Kinematic viscosity and speed of sound in gaseous CO, CO2, SiF4, SF6, C4F8, and NH3 from 220 K to 375 K and pressures up to 3.4 MPa

An acoustic Greenspan viscometer was used to measure the kinematic viscosity and speed of sound in the gases: CO, CO2, SiF4, SF6, C4F8, and NH3. The measurements cover the temperature range 220 K to 375 K, and pressures up to 3.4 MPa or 80% of the saturation pressure.The viscometer was calibrated at 298.16 K using five reference gases, Ar, He, N2, CH4, and C3H8, for which the viscosity and the speed of sound are known. With this calibration, we estimated the relative standard uncertainty of the kinematic viscosity ur(η/ρ) = 0.006 and the uncertainty of speed of sound ur(c) = 0.0001, except for very low pressures where the signal-to-noise ratio deteriorates and quality factor for the Helmholtz mode is ⩽20.