Thermohydrodynamic Analysis of Journal Bearings Considering Cavitation and Reverse Flow

1988 ◽  
Vol 110 (3) ◽  
pp. 439-447 ◽  
Author(s):  
H. H. Ott ◽  
G. Paradissiadis
Keyword(s):  
Boundary Condition ◽  
Theoretical Model ◽  
Energy Equation ◽  
Journal Bearing ◽  
Reverse Flow ◽  
Iterative Solution ◽  
Journal Bearings ◽  
Flow Area ◽  
Hydrodynamic Journal Bearing ◽  
Energy Equations

The flow field of a hydrodynamic journal bearing is calculated by the iterative solution of the system of Reynolds and energy equations. In the case of reverse flow at the film inlet, the temperature profile there can not be prescribed as a boundary condition but has to be determined from the flow in the film. This is achieved by a separate integration of the energy equation in the reverse flow area. The flow in the cavitation regions is approximated by a theoretical model leading to a form of the energy equation similar to that for pressure regions, thus enabling the integration of the energy equation over the whole film.

Research on Energy Equation of Lubrication Model on Large-Scale Journal Bearing System

2010 ◽  
Vol 145 ◽  
pp. 139-144
Author(s):  
Jian Mei Wang ◽  
Qing Xue Huang ◽  
Jian Feng Kang ◽  
Yang Fan
Keyword(s):  
Service Life ◽  
Large Scale ◽  
Energy Equation ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Calculation Results ◽  
Major Factors ◽  
Energy Equations ◽  
Bearing System

To prolong the service life of large-scale journal bearings, the major factors that have influences on bearing performances should be taken into account. By consideration of the variations of viscosity and density with pressure and temperature, a more thorough thermo-hydrodynamic lubrication model was established. With designation of variables with nondimensional parameters, a series of equations were nondimensionied, and the corresponding energy equations at different oil-film layers and boundaries were obtained respectively according to proper difference formats, and then solved by the integration of Finite Difference Method (FDM) with Boundary Element Method (BEM). Calculation results have proved that such complete mathematical model could provide great theoretical guide meaning to improve the lubrication performances and to prolong the service life of contact components of heavy journal bearings.

Thermohydrodynamic Lubrication in Laminar and Turbulent Regimes

1974 ◽  
Vol 96 (1) ◽  
pp. 48-56 ◽  
Author(s):  
Z. Safar ◽  
A. Z. Szeri
Keyword(s):  
Boundary Condition ◽  
Effective Viscosity ◽  
Radial Direction ◽  
Energy Equation ◽  
Homogeneous Boundary Condition ◽  
Journal Bearings ◽  
Kantorovich Method ◽  
Local Shear ◽  
Energy Equations ◽  
Laminar And Turbulent Regimes

The distribution of “effective viscosity”—assumed dependent on local shear and temperature—is obtained via iteration between the “long bearing” momentum and energy equations. In this treatment the shaft is isothermal and the bearing conducts heat only in the radial direction. This last assumption leads to essential simplifications: the bearing is replaced by an equivalent homogeneous boundary condition of the energy equation, which thus becomes amenable to solution by the Galerkin-Kantorovich method. The resulting effective viscosity is used to calculate the performance of finite journal bearings.

A Finite Volume Analysis of the Thermohydrodynamic Performance of Finite Journal Bearings

1990 ◽  
Vol 112 (3) ◽  
pp. 557-565 ◽  
Author(s):  
T. Han ◽  
R. S. Paranjpe
Keyword(s):  
Finite Volume ◽  
Numerical Scheme ◽  
Reverse Flow ◽  
Journal Bearings ◽  
Simultaneous Solution ◽  
Volume Analysis ◽  
Recirculating Flow ◽  
Supply Pressure ◽  
Good Sample ◽  
Energy Equations

A rigorous thermohydrodynamic (THD) analysis of finite journal bearings has been developed. THD analysis not only allows a more accurate prediction of the bearing performance characteristics, but it also provides the temperature distribution in the bearing. It involves the simultaneous solution of the Reynolds and energy equations and can handle a wide variety of flow situations, including reverse flow, recirculating flow, and cavitation. The overall numerical scheme is based on a fully conservative finite-volume formulation. The calculated results are compared with the published literature. The qualitative agreement is good. Sample calculations for a typical automotive bearing show that the oil supply pressure and supply configuration significantly affect the bearing performance.

Effect of Slip Boundary Condition and Non-Newtonian Rheology of Lubricants on the Dynamic Characteristics of Finite Hydrodynamic Journal Bearing

2021 ◽  
Author(s):  
Mohammad Arif ◽  
Saurabh Kango ◽  
Dinesh Kumar Shukla
Keyword(s):  
Boundary Condition ◽  
Dynamic Stability ◽  
Journal Bearing ◽  
Mass Parameter ◽  
Critical Mass ◽  
Slip Boundary Condition ◽  
Slip Effect ◽  
Slip Boundary ◽  
Slip Region ◽  
Hydrodynamic Journal Bearing

Abstract In the present study, the influence of various slip zone locations on the dynamic stability of finite hydrodynamic journal bearing lubricated with non-Newtonian and Newtonian lubricants has been investigated. Linearized equation of motion with free vibration of rigid rotor has been used to find the optimum location of the slip region with maximum stability margin limit. It has been observed that bearing with interface of slip and no-slip region near the upstream side of minimum film-thickness location is effective in improving the direct and cross stiffness coefficient, critical mass parameter, and critical whirling speed. The magnitude of dynamic performance parameters with slip effect is highly dependent on the rheology of lubricant. Shear-thinning lubricants combined with slip boundary condition shows higher dynamic stability as compared to the Newtonian lubricants under the conventional boundary condition. For all considered rheology of lubricants, the dynamic stability of bearing with slip effect is improving by increasing the eccentricity ratio.

Numerical study on steady state performance enhancement of partial textured hydrodynamic journal bearing

2019 ◽  
Vol 71 (9) ◽  
pp. 1055-1063 ◽  
Author(s):  
Sanjay Sharma ◽  
Gourav Jamwal ◽  
R.K. Awasthi
Keyword(s):  
Steady State ◽  
Journal Bearing ◽  
Performance Enhancement ◽  
Surface Texturing ◽  
Journal Bearings ◽  
Enhancement Ratio ◽  
Content Type ◽  
Maximum Value ◽  
Static Performance ◽  
Hydrodynamic Journal Bearing

Purpose The purpose of this paper is to provide the various steady state parameters of hydrodynamic journal bearings have been determined to get maximum performance enhancement ratio. For this, the bearings inner surface is textured with triangular shape with different texture depths and a number of textures in pressure increasing region. The textured region acts as a lubricant reservoir, which provides additional film-thickness and reduce friction. Therefore, enhance the overall performance of bearing. Design/methodology/approach In the present study, the effect of triangular shaped texture on the static performance characteristics of a hydrodynamic journal bearing has been studied. Different values of texture depths and a number of textures have been numerically simulated in pressure developing region. The static performance characteristics have been calculated by solving the fluid flow governing Reynolds equation using the finite element method, assuming iso-viscous Newtonian fluid. The performance enhancement ratio, which is the ratio of load carrying capacity (LCC) to the coefficient of friction (COF) has been calculated from results to finalized optimum design parameters. Findings The paper provides numerically obtained results indicate that surface texturing can improve bearing performance if the textured region is placed in the pressure increasing region. Moreover, surface texturing is the most effective at bearing performance enhancement when the bearing operates at lower eccentricity ratios and texture depth. The performance enhancement ratio, which is the ratio of LCC to the COF is found to be a maximum value of 2.198 at texture depth of 1.5, eccentricity ratio of 0.2 and the textured region located in the increasing pressure region. Research limitations/implications The present study is based on a numerical based research approach, which has its limitations. So, researchers are encouraged to investigate the same work experimentally. Practical implications The paper includes implications to be beneficial for designers for designing better hydrodynamic journal bearings. Originality/value For the triangular shaped texture, considered in the present study, the optimum values of texture depth and texture distribution region have also been determined. While designing, designers should focus on those values of texture depth, texture region and a number of textures, which give the maximum value of performance enhancement ratio, which represents maximum LCC at the lowest value of the COF.

Paper 6: A Thermohydrodynamic Analysis of Journal Bearings

1966 ◽  
Vol 181 (15) ◽  
pp. 117-126 ◽  
Author(s):  
D. Dowson ◽  
C. N. March
Keyword(s):  
Heat Conduction ◽  
Journal Bearing ◽  
Journal Bearings ◽  
General Nature ◽  
Two Dimensional ◽  
Approximate Representation ◽  
Full Account ◽  
Design Procedures ◽  
Experimental Findings ◽  
Energy Equations

A thermohydrodynamic analysis is discussed which takes account of the general nature of the experimental observations in work which forms part of a programme of research designed to develop an improved understanding of better design procedures for journal bearings. The analysis considers compatible solutions of the Reynolds, energy, and heat conduction equations for two-dimensional conditions. It is shown that the solutions are in reasonable agreement with experimental findings. The two-dimensional solutions of the Reynolds and energy equations take full account of the variation of lubricant properties along and across the film. A very simple and approximate representation is used to estimate the temperature distribution in the bush, but the solutions present a reasonable estimate of bush and shaft temperatures. The ‘thermohydrodynamic’ or ‘heat conduction’ solution to journal bearing problems will provide intermediate, and it is hoped more realistic, results between the extreme ‘isothermal’ and ‘adiabatic’ conditions.

Empirical Treatment of Hydrodynamic Journal Bearing Performance in the Superlaminar Regime

1970 ◽  
Vol 12 (2) ◽  
pp. 116-122 ◽  
Author(s):  
H. F. Black
Keyword(s):  
Reynolds Number ◽  
Field Equation ◽  
Experimental Work ◽  
Reynolds Equation ◽  
Pressure Field ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Theoretical Treatment ◽  
Hydrodynamic Journal Bearing

The application of a perturbation in terms of simple correlations for friction in turbulent Couette and ‘screw’ flows, together with a further empirical assumption consonant with the experimental work of Smith and Fuller (1), leads to a pressure field equation identical in form with the Reynolds equation. The load capacity of journal bearings throughout most of the superlaminar range may be represented by a single curve, and existing laminar solutions may be applied with the parameters modified by Reynolds number. The theory is compared with published experimental results, and with the most successful theoretical treatment (4). The correlations obtained confirm the adequacy of the theory to predict performance in the superlaminar régime.

scholarly journals Observation of Pressure Variation in the Cavitation Region of Submerged Journal Bearings

1982 ◽  
Vol 104 (2) ◽  
pp. 157-163 ◽  
Author(s):  
I. Etsion ◽  
L. P. Ludwig
Keyword(s):  
Journal Bearing ◽  
Reverse Flow ◽  
Ambient Pressure ◽  
Journal Bearings ◽  
Pressure Variation ◽  
Pressure Measurements ◽  
Pressure Profiles ◽  
Cavitation Region ◽  
Cavitation Pressure ◽  
Visual Observations

Visual observations and pressure measurements in the cavitation zone of a submerged journal bearing are described. Tests were performed at various shaft speeds and ambient pressure levels. Some photographs of the cavitation region are presented showing strong reverse flow at the downstream end of the region. Pressure profiles are presented showing significant pressure variations inside the cavitation zone, contrary to common assumptions of constant cavitation pressure.

Thermohydrodynamic Analysis for a Hydrodynamic Journal Bearing Groove

2005 ◽  
Vol 219 (4) ◽  
pp. 263-274 ◽  
Author(s):  
L Jeddi ◽  
M El Khlifi ◽  
D Bonneau
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Journal Bearing ◽  
Numerical Procedure ◽  
Navier Stokes ◽  
Element Formulation ◽  
Lubricant Flow ◽  
Hydrodynamic Journal Bearing ◽  
Feeding Pressure ◽  
Energy Equations

A numerical procedure is developed for the analysis of thermohydrodynamic behaviour of the hydrodynamic (HD) flow in the groove of a journal bearing. The Navier-Stokes and energy equations are written in terms of the primitive variables u, v, p, and T and solved simultaneously using the incremental load method and the finite element formulation. The numerical model is applied to the analysis of the velocities, the pressure, and the temperature patterns that characterize the lubricant flow in the HD groove. The effects of the runner velocity and the feeding pressure are investigated.

Comparison of Effects of Dimensional Manufacturing Tolerances and Journal Out-of-Roundness on Stability of Hydrodynamic Journal Bearing System

2011 ◽  
Vol 121-126 ◽  
pp. 1966-1971
Author(s):  
Wu Bin Xu ◽  
De Jian Zhou ◽  
Peter Ogrodnik ◽  
Mike Goodwin
Keyword(s):  
Theoretical Analysis ◽  
Taguchi Method ◽  
Journal Bearing ◽  
Journal Bearings ◽  
System Stability ◽  
Design Stage ◽  
Analysis Method ◽  
Manufacturing Tolerances ◽  
Hydrodynamic Journal Bearing ◽  
Bearing System

The manufacturing tolerances of a hydrodynamic journal bearing system are inevitable in manufacturing process. To examine and understand the effect of manufacturing tolerances on the system stability can help engineers to confidently choose reasonable tolerances at design stage. This study presented a theoretical analysis method to determine and compare the effects of dimensional manufacturing tolerances and journal out-of-roundness on system stability by Taguchi method. The results show that the journal out-of-roundness has the most significant effect on the system stability and the journal out-of-roundness appears to stabilize the system. The authors suggest that both dimensional manufacturing tolerances and journal roundness should be taken into account in the design of cylindrical journal bearings.

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