Ag-Ag2S decorated F-MWCNTs nanofluids for heat transfer applications

Automobiles, data centres, and electronic gadgets are facing a major issue of overheating due to the deterioration of the working parts. The excess heat generated, however, is eliminated using a liquid circulation system. Conventional fluids used in the circulation system reached their limit in completely removing generated heat. Hence, nanomaterials are dispersed in conventional fluids to form a new class of fluids known as nanofluids. Here, silver and silver(I) sulfide (Ag-Ag 2 S) alloy nanoparticles (AS NPs) were decorated on the surface of functionalized MWCNTs (F-MWCNTs) to prepare Ag-Ag 2 S/F-MWCNTs nanocomposite (AS:CNTs NC). The decoration and formation of the desired structure were proven by various spectroscopic analyses and microscopy. The AS:CNTs NC was then dispersed in Milli Q water to prepare nanofluids (0.2, 0.5, 1, and 2 v/v). The dispersion stability of the nanofluids was examined using zeta potential, an absorbance vs. time plot, and visual inspection. The thermophysical properties of the sample were assessed by evaluating the viscosity and thermal conductivity (TC). With the increase in the concentration of NC in the nanofluids, the viscosity increases at 0.2 v/v nanofluids, then decreases at 0.5 v/v and 1 v/v NC loading within the investigated shear range, and at 2 v/v, the measured viscosity is slightly lower than the base fluid. Additionally, the sample yielded approximately 115.08% and 192.28% enhancements in TC value at 30 °C and 50 °C, respectively, for 2 v/v concentration nanofluids. The enhancement in the TC indicates the suitability of the nanofluid for heat transfer applications. • Ag-Ag 2 S NPs were successfully synthesized by the chemical reduction approach. • Ag-Ag 2 S/F-MWCNTs nanocomposite was synthesized by the hydrothermal method. • Unusual non-monotonic viscosity trend was observed. • The viscosity is slightly less than base fluid for 2 v/v nanofluids • TC enhancement of 192.28% at 50 °C was achieved for 2 v/v nanofluids.