Electrical Conductivity of New Nanoparticle Enhanced Fluids: An Experimental Study.

Chereches Chereches,Minea Minea

doi:10.3390/nano9091228

Abstract

In this research, the electrical conductivity of simple and hybrid nanofluids containing Al2O3, TiO2 and SiO2 nanoparticles and water as the base fluid was experimentally studied at ambient temperature and with temperature variation in the range of 20–60 °C. A comparison of the experimental data with existing theoretical models demonstrated that the theoretical models under-predict the experimental data. Consequently, several correlations were developed for nanofluid electrical conductivity estimation in relation to temperature and volume concentration. The electrical conductivity of both simple and hybrid nanofluids increased linearly with both volume concentration and temperature upsurge. More precisely, by adding nanoparticles to water, the electrical conductivity increased from 11 times up to 58 times for both simple and hybrid nanofluids, with the maximum values being attained for the 3% volume concentration. Plus, a three-dimensional regression analysis was performed to correlate the electrical conductivity with temperature and volume fraction of the titania and silica nanofluids. The thermo-electrical conductivity ratio has been calculated based on electrical conductivity experimental results and previously determined thermal conductivity. Very low figures were noticed. Concluding, one may affirm that further experimental work is needed to completely elucidate the behavior of nanofluids in terms of electrical conductivity.

Highlights

Nanofluids are considered, at this point, a possible new generation of heat transfer fluids
By adding nanoparticles to water, the electrical conductivity increased from 11 times up to 58 times for both simple and hybrid nanofluids, with the maximum values being attained for the 3% volume concentration
The experimental data of simple and hybrid nanofluids at ambient temperature are summarized in Figures 1 and 2, while the electrical conductivity of water used for preparing the nanofluids was measured as κ = 25.77 μS/cm

Summary

Introduction

Nanofluids are considered, at this point, a possible new generation of heat transfer fluids. Regardless of the tremendous work, nanofluid property estimation requires further systematic studies and, despite all the published research in this area, electrical conductivity is the least studied property compared with thermal conductivity or even viscosity and specific heat [4,5,6]. The electrical conductivity of nanofluids is associated with the capacity of charged nanoparticles in the fluid to transport the charges toward corresponding electrodes once an electric potential is applied [7,8]. Abdolbaqi et al [9] discussed the relationship between thermal and electrical conductivity, which can be considered as an important parameter to assess the possibility of a specific nanofluid to be employed in an electrically active heat transfer application [9]. While the stability of a suspension depends on its electrostatic characteristics (for example, the zeta potential, which is very important in electrical conduction progression), electrical conductivity might provide important information about nanofluid stability [8,9,10]

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Conclusion