Effect of particle loading and temperature on the rheological behavior of Al2O3 and TiO2 nanofluids

Abstract

ABSTRACT Nanofluids, which are stable suspension of nanoparticles in a carrier liquid, have gained traction in the past two decades for multiple scientific traits and a wide range of industrial features; one of them pivots around their improved physical properties and superior heat transfer capabilities over pure fluid. Viscosity plays a vital role in fluid flow and heat transfer characteristics of a nanofluid, as it is linked to the pumping power of fluid. The presence of the particles in the surfacted host liquids alters the viscosity of the medium and in nanofluid, and hence nanofluid rheology needs to be characterized to gauge their suitability in thermal transport applications. The rheological behavior of Al2O3 and TiO2–water nanofluids, stabilized by two different surfactants, is measured at different concentrations (0.1–2.0%) and temperatures (293–333 K). Transmission electron microscopy and dynamic light scattering measurement are executed to describe particle morphology and size distribution, respectively, while zeta potential and UV-visible spectroscopy have been employed to identify the stability of the nanofluids. The result shows that viscosity of the prepared suspension diminishes with increment in temperature and increases with enhancement in concentration. Nanofluid also appears as a non-Newtonian fluid with a shear rate between 12 and 232s−1 as they exhibit shear thickening behavior.