Pentafluoroethane (HEC-125) and trifluoroiodomethane (CF3I) are considered as promising refrigerant alternatives, especially as components in mixtures, to replace CFCs or HCFCs. Effective uses of HFC-125 and CF3I requ...Pentafluoroethane (HEC-125) and trifluoroiodomethane (CF3I) are considered as promising refrigerant alternatives, especially as components in mixtures, to replace CFCs or HCFCs. Effective uses of HFC-125 and CF3I require that the thermophysical properties be accurately measured. In the present work, vapor pressure data of HFC-125 and CF3I have been measured in the temperature range from 292 to 337 K and 288 to 336 K, respectively. Maximum total pressure uncertainty of HEC-125 data is estimated to be within ±1.2 kPa and ±780 Pa for CF3I. Based on the data set and literature values, the vapor pressure equations for HEC-125 and CF3I have been developed. The relative deviation of the equations correlate the measurements within 0.022% for HEC-125 and 0.068% for CF3I, respectively.展开更多
The gaseous speed of sound, the ideal gas heat capacity at constant pressure, and the second Virial coefficient were determined for pentafluoroethane (HFC 125). A total of 49 data points of speed of sound for gas...The gaseous speed of sound, the ideal gas heat capacity at constant pressure, and the second Virial coefficient were determined for pentafluoroethane (HFC 125). A total of 49 data points of speed of sound for gaseous HFC 125 were measured for temperatures from 273 to 313 K and pressures from 32 to 479 kPa with a cylindrical, variable path acoustic interferometer. The ideal gas heat capacity at constant pressure and the second acoustic Virial coefficient were determined over the temperature range from the speed of sound measurements and were correlated as functions of temperature. An analytical expression for the second Virial coefficient derived using the square well intermolecular potential model was compared with the data.展开更多
文摘Pentafluoroethane (HEC-125) and trifluoroiodomethane (CF3I) are considered as promising refrigerant alternatives, especially as components in mixtures, to replace CFCs or HCFCs. Effective uses of HFC-125 and CF3I require that the thermophysical properties be accurately measured. In the present work, vapor pressure data of HFC-125 and CF3I have been measured in the temperature range from 292 to 337 K and 288 to 336 K, respectively. Maximum total pressure uncertainty of HEC-125 data is estimated to be within ±1.2 kPa and ±780 Pa for CF3I. Based on the data set and literature values, the vapor pressure equations for HEC-125 and CF3I have been developed. The relative deviation of the equations correlate the measurements within 0.022% for HEC-125 and 0.068% for CF3I, respectively.
基金Supported by the National Natural Science Foundation of China( No. 5 990 60 0 6)
文摘The gaseous speed of sound, the ideal gas heat capacity at constant pressure, and the second Virial coefficient were determined for pentafluoroethane (HFC 125). A total of 49 data points of speed of sound for gaseous HFC 125 were measured for temperatures from 273 to 313 K and pressures from 32 to 479 kPa with a cylindrical, variable path acoustic interferometer. The ideal gas heat capacity at constant pressure and the second acoustic Virial coefficient were determined over the temperature range from the speed of sound measurements and were correlated as functions of temperature. An analytical expression for the second Virial coefficient derived using the square well intermolecular potential model was compared with the data.
