Synergistic effect of synthesized Fe3O4@Graphene oxide nanohybrids on heat transfer enhancement and flow efficiency in nanofluids for advanced thermal applications

The advancement of hybrid nanofluids has attracted significant interest for their ability to address the limitations of single-component nanofluids in thermal management applications. This study focuses on the synthesis, characterization, and performance evaluation of Fe3O4@Graphene Oxide (Fe3O4@GO) nanohybrids, utilizing the exceptional thermal conductivity of GO along with the stability and magnetic properties of Fe3O4 to enhance heat transfer efficiency. Fe3O4@GO nanohybrids were synthesized via a modified chemical method and characterized using XRD, FTIR, and SEM, confirming uniform decoration of Fe3O4 nanoparticles on GO sheets. Experimental investigations in a helical coil heat exchanger revealed a maximum heat transfer enhancement (HTE) of 270 % for Fe3O4@GO nanofluids compared to 56 % for pure GO nanofluids at optimal conditions (0.1 wt% concentration, Reynolds number Re = 17,000). At Re = 8,000, Fe3O4@GO nanofluids exhibited a 50-120 % improvement in heat transfer efficiency, depending on concentration. The friction factor analysis demonstrated that Fe3O4@GO nanofluids reduced flow resistance more effectively than GO nanofluids, achieving up to 4 % drag reduction at Re = 11,000 and 0.075 wt% concentration. This improvement is attributed to the synergistic effects of Fe3O4 nanoparticles and GO, which enhance dispersion stability and reduce interfacial thermal resistance. Key thermophysical parameters, including Nusselt number and pressure drop, were optimized to ensure efficient thermal-hydraulic performance. The study highlights the role of Fe3O4 nanoparticles in improving the stability and heat transfer properties of GO nanofluids. The combination of high thermal conductivity, enhanced flow behavior, and reduced viscosity effects positions Fe3O4@GO nanofluids as promising candidates for high-performance thermal management applications. These findings provide significant insights into the design of advanced hybrid nanofluids for industrial heat exchanger systems, addressing limitations in traditional nanofluids.