Effect of TiO2 and CuO Based Nanolubricants on the Static Thermal Performance of Circular Journal Bearings

Abstract

Circular journal bearings constitute the heart of power generation equipments due to their simple design, ease in manufacturing and high load-carrying capacity. Hydrodynamic action in these bearings is manifested by the presence of a single oil film, which increases the oil film temperature at higher loads. However, in order to improve the performance of bearings and for overall optimization of equipment efficiency, lubricants with specialized additives are being explored. With the advancements in nanotechnology, lubricants have been blended with nanoparticles for enhancing tribological characteristics. The existing studies are more focused on examining the influence of nanolubricants for boundary lubrication regime. Hence, this article investigates the effect of CuO and TiO2 based nanolubricants in hydrodynamic lubrication regime by studying the static thermal characteristics of circular bearing. Comparative performance analysis has been conducted with both the nanoparticles based lubricants at different concentrations by mixing them in two mineral-based oils having different viscosities. The modified Krieger Dougherty method has been applied for determining the viscosity of nanolubricants. Hydrodynamic pressure and oil film temperature calculations have been performed by developing a model in MATLAB®R2020a software by considering the effect of variation in the thermophysical properties of nanolubricants. There has been a significant increase in load capacity with just small rise in oil film temperature with the use of nanolubricants. Load capacity with 2wt% addition of TiO2 increased by 14.23% at a journal speed of 2000rpm and eccentricity ratio of 0.6, while there was an increase of 9.23% in the case of CuO at the same parameters. The proposed methodology has an enormous potential for assessing the performance enhancement of turbomachinery used for power generation.