Thermal and Electrical Conductivities for Ester Oil Based Graphene Nana-sheets

Abstract

In this study, nanofluids were prepared using Graphene nano-sheets with two concentrations 0.002% and 0.004%. Thermal conductivity was studied to investigate thermal properties for nanofluid compared to pure oil. Thermal conductivity was calculated using the measured values of thermal diffusivity and specific heat values at range of temperatures of (30°C- 90°C). Thermal diffusivity and specific heat values were measured by LFA (Laser Flash analysis) and DSC (Differential Scanning Calorimetry), respectively. Furthermore, Broadband dielectric spectroscopy was used to measure electrical conductivity for nanofluids for a range of frequencies (0.1Hz to 1MHz) and a range of temperatures for heating and cooling. Temperatures range was from 20°C to 100°C for heating and from 95°C to 25°C for cooling with step 10°C. A decrement in thermal diffusivity and thermal conductivity and an increment in specific heat values and electrical conductivity values with increasing temperature were observed. For the optimum nano-sheets concentration, an enhancement of the thermal conductivity by 35% was observed.