J. Phys. IV France 125 (2005) 269-271
Measurements of thermal diffusivity of water-alcohol mixtures using a thermal-wave resonator cavityA. Matvienko and A. Mandelis
Center for Advanced Diffusion Wave Technologies, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, M5S 3G8, Canada
A photothermal technique for ultra-high resolution measurements of thermal diffusivity of liquid mixtures was developed. Frequency scan experiments using the thermal-wave resonator cavity (TWRC) method  were performed. A theoretical model describing the one-dimensional temperature field within the cavity was developed. Comparison between the theoretical and experimental data for signal amplitude and phase in water shows excellent agreement. To achieve the ultra-high sensitivity of the measurements for liquid mixtures at low concentrations we modified the thermal-wave resonator cavity method coupling it with a signal common-mode rejection demodulation (CMRD) scheme . This non-conventional technique has shown sensitivity of the photothermal signal to methanol in water at the level of 0.25% by volume.
© EDP Sciences 2005