Scientific Reports (Feb 2025)
To study the thermodynamic properties of magnetic field on water based CoFe2O4 nanofluids
Abstract
Abstract This study investigates the characteristics of cobalt ferrite nanofluids, focusing on their structural, thermal, electrical conductivity, and viscosity properties. The motivation behind this research lies in the potential applications of nanofluids in advanced thermal management systems due to their enhanced properties. Characterization techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometer measurements, were employed to analyze the nanofluids. X-ray diffraction results indicate that cobalt ferrite nanoparticles crystallize in a spinel structure with Fd-3 m symmetry. Dynamic light scattering and transmission electron microscopy confirm that the nanoparticles have dimensions of approximately 25 nm and exhibit specific ferromagnetic properties at temperatures below 435 K, as demonstrated by the magnetization curve. Thermal conductivity measurements were conducted across various volume fractions, ranging from 1 to 5%, and under magnetic fields of 0.05 and 0.1 T at temperatures of 300.15, 313.15, and 323.15 K. The findings reveal a significant dependence of thermal conductivity on both magnetic field and temperature. For instance, at 300.15 K, increasing the volume fraction from 1 to 5% results in a rise in thermal conductivity from 0.59 to 0.88 W/m.K, representing a 49% increase. Additionally, applying a magnetic field of approximately 0.1 T increases the thermal conductivity coefficient for a 1% volume fraction from 0.59 to 0.72 W/m.K, leading to a growth of about 22%. The electrical conductivity coefficient also varies with different volume fractions and magnetic field intensities, with a maximum increase of around 11% observed at a 4% volume fraction under a 0.1 T magnetic field. In terms of viscosity, no significant changes were noted for volume fractions below 1.5%, while a slight decrease in dynamic viscosity was observed for higher fractions with increasing magnetic field strength. These results demonstrate that the application of a magnetic field enhances the flow properties of the nanofluid, highlighting its potential for improved thermal management applications.
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