Thermo-hydraulic performance of a lubricant containing zinc oxide nano-particles: a two-phase oil

The first goal is to propose a two-variable equation for predicting the viscosity of zinc oxide-SAE50 nano-lubricant. In this way, the curve fitting was applied on laboratory data. Laboratory data have been reported in the temperatures ranging from 25 to 50°C of and the nanoparticles concentrations ranging from 0.125% to 1.5% previously. The presence of nano-particles leads to intensify the pressure descent and heat transfer, simultaneously. Therefore, the second goal was to evaluate the influence of nano-particles on the pressure descent and heat transfer. To achieve this goal, using existing relationships, heat transfer and pressure drop were estimated using nano-lubricant properties. Findings showed that the pressure drop ratio and coefficient of heat transfer augmented with increasing of ZnO concentration. Furthermore, calculations revealed that thermal performance factor enhances with increasing temperature and had a maximum value at volume concentration of 1%. It means that volume concentration of 1% is an optimal point in the preparation of this nano-lubricant.