Synthesis of highly stable nanofluids including polyvinyl alcohol-treated graphene oxide for improved heat dissipation in a tubular heat exchanger

摘要

Heat transfer rate and amount of pressure drop for highly stabled nanofluids loaded with polyvinyl alcohol-treated graphene oxide (PVA-GO) were experimentally investigated in a horizontal copper duct with the uniform heat flux on outer surface of test section. To meet those goals, we produced GO through a wet-based exfoliation method and followed by functionalization of GO with PVA. As a phase of study, some nanofluids including PVA-GO with different concentration were prepared and thermo-physical and rheological properties were experimentally obtained. The thermo-physical attributes such as thermal conductivity, viscosity and density of the synthesized samples with various PVA-GO concentrations (0.025, 0.05, and 0.1 mass%) were experimentally investigated at the first phase of this article. Possessing the thermo-physical properties open a precise gate to measure the heat transfer rate (h & Nu) and frication factor for water/PVA-GO nanofluids and finally compared with the working fluid (water). As the second phase of study, influence of parameters such as concentration of PVA-GO and the flow rate on heat transfer parameters such as Nu, friction factor, and performance index were investigated. Overall, processing heat transfer systems with highly conductive water/PVA-GO nanofluids even at low concentrations results in higher heat transfer rate and overall performance of system/cycles.