Title: Thermal conductivity enhancement of nanoparticles in distilled water

Authors: L. Syam Sundar, K.V. Sharma

Addresses: Centre for Energy Studies, J.N.T.U. College of Engineering, Jawaharlal Nehru Technological University, Hyderabad, Andhra Pradesh, India. ' Centre for Energy Studies, J.N.T.U. College of Engineering, Jawaharlal Nehru Technological University, Hyderabad, Andhra Pradesh, India

Abstract: This paper provides an overview of the important physical phenomena necessary for the determination of effective thermal conductivity of nanofluid. Increase in the specific area as well as Brownian motion are supposed to be the most significant reasons for the anomalous enhancement in thermal conductivity of nanofluid. Usual heat transfer fluids with suspended ultra fine particles of nanometre size are named as nanofluids, which have opened a new dimension in heat transfer processes. This work presents the increase of thermal conductivity with temperatures for nanofluids with water as base fluid and particles of Al₂O₃ or CuO as suspension material. Transient hot-wire method is used for the measurement of thermal conductivity. Heat retaining time is introduced and estimated experimentally. The heat retaining time of 0.8% volume fraction of Al2₂O₃ nanofluid increases up to 47.05% of the base fluid and 0.8% volume fraction of CuO nanofluid increases up to 61.7% of the base fluid. The results indicate an increase of enhancement of thermal conductivity with temperature found to be agreeing excellently with a wide range of different models as well as the data published in literature.

Keywords: nanofluids; thermal conductivity; suspensions; heat retaining time; particle size; nanoparticles; distilled water; nanotechnology; heat transfer fluids.

DOI: 10.1504/IJNP.2008.017619

International Journal of Nanoparticles, 2008 Vol.1 No.1, pp.66 - 77

Published online: 21 Mar 2008 *

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