The viscosity and speed of sound of gaseous nitrous oxide and nitrogen trifluoridewere measured using a Greenspan acoustic viscometer. The data span the temperaturerange 225 to 375 K and extend up to 3.4 MPa. The average relative uncertainty ofthe viscosity is 0.68 % for N2O and 1.02 % for NF3. The largest relativeuncertainties were 3.09 % and 1.08 %, respectively. These occurred at the highestdensities (1702 mol m 3 for N2O and 2770 mol m 3for NF3). The major contributor tothese uncertainties was the uncertainty of the thermal conductivity. The speeds ofsound measured up to 3.4 MPa are fitted by a virial equation of state that predictsgas densities within the uncertainties of the equations of states available in theliterature. Accurate measurements of the speed of sound in both N2O and NF3 have beenpreviously reported up to 1.5 MPa. The current measurements agree with these valueswith maximum relative standard deviations of 0.025 % for N2O and 0.04 % for NF3.
Citation: International Journal of Thermophysics
Pub Type: Journals
Equation of State, greenspan viscometer, nitrogen trifluoride, nitrous oxide, speed of sound, transport properties, viscosity