Effect of constant magnetic field on Fe3O4-Cu/water hybrid nanofluid flow in a circular pipe

The purpose of this study is to investigate experimentally the convective heat transfer of Fe3O4-Cu/water hybrid nanofluid flow and to obtain the optimum mixing ratio of the hybrid nanofluid in a straight pipe under the influence of a constant magnetic field, applied perpendicularly to the flow direction. An experimental test rig has been designed and built for this purpose followed by rigorous tests that were performed on it for various parameters such as flow rate (corresponding 994 < Re < 2337) and nanoparticle volume concentration (0 < phi < 0.02). The experimental data are consistent with the existing literature. Increasing flow rate has led to an increased Nu number. Furthermore, the addition of both Fe3O4 and Cu nanoparticles into the distilled water increases the convective heat transfer inside the pipe. A significant finding of the study is that the constant magnetic field enables up to 14% convective heat transfer enhancement as opposed to the absence of a magnetic field. Furthermore, 1.0 vol.% Fe3O4-1.0 vol.% Cu/Water hybrid nanofluid performs the best under the effect of the constant magnetic field. Accordingly, the constant magnetic field applied externally to the flow is a key factor to enhance the convective heat transfer.