Thermal conductivity enhancement of water by adding graphene Nano-sheets: Consideration of particle loading and temperature effects

Preparation, stability of Nano-fluid and the thermal conductivity of Graphene oxide/Water Nano-fluid with the aim of improving the thermal properties of water were experimentally studied. FESEM and XRD tests were used for characterization of nano-particles. After getting assured of the structure of nano-particles, a two-step method was applied to produce Graphene oxide/Water Nano-fluid. Optimal pH, DLS and TEM tests were used to determine the stability. The mass fraction range of the Nano-fluid in this study was 0-1.5%, and the thermal conductivity was measured in the temperature range of 20-60 degrees C according to ASTM 02717-95 standard. The results indicate that the Nano-fluid has the highest stability at optimum pH (pH = 8). The results of TEM and DLS tests show the sheet structure of the nano-particles and their Nanoscale dimensions in the base fluid, respectively. The thermal conductivity of the Nano-fluid in the study range indicates a significant increase and its maximum increase is 48.1%. Using the curve fitting method, a new correlational with high accuracy has been proposed. Finally, according to the results obtained, it can be said that the Nano-fluid, with respect to its thermal properties in the practical systems, is an appropriate alternative to water-based fluid.