An Aqua Based Reduced Graphene Oxide Nanofluids for Heat Transfer Applications: Synthesis, Characterization, Stability Analysis, and Thermophysical Properties

Abstract

In the recent years, system miniaturization and energy efficient are the two major area of focus of the researchers and scientist in solar collectors. The engineered colloidal fluids called nanofluids have replaced the conventional heat transfer fluids in solar systems due to its excellent thermal properties, optical properties, heat transfer rate, efficiency, and transmission and extinction coefficients. However, most of the research studies purchased the nanomaterials from the suppliers and this involves higher cost. Also, this also increases cost of the solar collectors. Hence, low cost graphite powder is converted into reduced graphene oxide (rGO) and detailed characterizations have been done in this work. Aqua based rGO nanofluids with 0.0005, 0.001, and 0.002 wt. % are prepared by two step method. The nanofluids are found to be stable up to 10 days because of oxygenated groups on the edge of rGO flakes. The rGO nanofluids show an enhancement in thermal conductivity and surface tension in comparison with the base fluid. Newtonian behavior in viscosity is observed for all the tested concentrations.