscosity is a useful fluid parameter used to describe a fluid’s internal friction or resistance to motion. Any operation that involves movement of a fluid, such as pumping, mixing, spreading, pouring or spraying, can be better defined by understanding the flow behavior of the fluids involved.

Typical Experimental Results:

viscosity

Viscosity of 5W-30 lubricating oil

Applications:

Controlled Ramp Rate Dilatant Fluid Pumping Systems
Food Products Newtonian Fluids Non-Newtonian Fluids
Paints Process Control Pseudoplastic
Pseudoplastic Yield Stress Rheopectic Tempterature Profiling
Thixotropic Time Sensitivity Viscosity Determination

For more information please read our application notes.
Viscosity of Motor Oil as a Function of Temperature

 

Key Specifications:

Temperature Range -20 to 300 C
Measurement Range 1 to 6 million cP
Accuracy ± 1.0% of full scale range
Repeatability ± 0.2%

 

Instruments: Brookfield LVDV-II+P Viscometer

viscosity 2

 

Viscosity of Motor Oil as a Function of Temperature

 

Viscosity is a useful fluid parameter used to describe a fluid’s internal friction or resistance to motion. A large viscosity will require a large shear force to overcome the internal friction. Shear forces can occur during operations such as pouring, mixing, spreading, or spraying.

 

The internal friction arises from attractive forces between the molecules of the fluid. When a shear force is applied, it must overcome the intermolecular forces in order to move the liquid.

 

AppNote-49

 

Newton defined viscosity, μ, by considering a situation like Figure 1 where two parallel planes of fluid of equal area, A, are separated by a distance, dx, and traveling at different velocities, V1 and V2. He assumed that the shear stress, τ, required to cause the difference in velocity was proportional to the change in velocity across dx, or the velocity gradient. Mathematically, it is expressed as Equation 1.

 

AppNote-50

 

Fluids that behave according to Equation 1 are called Newtonian. Typical Newtonian fluids are water and thin lubricating oils.

 

Motor oil viscosity is an important consideration for improving the performance and extending the lifetime of any engine. If the oil viscosity is too low, the lubrication layer between parts will be too thin to prevent engine parts from grinding against each other. However, if oil viscosity is too high, the oil may not pump properly during start-up when the engine is still cold. This requires that the correct viscosity oil be used.

 

To facilitate this, oils are classified based on their viscosity and given a certification grade, such as 5, 10, 20, 30 40, or 50; these grades are defined by the Society of Automotive Engineers (SAE). Some oils are given two ratings, such as 5W-30, to indicate oil that has been treated with additives to flow like SAE 5 oil at start-up but SAE 30 after the engine reaches operating temperature. This allows for better engine performance and lifetime.

 

A 5W-30 motor oil was tested using a Brookfield LV-II+ Pro Viscometer. This viscometer has a measuring range of 1 cP to 6•(10)6 cP (1 cP is equal to 10-3 Pa•s). Coupled with appropriate temperature control equipment, the LV-II+ provides excellent accuracy and repeatability in viscosity measurements at temperatures ranging from -20°C to 300°C. The measurement results are presented in Figure 2.

 

AppNote-51

 

 

ASTM Number Title Website Link
D2556-14 Standard Test Method for Apparent Viscosity of Adhesives Having Shear-Rate-Dependent Flow Properties Using Rotation Viscometry Link
D1084-08 Standard Test Methods for Viscosity of Adhesives Link
D1337-10 Standard Practice for Storage Life of Adhesives by Viscosity and Bond Strength Link
E2975-15 Standard Test Method for Calibration of Concentric Cylinder Rotation Viscometers Link

 

ISO Number Title Website Link
2555 Plastics– Resins in theliquid state or as emulsions or dispersions– Determination of apparent viscosity by the Brookfield Test method Link
3219 Plastics– Resins in theliquid state or as emulsions or dispersions– Determination of viscosity using a rotational viscometer with defined shear rate Link
7884-2 Glass– Viscosity and viscometric fixed points– Determination of viscosity by rotational viscometers Link