Viscosity of fluorinated propane isomers. 2. Measurements of three compounds and model comparisons

Viscosity data are reported for three fluorinated propane isomers in the saturated-liquid state over a combined temperature range from 248 to 348 K. The compounds are 1,1,1,3,3-pentafluoropropane (R245fa), 1,1,2,2,3-pentafluoropropane (R245ca), and 1,1,1,2,3,3,3-heptafluoropropane (R227ea). The measurements were carried out in sealed gravitational capillary viscometers. The estimated uncertainty of the measurements is +/-3.4%. Including earlier viscosity measurements on 1,1,1,3,3,3-hexafluoropropane (R236fa) and 1,1,1,2,3,3-hexafluoropropane (R236ea), the viscosity data of all five fluids were correlated within their experimental uncertainty in terms of the rough hard-sphere model. The experimental data were also compared with predictions of the extended corresponding-states method in NIST Standard Reference Database 23 (REFPROP). Deviations range between -20 and 15%.