Shear stability and thermophysical properties of titania nanofluids

An experimental study was carried out to investigate the structural stability of ethylene glycol based titanium dioxide nanoparticle suspensions (nanofluids) prepared with two-step method. Effect of particle concentration, fluid temperature, shear rate and shear duration were investigated. It was found that the temperature resolved thermal conductivity of nano fluid-, followed die trend of the base fluids, Thermal conductivity enhancement was dependent on particle loading but nearly independent of temperature. Shear stability tests suggested that the structure of nanoparticle aggregates was stable at a shear rate of 500-300 1/s over a temperatures range of 20-60°C. These findings shed some light to the interpretation of controversies surrounding the mechanisms of thermal conduction and convective heat transfer enhancement of nanofluids.