Adaptation of the FLASH method to the measurement of the thermal conductivity of liquids or pasty materials

This study proposes a modification of the well-known FLASH method in order to adapt it measurements on liquids or pasty materials. The new experimental procedure requires a suitable cylindrical receptacle filled with the sample to analyze. A classical FLASH measurement is applied to this receptacle. However, as the presence of the container disturbs the conductive transfer during the transient heating of the sample, we have recourse to an identification procedure, which takes into account the disturbing influence of the receptacle to compute the thermal conductivity of the material. The modified experimental apparatus as well as the identification procedure are described in detail. Thereafter, an exhaustive estimation of the measurement accuracy is performed. The measurement uncertainty proves to be lower than 4%. Finally, we applied our method to different liquid or pasty media. A good agreement is found between the experimental results obtained and the thermal conductivity indicated in the literature for these materials.