Measurement of thermal diffusivity of gold nanofluid according to particle size and temperature

Abstract

The thermal diffusivity of a gold nanofluid containing 20, 40, or 80 nm particles prepared by dispersing gold nanoparticles in ethylene glycol was measured from room temperature to 80°C using the thermal lens effect in dual laser beam mode consisting of an excitation laser (532 nm) and a probe laser (633 nm). Three samples with three different nanoparticle sizes were prepared at the same concentration (3 × 10-5 wt.%). The thermal diffusivity was 1.020 × 10-7 m2/s (20 nm), 1.379 × 10-7 m2/s (40 nm), and 2.126 × 10-7 m2/s (80 nm) at RT, and 1.211 × 10-7 m2/s (20 nm), 1.784 × 10-7 m2/s (40 nm), and 2.758 × 10-7 m2/s (80 nm) at 80°C. Overall, the thermal diffusivity of a gold nanofluid was proportional to the nanoparticle size and increased with increasing temperature.