Hydrothermal Performance of Ferrofluid Subjected to a Constant Magnetic Field Effect in a Teardrop Dimpled Tube

In this study, the effect of constant magnetic field (MF) on the thermohydraulic performance (THP) of turbulent Fe3O4/H2O flow in teardrop-shaped dimpled tube (TDDT) is numerically investigated. Numerical analyses were performed at Reynolds numbers (10,000≤Re≤50,000) under a constant heat flux (q" = 20 kW/m2) and MF strengths (0.03T≤B≤0.3 T) applied at x/D = 20 (320–420 mm from the TDDT inlet) while the Fe3O4/H2O volumetric concentration was varied in the range of 0.0%≤φ≤2.0%. The results show that the use of teardrop-shaped dimple increases the Nusselt number (Nu) by 33.6% at Re = 50,000 with only a 4.2% increase in the friction factor (ff). Applying a B = 0.3 T enhances Nu by 12.7% at Re = 10,000 and φ = 2.0% while causing only a 2.1% increase in ff. The study demonstrated that applying MF to magnetizable ferrofluids (FFs) can be effectively utilised in engineering applications, particularly in heat exchangers, electronic cooling, and thermal systems.