Two-lobe geometrically imperfect hybrid journal bearing operating with power law lubricant

Abstract

The present paper investigates the influence of journal’s geometric imperfections on the performance of capillary compensated two-lobe hybrid journal bearing system. Different geometric imperfections of journal, viz. barrel, bellmouth and circumferential waviness have been included in the study. A parameter called offset factor has been included in the analysis which distinguishes between two lobe and circular journal bearing. Further, the Reynolds equation has been modified by using power law model in order to deal with non-Newtonian effect of the lubricant. The numerically simulated results indicate that non-circularity of bearing and barrel shape irregularity significantly increase the values of [Formula: see text] and [Formula: see text] by a factor 36.47, 51.34 and 18.52%, respectively, with respect to the base bearing (circular ideal journal bearing) operating with non-Newtonian lubricant.

Dynamic analysis of a 2-lobe geometrically imperfect journal bearing system

“…The geometry of the 2-lobe hybrid journal bearing system is schematically shown in Figure 1. The fluid film pressure field in an incompressible isoviscous oil lubricating film of a multilobe hybrid journal bearing system is governed by the Reynolds equation and is expressed in non-dimensional form as 1,2,21 @ @ " h 3 12 "…”

“…Further, it has been observed that the journal center displacement of undulated journal in X direction is less and in Z direction is more when compared with bellmouth shaped journal center displacements(X, Z).Therefore, it is expected that bearing with undulated journal is more stable as compared to that of bellmouth shaped journal. 20,21…”

“…These irregularities are reported by various researchers in their theoretical and experimental analysis of journal bearing systems. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] Salama 9 experimentally and theoretically examined the long wave undulation effect on the parallel-faces thrust bearing performance. The result of his study indicates that the optimum bearing capacity occurred at a constant ratio of wavelength to amplitude.…”

“…Very recently, Jain and Sharma 21,22 examined the influence of geometric irregularities of journal on the performance of a 2-lobe hybrid journal bearing operated with power law lubricant 21 and turbulence effect on 4-lobe hybrid journal bearing, 22 respectively. It has been observed that bearing with barrel shape journal exhibits higher value of stability threshold speed margin than other types of irregularities in both bearing systems (2-lobe and 4-lobe hybrid journal bearing).…”

Combined influence of geometric irregularities of journal and turbulence on the performance of four-lobe hybrid journal bearing

“…Many researchers have included these irregularities in the theoretical and experimental analysis of fluid film journal bearing. 16–29…”