A Unified Fundamental Equation for the Thermodynamic Properties of H2O

Abstract

A new unified equation of state for H2O is presented, which includes the revised and extended scaling equation of Levelt Sengers, Kamgar–Parsi, Balfour and Sengers, is continuous over all single phase states of H2O from triple point pressure and temperature to 1000 MPa (or the melting line) and 1000 °C and provides accurate representation of existing thermodynamic data in that range. In addition it provides a smooth transition from singular critical region functions to the nonsingular far-field functions. This is demonstrated by the variations of isochoric specific heat, isothermal compressibility, speed of sound, specific heat ratio and coexistence line properties in the critical region.