Experimental Investigation of Heat Transfer and Pressure Drop Characteristics of Ferrofluids in the Presence of Magnetic Field and Laminar Flow Conditions

In this study, the heat transfer performance with forced convection of two different water-based nanofluids was investigated by applying to an alternating magnetic field in a minichannel. CoFe2O4-water and MnFe2O4-water nanofluids have been prepared at 0.5% vol. and tested. The tests were carried out in a minichannel under laminar flow conditions in the range of 300 – 1800 Reynolds numbers. Nusselt numbers of each fluid used in the experiments were calculated and compared. At 1500 Reynolds number, CoFe2O4-water nanofluid exhibited an increase of 12% compared to pure water, while MnFe2O4-water nanofluid showed an increase of 4%. Nusselt numbers enhanced in both nanofluids with the application of magnetic field on nanofluids. While this increase was more pronounced at low Reynolds numbers, a lower rate of increase was obtained at high Reynolds numbers. In addition, the use of nanofluids significantly increased the pressure drop compared to the base fluid. While CoFe2O4-water nanofluid increased the pressure drop almost 100% compared to pure water, MnFe2O4-water nanofluid increased 65% maximum. This increase in pressure drop caused an increase in the friction factor. It was detected that the friction factor for CoFe2O4-water and MnFe2O4-water nanofluids was 80% and 40% higher, respectively, than the base fluid.