Thermal Conductivity Measurement of Molten Salts by the Transient Hot-Wire Method: (2nd Report, Measurements of Molten NaNO₃ and KNO₃ Using Ceramic-Coated Probes)

The present paper reports absolute measurements of the thermal conductivity of molten salts by the transient hot-wire method using newly developed ceramic-coated probes. Al₂O₃ has been employed as the insulation material and the following techniques have been utilized to produce insulation layers: ion plating for a thin platinum hot-wire and plasma-spray for thick titanium struts. The measurements have been performed on pure NaNO₃ in the temperature range 311°C to 388°C and KNO₃ 349°C to 439°C. The experimental data have an estimated accuracy of ±3%. In comparison with the present results, most of he previous experimental data obtained by steady-state methods show higher values which may be due to the presence of convection and radiation.