Temperatures of maximum density in a pressure range from 15 MPa to −15 MPa generated for water in a metal Berthelot tube

Abstract

Water exhibits anomalous thermodynamic properties. For example, the specific heat capacity of water is at minimum at 36°C under atmospheric pressure. In order to investigate phase diagrams including thermodynamic meta-stable states, which are important to elucidate the anomalies, the temperatures of maximum density (TMDs) were estimated in a pressure range from +15 MPa to −15 MPa on the basis of data of temperatures and pressures measured for various densities of water in a metal Berthelot tube. The TMDs in the negative pressure region were not on an extrapolation of an equation of state for water. The trend was similar to that not observed by a Berthelot method of glass spiral capillaries but calculated from molecular dynamics computer simulations.

Keywords:

• water
• temperature of maximum density
• negative pressure
• the Berthelot method

Acknowledgements

We are very grateful to Dr. Y. Ohde for supervising this study. We also wish to thank Dr. Y. Tanzawa, Dr. M. Yao, Mr. K. Motoshita, Mr. T. Nakagawa, Mr. Y. Fukui and Mr. T. Yoshida for their support.