Wide-ranging absolute viscosity measurements of sub- and supercritical 1,1,1-trifluoroethane (R143a)

The viscosity of 1,1,1-trifluoroethane (R143a) was measured with a piezoelectrically actuated, torsionally vibrating quartz sensor. The measurements extended over a temperature range from 300 K to 440 K with pressures to 68 MPa and covered states from the dilute gas to the compressed liquid. The influence of the drive voltage on the torsional displacement of the vibrator in fluid and in vacuum was systematically investigated. Since R143a is highly polar, the sample conductance and susceptance were also monitored with the sensor to detect possible electroviscous contributions in the measured viscosities. None were identified so that the estimated uncertainty of the measurements remains at 2% at a 95% confidence level (coverage factor k = 2). The results agree well within this margin with literature data that were determined with four other viscometric techniques.