Thermophysical characteristics and forced convective heat transfer of ternary doped magnetic nanofluids in a circular tube: An experimental study

This experimental study investigated the influence of ternary-doped magnetic nanoparticles (NPs) on the thermophysical characteristics and forced convective heat transfer (FCHT) of nanofluids. Ternary-doped magnetic NPs were synthesized by combining multi-walled carbon nanotubes (MWCNTs) doped with zinc oxide (ZnO) and manganese ferrite (MnFe2O4) NPs to form a new composite material. The laminar FCHT and pressure drop were also measured in a circular tube under constant wall flux with and without a magnetic field (MF). The findings showed that increasing NP concentration improved the thermal conductivity (TC) of the nanofluid, and the inclusion of magnetic NPs enhanced the Nusselt number (Nu). The nanofluid with a concentration of 0.2 wt% in the field of 400 G and a Reynolds number (Re) of 2200 showed the highest improvement in the Nu, with an increase of 40 %. The highest increases in pressure drop were achieved in the presence of a 400G MF and at a Re of 800 for nanofluids containing 0.2 wt%, which was 8.2 %. The study's results can contribute to the design and optimization of nanofluid-based heat transfer (HT) systems, particularly in the field of magnetic nanofluids under the in-fluence of MF.