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NIST Authors in Bold
|Author(s):||E May; Michael R. Moldover; Robert F. Berg; John J. Hurly;|
|Title:||Transport Properties of Argon at Zero Density From Viscosity-Ratio Measurements|
|Published:||April 01, 2006|
|Abstract:||We determined the zero-density viscosity and thermal conductivity of argon with an uncertainty of only 0.039 % in the temperature range 200 K to 400 K. Our results will improve: (1) the argon-argon interatomic potential, (2) calculated boundary-layer corrections for primary acoustic thermometry, and (3) calibrations of laminar flow meters as well as instruments for measuring transport properties. At 298.15 K, we determined the ratio = 1.13800 0.00018 from measurements of the flow rate of these gases through a quartz capillary of known dimensions and simultaneously measuring the pressures at the ends of the capillary. Between 200 K and 400 K, we used a two-capillary viscometer to determine = 1.21167 0.82034 exp(-T/123.78 K) with an uncertainty of 0.025 %. From , we computed using the values of calculated ab initio. Finally, we computed the thermal conductivity of argon from and values of the Prandtl number that we computed from argon-argon interatomic potentials.|
|Keywords:||ab initio calculations,argon,gases,helium,interatomic potential,Prandtl number,thermal conductivity,transport properties,viscosity|
|PDF version:||Click here to retrieve PDF version of paper (494KB)|