Thermal conductivity of homogeneous materials is the rate of heat flux under steady state conditions through unit area, per unit temperature gradient in the direction perpendicular to that area. Thermal conductivity is easily determined from the net heat flux through the sample (average heat flux entering the hot side and leaving the cold side) The measuring method consists :
· to place on each side of the sample a heat flux sensor with an integral temperature sensors built in its sensing area
· to determine the thermal resistance of the whole assembly comprised between the measuring sections
· to determine thermal conductivity from the comparison with test sample or by comparing results obtained with samples of different thicknesses
Accessory : plates maintained at constant temperatures T and T+DT (with DT nearly equal to 10 °C) by integral circulation of a fluid at controlled temperature or thermofoil heater to produce a prescribed temperature difference between the measuring sectons