Measurement of thermal conductivity, heat capacity, and thermal diffusivity of sulfur and selenium in the liquid state

Abstract

The thermal properties (thermal activity, heat capacity, thermal conductivity, and thermal diffusivity) of liquid sulfur and selenium were measured in the temperature range 160–400°C. These measurements were performed using an experimental apparatus, based on the ac heated-wire (strip) technique. Liquid sulfur shows a second order phase transition at 225°C. The present study has considered four different mechanisms of heat transfer: conduction, electrons, internal electromagnetic radiation, and convection. The results showed that heat transfer is mainly due to conduction, whereas that due to electrons and electromagnetic radiation is very small indeed. Suppression of convection by the cell configuration was studied, as well as the effect of locating the strip or the wire in horizontal form, which permits heat flow in one direction. Moreover, stability of the third harmonic shows that there is no hydrodynamic flow inside the liquid, which means that the convection is taken in consideration within the time of measurements.