Correlation for the Vapor Pressure of Heavy Water From the Triple Point to the Critical Point

A new formulation has been developed to represent the vapor pressure of heavy water (D2O) from its triple point to its critical point. This work takes advantage of several developments since the publication of the best previous formulation: the availability of some new data in the lower part of the temperature range, the adoption of the ITS-90 temperature scale, and the adoption of recommended values for the critical constants by the International Association for the Properties of Water and Steam ~IAPWS!. The new formulation fits the available data within their scatter across the entire temperature range, and is constrained to pass through the values recommended by IAPWS for the critical point. The previous formulation can be made to provide a similarly good fit if its input temperatures are converted from ITS-90 to IPTS-68 before the vapor pressure is computed. The new formulation offers the advantage of computation without having to perform a temperature conversion. © 2002 American Institute of Physics.