Static and Dynamic Performance of Journal Bearings lubricated With Nano-Lubricant
In this paper, a suitable mathematical model was proposed to investigate the effect of adding nanoparticles to the base oil lubricating the cylindrical journal bearing on the dynamic characteristics of the bearing system. Suitable time dependent Reynold's equation has been perturbed in order to evaluate the static and dynamic characteristcs of the journal bearing. Modified Krieger and Dougherty viscosity model has been used to investigate the oil viscosity variation with the particle concentration of the Nano-particles. Asuitable computer program has been written in MATLAB to solve the govering equations. Titanium dioxied Nano-particles have been added to the base oil with different particle concentrations (0.1%,0.5%,1%, 1.5% and 2%) in order to enhance its viscosity. The computer programs has been validated by comparing some of the results calculated in this work with other published researches and it was found that the discrepancy is less than 2%.The investigations reveal that the change in oil viscosity due to the addition of the nanoparticles to the base oil has a pronounced effect on the linear dynamic coefficients. An increase in linear stiffness coefficient up to 20% has been obtained when the bearing lubricated with nanolubricant that has 0.5% particle concentration of the nanoparticles while the linear damping coefficients increase up to 31% for the bearing works at the same conditions.