Experimental study on viscosity of water based Fe–Si hybrid nanofluids

Abstract The hybrid nanofluids are new working fluids that contribute to the improvement of the heat transfer in the thermal systems. The main goal of the study is the development of new hybrid nanoparticles containing distinct iron-based and silicon nanophases (Fe–Si). First of all, the nanoparticles were synthesized using laser pyrolysis, then characterized using XRD and TEM and HR-TEM techniques. At the next step, the DLS analysis was used to examine the stability of the hybrid nanofluid. The dynamic viscosity of the hybrid nanofluid at different temperatures within the range of 20–50°C and concentrations of 0.25–1.0 wt% was measured. The results indicated that the maximum dynamic viscosity was achieved at the concentration of 1.0 wt% and a temperature of 25°C. The experimental results were compared to experimental data available in the literature and new correlations were proposed. Moreover, the correlations proposed by different researchers for dynamic viscosity prediction of hybrid nanofluids were compared and analyzed. The findings of this study may contribute to the understanding of mechanisms that lead to increase/decrease viscosity as well as find some methods of preparation that ensure high stability for a long-time period.