Absolute Measurements of the Thermal Conductivity of Aqueous NaCl Solutions at Pressures up to 40 MPa

The paper describes absolute measurements of the thermal conductivity of aqueous NaCl solutions in the concentration range 0 to 5 molality, the temperature range 0 to 80°C and the pressure range 0.1 to 40 MPa. An apparatus is based on the transient hot‐wire method using coated wire. The accuracy of the experimental results is estimated to be ± 0.5%. The results constitute the first measurements of the pressure effect on the thermal conductivity of NaCl solutions. The pressure coefficient of the thermal conductivity is compared with that of the viscosity. Three typical equations for predicting the thermal conductivity of aqueous electrolyte solutions are checked against the present experimental results. It is found that none of these equations can reproduce the present data within the experimental error.