Investigation on convective heat transfer and friction factor of silver–water nanofluid under laminar flow – an experimental study

Abstract

Laminar flow forced convective heat transfer and friction factor of silver-water nanofluids were experimentally examined under uniform heat flux condition in a horizontal circular pipe. Heat transfer coefficient and friction factor of nanofluids were experimentally evaluated as a function of particle volume concentration and Reynolds number. Reynolds number was varied from 500 to 2300 for the different particle volume fraction of 0.01, 0.05 and 0.1%. The experimental results indicate that both Nusselt number and heat transfer coefficient of the nanofluid increase with the increasing particle volume concentration and Reynolds number. The maximum enhancement of 36.1% in heat transfer coefficient was obtained for 0.1% volume fraction of nanoparticles at Reynolds number of 2300. Also, there is an increase in friction factor of nanofluid with the increase in nano-particle volume concentration. New correlations of Nusselt number and friction factor of nanofluids are proposed using the experimental data. The estimation of Nusselt number and friction factor of nanofluids using the proposed correlations are in good agreement with the experimental results.