Experimental, statistical, and numerical investigations for influence of using vegetable oil with mineral oil to enhance the flow characteristics through a closed hydraulic circuit

Abstract

The aim of this paper is to investigate the performance of a hydraulic system using an equi-volume percentage of vegetable oil and mineral oil as hydraulic fluids. The hydraulic system performance was tested at different operating conditions, such as temperature and velocity. A test rig with a definite pipe length and diameter was used. The experimental results showed that the presence of vegetable oil reduced the viscosity by 21, 18, 11, and 8% at 30, 40, 50, and 60 °C, respectively. The pressure drop (ΔP) through the hydraulic circuit was improved. The reason may be attributed to a reduction in viscosity. At 6 L/min and 60 °C, the maximum percentage of drag reduction (%Dr) was around 29%, while the maximum percentage of flow improvement (%FI) was around 21%. Statistical analysis was used to correlate %Dr as a function of dimensionless groups with a high correlation coefficient. Numerical analysis was conducted using ANSYS software. Experimental and numerical results were very close with high validity. A numerical model was used to study the effect of pipe geometry. Pressure drop was increased with pipe length and inclination angle, but it decreased with pipe diameter. In the literature, the experimental and numerical performance of hydraulic systems using a blend of vegetable and mineral oils as hydraulic fluid was limited. Therefore, the current study is quite new for the hydraulic system performance at different operating conditions.