Magnetically controlled ferrofluid flow in an eight-start corrugated tube: experimental assessment of coupled heat transfer enhancement and frictional penalty

The influence of a localized transverse magnetic field (MF) and nanoparticle mass fractions on the thermo-hydraulic performance of water-based Fe3O4 magnetofluids over laminar flow in both plain tube (PT) and eight-start spirally corrugated tube (SCT) heat exchangers has been experimentally investigated. Under the most intensified operating condition (ω = 3.0% Fe3O4 and B = 200 mT), the hybrid enhancement strategy yielded a maximum Nusselt number augmentation of 73.69% for the PT and 151.30% for the SCT. The corresponding peak performance evaluation criteria (PEC) values reached 1.69 and 1.74, respectively. indicating significant thermo-hydraulic superiority.