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Advances in Materials Science and Engineering
Volume 2013 (2013), Article ID 686409, 8 pages
http://dx.doi.org/10.1155/2013/686409
Research Article

Performance Analysis of Al2O3/Water Nanofluid with Cationic Chitosan Dispersant

1Department of Energy and Air-Conditioning Refrigeration Engineering, National Taipei University of Technology, Taipei City 10608, Taiwan
2Department of Mechanical Engineering, National Taiwan University, Taipei City 10617, Taiwan
3Graduate Institute of Mechanical and Electrical Engineering, National Taipei University of Technology, Taipei City 10608, Taiwan

Received 15 September 2013; Accepted 23 October 2013

Academic Editor: Ho Chang

Copyright © 2013 T. Y. Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study aimed to investigate the effect of the cationic chitosan dispersant on the thermal conductivity, dispersion, and the suspension of 15 nm Al2O3/water nanofluid. The study employed two-step method to mix the Al2O3 powder, deionized water, and dispersant to conduct an experiment of the settling properties and thermal conductivity of nanofluid in a stable environment, analyzing the adhesion of nanofluid to copper pipe walls in practical operations. The results indicated that 1.0 wt.% Al2O3/water nanofluid with 0.05 wt.% cationic chitosan dispersant increased its thermal conductivity up to 4.1% and 12.6% compared with nanofluid with deionized water at the temperature of 15°C and 55°C. At the flow ratio of 2 L/min, the overall heat conductivity improved by 8.3% and 17.4%, respectively, under 60 W and 150 W heating power. The solution performed better in dispersion and suspension than that in the original sample with no cationic chitosan dispersant. The cationic chitosan dispersant, as a result, was proved to improve the dispersion and suspension of nanofluid. It also helped to reduce the frequency of nanoparticles sticking to the pipe wall, increasing the practicability of nanofluid.