Thermal Conductivity of Aqueous Sr(NO3)2 and LiNO3 Solutions at High Temperatures and High Pressures

Abstract

Thermal conductivity of five aqueous Sr(NO3)2 solutions of molality (0.249, 0.525, 1.181, 2.025, and 3.150) mol·kg-1 and four aqueous LiNO3 solutions of molality (1.0, 1.7, 2.8, and 3.9) mol·kg-1 have been measured with a concentric-cylinder (steady) technique. Measurements were made at five isobars (0.1, 10, 20, 30, and 40) MPa for H2O+Sr(NO3)2 and at four isobars (0.1, 10, 20, and 30) MPa for H2O+LiNO3 solutions. The range of temperature was (293.15 to 591.06) K. The total uncertainty of thermal conductivity, pressure, temperature, and molality measurements were estimated to be less than 2%, 0.05%, 30 mK, and 0.02%, respectively. The measured values of thermal conductivity were compared with data and correlations reported in the literature. The reliability and accuracy of the experimental method was confirmed with measurements on pure water, toluene, and H2O + NaCl with well-known thermal conductivity values. The experimental and calculated values of thermal conductivity for pure water from IAPWS formulation show excellent agreement within their experimental uncertainties (AAD within 0.44%) in the temperature range from (308.4 to 704.2) K and at pressures up to 60 MPa. Correlation equations for thermal conductivity of the solutions studied were obtained as a function of temperature, pressure, and composition by a least-squares method from the experimental data. The AAD between measured and calculated values from this correlation equation for the thermal conductivity was (0.5 to 0.7) %.