Study on the PVT x Properties for Mixtures of Alternative Refrigerants

测量了HFC32+HFC125、HFC134a和HFC125+HFC134a二元混合物在283K~353K和近饱和压力至约20MPa时的液相PVT性质。样品容器(约64 cm)被悬挂在电子天平(1200(]sy.+-)上。[0.001g)，通过直接称重所含样品的容器毛重来观察密度。手动油泵产生的压力通过毛细管传递给样品。将包括样品容器在内的悬浮机构浸入控制在(]sy+-内的液体恒温器中。[)0.02K。温度由石英温度计测量。压力由两个最大压力为5(]sy.+-的精密应变片测量。[)0.003 Mpa和25(]SY+-。[)0.008 Mpa。样品容器中的体积由298.15K和0.1 Mpa下测量的甲醇的比容获得。在不同的温度和压力下，观测了不同密度的纯HFC32、HFC125、HFC134a和HFC152a(纯度大于99.6%)的密度，证实了密度计的可靠性是在(]sy.+-范围内测量的。[)0.002g/m&lt；@d13@&gt；d1与参考值比较。混合物是通过称量制备的，不确定度在(]sy.+-以内。测定了HFC32/HFC125、HFC32/HFC134a和HFC125/HFC134a三种二元液体混合物在不同温度和压力下的密度。超声波测速仪还测量了这些系统估算饱和液体密度所需的泡点压力。在这些混合物中，对HFC32/HFC125的浓度进行了详细的窄区间浓度测量，因为该体系具有共沸混合物。用Fuller状态方程和Peng-Robinson状态方程对这些结果进行了关联，并具有较高的精度。

The PVT properties in the liquid phase for binary mixtures of HFC32 +HFC125, +HFC134a, and HFC125 + HFC134a were measured at from 283K to 353K and from near the saturated pressure to about 20 MPa.The method used in this work was the new direct-weighing technique. The sample vessel (about 64cm<@D13@>D1) was suspended to an electric balance (1200(]SY.+-。[)0.001g), and the densities were observed by direct weighing the gross weight of vessel contained the sample. The pressure generated by a hand oil pump was transmitted to the sample through the capillary tube. The suspension mechanism including the sample vessel was immersed in a liquid thermostat controlled within (]SY.+-。[)0.02K.The temperature was measured by a quartz thermometer. The pressure was measured by two precision strain gauges of maximum pressure : 5(]SY.+-。[)0.003 MPa and 25(]SY.+-。[)0.008 MPa.The volume in the sample vessel was obtained from the specific volume of methanol measured at 298.15K and 0.1MPa. The densities of pure HFC32, HFC125, HFC134a and HFC152a (purity : better than 99.6%) having the different density were observed at several temperatures and pressures, and the reliability of densimeter were confirmed to be measure an uncertainty within (]SY.+-。[)0.002g/m<@D13@>D1 compared with reference values.The mixtures were prepared by weighing with an uncertainty of within (]SY.+-。[)0.0003 mole, and the densities of liquid binary mixtures of HFC32/HFC125, HFC32/HFC134a and HFC125/HFC134a were measured at several temperatures and pressures. The bubble point pressures for these systems required to estimate the saturated liquid density were also measured by the instrument for ultrasonic speed measurement. Among these mixtures, They for HFC32/HFC125 were measured in detail for narrow interval concentrations, because that system has an azeotropic mixture. These results were correlated by the Fuller's equation of state and the Peng-Robinson's equation of state with a reasonable accuracy.