Dispersion of ternary nanopowders zinc oxide, silica, and yttrium oxide in water-based fluid for characterization and viscosity assessment of the engineered nanocolloid

In recent years, the rheological and thermal characteristics of nanofluids (NFs) have received considerable attention due to their potential benefits in industrial heat transfer applications. The present work experimentally investigated the influence of temperature (T) and solid volume fraction (SVF) on the dynamic viscosity (μ) of a ternary hybrid nanofluid (THNF) composed of ZnO, Y₂O₃, and SiO₂ nanoparticles dispersed in distilled water. All samples were prepared using the conventional two-step method, with SVFs ranging from 0.06% to 0.10% and temperatures between 20 °C and 60 °C. The Stability of the suspensions was verified through zeta potential measurements, confirming sufficient electrostatic repulsion among nanoparticles. The viscosity measurements were carried out using a Brookfield digital viscometer at steady-state conditions. Experimental findings revealed that μ consistently decreases with increasing temperature owing to the thermal weakening of intermolecular interactions. In contrast, it increases with higher nanoparticle loading due to enhanced particle–fluid interactions and agglomeration effects. Among all tested samples, the ZnO-based MNF exhibited the highest viscosity, reaching 1.950 mPa.s at 50 °C and 0.10% SVF, representing a 256% increase relative to the base fluid (BF). The ternary hybrid nanofluid also demonstrated substantial thickening behavior, attributed to combined interaction among its constituent oxides, which promotes stronger microstructural clustering. Finally, an empirical correlation was developed to predict μ as a function of T and SVF. The proposed model showed excellent agreement with experimental data, confirming its robustness and potential utility for engineering and design purposes in nanofluid-based thermal systems.