RELATIONS BETWEEN THE DIFFERENCES OF DIFFERENT PROPERTIES OF FREONES ON THE SATURATION LINES UPON LIQUID-VAPOR PHASE TRANSITION

To construct a generalized dependency, a scale for the unknown quantities and variables must be selected. The states of points are located in P-V-T (pressure-volume-temperature) space. The scale for the construction of generalized dependences of the studied properties and variables of the problem must be sustainable. In order to find a sustainable transition from liquid to vapor the behavior of the characteristic function of free energy is investigated. Since the phase transition occurs at a constant temperature, free energy is equal to expansion work. In the analysis of the liquid-vapor transition, the curve of the temperature dependence of expansion work for all investigated substances has a maximum. The temperature corresponding to the maximum expansion work is denoted by Tm. It was noted that temperature Tm associated with Tc (critical) with the simple relation Tm =0.76Tс with a spread of 2%. Naturally, this state corresponds to the free energy minimum value, and in accordance with the principle of minimality of characteristic functions of this process is stable. Therefore, the parameters of this process were chosen as the bringing scale in the construction of dimensionless dependencies. In this paper we use the method of constructing generalized dependencies in the reduced form, based on the characteristic functions minimality principle. Approximating formulas were obtained for calculating reduced heat of evaporation from reduced density, entropy, and freons surface tension. The reduction scale is considered on the liquid and vapor saturation line under substances consideration. The characteristic functions minimality principle is used. In the course of the analysis, calculation formulas were derived for pure freons both individually and in a combined form. The interrelation between the differences of these thermodynamic properties on the saturation line during a liquid-vapor phase transition is shown. This makes it possible to determine some properties using other methods by calculation.

vaporization heat, entropy, density, surface tension, scale of reduction, freon

1. Arutyunov B.A., Arutyunov A.B. Thermodynamics and properties of substances. Moscow: Moscow Technological University (MIREA) Publ., 2016. 214 p. (in Russ.).

2. Arutyunov B.A., Rytova E.V., Raeva V.M., Frolkova A.K. Methods for calculating the evaporization heats of hydrocarbons and their mixtures in a wide temperature range // Theoretical Foundations of Chemical Engineering. 2017. V. 51. № 5. P. 742–751. (in Russ.).

3. Arutyunov B.A., Rytova E.V. Correlation of the evaporization heats and surface tension in the generalized dimensionless form for hydrocarbons // IV Int. Sci. and Techn. Conf. "Modern Methods and Means of Research into Thermophysical Properties". May 17-18, 2017. Saint-Petersburg: Universitet ITMO Publ., 2017. P. 184–188. (in Russ.).

4. Rid R., Prausnic Dzh., Shervud T. Gases and liquids properties / Transl. from Engl. ed. by B.I. Sokolov. 3rd Ed. Leningrad: Khimiya Publ., 1982. 592 p. (in Russ.).

5. Vargaftik N.B. Handbook of Thermophysical Properties of Gases and Liquids. Moscow: Nauka Publ., 1972. 720 p. (in Russ.).

6. Jacobsen R.T., Penoncello S.G., Lemmon E.W. A fundamental equation for trichlorofluoromethane (R11) // Fluid Phase Equilibria. 1992. V. 80. P. 45–56.

7. Marx V., Pruss A., Wagner W. Neue Zustandsgleichungen fuer R 12, R 22, R 11 und R 113. Beschreibung des thermodynamishchen Zustandsverhaltens bei Temperaturen bis 525 K und Druecken bis 200 MPa // Duesseldorf: VDI Verlag, Series 19 (Waermetechnik/Kaeltetechnik), No. 57, 1992.

8. Bogdanov S.N., Burtsev S.I., Ivanov O.P., Kupriyanova A.V. Refrigeration Equipment. Air Conditioning. Properties of Substances: Handbook / Ed. by S.N. Bogdanov. St. Petersburg: SPbGAHPT, 1999. 320 p. (in Russ.)

9. Magee J.W., Outcalt S.L., Ely, J.F. Molar heat capacity C(v), vapor pressure, and (p, rho, T) measurements from 92 to 350 K at pressures to 35 MPa and a new equation of state for chlorotrifluoromethane (R13) // Int. J. Thermophys. 2000. V. 21. № 5. P. 1097–1121.

10. Platzer B., Polt A., Maurer, G. Thermophysical properties of refrigerants // Berlin: Springer-Verlag. 1990. 488 p.

11. Kamei A., Beyerlein S.W., Jacobsen, R.T. Application of nonlinear regression in the development of a wide range formulation for HCFC-22 // Int. J. Thermophysics. 1995. V. 16. P. 1155–1164.

12. Penoncello S.G., Lemmon E.W., Jacobsen R.T, Shan Z. A Fundamental equation for trifluorormethane (R-23) // J. Phys. Chem. Ref. Data. 2003. V. 32. № 4. P. 1473–1499.

13. Tillner-Roth R., Yokozeki A. An international standard equation of state for difluoromethane (R-32) for temperatures from the triple point at 136.34 K to 435 K and pressures up to 70 MPa // J. Phys. Chem. Ref. Data. 1997. V. 25. № 6. P. 1273–1328.

14. Lemmon E.W., Jacobsen R.T. Equations of state for mixtures of R-32, R-125, R-134a, R-143a, and R-152a // J. Phys. Chem. Ref. Data. 2004. V. 33. № 2. P. 593–620.

15. Lemmon E.W., Span R. Short fundamental equations of state for 20 industrial fluids // J. Chem. Eng. Data. 2006. V. 51. P. 785–850.

16. Younglove B.A., McLinden M.O. An international standard equation of state for the thermodynamic properties of refrigerant 123 (2,2-dichloro-1,1,1-trifluoroethane) // J. Phys. Chem. Ref. Data. 1994. V. 23. P. 731–779.

17. De Vries B., Tillner-Roth R., Baehr H.D. Thermodynamic properties of HCFC 124 // Proceed. of the 19th Int. Congress of Refrigeration. 1995. V. IVa. P. 582–589.

18. Lemmon E.W., Jacobsen R.T. A New functional form and new fitting techniques for equations of state with application to pentafluoroethane (HFC-125) // J. Phys. Chem. Ref. Data. 2005. V. 34. № 1. P. 69–108.

19. Tillner-Roth R., Baehr H.D. An international standard formulation of the thermodynamic properties of 1,1,1,2-tetrafluoroethane (HFC-134a) for temperatures from 170 K to 455 K at pressures up to 70 MPa // J. Phys. Chem. Ref. Data. 1994. V. 23. P. 657–729.

20. Okada M., Higashi Y. Experimental surface tensions for HFC-32, HCFC-124, HFC-125, HCFC-141b,HCFC-142b, and HFC-152a // Int. J.Thermophysics. 1995. V. 16. № 3. P. 791-800.

21. Lemmon E.W., Jacobsen R.T. An international standard formulation for the thermodynamic properties of 1,1,1-trifluoroethane (HFC-143a) for temperatures from 161 to 450 K and pressures to 50 MPa // J. Phys. Chem. Ref. Data. 2000. V. 29. № 4. P. 521–552.

22. Schmidt J.W., Carrillo-Nava E., Moldover M.R. Partially halogenated hydrocarbons CHFCl-CF3, CF3-CH3,CF3-CHF-CHF2, CF3-CH2-CF3, CHF2-CF2-CH2F,CF3-CH2-CHF2, CF3-O-CHF2: Critical temperature, refractive indices, surface tension and estimates of liquid, vaporand critical densities // Fluid Phase Equilibria. 1996. V. 122. P. 187–206.

23. Outcalt S.L., McLinden M.O. A modified benedict-webb-rubin equation of state for the thermodynamic properties of R152a (1,1-difluoroethane) // J. Phys. Chem. Ref. Data. 1996. V. 25. № 2. P. 605–636.

24. McLure I.A., Soares V.A.M., Edmonds B. Surface tension of perfluoropropane, perfluoron-butane, perfluoro-n-hexane, perfluoro-octane, perfluorotributylamine and n-pentane // J. Chem. Soc., Faraday Trans. 1. 1982. V. 78. № 7. P. 251–257.

25. Huber M.L., Ely J.F. A predictive extended corresponding states model for pure and mixed refrigerants including an equation of state for R134a // Int. J. Refrigeration. 1994. V. 17. P. 18–31.

26. Froeba A.P., Krzeminski K., Leipertz A. Thermophysical properties of 1,1,1,3,3-pentafluorobutane (R365mfc) // Int. J. Thermophys. 2004. V. 25. № 4. P. 987–1004.