Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

The Effective of Sonication Time on Effective Thermal Conductivity of Glycerol-MgO Based Nanofluids

Get access (open in a dialog) DOI: 10.1615/IHTC15.min.008595
pages 4899-4905

Abstrakt

This study investigates the effect of sonication time on the effective thermal conductivity (keff) of Glycerol based nanofluids. These were prepared from three different sizes (20, 40 and I00 nm) magnesium oxide (MgO) anoparticles. The nanoparticles were dispersed and deagglomerated in the glycerol using an ultrasound mixer (UP200S model with 24 kHz and 200 W, Hielscher Ultrasonics GmbH, Germany) operated at different sonication times (30min, Ih, 2h, 3h and 5h). The sonication decreases the average cluster and improves the dispersion of nanoparticles during the preparation of nanofluids. The effective thermal conductivity of produced nanofluids is measured using KD2-Pro device (Decagon Inc., Pullman, WA, USA). The experimental results obtained at room temperature, show time dependence increase of the effective thermal conductivity of nanofluids with sonication up to an optimum (stable) value. Thereafter, the effective thermal conductivity of most glycerol nanofluids becomes almost constant with the increase in sonication time. The experimental results of glycerol-magnesium oxide nanofluids were discussed in detail as function of sonication time, nanoparticle diameter and volume fraction.