M.S. (Master of Science)
Department of Mechanical Engineering
A nanofluid is a generally considered to be base fluid that contains nanoparticle suspensions, where the nanoparticles could either be metals, metal oxides, or non-metals. Rheological properties of nanofluids play an important role in determining heat transfer capacity and pumping power of a fluid as they have the potential to improve heat transfer capacity and pumping power over a base fluid. This research can give us a clear understanding of how particle concentration and type of nanoparticle affect the viscosity of a nanofluid, which is the main parameter that influences the rheological properties of a fluid based on range of shear rates for various concentrations. Nanoparticles used for the experimentation are Al₂O₃ (5 nm) and TiO₂ (5 nm) with paraffin oil (white, CAS No: 8020-83-5) as the base fluid. Nanofluids containing single and mixture of nanoparticles at 0.2--1.5 % volumetric concentrations are prepared using two step method with a sonication time of 12 hours and viscosity is measured using Brookfield Dv2T rotational viscometer with a cone (CPA-40Z) and plate apparatus. Results show that the Newtonian behavior exhibited by the base fluid changes to a non-Newtonian shear thinning behavior upon addition of nanoparticles and the viscosity increases with increasing the particle concentration. Viscosity of Al₂O₃ nanofluids was higher than the viscosity of TiO₂ nanofluids and the viscosity of hybrid nanofluids was lower than Al₂O₃ nanofluids but higher than TiO₂ nanofluids at lower concentrations, this trend follows up to 0.5% volumetric concentration but deviates for higher concentrations such as 1% and 1.5%.
Hasan, Syed Mahmood, "Non-Newtonian rheological characteristics of oil-based metal oxide nanofluids" (2017). Graduate Research Theses & Dissertations. 4130.
vii, 55 pages
Northern Illinois University
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