Viscosity and CHF of Water-γ-Fe2O3 Nanofluids Utilizing γ-Fe2O3 Nanoparticles Synthesized from Local Material Using Carbon Reduction

Nanofluids have great potential to replace conventional coolant such as water and ethylene glycol. The nanofluids may be prepared from the nanoparticles synthesized from local material. gamma-Fe2O3 nanoparticles can be potentially economical for nanofluids. Herein, the gamma-Fe2O3 nanoparticles were successfully synthesized via carbon reduction and precipitation methods from a local material of yarosite. XRD data revealed that the gamma-Fe2O3 nanoparticles had been successfully synthesized from yarosite, possessing maghemite structure. The nanofluids were then produced from the prepared gamma-Fe2O3 nanoparticles and water as the base fluid. According to TEM and BET analysis, the particle size and specific surface area of the nanoparticles were 13.3 nm and 166 m(2)/g, respectively. From zeta potential data, it was known that the optimum concentration of the citric acid (CA) dispersant was 15% of the nanoparticles mass. Critical Heat Flux (CHF) of the water-gamma-Fe2O3 nanofluids was larger than that of water, and increased with nanoparticles concentration until certain optimum concentration. The largest CHF enhancement was (4% for gamma-Fe2O3 concentration of 0.0133 vol%. The CHF data demonstrated that the nanofluids prepared in this work were effective and could be potentially applied for automotive coolant, metal forming fluid, and fluid for RVCS and ECCS in nuclear reactor.