Effect of C60-SiO 2 hybrid nanoparticles on thermophysical and tribological properties of a multigrade engine oil: an ex
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Effect of C60‑SiO2 hybrid nanoparticles on thermophysical and tribological properties of a multigrade engine oil: an experimental study Seyed Hadi Rostamian1 · Seyfolah Saedodin2 · Seyed Abbas Asgari1 · Amir Hasan Salarian1 Received: 30 March 2020 / Accepted: 30 September 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract In this study, the thermophysical and tribological properties of a hybrid nanofluid containing fullerene-silica nanoparticles in a multigrade engine oil have been investigated. The nanoparticles were suspended in SAE 5W30 engine oil with a volume fraction of 0.1 to 1% using the two-step method. The results showed that thermal conductivity of nanofluid increased by approximately 9% at 1% volume fraction, and at ambient temperature, rather than the base oil. Investigation of shear stress variations for base fluid and nanofluids at different concentrations revealed that the rheological behavior of the nano-oil is non-Newtonian and shear thinning. Also, the results represented that by increasing the concentration, the nanofluid dynamic viscosity had an erratic trend. The highest increase was 14% and occurred at 1% volume fraction and 5 °C. Also, the behavior of nanofluids against temperature was in accordance with the conventional fluids. Besides, viscosity decreased after the enhancement of temperature in all volume fractions. The wear test was carried out using a pin-on-disk device based on the ASTMG99 standard. The results revealed that the wear rate decreased by 18% in comparison with the base oil at concentration of 1% and temperature of 25 °C. Finally, in order to predict the viscosity of nanofluid, a precise equation was presented based on the experimental data in terms of three variables of temperature, volume fraction and shear rate by using response surface methodology (RSM). Two-degree polynomial function with R2 = 0.9983 has been employed as the optimal function to model the viscosity of nanolubricant. Keywords Hybrid nanofluid · Thermophysical properties · Tribological behavior · Fullerene nanoparticles (C60) · Silica (SiO2) · Engine oil List of symbols ANOVA Analysis of Variance XRD X-ray powder diffraction DLS Dynamic light scattering RSM Response surface methodology C.V. Coefficient of variation R2 Regression coefficient n Power index m Strength index U Uncertainty S Standard deviation * Seyed Hadi Rostamian [email protected] 1
School of Engineering, Damghan University, Damghan 36716‑41167, Iran
Faculty of Mechanical Engineering, Semnan University, Semnan 35131‑19111, Iran
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N Number of measurement T Temperature (°C) Solid volume fraction (%) ∅ 𝛾̇ Shear rate (s−1) μ Dynamic viscosity (cP) Wt. Mass fraction Vol. Solid volume fraction Wr Wear rate (m3 N−1 m−1) Δm Mass loss (gr) ρ Sample density (gr m−3) l Distance (m) F Applied load (N)
Introduction The study of lubricants has gained a special place among the sciences with the emergence of new debates such as optimizing the consumption and conservation of non-renewable
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