Thermal turbulent lubrication analysis of rough surface journal bearing with journal misalignment

Abstract The purpose of this study is to investigate the role of the misalignment journal, caused by journal elastic deformation, on the transient wear and mixed lubrication performances using a numerical model. In the numerical model, the transient geometry lubrication clearance considering the journal misalignment, the transient elastic deformation and the transient wear depth are incorporated to evaluate the transient film thickness during wear process. The evolutions, under different external loads, of the wear depth, wear rate, elastic deformation, film thickness, fluid pressure and contact pressure are calculated by the numerical model. Furthermore, the calculated results of the misaligned journal bearing are compared with those of the aligned journal bearing. The results show that the distributions of the wear depth, film pressure and elastic deformation are asymmetric along the axial direction and the peak values of them shift toward the back end when the journal misalignment is considered. The maximum wear depth, maximum fluid pressure, maximum contact pressure and maximum elastic deformation of the misaligned journal condition are significantly larger than those of the aligned journal condition.

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Effects of double parabolic profiles with groove textures on the hydrodynamic lubrication performance of journal bearing under steady operating conditions

Mechanics & Industry ◽

10.1051/meca/2020018 ◽

2020 ◽

Vol 21 (3) ◽

pp. 301

Author(s):

Chongpei Liu ◽

Wanyou Li ◽

Xiqun Lu ◽

Bin Zhao

Keyword(s):

Journal Bearing ◽

Hydrodynamic Lubrication ◽

Operating Conditions ◽

Lubricating Oil ◽

Asperity Contact ◽

Adiabatic Flow ◽

Lubrication Performance ◽

Load Carrying ◽

Edge Wear ◽

Journal Misalignment

The textures on the bushing surface have important effects on the performance of journal bearing. In this study, the effects of double parabolic profiles with groove textures on the hydrodynamic lubrication performance of journal bearing under steady operating conditions are investigated theoretically. The journal misalignment, asperity contact and thermal effects are considered, while the profile modifications due to running-in are neglected. The Winkler/Column model is used to calculate the elastic deformation of bushing surface and the adiabatic flow hypothesis is adopted to obtain the effective temperature of lubricating oil. The numerical solution is established by using finite difference and overrelaxation iterative methods, and the rupture zone of oil film is determined by Reynolds boundary conditions. The numerical results reveal that the double parabolic profiles with groove textures with proper location and geometric sizes can increase load carrying capacity and reduce friction loss under steady operating conditions, which effectively overcome the drawbacks of double parabolic profiles. This novel bushing profile may help to reduce the bushing edge wear and enhance the lubrication performance of journal bearing.

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A Study of Misaligned Micropolar Lubricated Membrane Compensated Hybrid Journal Bearing System

Journal of Tribology ◽

10.1115/1.4004456 ◽

2011 ◽

Vol 133 (3) ◽

Cited By ~ 4

Author(s):

Satish C. Sharma ◽

E. Rajasekhar Nicodemus ◽

Nathi Ram

Keyword(s):

Reynolds Equation ◽

Flow Characteristic ◽

Journal Bearing ◽

Lubricating Oil ◽

Micropolar Theory ◽

Shaft Deflection ◽

Journal Misalignment ◽

Raphson Method ◽

System Operating ◽

Bearing System

The present work aims to analytically study the performance of misaligned four-pocket, membrane compensated, hybrid journal bearing system operating with micropolar lubricant. In the present study, the flow characteristic of the lubricating oil containing additives and contaminants has been modeled using Erigen’s micropolar theory. The journal misalignment which may occur as a result of noncentral loading, improper assembly, shaft deflection due to elasticity and thermal distortions, etc. has been accounted for in the present study by defining a pair of misalignment parameters in vertical and horizontal directions (i.e., δ and σ).The modified Reynolds equation governing the flow of micropolar lubricant in the clearance space of a misaligned bearing has been solved using FEM and Newton Raphson method along with the appropriate boundary conditions. The numerically simulated results suggest that the effect of journal misalignment is to cause degradation in bearing performance, whereas the influence of micropolar effect of lubricant is to enhance the bearing performance. Therefore, it is imperative to account for the effect of misalignment and lubricant behavior during the design process in order to generate accurate bearing characteristics data.

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Effect of Journal Misalignment on the Oil Film Pressure and Temperature Distribution of 3-Lobe Offset Journal Bearing

World Tribology Congress III, Volume 2 ◽

10.1115/wtc2005-63828 ◽

2005 ◽

Author(s):

S. Strzelecki ◽

Z. Towarek

Keyword(s):

Temperature Distribution ◽

High Speed ◽

Journal Bearing ◽

Journal Bearings ◽

Good Stability ◽

Rotating Machines ◽

Film Pressure ◽

Bearing Design ◽

Journal Misalignment ◽

Oil Film Pressure

The design of turbines and compressors operating at the high rotational speeds applies the 3-lobe journal bearings. In many cases the classic 3-lobe journal bearings supporting the rotors, are showing the problem of rotor stability. This problem can be avoided by the application of 3-lobe Offset bearings. This type of bearing fulfils the conditions of reliable bearing design and good stability in the case of high speed rotating machines.

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Research on the Static and Dynamic Characteristics of Misaligned Journal Bearing Considering the Turbulent and Thermohydrodynamic Effects

Journal of Tribology ◽

10.1115/1.4029333 ◽

2015 ◽

Vol 137 (2) ◽

Cited By ~ 22

Author(s):

Guohui Xu ◽

Jian Zhou ◽

Haipeng Geng ◽

Mingjian Lu ◽

Lihua Yang ◽

...

Keyword(s):

Film Thickness ◽

Dynamic Characteristics ◽

Journal Bearing ◽

Journal Bearings ◽

Static And Dynamic Characteristics ◽

Oil Film ◽

Stiffness And Damping ◽

Film Stiffness ◽

Journal Misalignment ◽

Oil Film Pressure

Journal misalignment usually exists in journal bearings that affect nearly all the bearings static and dynamic characteristics including minimum oil film thickness, maximum oil film pressure, maximum oil film temperature, oil film stiffness, and damping. The main point in this study is to provide a comprehensive analysis on the oil film pressure, oil film temperature, oil film thickness, load-carrying capacity, oil film stiffness, and damping of journal bearing with different misalignment ratios and appropriately considering the turbulent and thermo effects based on solving the generalized Reynolds equation and energy equation. The results indicate that the oil thermo effects have a significant effect on the lubrication of misaligned journal bearings under large eccentricity ratio. The turbulent will obviously affect the lubrication of misaligned journal bearings when the eccentricity or misalignment ratio is large. In the present design of the journal bearing, the load and speed become higher and higher, and the eccentricity and misalignment ratio are usually large in the operating conditions. Therefore, it is necessary to take the effects of journal misalignment, turbulent, and thermal effect into account in the design and analysis of journal bearings.

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Calculation of Journal Bearing Dynamic Characteristics Including Journal Misalignment and Bearing Structural Deformation©

Tribology Transactions ◽

10.1080/05698190490278994 ◽

2004 ◽

Vol 47 (1) ◽

pp. 94-102 ◽

Cited By ~ 26

Author(s):

OMIDREZA EBRAT ◽

ZISSIMOS P. MOURELATOS ◽

NICKOLAS VLAHOPOULOS ◽

KUMAR VAIDYANATHAN

Keyword(s):

Dynamic Characteristics ◽

Journal Bearing ◽

Structural Deformation ◽

Journal Misalignment

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An Experimental Study of Journal Bearing Lubrication Effected by Journal Misalignment as a Result of Shaft Deformation Under Load

Journal of Tribology ◽

10.1115/1.2033007 ◽

2005 ◽

Vol 127 (4) ◽

pp. 813-819 ◽

Cited By ~ 24

Author(s):

Jun Sun ◽

Changlin Gui ◽

Zhiyuan Li

Keyword(s):

Journal Bearing ◽

Friction Pair ◽

Obvious Effect ◽

Oil Film ◽

Lubrication Performance ◽

Mechanical Devices ◽

Journal Misalignment ◽

Shaft Deformation ◽

Oil Film Pressure ◽

Bearing Friction

Journal bearing friction pair system is one of the most general and essential parts used in various mechanical devices. A special test bench is developed for the study on lubrication performance of cylindrical journal bearings. The effect of journal misalignment as a result of shaft bending under load is studied. The results show obvious changes at distribution and value of oil film pressure, oil film thickness and oil temperature of journal bearing due to journal misalignment. The higher the load on the shaft, the larger the journal misalignment resulted from shaft deformation, the more obvious effect on lubrication performance of journal bearing.

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Analysis of a Finite Grooved Misaligned Journal Bearing Considering Cavitation and Starvation Effects

Journal of Tribology ◽

10.1115/1.2920231 ◽

1990 ◽

Vol 112 (1) ◽

pp. 60-67 ◽

Cited By ~ 42

Author(s):

D. Vijayaraghavan ◽

T. G. Keith

Keyword(s):

Journal Bearing ◽

Numerical Procedure ◽

Diameter Ratio ◽

Film Rupture ◽

Supply Pressure ◽

Starvation Effects ◽

Inlet Conditions ◽

Journal Misalignment ◽

Length To Diameter Ratio

The effect of journal misalignment on the predicted performance of a finite grooved journal bearing is analyzed in this paper. The numerical procedure used incorporates a cavitation algorithm, which automatically predicts film rupture and reformation in the bearings. The misalignment considered varies in magnitude and direction with reference to the boundaries of the bearing. In addition to the misalignment, the effect of lubricant starvation at the groove is also considered and compared with flooded inlet conditions. The effects of various degrees of starvation, or higher lubricant supply pressure, bearing length to diameter ratio and groove size are also investigated.

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

Industrial Lubrication and Tribology ◽

10.1108/ilt-06-2019-0221 ◽

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.

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Thermohydrodynamic Lubrication Analysis of Misaligned Plain Journal Bearing With Rough Surface

Journal of Tribology ◽

10.1115/1.4000515 ◽

2009 ◽

Vol 132 (1) ◽

Cited By ~ 24

Author(s):

Jun Sun ◽

Mei Deng ◽

Yonghong Fu ◽

Changlin Gui

Keyword(s):

Surface Roughness ◽

Thermal Effect ◽

Journal Bearing ◽

Journal Bearings ◽

Operating Conditions ◽

Eccentricity Ratio ◽

Oil Viscosity ◽

Oil Film ◽

Lubrication Performance ◽

Journal Misalignment

Journal misalignment exists generally in journal bearings. When severe journal misalignment takes place, the minimum film thickness of journal bearings reduces greatly. In this condition, the surface roughness, the oil viscosity-pressure relationship (VPR), and the thermal effect have obvious effects on hydrodynamic lubrication performance of misaligned bearings. In this paper, the oil film pressure, oil film temperature, load-carrying capacity, end leakage flow rate, frictional coefficient, and misalignment moment of a journal bearing with different angles of journal misalignment and surface roughness, and considering oil VPR and thermal effect, were calculated based on the generalized Reynolds equation, energy equation, and solid heat conduction equation. The results show that the oil VPR and surface roughness have a significant effect on the lubrication of misaligned journal bearings under large eccentricity ratio. The thermal effect will affect obviously the lubrication of misaligned journal bearings when eccentricity ratio and angle of journal misalignment are all large. In the present design, the size of the journal bearing is compact more and more, and the eccentricity ratio and angle of journal misalignment are usually large in operating conditions. Therefore, it is necessary to take the effects of journal misalignment, surface roughness, oil VPR, and thermal effect into account in the design and analyses of journal bearings.

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