PVT Measurements and Critical Parameters of Water

ABSTRACTThe PVT properties and vapor-pressures of water have been measured in the critical region by using a constantvolume apparatus immersed in the constant-temperature bath with the procedure of varying the sample mass along a prescribed isotherm. Ninety-one PVT and five vapor-pressure measurements along 11 isotherms cover the region of temperatures 643 to 673 K and of pressures 19.7 to 38.6 MPa, which corresponds to a density variation from 108 to 618 kg/m3. The experimental uncertainties of temperature, pressure and density are estimated 4 mK, 5 kPa and 0.04%, respectively. Based on these measurements, the critical parameters of water are proposed to be 647.061 K, 22.041 MPa and 322.4 kg/m3 by the scaling law analysis.