A calculation of the saturation properties of ordinary water

In this paper in consistence with the International Formulation of the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use (IAPWS Formulation 1995) is developed method for computing values of thermodynamic properties on the saturated curve. The following properties on the saturated line of ordinary water substance are calculated: vapour pressure, specific volumes, specific enthalpies and specific heat of vaporisation. The results for values of this properties are given in table for temperatures between 273, 15 K and 403,15 K, in intervals from 1 K and 10 figures accuracy. Explicit equations are developed by using the least-square fit method for saturated pressure and specific volumes of both the saturated liquid and the saturated vapour in accordance with IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam (IAPWS-IF97). So obtained equations have validity in temperature interval from 273,15 K to 647,096 K. The percentage deviations of this approximate functions from accuracy values are presented. This equations are used as auxiliary functions for calculation of the starting values for equations of the phase - equilibrium condition solving.