Experimental high temperature coefficients of compressibility and expansivity of liquid sodium and other related properties

The subcooled compressibility of liquid sodium was directly measured up to 200 atm between 900 K and 1867 K, utilizing a new multi-property apparatus which was previously tested with water. The experimental data were correlated by a 6-term equation with a standard deviation of 9.2 percent. The equation can be used to estimate the subcooled compressibilities and densities of liquid sodium up to 2300 K and 500 ata. The thermal expansion of liquid sodium was also measured along the isobars 1 ata, 28.9 ata and 69 ata. Densities within 1 percent of those obtained from the compressibilities were obtained. The above compressibility data were used to calculate the thermal pressure coefficient of saturated liquid sodium. Also, Bhise and Bonilla's correlations for the vapor pressure and the saturated liquid density of sodium were improved by including more data in the analysis. The critical temperature and density were thus reestimated as 2508.7 K and 0.2141 g/cc. Furthermore, a new correlation was developed to determine the heat of vaporization of sodium up to the critical point, which was then used to estimate the internal energy and the entropy of vaporization and the saturated vapor density of sodium up to the critical point