Acoustic Determination of Thermophysical Properties and Critical Parameters for the Mixture (51 wt % R143a + 49 wt % R125) and Critical Line of xCO2 + (1 - x)(51 wt % R143a +

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• 作者：Jos&eacute ; M. S. S. Esperanç ; a ; Pedro F. Pires ; Henrique J. R. Guedes ; Nuno Ribeiro ; T&acirc ; nia Costa ; Ana Aguiar-Ricardo
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2006
• 出版时间：November 2006
• 年：2006
• 卷：51
• 期：6
• 页码：2161 - 2169
• 全文大小：147K
• 年卷期：v.51,no.6(November 2006)
• ISSN：1520-5134

文摘

The thermophysical properties and critical parameters for the alternative refrigerant (51 wt % of 1,1,1-trifluoroethane(R143a) + 49 wt % of pentafluoroethane (R125))-very close to the composition of R507 (50 wt % of eachmixture component)-were investigated using two different acoustic techniques. The critical behavior of the systemxCO₂ + (1 - x)(51 wt % R143a + 49 wt % R125) was also investigated. Experimental data of speed of soundin liquid (51 wt % R143a + 49 wt % R125) from T = (253 to 338) K and pressures up to 65 MPa were measuredusing a pulse-echo method. Derived thermodynamic properties were calculated, combining our experimental datawith density and isobaric heat capacity values published by other authors. Measurements of the critical temperatureT_c and pressure p_c on (51 wt % R143a + 49 wt % R125) and mixtures of xCO₂ + (1 - x)(51 wt % R143a + 49wt % R125) were performed using another simple ultrasonic time-delay technique. The binary critical line wasdetermined over the whole composition range showing that this system deviates only slightly from ideality sincethe critical line is a continuous line. The Peng-Robinson equation of state with conventional mixing and combiningparameters was used to correlate the binary experimental data.