AC hot wire measurement of thermophysical properties of nanofluids with 3 omega method
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS, cilt.153, ss.349-352, 2008 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 153
- Basım Tarihi: 2008
- Doi Numarası: 10.1140/epjst/e2008-00459-7
- Dergi Adı: EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.349-352
- Dokuz Eylül Üniversitesi Adresli: Evet
Özet
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.