viscosity
viscosity
(OP)
SSU is a unit of viscosity. I believe it is unit for kinematic viscosity (centistokes) and not dynamic viscosity (centiPoise). The relationship between centistokes and SSU is something like logarithmic or exponential - I dont know, but that is what I am trying to find! Where can I find an equation relating the two? Does this equation change depending on the fluid and fluid properties (pressure, temperature etc.)





RE: viscosity
CentiPoises (cp) = CentiStokes (cSt) x Density
SSU(Note1) = Centistokes (cSt) * 4.55
Degree Engler(Note1) * 7.45 = Centistokes (cSt)
Seconds Redwood(Note1) - 4.05 = Centistokes (cSt)
Note1 - centistokes greater than 50
There are two related measures of fluid viscosity - known as dynamic (or absolute) and kinematic viscosity.
I found this via google at:
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"Do not worry about your problems with mathematics, I assure you mine are far greater."
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RE: viscosity
From the brochure DG-400 by EXXON we can read:
"Many petroleum products are graded according to the ISO Viscosity Classification System, approved by the International Standards Organization (ISO). Each ISO viscosity grade number corresponds to the mid-point of a viscosity range expressed in centistokes (cSt) @ 40ºC. For example, a lubricant with an ISO grade of 32 has a viscosity within the range of 28.8-35.2, the mid-point of which is 32.
Rule-of-Thumb: the comparable ISO grade of a given product whose viscosity in SUS at 100ºF is known can be determined by using the following conversion formula:
SUS @100ºF + 5 = cSt @40ºC. "
RE: viscosity
Centistokes (Z), are estimated from SSU (S) as follows:
A similar thread in the past dealt with this subject, but I'm too lazy to look for it.
RE: viscosity
For S values less than around 30 SSU, the value of Z calculated per your formula is -ve! Is that correct?
RE: viscosity
Visit www.viscosity.com where Norcross maintains a nice set of conversions.
Go here for a converter: http://www.softslide.com/volumes/v3/t3/p1/
More tables here:
http:
not forgeting:
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JMW
www.ViscoAnalyser.com
RE: viscosity
The author is a regular participant of Eng-Tips.
www.katmarsoftware.com
RE: viscosity
RE: viscosity
To picasa, according to the approximate formulas I quoted from old argentine YPF tables, definitely yes. Tabulated values I have for 210oF are:
Z S Z by formula % deviation
2.0 32.8 1.47 -26.5
2.5 34.6 2.18 -12.8
3.0 36.3 2.83 - 2.3
3.5 37.9 3.42 - 2.3
4.0 39.4 3.89 - 2.8
4.5 41.0 4.5 zero
5.0 42.6 5.05 1.0
10 59.2 10.08 0.8
20 98.2 20.2 1.0
50 233.0 51.8 3.6
70 325.7 73.0 4.3
90 418.7 94.1 4.6
100 465.2 104.7 4.7
Which shows the formulas are a gross approximation, and a graph would better serve for extrapolation at the lower end.
Also, please note that temperatures slightly affect the conversion.
Beside all that, the conversion factor above 70 cS is said to be constant, 4.62 for 100oF, and 4.652 for 210oF.
RE: viscosity
JMW
www.ViscoAnalyser.com
RE: viscosity
JMW
www.ViscoAnalyser.com