Analysis of capillary compensated hydrostatic journal bearing operating with micropolar lubricant

Abstract

PurposeThe paper seeks to study, theoretically, the performance characteristics of capillary compensated multi‐recessed hydrostatic journal bearings operating with micropolar lubricant. The finite element method is used to solve the modified Reynolds' equation governing the micropolar lubricant flow in the clearance space of a hydrostatic journal bearing. The performance characteristics of bearing operating with micropolar lubricant are presented and compared with that of Newtonian lubricant, for a wide range of non‐dimensional load, capillary restrictor design parameter and micropolar parameters.Design/methodology/approachThe modified Reynolds' equation governing the flow of the micropolar lubricant is solved along with restrictor flow equation by finite element method so as to obtain fluid‐film pressures. The iterative procedure is repeated until the converged solution for the fluid‐film pressure field is obtained.FindingsA study of four‐pocket hydrostatic journal bearing system capillary compensated and operating with micropolar lubricant is presented. The following conclusions are made from the results presented in this study: at a constant load, pocket pressures and minimum film thickness, stiffness coefficients and, the damping coefficients increase with increase in micropolar effect of lubricant as compared to the Newtonian lubricant; the influence of the micropolar parameters of lubricant is more significant upon the minimum fluid‐film thickness at higher values of load and lower values of restrictor design parameter; the non‐dimensional flow decreases with increase in the micropolar effect of the lubricant a given values of restrictor design parameter and load; and the stiffness coefficient in the direction of load is found to be influenced by the micropolar parameters and more significantly at lower values of restrictor design parameter and load.Originality/valueStudies of capillary compensated multi‐recess hydrostatic journal bearing operating with micropolar fluid/lubricant are not available in the existing literature to the best of authors' knowledge. Although, such bearing has been studied with Newtonian lubricant and available in open literature. Therefore, this paper is an original piece of work in the area of micropolar lubrication and compensated hydrostatic bearings.

A Comparative Linear and Nonlinear Stability Analysis of Hybrid Journal Bearing Operating with Micropolar Lubricant

“…The Modified Reynolds equation governing the flow of a micropolar lubricant in the convergent area of a hybrid journal bearing incorporating the micropolar parameters with usual assumptions of the lubrication film and constancy of the characteristics coefficients across the film of micropolar lubricant is given as [8]: ( , , ) 12…”

“…The fluid-film thickness expression for a rigid symmetric hole-entry hybrid journal bearing system, in non-dimensional form is given as [8]:…”

“…Using Galerkin's Orthogonality conditions and following the usual assembly procedure, the global system of equation is obtained as [8]:…”

“…In the present work, capillary has been used as restrictor. The flow of micropolar lubricant through capillary restrictor in dimensionless form is given by [8]:…”

“…Wang et al [7] discussed that micropolar fluids exhibit increase in load capacity and temperature and decrease in coefficient of friction and side leakage flow as compared to Newtonian fluids. An analysis of capillary compensated hydrostatic journal bearing operating with micropolar lubricant was carried out by Verma et al [8]. Sharma et al [9] performed a study on slot-entry hybrid journal bearing operating with Micropolar lubricant.…”