Non-Steady-State, Hot Wire, Thermal Conductivity Apparatus

A non‐steady‐state, hot wire apparatus has been constructed to measure the absolute or relative thermal conductivities of fluids. With the use of a four‐lead bare wire probe, a precision of 0.1%, and an absolute accuracy of $\text{± 1\%}$ have been obtained. A quartz‐coated film sensor is used to obtain relative thermal conductivity data for salt water solutions with a precision of 1% and an over‐all accuracy of $\text{± 2\%}$ . A comparison is made with experimental data available from the literature. For toluene, a comparison is made with the extrapolated values of Poltz and Jugel from which errors due to radiation have been eliminated for the parallel plate apparatus. The values agree within experimental error.