Developing a Novel Hybrid Nanofluid Preparation Method Using the Droplet Generation Method: Predicting the Thermal Conductivity, Viscosity, and Magnetic Properties Compared to the Conventional Two-Step Method

This study focuses on utilizing a novel method, the droplet generation method (DGM), to prepare hybrid nanofluids. The aim is to compare thermophysical properties, including thermal conductivity (TC) and viscosity, and magnetic properties between the DGM and two-step method (TSM). To prepare a bio-nanofluid, both fluid and nanoparticles must be biocompatible. Therefore, simulated body fluid (SBF) and olive oil were used to prepare this hybrid bio-nanofluid, and for the magnetic particle, iron oxide (Fe₃O₄) was used. Phase and microstructural examinations were conducted using XRD, FTIR, and FE-SEM. The KD2 Pro and DV2 Pro devices were employed to measure the thermal conductivity and viscosity of the samples, respectively. For both samples prepared using DGM and TSM, different volume fractions ranging from 0.01% to 1.00% and temperatures varying from 20°C to 40°C were measured individually. In TSM, from 20°C to 40°C, for 0.10% and 1.00% v.v, TC increased by 6.31% and 10.14%, respectively, while in DGM, it decreased by 0.48% and 1.23%, respectively. At a shear rate of 12.23 s⁻¹, from 20°C to 40°C, for 0.10% and 1.00% v.v, in the TSM, the viscosity decreased by 31.39% and 34.99%, respectively, while in DGM, it decreased by 25.11% and 28.83%, respectively. At a shear rate of 122.3 s⁻¹, from 20°C to 40°C, for 0.10% and 1.00% v.v, in the TSM, the viscosity decreased by 22.92% and 29.25%, respectively, while in DGM, it decreased by 17.42% and 23.85%, respectively. The results of this study contribute to understanding the effect of DGM on altering thermophysical properties of bio-nanofluids.