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.

Enhancement of steady state performance of hydrodynamic journal bearing using chevron-shaped surface texture

2019 ◽  
Vol 233 (12) ◽  
pp. 1833-1843 ◽  
Author(s):  
Sanjay Sharma ◽  
Gourav Jamwal ◽  
Rajeev K Awasthi
Keyword(s):  
Steady State ◽  
Surface Texture ◽  
Journal Bearing ◽  
Performance Enhancement ◽  
Surface Texturing ◽  
Design Parameters ◽  
Enhancement Ratio ◽  
Shaped Surface ◽  
Hydrodynamic Journal Bearing ◽  
Steady State Performance

In the present study, the optimum design parameters of chevron-shaped surface texture have been determined for the steady state performance enhancement of a hydrodynamic journal bearing. The fluid flow governing Reynolds equation has been solved using the finite element method, assuming iso-viscous and Newtonian fluid to obtain the static performance characteristics of textured hydrodynamic journal bearing. Different texture depths, areas and distributions have been numerically simulated and a set of optimum texture parameters has been determined based on the maximum performance enhancement ratio. The numerically obtained results indicate that surface texturing can improve bearing performance if the textured region is placed in the pressure build-up region. Moreover, surface texturing is the most effective at bearing performance enhancement when the bearing operates at lower eccentricity ratios. The performance enhancement ratio, which is the ratio of load-carrying capacity to coefficient of friction is found to be maximum at texture depth of 0.4, k = 0.3, textured zone located in the increasing pressure region and eccentricity ratio of 0.2.

Effect of Surface Texturing on the Steady-State Properties and Dynamic Coefficients of a Plain Journal Bearing: Experimental Study

2011 ◽  
Author(s):  
Azzedine Dadouche ◽  
Martin J. Conlon ◽  
Waldemar Dmochowski ◽  
Waldemar Koszela ◽  
Lidia Galda ◽  
...  
Keyword(s):  
Steady State ◽  
Journal Bearing ◽  
Surface Texturing ◽  
Spherical Shape ◽  
Journal Bearings ◽  
Laser Surface Texturing ◽  
Textured Surface ◽  
Dynamic Coefficients ◽  
Internal Surfaces ◽  
Effect Of Surface

The last decade has seen a significant and increased interest in surface texturing technologies esulting in improving the overall tribological properties of mechanical components. Several techniques could be used to modify the surface topography with laser surface texturing becoming most popular recently. In this investigation, rig experiments have been performed on plain and textured-surface journal bearings with an aspect ratio of 1.1 under a variety of loads and speeds. Percussive burnishing (embossing) was used to create the dimples on the internal surfaces of the test bearings. The dimples have a spherical shape with a diameter of 1 mm and a depth of 60 micrometers. Pit-area ratio was in the range 5–20% of the total bearings surfaces. The effects of surface-texturing and dimple density on the bearing steady-state characteristics and dynamic coefficients are analyzed and discussed in this paper.

Comparison of static performance characteristics of different configurations of slot-entry hybrid journal bearing operating with non-Newtonian lubricants

2014 ◽  
Vol 66 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Hem Chander Garg ◽  
Vijay Kumar
Keyword(s):  
Journal Bearing ◽  
Research Work ◽  
Flow Equation ◽  
Journal Bearings ◽  
Performance Characteristics ◽  
Content Type ◽  
Wide Range ◽  
Static Performance ◽  
Fluid Film Thickness ◽  
Newtonian Behavior

Purpose – The slot-entry hybrid journal bearings have been successfully used in various engineering applications because of their good performance over wide range of speed and load, besides their relative simplicity in manufacturing. Most of the research work pertaining to non-recessed journal bearing assumes standard symmetric and asymmetric configurations. However, many more configurations are possible by changing the position of slot which may improve the performance of the slot-entry journal bearing. In the present work study of static performance characteristics of slot-entry journal bearing of different configuration has been carried out. The paper aims to discuss these issues. Design/methodology/approach – FEM has been used to solve the Reynolds equation governing the flow of lubricant in the bearing clearance space along with the restrictor flow equation. The non-Newtonian lubricant has been assumed to follow the cubic shear stress law. The performance characteristics of slot-entry hybrid journal bearings are computed by developing a computer program. Findings – The simulated results of bearing characteristics parameters in terms of minimum fluid-film thickness and bearing flow have been presented for the wide range of various values of non-linearity factor and external load. It is found that there is an increase in the oil requirement for slot-entry hybrid journal bearing with the specified operating and geometric parameters, when the viscosity of the lubricant decreases due to the non-Newtonian behavior of the lubricant. The effect of the decrease in the viscosity of the lubricant due to non-Newtonian behavior of the lubricant diminishes the attitude angle. The computed performance characteristics are helpful for the bearing designer while choosing a particular configuration of bearing. Research limitations/implications – The performance characteristics have been computed by considering the non-Newtonian lubricants. The thermal effects have been ignored in the analysis so as to obviate the mathematical complexity. Originality/value – Get idea from already published manuscripts.

Effect of surface texturing on the dynamic characteristics of hydrodynamic journal bearing comprising concepts of green tribology

2018 ◽  
Vol 232 (11) ◽  
pp. 1365-1376 ◽  
Author(s):  
Shivank Matele ◽  
KN Pandey
Keyword(s):  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Surface Texturing ◽  
Stability Margin ◽  
Journal Bearings ◽  
Textured Surface ◽  
Viable Option ◽  
Hydrodynamic Journal Bearing ◽  
Green Tribology ◽  
Effect Of Surface

Surface texturing has emerged as a viable option for enhancing the surface properties. The present study analyzes the effect of full and partial micro-textured surface, at different locations and different kinds of dimple geometries, on the dynamic characteristics of hydrodynamic journal bearings and made a comparative study with the non-textured bearings. Three different kinds of dimple geometries, namely, circular texture, square texture, and densely distributed square texture have been adopted for study. The important dynamic characteristics of bearings were evaluated and stability charts were plotted. Location of the texture was found as an important parameter for improved dynamic characteristics though the extent of improvement depends largely on the geometry of texture. The partial textured bearing with proper geometry and location was found to be more stable. Stability margin of such bearings was more in comparison to the plain journal bearings and the relative improvement was found to be the maximum for circular texture and minimum for square texture. The study also shows the potential of surface texturing to make contribution in the accomplishment of the objectives of green tribology.

Effect of Surface Roughness on the Pressure Generation in a Finite Rough Hydrodynamic Journal Bearing under Micropolar Lubrication in Steady-State

2016 ◽  
Vol 15 (0) ◽  
pp. 39
Author(s):  
Gautam Kumar ◽  
Sujeet Kumar Jha ◽  
Ujjal Baidya ◽  
Santanu Das ◽  
Sanjoy Das
Keyword(s):  
Surface Roughness ◽  
Steady State ◽  
Journal Bearing ◽  
Hydrodynamic Journal Bearing ◽  
Micropolar Lubrication ◽  
Effect Of Surface

The Effect of Lubricant Inertia in Journal-Bearing Lubrication

1957 ◽  
Vol 24 (4) ◽  
pp. 494-496
Author(s):  
J. F. Osterle ◽  
Y. T. Chou ◽  
E. A. Saibel
Keyword(s):  
Reynolds Number ◽  
Steady State ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Hydrodynamic Theory ◽  
Simple Relationship ◽  
Inertia Effect ◽  
Laminar Regime ◽  
Steady State Operation

Abstract The Reynolds equation of hydrodynamic theory, modified to take lubricant inertia into approximate account, is applied to the steady-state operation of journal bearings to determine the effect of lubricant inertia on the pressure developed in the lubricant. A simple relationship results, relating this “inertial” pressure to the Reynolds number of the flow. It is found that the inertia effect can be significant in the laminar regime.

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.

Investigation the combined effects of wear and turbulent on the performance of hydrodynamic journal bearing operating with couple stress fluids

2019 ◽  
Vol 10 (6) ◽  
pp. 825-837
Author(s):  
Mushrek A. Mahdi ◽  
Ahmed Waleed Hussein
Keyword(s):  
Couple Stress ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Performance Characteristics ◽  
Turbulent Regime ◽  
Hydrodynamic Bearings ◽  
Content Type ◽  
Hydrodynamic Journal Bearing ◽  
Local Reynolds Number ◽  
Couple Stress Fluids

Purpose The purpose of this paper is to investigate the combined effect of wear and turbulence on the performance of a hydrodynamic journal bearing operating under Newtonian and couple stress fluids (CSF). Design/methodology/approach The analysis consists of a modified Reynolds equation of incompressible thin viscous films, and the film thickness model taking into account the wear effect. The governing equation was solved numerically using the finite difference approach. Findings The effect of both the wear parameter and the local Reynolds number on the performance characteristics of bearing has been presented and discussed. The obtained results observed that the characteristics of the intact and worn bearing in turbulent and laminar have been enhanced due to the non-Newtonian fluid (CSF) effect. Also, the results display that bearing worn and the turbulent regime cannot be neglected in calculating the performance characteristics of the bearing lubricated with Newtonian and non-Newtonian fluids. The results achieved from this study, specify that the bearing characteristics are significantly affected by these effects. Originality/value The paper investigates the behavior of hydrodynamic bearings considering different aspects simultaneously is interesting, and the application meets the current needs of improvement in modeling hydrodynamic bearings under different conditions.

Steady-State and Dynamic Behaviour of Multi-Recess Hybrid Oil Journal Bearings

1979 ◽  
Vol 21 (5) ◽  
pp. 345-351 ◽  
Author(s):  
M. K. Ghosh ◽  
B. C. Majumdar ◽  
J. S. Rao
Keyword(s):  
Perturbation Theory ◽  
Steady State ◽  
Theoretical Analysis ◽  
Dynamic Behaviour ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Time Dependent ◽  
Damping Coefficients ◽  
Stiffness And Damping

A theoretical analysis of the steady-state and dynamic characteristics of multi-recess hybrid oil journal bearings is presented. A perturbation theory for small vibrations is used to solve an incompressible, finite journal bearing with a time-dependent term. Load capacity, attitude angle, friction parameter, stiffness and damping coefficients are evaluated for a capillary-compensated bearing.

Linear stability analysis of finite hydrodynamic journal bearing under turbulent lubrication with coupled-stress fluid

2016 ◽  
Vol 68 (3) ◽  
pp. 386-391 ◽  
Author(s):  
Abhishek Ghosh ◽  
Sisir Kumar Guha
Keyword(s):  
Stability Analysis ◽  
Newtonian Fluid ◽  
High Speed ◽  
Journal Bearing ◽  
Slenderness Ratio ◽  
Linear Perturbation ◽  
Content Type ◽  
Hydrodynamic Journal Bearing ◽  
The Stability ◽  
Coupled Stress

Purpose Several researchers have observed that to satisfy modern day’s need, it is essential to enhance the characteristics of journal bearing, which is used in numerous applications. Moreover, the use of Newtonian fluid as a lubricant is diminishing day by day, and the use of Non-Newtonian fluids is coming more into picture. Furthermore, if turbo-machinery applications are taken into account, then it can be seen that journal bearings are used for high speed applications as well. Thus, neglecting turbulent conditions may lead to erroneous results. Hence, this paper aims to present focuses on studying the stability characteristics of finite hydrodynamic journal bearing under turbulent coupled-stress lubrication. Design/methodology/approach First, the governing equation relevant to the problem is generated. Then, the dynamic analysis is carried out by linear perturbation technique, leading to three perturbed equations, which are again discretized by finite difference method. Finally, these discretized equations are solved with the help of Gauss-Seidel Iteration technique with successive over relaxation scheme. Consequently, the film response coefficients and the stability parameters are evaluated at different parametric conditions. Findings It has been concluded from the study that with increase in value of the coupled-stress parameter, the stability of the journal may increase. Whereas, with increase in Reynolds number, the stability of the journal decreases. On the other hand, stability increases with increasing values of slenderness ratio. Originality/value Researches have been performed to study the dynamic characteristics of journal bearing with non-Newtonian fluid as the lubricant. But in the class of non-Newtonian lubricants, the use of coupled-stress fluid has not yet been properly investigated. So, an attempt has been made to perform the stability analysis of bearings with coupled-stress fluid as the advanced lubricant.

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