The application of nanofluid systems containing iron oxide nanoparticles in double pipe heat exchanger

The thermophysical properties of fluids, including water, ethylene glycol, and oils utilized in heat transfer applications, are typically lower than those of metals and metal oxides. The colloidal stabilization of nanoparticles in these carrier fluids has been shown to result in a substantial enhancement of the thermophysical properties of the base fluid, including density, viscosity, and thermal conductivity. This increase is observed to vary in accordance with the particle concentration. Consequently, there is a growing interest in investigating the efficacy of nanofluids in heat transfer applications. In this study, the colloidal stabilization of iron oxide nanoparticles, synthesized by the co-precipitation method and modified with PAA, was achieved in an aqueous medium, and the relevant thermophysical properties were measured as a function of temperature and concentration. Finally, the heat transfer performance of the water-based nanofluid containing iron oxide nanoparticles was investigated by utilizing a double-pipe heat exchanger. The results obtained demonstrate that iron oxide nanoparticles modified with PAA exhibit adequate colloidal stability in aqueous medium across a range of concentrations. It was determined that the addition of nanoparticles leads to a concentration-dependent increase in the density and viscosity values of the carrier fluid, accompanied by a decrease in its thermal conductivity. In the experimental analysis of the relevant nanofluid utilizing a double-pipe heat exchanger, it was observed that the convective heat transfer coefficient decreased with the incorporation of nanoparticles in comparison to the base fluid which was attributed to the relatively higher viscosity and lower thermal conductivity values of the nanofluid.