Previously reported as well as unpublished experimental data for the viscosity of dilute water vapor in the temperature range from (297 to 528) K, which were obtained using an oscillating-disk viscometer, have been re-evaluated and extrapolated to the limit of zero density. The relative combined expanded (k = 2) uncertainty of the re-evaluated data is 0.2 % at room temperature (297 K to 302 K), 0.4 % at higher temperatures up to 450 K, and 1.0 % at temperatures above 450 K. The classical kinetic theory of molecular gases has been applied to compute the viscosity in the limit of zero density for temperatures between (250 and 2500) K using a highly accurate ab initio potential for the H2O molecule pair. In the temperature range from (311 to 438) K, the experimental zero-density data differ by only about +0.1 % from the calculated values. A new correlation for the zero-density limit, based on both the experimental data and the theoretically calculated values, is proposed. The relative combined expanded (k = 2) uncertainty of the correlation is estimated to be 0.4 % between (300 and 500) K, increasing to 0.8 % at 250 K and 2.0 % at 2500 K. The new correlation represents a significant improvement over the current IAPWS zero-density correlation.
Compounds
#
Formula
Name
1
H2O
water
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.