Tuning the thermal properties of aqueous nanofluids by taking advantage of size-customized clusters of iron oxide nanoparticles

In this study, the thermal conductivity of aqueous nanofluids containing clusters iron oxide (Fe3O4/γ-Fe2O3) nanoparticles has been investigated experimentally for first time, with aim assessing role a controlled aggregation in these final nanofluids. For that, different cluster size (46–240 nm diameter range) were synthesized by solvothermal method and fully characterized transmission electron microscopy, X-ray diffraction Raman spectroscopy. The rheological behavior optimal was also studied rotational rheometry. obtained dispersing water taking into account solid volume fractions (from 0.50 to 1.5 wt%) experiments conducted temperature range from 293.15 K 313.15 K. study reveals quantifies enhancements nanofluid increase temperature. Furthermore, wt% concentration within whole proposed offers great stability improved heat transfer applications an small dynamic viscosity increase. addition, larger nanoparticles, greater designed Fe3O4/γ-Fe2O3 cluster-based nanofluids, values following constant upward trend reaching maximum 4.4% largest (average 240 nm). These results open door development oxide-based on which advantage optimized using size-customized clusters.