Sutherland's Law  Helium
Hi,
I was wondering if someone knew the constant in the Sutherland's relation for Helium gas. Thanks in advance, Nashat 
Re: Sutherland's Law  Helium
Hi Nashat,
I do not have exactly the data you ask for, but can suggest the following way to get it: o Data for He may be found in http://properties.nist.gov/SemiProp/Gases/He.html o Choose a reference temperature and its associated viscosity. o Assume a value for the missing parameters, S. o Use a leastsquares curve fit to find the value of S that most closely follows the experimental data from NIST. I hope this helps. 
Re: Sutherland's Law  Helium
I found the formula for the air:
nul=1.486*10e6*(T^1.5)/(110.6+T) for the Helium shouldn't be far. Take a look at Schlichting or A. Walz. "Boundary Layers of flow and Temperature". M.I.T. Press. 1969 
Re: Sutherland's Law  Helium
Use LennardJones potentials, more data available and more accurate

Re: Sutherland's Law  Helium
Here are the constants of the Sutherland law for Helium :
mu0 = 3.93267e5 T0 = 809 C0 = 147.2 Hope it helps someone. Alexandre Chatelain. PhD student  LES of Heat Transfer. CEA Grenoble  LEGI/Most Team  FRANCE. 
Re: Sutherland's Law  Helium
Thanks a lot for your replies. I'll give the data from NIST a try. Thanks Rami.
Nash'at 
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