A universal equation of state for R717 allowing for features of the critical area

UDC 536.71

A universal equation of state for R717 allowing for features of the critical area

Rykov S.V., Kudryavtseva I.V., Demina L.U.


Abstract
The present paper realizes a method of quasi-critical points to build the universal equation of state for ammonia that will describe a wide vicinity of the critical point in conformity with the requirements of present-day physics of critical phenomena. The proposed universal equation quite accurately describes solid experimental values of saturated vapor pressure, as well as data on fluid density in the temperature range from196K up to the critical one.The value declination of equilibrium properties of ammonia that have been calculated by the asymmetric universal equation of state, from experimental and tabled data allow to conclude that the equation proposed reproduces equilibrium properties of ammonia with satisfying accuracy both in the regular domain and in the vicinity of the critical point.

Keywords: single equation of state, ammonia, refrigerant R717, method of pseudocritical points, equilibrium properties, regular domain, critical point, thermodynamic properties, phase equilibrium.


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