Enhanced thermal diffusivity of water based ZnO nanoflower/rGO nanofluid using the dual-beam thermal lens technique

In this paper we report the results of the thermal diffusivity of water based ZnO nanoflower and ZnO nanoflower/rGO composites prepared by varying the rGO concentrations (3.3%, 4.8% and 6.3%, labelled as ZnO/rGO1, ZnO/rGO2 and ZnO/rGO3, respectively) using an in situ hydrothermal method. The dual beam thermal lens technique has been employed for the study of the thermal diffusivity of the samples. It is observed that the ZnO Nano fluid shows better thermal diffusivity compared to water and on further investigations with the ZnO/rGO composites we observed that the ZnO/rGO1 nanofluid displays an enhanced thermal diffusivity by 2.5 times that of the ZnO nanofluid. The experiments also give a great insight into the optimum value of the ZnO/rGO compositions for efficient thermal diffusion, inter-particle interaction, as well as its dependence on Brownian motion and agglomeration dynamics in nanofluid experiments. [Display omitted] •Dual beam thermal lens technique is used to study the thermal diffusivity of ZnO/rGO nanofluid.•Thermal diffusion of the nanofluid increases when compared to water.•Concentration of rGO in the composite affects the thermal diffusivity of the fluid.