An experimental and theoretical investigation on heat transfer capability of Mg (OH)2/MWCNT-engine oil hybrid nano-lubricant adopted as a coolant and lubricant fluid

The major objective of the present study is to investigate the heat transfer capability of Mg (OH)(2)/MWCNT- engine oil hybrid nano-lubricant. First, the effects of temperature and Solid volume fraction on the dynamic viscosity and thermal conductivity of Mg (OH)2/MWCNT- engine oil hybrid nano lubricant have been experimentally investigated. The experiments have been conducted in various temperatures (25 degrees C, 30 degrees C, 35 degrees C, 40 degrees C, 45 degrees C, 50 degrees C, 55 degrees C, and 60 degrees C) and solid concentrations (0.25%, 0.5%, 0.75%, 1%, 1.5%, and 2%). Based on the measurements, it is found that the studied nano-lubricant showed Newtonian behavior in all the studied temperatures and solid concentrations. Furthermore, the experimental results indicated that the dynamic viscosity of the nano-lubricant increases with an increase in solid concentration while it decreases with an increase in temperature. The thermal conductivity of the nanofluid showed increasing trend as the solid concentration and temperature increased. The minimum and maximum enhancement were about 13% and 50%, respectively. Based on experimental data, two new trustworthy correlations to predict the dynamic viscosity and thermal conductivity of the nano-lubricant has been proposed. Finally, the heat transfer capability of the nanofluid has been theoretically investigated in both the internal laminar and turbulent flow regimes and it is found that the studied nanofluid can be advantageous in heat transfer applications. (C) 2017 Elsevier Ltd. All rights reserved.