1992 年 58 巻 556 号 p. 3703-3708
We have developed a new apparatus to measure the thermal diffusivity of liquids by the forced Rayleigh scattering method using a CO2 laser. In the case of employing the infrared wavelength laser as a heating source, it is less necessary to add dye substances in samples than with the previously used Ar+ laser. The purpose of the present study is to develop a practical forced Rayleigh scattering apparatus applicable to a wide range of substances and conditions. In the present study, we have invented a free-surface-heating technique which does not require any cell windows. In order to demonstrate the applicability of the present apparatus without adding dye substances, we have preliminarily measured the thermal diffusivity of molten KNO3 and a molten carbonate mixture (Li2CO3-Na2CO3-K2CO3=43.5-31.5-25.0mol%) in the temperature range up to about 1000K.