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In this study, the flow of Cu/oil nanofluids over an impermeable semi‐infinite plate was investigated. A complete single‐phase modeling of nanofluids flowing over a semi‐infinite plate was performed, bringing into account, real experimental data of oil‐based nanofluids. The empirical correlations revealed that the viscosity and thermal conductivity of the pure oil and oil‐based nanofluids strongly depend on temperature. The similarity transformation method was utilized to transform governing partial differential equations into coupled nonlinear ordinary differential equations solved by employing the standard Runge–Kutta. The results showed that even low volumetric fraction of copper/oil nanofluids noticeably enhanced the heat transfer; however, such behavior was not predicted accounting the classic modeling of nanofluids. Furthermore, both hydrodynamics and thermal characteristics were reliant on the thermal boundary conditions, which this seems to have received a marginal focus in the existing literature. [ABSTRACT FROM AUTHOR]

Thermal oils due to their high ability in cooling and lubricating have many applications in high-tech industries such as automotive industry. Dispersing nanoparticles in a thermal oil (which the resulted new liquid is called nanofluid) can modify further the cooling and lubrication efficiencies. This review paper aims to present the recent advances in the preparation methods and thermophysical properties measurements of oil-based nanofluids. Effects of various parameters such as nanoparticle concentration, size, and temperature on the values of properties including thermal conductivity, viscosity, density, and specific heat are reviewed. The correlations available for the properties of oil-based nanofluids are gathered from the literature that could be a worthy source for those who aim to work on oil-based nanofluids. Unlabelled Image [ABSTRACT FROM AUTHOR]

In this study, thermo-physical properties including thermal conductivity, viscosity, density and specific heat capacity of an oil based nanofluid including silver as to be nanoparticles have been experimentally studied. The results indicate an enhancement in thermal conductivity which was depended on bulk temperature and volume fraction of utilized nanofluids. Viscosity data show a significant increment through volume fraction increasing. In addition, the specific heat capacity and density of nanofluids were studied experimentally and it was found that, all measured rheological properties of these nanofluids, were not in agreement to published correlations. [ABSTRACT FROM AUTHOR]

In this study, a colloidal suspension consists of Cu nanoparticles and engine oil has been made by a one- step method known as Electrical Explosion of Wire (E.E.W) in three different weight concentrations of 0.2%, 0.5% and 1%. After studying physical properties of the applied nanofluids via high resolution transmission electron microscopy and measuring zeta potential for the stability analysis, thermo-physical properties such as thermal conductivity and viscosity, have been experimentally studied. Measured data of thermal conductivity and viscosity of applied nanofluids have been compared to the predicted ones through the proposed correlations for thermal conductivity and viscosity of oil based nanofluids and acceptable agreements between the two have been achieved. The range of thermal conductivity of higher weight concentration was measured to be from 0.153 to 0.17 (W/m. K) in the temperature range from 40 C to 100 C, while pure engine oil exhibits a decreasing trend in contradictory. Secondly, viscosity variations through capturing Newtonian or non- Newtonian behavior of utilized nanofluids has been investigated. The viscosity range for higher weight concentration nanofluid was observed from 235 cP to 35 cP in the applied temperature range. Finally, thermal conductivity and viscosity enhancements of 49% and 37% were observed for 1% weight fraction of utilized nanofluids. [ABSTRACT FROM AUTHOR]

An oil based nanofluid including silver as to be nanoparticles was created by EEW method as a one-step method in three different volume fractions have been experimentally studied. Assessing the stability and viscosity of the nanofluids was involved in this work. The results show that the nanofluids behave in both of Newtonian and non-Newtonian in different volume concentrations. Also, an enhancement in viscosity of nanofluids has been recognized. In addition, based on the experimental results of this study and the other previous published studies on the oil based nanofluids, a correlation for predicting viscosity of oil based nanofluids has been developed and a good agreement between the experimental viscosity of applied nanofluids in this study and the predicted one has been achieved. [ABSTRACT FROM AUTHOR]