AC hot wire measurement of thermophysical properties of nanofluids with 3 omega method
Articles > Article · 2008
Authors: A. Turgut, C. SAUTER, M. CHIRTOC, J. F. HENRY, Şebnem TAVMAN, I. Tavman, J. PELZL
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS, Journal Indexed in SCI Expanded, International, 2008, vol 153, pp 349-352
DOI: 10.1140/epjst/e2008-00459-7
Summary
We present a new application of a hot wire sensor for simultaneous and independent measurement of thermal conductivity k and diffusivity a of (nano)fluids, based on a hot wire thermal probe with ac excitation and 3 omega lock-in detection. The theoretical modeling of imaginary part of the signal yields the k value while the phase yields the alpha value. Due to modulated heat. flow in cylindrical geometry with a radius comparable to the thermal diffusion length, the necessary sample quantity is kept very low, typically 25 mu l. In the case of relative measurements, the resolution is 0.1% in k and 0.3% in alpha. Measurements of water-based Aerosil 200V nanofluids indicate that ultrasound treatment is more efficient than high pressure dispersion method in enhancing their thermal parameters.