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A method of describing the saturation line based on the apparent heat of vaporization and Clausius-Clapeyron equation

DOI: 10.21047/1606-4313-2017-16-2-66-72
UDC 536.71

A method of describing the saturation line based on the apparent heat of vaporization and Clausius-Clapeyron equation

Rykov S.V. , Kudryavtseva I.V. , Poltoratskiy M.I., Rykov V.A., Klimovich M.V.

For citation: Rykov S.V., Kudryavtseva I.V., Poltoratskiy M.I., Rykov V.A., Klimovich M.V. A method of describing the saturation line based on the apparent heat of vaporization and Clausius-Clapeyron equation. Vestnik Mezhdunarodnoi akademii kholoda. 2017. No 2. p. 66-72

Abstract
Introducing the apparent heat of evaporation in the structure of Clausius-Clapeyron equation is shown to allow describing the steam branch of the phase equilibrium lines from the triple point to the critical point. In the neighborhood of the triple point a transition to a state close to the ideal-gas one is provided, and in neighborhood of critical point "completed" scaling, according to which the behavior of the average diameter is determined by the exponent 2β (where βis the critical index of the coexistence curve) is enforced. The method in question is tested on the description for the steam branch of R218 refrigerant phase equilibrium lines. The description accuracy of the vapor pressure density on the line of elasticity and the apparent heat of vaporization for R218 refrigerant corresponds to the experimental one. It is shown that near the triple point the density of R218 is inflated by 0.2% compared to the density calculated on the basis of the model for an ideal gas, and the apparent heat of vaporization calculated on the basis of the proposed method differs from the values calculated by the model for an ideal gas by only 0.03%.

Keywords: saturation line, elasticity line, average diameter, critical indices, critical point, triple point, R218, thermodynamic properties.

All references

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