Viscosity measurements on gaseous ethane

A vibrating-wire viscometer was used to measure the viscosity of gaseous propane at subcritical temperatures (298.15, 323.15, 348.15, and 366.15) K and at supercritical temperatures (373.15, 398.15, and 423.15) K. At the subcritical temperatures, the isothermal series of measurements were restricted to 95% of the saturated vapor pressure. The maximum pressure for the supercritical isotherms was 20 MPa. In general, the measurements are characterized by a reproducibility of ±0.05% and a total uncertainty between ±0.25% and ±0.4%. However, close to the critical point, an uncertainty of ±3% had to be accepted, mainly due to the uncertainty of the density. The new data are the most accurate values in the range of the measurements and should be used in a database for the viscosity of fluid propane.