MEASUREMENTS OF LIQUID THERMAL-CONDUCTIVITY AND DIFFUSIVITY BY THE TRANSIENT HOT-STRIP METHOD

The basic idea of the transient hot-strip method is similar to that of the transient hot-wire method. A thin strip of platinum serves as both a heating element and a resistance thermometer. The time history of the heat source temperature allows for evaluating both the thermal conductivity (within at least an accuracy of 1 or 2% with either method) and the thermal diffusivity. The latter may be obtained from hot-strip experiments within an accuracy of 3 or 4% compared to about 10% for hot-wire. In the present contribution the hot-strip method is applied to various liquids. Thermal conductivities and diffusivities obtained for water, glycerol, toluene, n-heptene, acetone, CFC 113 at ambient pressure and temperature agree with "standard reference data" within 2% (conductivity) and 3% (diffusivity). Finally the experimental set-up is used to measure conductivity and diffusivity of HFC 152a which is thought to become an alternative for CFC 12. Results are presented for saturated liquid up to p = 60 bar.