Comparing Mathematical Models to Calculate the Thermal Conductivity of Nanofluids

Document Type: Original Article

Authors

1 Department of chemical engineering,university of Isfahan, Isfahan, Iran

2 Department of petroleum engineering,university of petroleum, Ahwaz, Iran

Abstract

Nanofluid is a new class of heat transfer fluids engineered by dispersing metallic or nano_ metallic
nanoparticles with a typical size of less than 100 nm in the conventional heat transfer fluids.In order to study
the heat transfer behavior of the nanofluids,precise values of thermal and physical properties such as thermal
conductivity of the nanofluids is required . There are a few well_known correlations for predicting the thermal
conductivity of nanofluids which are often cited by researchers to calculate the convective heat transfer
behaviors of the nanofluids.Each researcher has used different models of the thermal conductivity in their
works. This article aims to summarize the various models for predicting the thermal conductivity of
nanofluids which have been commonly cited by a number of researchers and use them to calculate the
experimental and theoretical convective heat transfer coefficient of nanofluid flowing in heat
exchangers.Results show that difference between calculated thermal conductivity from models increases
with increasing the volume concentrations and also slightly increases with thermal conductivity of
nanoparticles.Experimental results show that aggregation of nanoparticles have significant effect on the
predicted values of thermal conductivity of nanofluids.


Keywords