Graphene nanoplatelets–silver hybrid nanofluids for enhanced heat transfer
Document Type
Article
Publication Date
1-1-2015
Abstract
In the present experimental work, a new synthesis method is introduced for decoration of silver on the functionalized graphene nanoplatelets (GNP-Ag) and preparation of nanofluids is reported. The thermo-physical properties, heat transfer performance and friction factor for fully developed turbulent flow of GNP-Ag/water nanofluids flowing through a circular tube at a constant heat flux were investigated. GNP-Ag uniform nanocomposite was produced from a simple chemical reaction procedure, which includes acid treatment for functionalization of GNP. The surface characterization was performed by various techniques such as XRD, FESEM, TEM and Raman. The GNP-Ag nanofluids were prepared by dispersing the nanocomposite in distilled water without the assistance of a surfactant and/or ultrasonication. The prepared nanofluids were found to be stable and no sedimentation was observed for a long time. The experimental data for GNP-Ag nanofluids were shown improvements of effective thermal conductivity and heat transfer efficiency in comparison with the corresponding to the base-fluid. The amount of enhancement was a function of temperature and weight concentration of nanoparticles. Maximum enhancement of Nusselt number was 32.7% with a penalty of 1.08 times increase in the friction factor for the weight concentration of 0.1% at a Reynolds number of 17,500 compared to distilled water. Improved empirical correlations were proposed based on the experimental data for evaluation of Nusselt number and friction factor.
Keywords
GNP–Ag nanocomposite, Hybrid nanofluid, Nusselt number, Friction factor, Turbulent flow
Divisions
fac_eng,CHEMISTRY
Funders
High Impact Research Grant UM.C/HIR/MOHE/ENG/45,UMRG Grant RP012C-13AET, University of Malaya, Malaysia
Publication Title
Energy Conversion and Management
Volume
100
Publisher
Elsevier