Originally Posted By: Tempest
Quote:
Given that density and HTHS are related figures
Please provide some information to show this.
Originally Posted By: CATERHAM
Originally Posted By: Newtonville
I found wikipedias notes on "viscosity" interesting as well as this English site
http://www.kewengineering.co.uk/Auto_oils/oil_viscosity_explained.htm
It seems it is entering the realm of chemical engineering/fluid dynamics.
Basically I see dynamic and kinematic viscosity described, dynamic being kinematic divided by density. One is in cSt, other cP. In very complex molecules in solution with other complex molecules, or additives, tracking the density changes at temperatures, pressures, and shears would be challenging? Since HTHS test uses the same cP units as dynamic viscosity, as decribed on sites, aren't they one and the same? Is HTHS= dynamic viscosity at 150c?
Maybe Pennzoil's "adaptive molecules" are not to be made fun of so much after all.
Actually, dynamic viscosity is the kinematic viscosity times (not divided by) the oil's density. It doesn't equal the HTHS viscosity because it doesn't factor in the pressure-viscosity coefficients of different oil chemistries.
See the following paper, particularly page 8, which goes into some detail on the relationship between HTHS vis and dynamic vis:
http://www.kulikow.com/project/Literature/PEG-Esters/NoLowSAPEngineOil-JAI2008.pdf.pdf
I interpreted this to mean density as a factor in calculating dynamic viscosity of with it's relationship to HTHS being discussed in that paper. I don't mean that they are directly correlating. I'm just curious if we can use some of the data to determine (roughly) how VII dependent an oil is.