The Experimental Study of Convection Heat Transfer Characteristics and Pressure Drop of Magnetite Nanofluid in a Porous Metal Foam Tube

摘要

In the present study, the laminar forced convection heat transfer improvement and pressure loss of magnetite /water nanofluid flowing through a porous metal foam tube have been studied experimentally. To reach this goal, the magnetite nanoparticles with 30 nm diameter are synthesized. The investigation of the effect of nanoparticle weight fraction and Reynolds number on the convection heat transfer and pressure drop characteristics are two objectives of this work. The experimental observations reveal that the increment of nanoparticle weight fraction and Reynolds number improves the Nusselt number. Furthermore, the Nusselt number enhancement is more pronounced for the high Reynolds numbers due to the addition of nanoparticles. By dispersing 1% weight fraction of magnetite nanoparticles inside DI-water, 7.4 and 11.7% heat transfer enhancements are achieved at and 1000, respectively. A slight increase in magnetite nanofluid pressure drop is observed rather than that of DI-water due to the increment of nanofluid viscosity by nanoparticle dispersion inside the water. A performance index is proposed to consider the effects of Nusselt number enhancement and pressure drop simultaneously. It is shown that the performance index is higher than unity at all conditions in this study. Therefore, the convection heat transfer improvement dominates the pressure loss. A novel correlation is derived and presented based on the experiments to predict the Nusselt number.