Stability evaluation of three-layered journal bearing with slip/partial slip

2017 ◽  
Vol 69 (3) ◽  
pp. 334-341 ◽  
Author(s):  
T.V.V.L.N. Rao ◽  
A.M.A. Rani ◽  
M. Awang ◽  
F.M. Hashim
Keyword(s):  
Surface Layer ◽  
Frequency Ratio ◽  
Journal Bearing ◽  
Core Layer ◽  
High Viscosity ◽  
Partial Slip ◽  
Bearing Surface ◽  
Content Type ◽  
Linearized Stability ◽  
Slip Region

Purpose This paper aims to present stability of a three-layered journal bearing considering magnitude of the layers’ thicknesses and viscosities with slip/partial slip on the bearing surface. Design/methodology/approach Modified Reynolds equation based on one-dimensional analysis is derived for a three-layered journal bearing with slip/partial slip. Dynamic coefficients are derived based on infinitesimal perturbation method. Linearized stability analysis is presented taking into account slip/partial slip on bearing surface; thicknesses and viscosities of bearing surface layer; and core layer and journal surface layer. Findings Results of threshold speed and critical whirl frequency ratio coefficients (Cω, CΩ), stiffness (Kij for i = x,y) and damping (Bij for i = x, y) coefficients and threshold speed (ωs) and critical whirl frequency ratio (Ωs) are presented. The bearing surface is analyzed for slip (total surface with slip) and partial slip (partial surface with slip). The slip-on bearing surface reduces stability, while partial slip improves bearing stability. The threshold speed coefficient (Cω) decreases with slip on bearing surface. The threshold speed (ωs) and critical whirl frequency ratio (Ωs) are influenced by the variation of threshold speed coefficient (Cω) and critical whirl frequency ratio coefficient (CΩ), respectively. A three-layered journal bearing with partial slip and thick high viscosity bearing surface layer results in higher threshold speed coefficient and has a potential to improve stability of journal bearing. The analyses indicate that optimal angular extent of partial slip region (θs) enhances the stability of journal bearing. Originality/value The paper presents parametric study of stability coefficients (Cω and CΩ) and evaluation of threshold speed (ωs) and critical whirl frequency ratio (Ωs) of a three-layered journal bearing with slip/partial slip.

Stabilization of Journal Bearing Using Two-Layered Film Lubrication

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
T. V. V. L. N. Rao
Keyword(s):  
Frequency Ratio ◽  
Journal Bearing ◽  
Fluid Layer ◽  
Load Capacity ◽  
High Viscosity ◽  
Fluid Film ◽  
Low Viscosity ◽  
Linearized Stability ◽  
Viscosity Fluid ◽  
Layered Fluid

The purpose of this paper is to present the linearized stability analysis of two-layered fluid film in the journal bearing. In this work, a modified classical Reynolds equation is derived under dynamic conditions consisting of two layers of fluid film described by Newtonian viscosities. The magnitude of lubricant layer’s film thickness and viscosities are taken into consideration. The Reynolds boundary conditions are used in the analysis of classical one-dimensional journal bearing to predict the stiffness and damping coefficients, threshold speed and critical whirl frequency ratio. The coefficients of load capacity, threshold speed, and critical whirl frequency ratio (Cw, Cω, CΩ) for two-layered film with reference to homogeneous film are computed as a function of the two parameters: (i) higher to lower dynamic viscosity ratio of two-layered fluid film (β), and (ii) thickness ratio of fluid layer attached to journal and bearing (γ). Higher threshold speed is obtained for thick high viscosity fluid film attached to the bearing surface and a thin low viscosity fluid film attached to the journal surface.

Resistance to cast iron seizure determined by the technological condition of the surface layer

2015 ◽  
Vol 67 (1) ◽  
pp. 17-21
Author(s):  
Stanislaw Laber
Keyword(s):  
Surface Layer ◽  
Cast Iron ◽  
Design Methodology ◽  
Friction Pair ◽  
Ground Surface ◽  
Technological Condition ◽  
Bearing Surface ◽  
Content Type ◽  
The Moment ◽  
Surface Curve

Purpose – The aim of this study was to evaluate a surface layer of the condition resistance to seizure. The surface layer was shaped in the processing grinding and burnishing. Design/methodology/approach – The resistance to seizure tests were carried out on a test station specially designed by the author. It is possible to simultaneously test the same two pairs of pivot–pan kinematic pairs on this station. Moreover, the time, route and the temperature of the friction area were registered. The time of sliding group operation from the moment when a lubricant is no longer added to the friction pair to the moment the sliding group reaches the critical temperature T = 418 K (145°C) is taken as a seizure indicator. Findings – The structure and state of the surface layer have an influence on the seizure of the surface of cooperating elements. Greater resistance to the seizure of the burnished surface in comparison to the ground surface is associated with differences in the state of the surface layer. The burnished surface has a smaller surface roughness and a higher value of the bearing surface curve, and the compressive stress occurs more often in the surface layer. Originality/value – There have been no studies on the effects of burnishing machining and grinding of cast iron in resistance to seizure.

Analysis of Single-Grooved Slider and Journal Bearing With Partial Slip Surface

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
T. V. V. L. N. Rao
Keyword(s):  
Shear Stress ◽  
Pressure Distribution ◽  
Journal Bearing ◽  
Slip Surface ◽  
Partial Slip ◽  
Maximum Pressure ◽  
Slider Bearing ◽  
Slip Coefficient ◽  
One Dimensional ◽  
Slip Region

In this paper, pressure and shear stress are derived under steady state using one-dimensional analysis of the single-grooved slider bearing and journal bearing with partial slip on the stationary surface. The Reynolds boundary conditions are used in the analysis of journal bearing to predict the extent of the full film region. In the cases of partial slip slider and journal bearing, the pressure distribution is higher compared with the conventional bearing with no slip. In the case of partial slip on both slider and journal bearing surfaces, the single-groove, immediately followed by the partial slip region, results in the increase in pressure distribution. The results also show that in comparison to the conventional bearing with no slip, in the cases of partial slip slider and journal bearing, the shear stress increases before the region of slip/no slip interface, while the shear stress decreases in the region of no slip. In the case of the partial slip region on bearing surfaces, the shear stress distribution is lower in the region immediately after the groove. Significant pressure distribution is obtained due to the influence of partial slip on the slider bearing with uniform film thickness and the concentric journal bearing. The maximum pressure occurs at the end of the region of groove, immediately followed by the region of the partial slip. It is found that the pressure distribution of the slider and journal bearing with partial slip surface are not influenced with the further increase in the nondimensional slip coefficient (A) from 10 to 100.

Effect of partial grooving on the performance of hydrodynamic journal bearing

2017 ◽  
Vol 69 (4) ◽  
pp. 574-584 ◽  
Author(s):  
Anil B. Shinde ◽  
Prashant M. Pawar
Keyword(s):  
Carrying Capacity ◽  
Power Loss ◽  
Journal Bearing ◽  
Fluid Film ◽  
Frictional Torque ◽  
Load Carrying Capacity ◽  
Bearing Surface ◽  
Film Pressure ◽  
Content Type ◽  
Load Carrying

Purpose This study aims to improve the performance of hydrodynamic journal bearings through partial grooving on the bearing surface. Design/methodology/approach Bearing performance analysis is numerically carried out using the thin film flow physics of COMSOL Multiphysics 5.0 software. Initially, the static performance analysis is carried out for hydrodynamic journal bearing system with smooth surface, and the results of the same are validated with results from the literature. In the later part of the paper, the partial rectangular shape micro-textures are modeled on bearing surface. The effects of partial groove pattern on the bearing performance parameters, namely, fluid film pressure, load carrying capacity, frictional power loss and frictional torque, are studied in detail. Findings The numerical results show that the values of maximum fluid film pressure, load carrying capacity, frictional power loss and frictional torque are considerably improved due to deterministic micro-textures. Bearing surface with partial groove along 90°-180° region results in 81.9 per cent improvement in maximum fluid film pressure and 75.9 per cent improvement in load carrying capacity as compared with smooth surface of journal bearing, with no increase in frictional power loss and frictional torque. Maximum decrease in frictional power loss and frictional torque is observed for partially grooving along 90°-360° region. The simulations are supported by proof-of-concept experimentation. Originality/value This study is useful in the appropriate selection of groove parameters on bearing surface to the bearing performance characteristics.

Effect of surface roughness, viscosity-pressure relationship and elastic deformation on lubrication performance of misaligned journal bearings

2014 ◽  
Vol 66 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Jun Sun ◽  
Xinlong Zhu ◽  
Liang Zhang ◽  
Xianyi Wang ◽  
Chunmei Wang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Elastic Deformation ◽  
Journal Bearing ◽  
Pressure Effect ◽  
Journal Bearings ◽  
Bearing Surface ◽  
Compliance Matrix ◽  
Content Type ◽  
Lubrication Performance ◽  
Lubrication Characteristics

Purpose – Current lubrication analyses of misaligned journal bearings were generally performed under some given preconditions. To make the lubrication analysis closer to the actual situation and usable to the journal bearing design, the purpose of this paper was to calculate the lubrication characteristics of misaligned journal bearings considering the viscosity-pressure effect of the oil, the surface roughness and the elastic deformation of the journal bearing at the same time. Design/methodology/approach – The lubrication of bearings was analyzed using the average Reynolds equation. The deformation of the bearing surface under oil film pressure was calculated by a compliance matrix method. The compliance matrix was established by finite element analysis of the bearing housing. The viscosity-pressure and viscosity–temperature equations were used in the analysis. Findings – The oil viscosity-pressure relationship has a significant effect on the lubrication of misaligned journal bearings. The surface roughness will affect the lubrication of misaligned journal bearings when the eccentricity ratio and angle of journal misalignment are all large. The directional parameter of the surface has an obvious effect on the lubrication of misaligned journal bearings. The deformation of the bearing surface has a remarkable effect on the lubrication of misaligned journal bearings. Originality/value – The lubrication characteristics of misaligned journal bearings were calculated considering the viscosity-pressure effect of the oil, the surface roughness and the elastic deformation of the journal bearing at the same time. The results of this paper are helpful to the design of the bearing.

Static and stability analysis of partial slip texture multi-lobe journal bearings

2019 ◽  
Vol 234 (4) ◽  
pp. 567-587
Author(s):  
TVVLN Rao ◽  
Ahmad M A Rani ◽  
Norani M Mohamed ◽  
Hamdan H Ya ◽  
Mokhtar Awang ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Partial Slip ◽  
Pressure Gradients ◽  
Capacity Coefficient ◽  
Texture Region ◽  
Linearized Stability ◽  
Infinitesimal Perturbation

This paper presents one-dimensional analysis of modified dynamic Reynolds equation derived for partial slip texture multi-lobe journal bearings. The novelty included in this study is the configuration of partial slip texture region on the bottom bearing lobe surface of a multi-lobe journal bearing under a constant vertical load. The nondimensional pressure and shear stress for steady-state and nondimensional pressure gradients for dynamic coefficients for each lobe with partial slip texture configuration are derived based on narrow groove theory. Linearized stability analysis is evaluated using infinitesimal perturbation method. Results of static and stability characteristics of partial slip texture multi-lobe (two-axial groove, elliptical, three-lobe and offset) journal bearings are presented. Partial slip texture configuration significantly enhances load capacity, coefficient of friction, and stability of two-lobe journal bearing.

LOAD CAPACITY COEFFICIENT EVALUATION OF THREE-LAYERED JOURNAL BEARING WITH SLIP

2016 ◽  
Vol 78 (6-10) ◽  
Author(s):  
T. V. V. L. N. Rao ◽  
A. M. A. Rani ◽  
M. Awang ◽  
F. M. Hashim
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
High Viscosity ◽  
Bearing Surface ◽  
Surface Layers ◽  
Navier Slip ◽  
Slip Boundary ◽  
Capacity Coefficient ◽  
Navier Slip Boundary Conditions

Analysis of three-layered journal bearing with slip on bearing surface is presented. A modified classical Reynolds equation is derived for slip on bearing surface taking into consideration of bearing surface, core and journal surface layers. The modified Reynolds equation is derived taking into consideration of lubricant layer’s film thickness, viscosities and slip on the bearing surface. Navier slip boundary conditions are used to analyze slip. Results of load capacity coefficient are presented for three-layered and two-layered journal bearing with slip. The load capacity coefficient decreases with bearing surface with slip. For a three-layered journal bearing with slip, high viscosity bearing surface layer results in higher load capacity coefficient.

Investigation of sustainability of lubricated journal bearing under relevant design parameters

2018 ◽  
Vol 70 (4) ◽  
pp. 789-804 ◽  
Author(s):  
M.M. Shahin ◽  
Mohammad Asaduzzaman Chowdhury ◽  
Md. Arefin Kowser ◽  
Uttam Kumar Debnath ◽  
M.H. Monir
Keyword(s):  
Aspect Ratio ◽  
Elastic Strain ◽  
Journal Bearing ◽  
Design Parameters ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Stress Formation ◽  
Bearing Design ◽  
The Stability ◽  
Bearing Friction

Purpose The purposes of the present study are to ensure higher sustainability of journal bearings under different applied loads and to observe bearing performances such as elastic strain, total deformation and stress formation. Design/methodology/approach A journal bearing test rig was used to determine the effect of the applied load on the bearing friction, film thickness, lubricant film pressure, etc. A steady-state analysis was performed to obtain the bearing performance. Findings An efficient aspect ratio (L/D) range was obtained to increase the durability or the stability of the bearing while the bearing is in the working condition by using SAE 5W-30 oil. The results from the study were compared with previous studies in which different types of oil and water, such as Newtonian fluid (NF), magnetorheological fluid (MRF) and nonmagnetorheological fluid (NMRF), were used as the lubricant. To ensure a preferable aspect ratio range (0.25-0.50), a computational fluid dynamics (CFD) analysis was conducted by ANSYS; the results show a lower elastic strain and deformation within the preferable aspect ratio (0.25-0.50) rather than a higher aspect ratio using the SAE 5W-30 oil. Originality/value It is expected that the findings of this study will contribute to the improvement of the bearing design and the bearing lubricating system.

Non-linear stability analysis of micropolar fluid lubricated journal bearings with turbulent effect

2019 ◽  
Vol 71 (1) ◽  
pp. 31-39
Author(s):  
Subrata Das ◽  
Sisir Kumar Guha
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Micropolar Fluid ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Turbulent Regime ◽  
Content Type ◽  
Non Linear ◽  
The Stability ◽  
Bearing System

Purpose The purpose of this paper is to investigate the effect of turbulence on the stability characteristics of finite hydrodynamic journal bearing lubricated with micropolar fluid. Design/methodology/approach The non-dimensional transient Reynolds equation has been solved to obtain the non-dimensional pressure field which in turn used to obtain the load carrying capacity of the bearing. The second-order equations of motion applicable for journal bearing system have been solved using fourth-order Runge–Kutta method to obtain the stability characteristics. Findings It has been observed that turbulence has adverse effect on stability and the whirl ratio at laminar flow condition has the lowest value. Practical implications The paper provides the stability characteristics of the finite journal bearing lubricated with micropolar fluid operating in turbulent regime which is very common in practical applications. Originality/value Non-linear stability analysis of micropolar fluid lubricated journal bearing operating in turbulent regime has not been reported in literatures so far. This paper is an effort to address the problem of non-linear stability of journal bearings under micropolar lubrication with turbulent effect. The results obtained provide useful information for designing the journal bearing system for high speed applications.

Sign in / Sign up

Export Citation Format

Share Document