Experimental approach for thermal contact resistance estimation at the glass / metal interface

An experimental device is designed and developed in order to estimate thermal conditions at the Glass / Metal contact interface. The device is made of two parts: the upper part contains the tool (piston) made of bronze and a heating device to raise the temperature of the piston to 700 C. The lower part is composed of a lead crucible and a glass sample. The assembly is provided with a heating system, an induction furnace of 6 kW for heating the glass up to 950 C. Both parts are put in contact through a mechanical system consisting of a pneumatic cylinder sliding on a column and a pump providing the required pressure in the enclosure. The developed experimental procedure has permitted the estimation of the Thermal Contact Resistance TCR using a developed measurement principle based on an inverse technique. The semi-transparent character of the glass has been taken into account by an additional radiative heat flux and an equivalent thermal conductivity. After the set-up tests, reproducibility experiments for a specific contact pressure have been carried out. Results shows a good repeatability of the registered and estimated parameters such as the piston surface temperature, heat flux density and TCR. The maximum dispersion of the estimated TCR doesn't exceed 6%.