Understanding Coefficient of Viscosity for SAE 10W-30 Oil at 25°C

[jabers]

How do I tell what the coefficient of viscosity is of SAE 10W-30 oil? It is at 25 degrees C. My book says that multigrade oils like this have a non Newtonian blending additive. This doesn't mean I have to treat the substance as non Newtonian does it?

Any help would be appreciated.

 

[CWatters]

Google found this chart but I don't know the source of the data..

 

[CWatters]

Looks like the viscosity is only specified at a few temperature points and those can vary depending on the grade. Scroll down...

http://www.tribology-abc.com/abc/viscosity.htm

 

[CWatters]

How do I tell what the coefficient of viscosity is of SAE 10W-30 oil? It is at 25 degrees C. My book says that multigrade oils like this have a non Newtonian blending additive. This doesn't mean I have to treat the substance as non Newtonian does it?

Any help would be appreciated.

I suspect it depends on what experiment you have planned. Presumably the additive makes the oil thicker when under pressure in bearings etc, while at the same time makes it easy to pump around the engine.

If you are doing simple lab experiments dropping balls into oils or something then you might be ok. If you are doing something more exotic beware...

http://en.wikipedia.org/wiki/Motor_oil

Quote from ASTM report on the matter: "The rapid growth of non-Newtonian multigraded oils has rendered kinematic viscosity as a nearly useless parameter for characterising "real" viscosity in critical zones of an engine.