MIXED CONVECTION HEAT TRANSFER OF SIO2-WATER AND ALUMINA-PAO NANO-LUBRICANTS USED IN A MECHANICAL BALL BEARING

In this study, the mixed convection heat transfer in a mechanical ball bearing filled with nano-lubricants were investigated theoretically. our case, including eight balls revolving counter clockwise while inner shaft rotates direction and outer walls of kept at constant hot cold temperatures, respectively. Two kinds SiO2-water Alumina- Polyalphaolefin (PAO) different shapes nanoparticles considered. The governing equations velocity, pressure, temperature formulation solved based on Galerkin finite element method. parameters such as nanoparticle volume fraction, Reynolds Rayleigh numbers, etc., discussed. It turns out that average Nusselt number increases by increasing fraction (averagely 15% for each 0.02 increase) oil-based nano-lubricant has greater than water one. More importantly, Nono-rod Alumina was found to show much performance 5%) spherical alumina nano-rod Alumina-PAO best maximum numbers transfer.