No abstract

The imperative characteristics of micropolar (non-Newtonian) fluid-lubricated short single-layered porous journal bearing are analysed theoretically by an iterative method. With the presence of very few available data for micropolar lubrication, the results acquired in the present study are compared with previously published results using the conventional lubricant and found to be in the perfect covenant. The modified Reynolds equation in case of micropolar fluid is derived and solved numerically to investigate bearing characteristics and to show the comparison with published results in the form of design charts. The results established that the micropolar fluid significantly improves lubricating conditions and load capacity as compared with the corresponding Newtonian case. It has been observed that micropolar fluid-lubricated porous journal bearing gives high load-carrying capacity than other conventional lubricants.

The features of micropolar fluid (a non-Newtonian fluid)–lubricated short single-layered porous hydrostatic journal bearing are analyzed theoretically by an iterative method. To investigate hydrostatic journal bearing characteristics, a modified Reynolds equation in the case of micropolar fluid is derived and solved numerically. The obtained results in this work are validated by comparing the same with previously published results with Newtonian and non-Newtonian lubricants in the form of design charts. The static stiffness and load-carrying capacity of the investigated bearing are 80% and 75% higher than conventional hydrostatic bearings. The porous hydrostatic journal bearing exhibits more economical performance as it requires 40% low flow rate and low pump power, and it generates 50% less heat in contrast with other hydrostatic bearings.

A theoretical framework of single-layered PHB (porous hydrostatic bearing) lubricated by nano-oil has been developed here. The impact of nano-oil on the presentation of said hydrostatic bearing has been concentrated with the assistance of modified Darcy's law and distinctive boundary conditions. The different nanoparticles are utilized as an added substance of conventional lubricants to upgrade its consistency. The statement of dimensionless exhibition attributes of the researched bearing has been determined by utilizing the modified Krieger-Dougherty viscosity model of nano-fluid and modified Darcy's flow model. The outcomes uncovered that the exhibition qualities are fundamentally improved with the utilization of nano-lube oil as contrasted and the equivalent of other Newtonian and micropolar fluids. Thus, the present investigation is validated with perfect covenant.

Bearings are designed to support the loads normally applied to the shaft, while allowing relative movement between two machine elements. Journal or sliding bearings are perhaps the most well-known sorts of hydrodynamic bearings. The journal bearings contain no rolling elements and these bearings’ design and construction are simple, but their operation and theory are complex. Due to this and other advantages, journal bearings are much preferred in engineering applications. Simultaneously, the associated research and development have resulted in reasonable progress and therefore, a thorough review of these is earnestly felt. The static and dynamic characteristics of hydrodynamic journal bearings mainly depend on the lubricant viscosity and other factors such as load, speed, friction, and eccentricity. The review analysis focused on nanofluid lubricated hydrodynamic journal bearings are one of the rare topics of interest among tribologists. The use of a nanofluid as a lubricant is very important as it significantly improves the performance characteristics of the investigated bearing. The aggregation of nanoparticles in lubricants available commercially can cause a sharp increase in pressure drop and significantly improve the lubricant viscosity, which leads to an increase in load-carrying capacity. The tribological properties of various lubricants/base oils can be augmented by nanoparticles containing the lubricant. Studies have shown that compared to other conventional engine oils the load-carrying capacity is increased with nanoparticles containing the lubricant.