DETERMINATION OF THERMAL PROPERTIES FROM STEADY-STATE HEAT TRANSFER MEASUREMENTS ON A HEATED TUNGSTEN WIRE IN VACUUM AND HELIUM GAS.

A hot-wire column type instrument for the accurate measurement of the thermal properties of gases, metal surfaces, and metal-gas interface over a wide temperature range is under development. A tungsten wire is used in the test reported here. Thermal properties are determined as a function of temperature in the range 400-2500 K. These properties are the resistivity, tensile breaking stress, the total hemispherical emittance of the tungsten wire, and the thermal conductivity of helium. These properties are computed from the knowledge of steady-state heat transfer data from tungsten wire in vacuum and in the presence of helium at pressures covering the temperature-jump and continuum regimes. Measured properties are discussed in the light of literature values wherever available.