kinematic viscocity 1

[1296]

how do i calculate the kinematic viscocity of fluids.can some one help me in getting some usefull formulae.i want the value of kinematic viscocity at a particular temperature.

 

[macmet]

http://www.google.com

you can find the kinematic viscosity of many common fluids doing a simple search.

 

[1296]

i have done some search on kinematic viscocity but i could not find the values at a particular temperature.
i even found out the formula for kinematic viscocity as dynamic viscocity over density.
but this does not solve my problem i am looking for other ways to find out kinematic viscocity taking temperature into account and other parameters not just density and dynamic viscocity.

 

[macmet]

what exactly are you looking for?

 

[1296]

Actually i want the kinematic viscocity of various cryogenic fluids at room temperature(25C or 77F).
I got the information regarding few liquids but still need to know many.I searched various sites but could not get at that particular temperature.

 

[25362]

Until you find what you want call it viscosity with an s.

 

[macmet]

You can try the formula they use on this webpage

http://www.ae.su.oz.au/aero/fprops/propsoffluids/node5.html

eqn 1.10

See if it fits your other data

Good luck

 

[katmar]

Hi 1296,

In my experience it is a lot easier to find tabulations of dynamic viscosity than of kinematic viscosity. You will probably have better luck if you search for the dynamic viscosity and the density as a function of temperature and then convert to kinematic for yourself.

Probably the best free online compilation of physical properties is at

http://webbook.nist.gov/

If you have trouble with the variety of units that viscosity is used in, download my free units conversion program Uconeer (

http://www.katmarsoftware.com).

This program has conversion factors for both kinematic and dynamic viscosity, and if you enter the density it will convert beteen the two as well.

regards
Katmar

 

[1296]

hi macmet,
Your information is good but this equation gives more unknowns which we have to find out.Do you have any information regarding how to find out those values?
Your help will be appreciated.
Thank You

 

[macmet]

Do you know the viscosity at any other temperature? I have a few charts available but without knowing what you're looking at I can't help any further.

cheers

 

[jmw]

Viscosity temperature relationships are usually logarithmic.
For example: for hydrocabons (above 2 cst) the ASTM D341 model is:
log.10.log10(v-0.7) = A -B.log10(T+273) where v is the kinematic viscosity at temperature T deg C.
The relationship for other liquids is often modelled by the Anderade equation.
For a nominal sum you can source a solution from Cheresources (

http://www.cheresources.com/cheplusstore/catalogue.php?exp=&cat=16)

Note that you will require to know the viscosity at two different temperatures to define the curve for any specific liquid.

JMW

http://www.ViscoAnalyser.com

 

[TD2K]

If you need to calculate a viscosity, "The Properties of Gases and Liquids" by Reid, Praunitz and Sherwood is good. I have an older 3rd edition, there are later editions out with one of the authors (who is deceased) being replaced with a new person but the title is the same.