Heat Transfer Performance of Functionalized Graphene Nanoplatelet Aqueous Nanofluids.

Roberto Agromayor,Jose Fernandez-Seara,David Cabaleiro,Luis Lugo,Angel Pardinas,Javier Vallejo

doi:10.3390/ma9060455

Abstract

The low thermal conductivity of fluids used in many industrial applications is one of the primary limitations in the development of more efficient heat transfer systems. A promising solution to this problem is the suspension of nanoparticles with high thermal conductivities in a base fluid. These suspensions, known as nanofluids, have great potential for enhancing heat transfer. The heat transfer enhancement of sulfonic acid-functionalized graphene nanoplatelet water-based nanofluids is addressed in this work. A new experimental setup was designed for this purpose. Convection coefficients, pressure drops, and thermophysical properties of various nanofluids at different concentrations were measured for several operational conditions and the results are compared with those of pure water. Enhancements in thermal conductivity and in convection heat transfer coefficient reach 12% (1 wt %) and 32% (0.5 wt %), respectively. New correlations capable of predicting the Nusselt number and the friction factor of this kind of nanofluid as a function of other dimensionless quantities are developed. In addition, thermal performance factors are obtained from the experimental convection coefficient and pressure drop data in order to assess the convenience of replacing the base fluid with designed nanofluids.

Highlights

Energy is one of the most valuable resources in our society and, during the last years, many efforts have been made to increase energy efficiency and encourage the use of renewable energies.A wide variety of applications, such as those involved in the field of solar and geothermal energy, entails thermal energy transference from one fluid to another
The low thermal conductivity of the fluids commonly used in industrial applications, such as water or glycols, has hindered any heat transfer enhancement
The aim of this paper is to study the single-phase flow and thermal behavior of different sulfonic acid-functionalized graphene nanoplatelet aqueous nanofluids from an experimental point of view

Summary

Introduction

Energy is one of the most valuable resources in our society and, during the last years, many efforts have been made to increase energy efficiency and encourage the use of renewable energies. A wide variety of applications, such as those involved in the field of solar and geothermal energy, entails thermal energy transference from one fluid to another. Heat management has emerged as one of the fields with the highest potential to improve thermal performance. The low thermal conductivity of the fluids commonly used in industrial applications, such as water or glycols, has hindered any heat transfer enhancement. To overcome this problem, several authors have suggested the use of fluids with improved thermal properties

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