Thermal Conductivity of Aqueous CaCl2 Solutions at High Temperatures and High Pressures

Abstract

The thermal conductivities of four aqueous CaCl2 solutions of (5, 10, 15, and 20) mass% have been measured with a coaxial-cylinder (steady-state) technique. Measurements were performed in the temperature range from (293.15 to 573.15) K and at pressures up to 40 MPa. The expanded uncertainty of thermal conductivity, pressure, temperature, and concentration measurements at the 95 % confidence level with a coverage factor of k = 2 were estimated to be 2, 0.05 %, 30 mK, and 0.01 %, respectively. Isobaric temperature maxima of the measured thermal conductivities are found around 423 K. Existing thermal conductivity correlation models for aqueous salt solutions were examined using the measured results for CaCl2(aq). The measured thermal conductivity data are also compared with the reported data and the values calculated from various prediction techniques. The agreement between measured and predicted values of the thermal conductivity of CaCl2(aq) is within 0.3 %. A wide-ranging correlation model was developed using the measured thermal conductivity data and the new IAPWS formulation for the thermal conductivity of pure water. The average absolute deviation between the measured and calculated values of thermal conductivity is 0.21 %.