Impact of magnetic field and ferrofluid on the intensification of heat exchange in a minichannel of particular shape

In this investigation, we analyzed heat transmission of a magnetic fluid flow subject to the impact of a magnetic field in a minichannel having one inlet and two outlets and which is bent at a certain position. Effect of Reynolds number, magnetic field intensity and position of magnets on heat transmission and flow dynamics was explored. The volume fraction of the magnetic nanofluid Fe3O4 has the value 0.6%. Magnetic fluid used aims to cool the minichannel studied. Strength of the magnetic field takes values 800, 1200, 1400 respectively while the Reynolds number varies in an interval from 150 to 210 and for this study, three different positions of the magnets corresponding to a single source of the magnetic field followed by a fourth corresponding to a doublet of sources are examined. Results obtained show a maximum improvement in heat transmission rate of 13.95% for a source situated at 7.5 mm, an improvement in heat transmission of 14.15% for a source positioned at 15 mm, an intensification of heat transfer for a source placed at 27.5 mm of 25.51% and a rise in heat transmission of 16.23% for a doublet of sources placed at 7.5 mm and 15 mm respectively. For magnetic field used, it is noticed a diminution in pressure loss which results from fluid becoming unadhered to the surface located at the bottom of the channel. According to results found, a better heat transmission is obtained once magnets are positioned toward channel outlet. These results contribute to the improvement of the thermal efficiency of several energy systems and in particular the case of small compact exchangers with low Reynolds number flow. It can also represent a flow of fluid in a main artery having a narrowing and a bifurcation at the exit.