Measurement and Empirical Models of Thermal Conductivity of Trifluoroiodomethane (CF 3 I)

This research is focused on the experimental measurement of the thermal conductivity of CF 3 I and the subsequent development of empirical models, which are integral to engineering system design calculations. CF 3 I is identified as a potential key component in the formulation of future refrigerant mixtures, owing to its non-explosive nature, low toxicity, and minimal contribution to ozone layer depletion and global warming. Its applicability is further reinforced by its advantageous thermodynamic properties, including a low boiling point and a high critical temperature, making it a vital constituent in refrigerant mixtures. The study employs the well-established transient hot-wire method to measure the thermal conductivity of CF 3 I in both its liquid and vapor phases. This method is characterized by the sequential arrangement of two platinum wires which are linked in parallel to nullify any impacts from axial heat conduction. Experimental data were methodically gathered across a range of temperatures, spanning from 311 K to 374 K for the liquid phase and from 312 K to 394 K for the vapor phase, under varying pressures from 1.5 MPa to 4.0 MPa and 0.5 MPa to 3.0 MPa, respectively. The combined uncertainties associated with these measurements were meticulously calculated, amounting to 1.8% for the liquid phase and 2.0% for the vapor phase. Furthermore, the research advanced to the development of thermal conductivity models for CF 3 I, employing both the Extended Corresponding States method and the modified Residual Entropy Scaling method. These models effectively encapsulate the empirical findings, fitting within the established uncertainty limits with reasonable extrapolating behavior. Critically, these models are expected to play a pivotal role in predicting the thermal conductivity of refrigerant mixtures that incorporate CF 3 I as a component, marking a significant contribution to the field of refrigerant technology.