Viscosity Measurements on Natural Gas: Re-evaluation

Previous experimental viscosity data for natural gas, published by Schley et al. [Int. J. Thermophys. 25, 1623 (2004)] and originally obtained using a vibrating-wire viscometer in the temperature range between 260 K and 320 K, were re-evaluated after an improved re-calibration. For this purpose, a new reference value for the viscosity of argon at 298.15 K and at zero density, proposed by Vogel et al. [Mol. Phys. 108, 3335 (2010)] and further updated by Hellmann [private communication (2020)], was applied. In addition, the density computed from the measured temperatures and pressures was determined using the equation of state by Kunz and Wagner [J. Chem. Eng. Data 57, 3032 (2012)] instead of employing a calculation according to the International Standard ISO 12213 nowadays out of date.