Measurement of kinematic viscosity and thermal conductivity of 3,3,4,4,5,5-HFCPE in liquid and vapor phases

Abstract

1H, 2H-hexafluorocyclopentene (3,3,4,4,5,5-HFCPE) is being expected as a suitable alternative working fluid for organic Rankine cycles and high-temperature heat pumps due to the attractive environmentally friendly properties, particularly for the low GWP value. The key objectives are to measure the kinematic viscosity and thermal conductivity of 3,3,4,4,5,5-HFCPE in both liquid and vapor phases, as well as to establish simple correlations at saturation conditions. In this study, the kinematic viscosity measurements were performed by the tandem capillary tubes method over the pressures up to 4.0 MPa and temperatures from 332 to 494 K for the liquid phase and from 413 to 514 K for the vapor phase. The measurement uncertainties were calculated using the propagation law of uncertainties by the GUM guideline, where the expanded uncertainties were estimated at 2.2% for the liquid phase and 2.9% for the vapor phase with k = 2 and a 95% confidence level. On the other hand, the thermal conductivity measurements were performed by the transient hot-wire technique at pressures up to 4.0 MPa and temperatures from 333 to 473 K for the liquid phase, and from 393 to 473 K for the vapor phase. The expanded uncertainties were calculated as 3.0% and 3.5% for liquid and vapor phases with k = 2 and a 95% confidence level, respectively. Also, simple correlations were developed to predict the kinematic viscosity and thermal conductivity at saturated conditions.