Experimental and Numerical Study of Convective Heat Transfer and Laminar Flow of a MWCNTs Nanofluid in a Horizontal Tube

In this study, an experimental and numerical study of forced convective heat transfer in a horizontal circular tube is investigated in a laminar flow of a MWCNTs nanofluid under a constant heat flux boundary condition. The preparation of nanofluids containing MWCNTs has been developed and tested, and their thermophysical properties were characterized. The MWCNTs nanofluid behaviour was evaluated using heat transfer coefficient, Nusselt number, pressure drop, friction factor and wall shear stress and a comparison with the base fluid was established. A computational fluid dynamic approach based on the finite volume method was used to develop a simulation model, which was successfully validated. The results indicate an average enhancement in the heat transfer coefficient of 10% and 14% with corresponding pressures drop rises of 9.8 and 16.2% for the (0.25% MWCNTs) and (0.5% MWCNTs) nanofluids, respectively, with respect to the base fluid. Moreover, heat transfer coefficient, pressure drop and wall shear stress rise consistent with an increase in both Reynolds number and particle volume fraction, while the friction factor was found to decrease. Furthermore, the numerical model proposed correlates well with the experimental data.