Synthesis and characterization of magnetic γ- Fe2O3 nanoparticles: Thermal cooling enhancement in a sinusoidal headbox

Nano-size maghemite (γ-Fe2O3) particles were prepared in one step using ultrasound radiation. The obtained nanoparticles were characterized by SEM, TEM , XRD, FTIR, and VSM. The results revealed that the synthesized nanoparticles were spherical, mono-dispersed and uniform. Furthermore, the crystalline structure of nanoparticles endorsed by X-ray diffraction study. The FTIR spectra have provided information on the structure of the surface of nanoparticles. TEM analysis showed that the average particle size of the γ -Fe2O3 are about 15 nm. The formed nanoparticles exhibited unique magnetic behavior with magnetic saturation values of~68 emu/g. By utilizing properties of synthetic γ -Fe2O3 nanoparticles, a three-dimensional incompressible nanofluid flow in a confined sinusoidal converging jet in turbulent flow regime was numerically investigated. Results were obtained for the flow structure at different Reynolds numbers for steady asymmetric jet development at various values of the duct-to-jet width ratio (aspect ratio),different amplitudes and different volume fractions of nanoparticles. The results showed that by increasing the Reynolds number, aspect ratio, amplitude and volume fraction of γ -Fe2O3 nanoparticles, the averaged Nusselt number will increase.