Nanofluids Containing γ-Fe2O3 Nanoparticles and Their Heat Transfer Enhancements
1 Department of Physics, Center of Functional Nanomaterials and Devices, East China Normal University, 200241, Shanghai, China
2 School of Urban Development and Environmental Engineering, Shanghai Second Polytechnic University, 201209, Shanghai, China
Nanoscale Research Letters 2010, 5:1222-1227 doi:10.1007/s11671-010-9630-1Published: 20 May 2010
Homogeneous and stable magnetic nanofluids containing γ-Fe2O3 nanoparticles were prepared using a two-step method, and their thermal transport properties were investigated. Thermal conductivities of the nanofluids were measured to be higher than that of base fluid, and the enhanced values increase with the volume fraction of the nanoparticles. Viscosity measurements showed that the nanofluids demonstrated Newtonian behavior and the viscosity of the nanofluids depended strongly on the tested temperatures and the nanoparticles loadings. Convective heat transfer coefficients tested in a laminar flow showed that the coefficients increased with the augment of Reynolds number and the volume fraction.