The transient hot-wire technique is widely used for absolute measurements of the thermal conductivity of fluids. Refinement
of this method has resulted in a capability for accurate and simultaneous measurement of both thermal conductivity and thermal
diffusivity together with a determination of the specific heat. However, these measurements, especially those for the thermal
diffusivity, may be significantly influenced by fluid radiation.
The present work investigates the effect of fluid radiation on the measurements of the thermal conductivity of propane. Recently
developed corrections have been used to examine this assumption and rectify the influence of even weak fluid radiation. Measurements
at 372 K with a hot-wire instrument demonstrate the presence of radiation effects in both the liquid and vapor phase. The
influence is much more pronounced in liquid propane at 15.5 MPa than in the vapor phase at 881.5 kPa. The technique employed
to obtain radiation-free thermal conductivity measurements is described.