Non-linear Transient Analysis of Submerged Oil Journal Bearings Considering Surface Roughness and Thermal Effects

Abstract

A time-transient non-linear analysis has been carried out to study the influence of surface roughness and viscosity-temperature dependency on stability of a submerged oil journal bearing. The average Reynolds equation has been solved simultaneously along with the energy equation and heat-transfer equation in bush and shaft. The cavitation model, proposed by Kicinski along the lines of Jacobsson-Floberg theory, has been modified to account for the surface roughness effects. The effect of various surface roughness parameters, such as the composite surface roughness, roughness orientation pattern and variance ratio, on the stability has been studied. The non-linear transient analysis of submerged oil journal bearings under (a) a unidirectional constant load, (b) a unidirectional periodic load and (c) a variable rotating load is performed.

The Stability Margin of a Roughened Hole-Entry Hybrid Journal Bearing System

“…It may be noted that the shear flow factor (φ s ) in the modified average Reynolds equation (Eq. [4]) plays a similar role as that of the average fluidfilm thickness (h T ) in the fluid-film pressure generating process. Because the fluid-film pressure generation requires a negative fluid-film gradient, additional pressure generation is also expected from the negative ∂φ s ∂α term in the Reynolds equation.…”

“…The pressure flow factors φ x and φ y in Eq. [4] are used as correction factors to modify the pressure-induced flow of lubricant between two smooth surfaces and are expressed as (Patir and Cheng (5))…”

“…[4] and following the usual assembly procedure, the following global system equation is derived (Nagaraju,et al (8)):…”

Influence of couple stress lubricant on the performance of textured two-lobe slot-entry hybrid journal bearing system

“…From the review of published literature, [12][13][14] it has been noticed that surface roughness has a significant effect on the lubrication health of machinery. For moving part it determines how the surface will wear, how well it will retain lubricant, and how well it will support an external load.…”

Nonlinear transient response of rough symmetric two lobe hole entry hybrid journal bearing system

“…As a result of this, the bearing response gets changed. Several studies pertaining to the influence of surface roughness on the performance characteristics of hydrodynamic journal bearings and hybrid journal bearings have been reported in the literature (Christensen,1969; Patir and Cheng, 1978, 1979; Ramesh et al.,1995; Turaga et al., 1999, 2000; Lin, 2007; Jagadeesha et al., 2012; Fayolle and Childs, 1999; Nagaraju et al., 2002, 2007; Basavaraja et al., 2009). A stochastic model for random rough surface has been developed by Christensen and Tonder (1973).…”