Steady-state performance analysis of misaligned double-layered porous journal bearings under coupled-stress lubrication with slip flow and additives percolation effect

2018 ◽  
Vol 233 (6) ◽  
pp. 841-858 ◽  
Author(s):  
Shitendu Some ◽  
Sisir K Guha
Keyword(s):  
Steady State ◽  
Performance Analysis ◽  
Slip Flow ◽  
Velocity Slip ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Graphical Form ◽  
Percolation Effect ◽  
Coupled Stress ◽  
Steady State Performance

The aim of this paper is to address the effect of misalignment of the double-layered porous journal bearing on the steady-state performance analysis under coupled-stress lubrication with velocity phenomenon at the fine porous interface. Here, the misalignment caused by shaft displacement, e.g. axial (vertical displacement) and twisting (horizontal displacement) is considered. This analysis includes velocity slip phenomenon on the basis of Beavers-Joseph criteria. Moreover, the present analysis also focuses on the percolation effect of the additives into the pores of the porous layers. Steady-state film pressures are obtained by solving the modified Reynolds equation based on the coupled-stress lubrication theory. Under various parametric conditions, pressure profiles in the film region are discussed and demonstrated in the graphical form. Using these film pressure values, steady-state characteristics in terms of bearing load carrying capacity, attitude angle, frictional parameter, side leakage and misalignment moment are evaluated at various parametric conditions and represented in the graphical form.

Static characteristics of hydrostatic doubled-layered porous journal bearings with slip flow including additives percolation into pores under coupled stress lubrication

2017 ◽  
Vol 232 (8) ◽  
pp. 927-939 ◽  
Author(s):  
Shitendu Some ◽  
Sisir K Guha
Keyword(s):  
Steady State ◽  
Reynolds Equation ◽  
Slip Flow ◽  
Journal Bearings ◽  
Static Characteristics ◽  
Governing Equations ◽  
Modified Reynolds Equation ◽  
Film Interface ◽  
Coupled Stress ◽  
Steady State Performance

A theoretical analysis of the steady-state characteristics of finite hydrostatic double-layered porous journal bearings dealing with the effects of slip flow at the fine porous layer–film interface and percolation of additives into pores under the coupled stress fluid lubrication is presented. Based on the Beavers–Joseph’s criterion for slip flow, the modified Reynolds equation applicable to finite porous journal bearings lubricated with coupled stress fluids have been derived. The governing equations for flow in the coarse and fine layers of porous medium incorporating the percolation of polar additives of lubricant and the modified Reynolds equation are solved simultaneously using finite difference method satisfying appropriate boundary conditions to obtain the steady-state performance characteristics for various parameter namely percolation factor, slip coefficient, bearing feeding parameter, coupled stress parameter, and eccentricity ratio. The results are exhibited in the form of graphs, which may be useful for design of such bearing.

Non-linear stability analysis of two-layered porous journal bearings with velocity slip and percolation effect of additives of coupled-stress lubricant

2020 ◽  
Vol 235 (1) ◽  
pp. 46-60
Author(s):  
Shitendu Some ◽  
Sisir K Guha
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Journal Bearing ◽  
Velocity Slip ◽  
Operating Conditions ◽  
Graphical Form ◽  
Non Linear ◽  
Percolation Effect ◽  
Coupled Stress

In this paper a non-linear stability analysis of the two-layered porous journal bearing under coupled-stress lubricant has been presented with velocity slip phenomenon and additive’s percolation effect. In this non-linear transient analysis, system stability is determined by tracing the locus of the journal center and various trajectories of journal center locus have been represented in graphical form for different operating conditions. Furthermore, stability characteristics in respect of critical mass parameter and whirl ratio have been studied under various parametric conditions and a comparison between the linear and non-linear stability analysis have been demonstrated. To acquire the non-dimensional pressure values, non-dimensional transient Reynolds equation has been solved and with these pressure values, bearing load carrying capacity are derived. Fourth order Runge-Kutta method is used to solve the second order equations of motion for journal bearing system to obtain the stability characteristics. Results of this analysis may be helpful for designing such bearings.

Effect of journal misalignment and coupled-stress lubricant on the film pressure of a double-layered porous journal bearing

2019 ◽  
Vol 72 (3) ◽  
pp. 315-323
Author(s):  
Shitendu Some ◽  
Sisir Kumar Guha
Keyword(s):  
Steady State ◽  
Journal Bearing ◽  
Tangential Velocity ◽  
Velocity Slip ◽  
Content Type ◽  
Porous Bearing ◽  
Pressure Profiles ◽  
Percolation Effect ◽  
Journal Misalignment ◽  
Coupled Stress

Purpose In the application of hydrostatic double-layered porous journal bearings, misalignment of bearing systems is a major problem. On the other hand, the use of coupled-stress fluid as a lubricant is more practical in the present days. Furthermore, in case of porous bearing, neglecting slip effect and percolation effect of additives into the pores may lead to erroneous result. Hence, this paper aims to address the effect of journal misalignment and coupled-stress lubricant on the steady-state film pressure of the double-layered porous journal bearing with tangential velocity slip and percolation effect. Design/methodology/approach First, considering the tangential velocity slip, the most general modified Reynolds type equation has been derived for the film region and the governing equations for flow in the coarse and fine layers of porous medium, incorporating the percolation effect for a double-layered porous bearing. Here, considering the misalignment caused by shaft displacement. Film thickness expression established considering the effect of misalignment. Steady-state film pressures are obtained by solving modified Reynolds equation based on the coupled-stress lubrication theory. Effects of journal misalignment and coupled-stress lubricant on the pressure profiles in the film region are discussed and demonstrated in the graphical form. Findings In this paper, effects of journal misalignment and coupled-stress lubricant on the pressure profiles in the film region are obtained. In general, higher degree of misalignment gives higher steady-state pressure value in the film region, and this pressure increases due to increase in coupled-stress parameter up to a certain limit. Originality/value To the best of the author’s knowledge, there is no literature available, so far, that addresses the analysis of the steady-state pressure in the film region of a doubled–layered porous journal bearing under misaligned condition with coupled-stress lubricant. But in this paper all these points are included, which makes this article valuable in design purpose.

Effect of Slip Flow on the Steady-State Performance of Aerostatic Porous Journal Bearings

1984 ◽  
Vol 106 (1) ◽  
pp. 156-162 ◽  
Author(s):  
K. C. Singh ◽  
N. S. Rao ◽  
B. C. Majumdar
Keyword(s):  
Steady State ◽  
Slip Velocity ◽  
Load Capacity ◽  
Finite Thickness ◽  
Slip Flow ◽  
Velocity Slip ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Mass Rate ◽  
Steady State Performance

A theoretical solution is presented to predict the steady-state performance characteristics of aerostatic porous journal bearings of finite thickness considering three dimensional flow in the porous media. The analysis takes into account the velocity slip at the film bearing interface by using Beavers-Joseph criterion. Results are presented in dimensionless form for load capacity and mass rate of flow for different operating conditions and bearing dimensions. Solution is also obtained for modified slip velocity conditions and both the results are compared. It is observed that there is no agreement between two models except for few values of slip parameters. Hence, it is preferable to use the Beavers-Joseph model in order to account for all values of slip parameters. The effect of slip velocity on the static characteristics is discussed.

scholarly journals Line-Start Permanent-Magnet Motor Single-Phase Steady-State Performance Analysis

2004 ◽  
Vol 40 (2) ◽  
pp. 516-525 ◽  
Author(s):  
T.J.E. Miller ◽  
M. Popescu ◽  
C. Cossar ◽  
M. McGilp ◽  
G. Strappazzon ◽  
...  
Keyword(s):  
Steady State ◽  
Performance Analysis ◽  
Permanent Magnet ◽  
Single Phase ◽  
Permanent Magnet Motor ◽  
Steady State Performance

Linear stability analysis of double-layered porous journal bearings under coupled-stress lubrication with slip flow and percolation effect of additives

2019 ◽  
Vol 71 (3) ◽  
pp. 447-458 ◽  
Author(s):  
Shitendu Some ◽  
Sisir Kumar Guha
Keyword(s):  
Linear Stability ◽  
Mass Parameter ◽  
Critical Mass ◽  
Slip Flow ◽  
Tangential Velocity ◽  
Journal Bearings ◽  
Content Type ◽  
Percolation Effect ◽  
The Stability ◽  
Coupled Stress

Purpose In the application of hydrostatic double-layered porous journal bearings, instability of bearing systems is a major problem. On the other hand, the use of non-Newtonian fluid as a lubricant is more practical in the present days. Furthermore, in case of porous bearing, neglecting slip effect and percolation effect of additives into the pores may lead to erroneous result. Hence, this paper aims to present the linear stability analysis of finite hydrostatic double-layered porous journal bearings lubricated with coupled-stress lubricant with tangential velocity slip and percolation effect. Design/methodology/approach First, considering the tangential velocity slip, the most general modified Reynolds-type equation has been derived for the film region and the governing equations for flow in the coarse and fine layers of porous medium incorporating the percolation effect. A linearized first-order perturbation method has been applied to obtain the threshold of stability in terms of critical mass parameter. The effect of various parameters on the stability is investigated and represented in the form of graphs. Furthermore, a comparison between the stability of double- and single-layered porous journal bearings has been exhibited. Findings In this paper, threshold of stability has been obtained in terms of critical mass parameter. The effect of slip coefficient, percolation factor, coupled-stress parameter, eccentricity ratio and bearing feeding parameter on the stability has been found. Originality/value There is no literature available so far that addresses the analysis of the linear stability of externally pressurized double-layered porous journal bearings with slip flow, including the percolation effect under coupled-stress lubrication. But in this paper, all these points are included which made this paper valuable in design purpose.

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