抄録
A method of measuring temperature and thermal properties of nonconductive fluids was experimentally studied, where 1ω and 3ω components of the voltage drop across a thin metal wire probe heated with an AC current of frequency ω were measured. The temperature distribution of a weak natural convection plume from a horizontal wire in water was visualized by this method and it was shown that background noise and self-heating of the probe limit the measurement resolution. Thermal conductivity measurements were performed for air, water, ethanol, etc. using a 10μm-diameter platinum wire, with applied AC frequency ranging from 0.1 Hz-10 kHz. Since thermal conductivity is derived from the measured 3ω component by comparing with a thermal conduction model, the effect of natural convection from the probe itself was important and a restriction on applicability of the method was obtained in terms of the Rayleigh and Fourier numbers.
