FEM analysis for different configurations of non‐recessed hole‐entry hybrid journal bearings for non‐Newtonian lubricants

Purpose -The purpose of this work is to investigate the static performance characteristics of thermohydrodynamic journal bearing operating under nanolubricants (lubricants containing per cent weight concentration of nanoparticles). Design/methodology/approach -Addition of nanoparticles in the lubricant increases lubricant viscosity. To study the effect of this variation on journal bearing, analytical models are developed for the relationship between viscosity, 0-0.5 per cent weight concentration of nanoparticles and temperature range of 300-900°C. To obtain pressure and temperature distribution, modified Reynolds and energy equations are solved by using the finite element method. The viscosity field (varies with temperature and per cent weight concentration of nanoparticles) is updated in these two equations by using the developed analytical model. The steady-state performance characteristics are computed for various values of eccentricity ratios for non-thermoviscous (viscosity of lubricant varies with per cent weight concentration of nanoparticles) and thermoviscous (viscosity of lubricant varies with per cent weight concentration of nanoparticles and temperature) cases. The lubricant and the nanoparticles used for the present work are SAE15W40, copper oxide (CuO), cerium oxide (CeO 2 ) and aluminum oxide (Al 2 O 3 ). Findings -The pressure and temperature distribution across the lubricant film in the clearance space of journal bearing and static performance characteristics are calculated. Originality/value -The computed results show that addition of nanoparticles in the lubricant influences the performance characteristics considerable in thermoviscous case than non-thermoviscous case.

Section: Solution Proceduresmentioning

confidence: 99%

Section: Solution Proceduresmentioning

confidence: 99%

Static characteristics of thermohydrodynamic journal bearing operating under lubricants containing nanoparticles

Kalakada

Kumarapillai

2015

“…Garg et al (2006) presented a comprehensive review of the developments in the design and application of hydrostatic and hybrid journal bearing systems and concluded that more extensive research is needed, both analytically as well as experimental, to consider the extension of these bearings into high speed applications. Duvedi et al (2006) carried out the theoretical analysis of capillary compensated non-recessed hole-entry hybrid journal bearing lubricated with non-Newtonian lubricant. Garg et al (2009) studied the performance of a capillary compensated hole-entry journal bearing system and found that the value of minimum fluid-film thickness ( h min ) reduces due to the decrease in viscosity because of consideration of thermal effects and the non-Newtonian behavior of the lubricant.…”

Section: Introductionmentioning

confidence: 99%

Thermohydrostatic rheological analysis of constant flow valve compensated multiple hole-entry hybrid journal bearings

Garg

Kumar²

2014

Purpose -The changing technological scenario necessitated hybrid journal bearings to operate under severe conditions of heavy load and high speed resulting into temperature rise of the lubricant fluid-film and bearing surface. To predict the performance of a bearing realistically, theoretical model must consider the combined influence of the rise of temperature and non-Newtonian behavior of the lubricant. The aim of the present paper is to study the effect of viscosity variation due to temperature rise and non-Newtonian behavior of the lubricant on performance of constant flow valve compensated multiple hole-entry hybrid journal bearings. Design/methodology/approach -Finite element method has been used to solve Reynolds equation along with restrictor flow equation, 3D energy equation and 3D conduction equation using suitable iterative technique. The non-Newtonian lubricant has been assumed to follow cubic shear stress law. Findings -The thermohydrostatic rheological performances of symmetric and asymmetric hole-entry hybrid journal bearing configurations are studied. The computed results illustrate that variation of viscosity due to rise in temperature and non-Newtonian behavior of the lubricant affects the performance of hole-entry hybrid journal bearing system quite significantly. Originality/value -In the present work, the influences of the viscosity variation due to temperature rise and non-Newtonian behavior of the lubricant on the performance characteristics of non-recessed hole-entry hybrid journal bearing with symmetric and asymmetric configurations compensated with constant flow valve restrictors have been investigated for generating the design data to be used by bearing designer. The design data computed in the present thesis are a contribution in field of knowledge of bearing design. NomenclatureDimensional parametersThe current issue and full text archive of this journal is available at Subscripts and superscriptsstate condition ori ¼ orifice p ¼ parameter due to pressure R ¼ restrictor r ¼ reference value s ¼ supply pressure T ¼ parameter due to temperature, transpose of matrix x, y, z ¼ components in X, Y and Z directions * ¼ concentric operation · ¼ first derivative w.r.t. time · · ¼ second derivative w.r.t. time Abbreviations CFV ¼ constant flow valve FEM ¼ finite element method THS ¼ thermohydrostatic

“…Garg et al (2006) presented a comprehensive review of the developments in the design and application of hydrostatic and hybrid journal bearing systems and concluded that more extensive research is needed, both analytically as well as experimental, to consider the extension of these bearings into high speed applications. Duvedi et al (2006) carried out the theoretical analysis of capillary compensated non‐recessed hole‐entry hybrid journal bearing lubricated with non‐Newtonian lubricant. Jadon and Singh (2007) studied the effect of the cut‐off the supply of the lubricant to the holes of the hybrid journal bearing and found that the performance of the bearing is affected.…”

Section: Introductionmentioning

confidence: 99%

Static performance characteristics of hybrid journal bearings with plugged entry holes

Garg

Kumar

2013

PurposeThis paper aims to investigate the effect of plugging of holes on the static performance characteristics of a constant flow valve compensated hole‐entry hybrid journal bearing system operating with Newtonian and non‐Newtonian lubricants. The analysis considers the generalized Reynolds equation governing the flow of lubricant having variable viscosity in the clearance space and equation of flow of lubricant through constant flow valve restrictor. The non‐Newtonian lubricant is assumed to follow the power law. The performance characteristics are computed for the two values of power law index (n=1.0 and 0.566). The computed results indicate that the blockage of holes during operation will not be the likely causes for the imminent failure of a well‐designed non‐recessed hole‐entry hybrid journal bearing.Design/methodology/approachFinite element method has been used to solve generalized Reynolds equation governing the flow of lubricant having variable viscosity in the clearance space and equation of flow of lubricant through constant flow valve restrictor.FindingsThe computed results indicate that the blockage of holes during operation will not be the likely causes for the imminent failure of a well‐designed non‐recessed hole‐entry hybrid journal bearing. The bearing configuration with plugged holes provides sufficient fluid film thickness and low power requirement as less lubricant is required to be pumped in the bearing.Originality/valueTo the best of the author's knowledge, no study which considers the influence of plugging of holes on the static performance characteristics of a constant flow valve compensated hole‐entry hybrid journal bearing system operating with Newtonian and non‐Newtonian lubricant is yet available in the literature.