2011 年 28 巻 4 号 p. 415-426
An experimental apparatus for measuring PρTx (pressure-density-temperature-composition) properties along isochores was constructed. After the calibration of pressure sensor and the determination of the inner volume of sample vessel, the reproducibility of the experimental apparatus was confirmed by the measurement of isochores for pure HFC-134a (1,1,1,2-tetrafluoroethane). The PρTx properties of the 50 mass% HFO-1234ze(E) (trans-1,3,3,3-tetrafluoropropene) + 50 mass% HFC-32 (difluoromethane) mixtures and those of the 75 mass% HFO-1234ze(E) + 25 mass% HFC-32 mixtures were measured for five isochores including 128 PρTx property data points and for seven isochores including 188 PρTx property data points, respectively. The critical pressures were determined from the present isochores close to the critical density against the critical temperature. The relationship between pressure and temperature at vapor-liquid equilibrium was graphically determined from thepresentisochores.