Numerical optimization of surface texture for improved tribological performance of journal bearing at varying operating conditions

2018 ◽  
Vol 70 (9) ◽  
pp. 1608-1618 ◽  
Author(s):  
Ali Usman ◽  
Cheol Woo Park
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Tribological Performance ◽  
Operating Conditions ◽  
Content Type ◽  
Load Carrying ◽  
Recent Developments ◽  
Effect Of Surface ◽  
Generalized Reynolds Equation

Purpose Journal bearings are used in numerous rotary machines. The load carrying capacity and friction of a bearing have been major concerns in design. Recent developments in surface texturing have showed potential outcomes to improve the tribological characteristics of mating surfaces. This study aims to investigate surface textures, which are transverse to the sliding direction, for frictional response of the journal bearing. Design/methodology/approach A hydrodynamic lubrication model is considered to evaluate the effect of surface texturing on the performance of a journal bearing at varying operating conditions. The two-dimensional generalized Reynolds equation, coupled with mass-conserving Elrod cavitation algorithm, is solved to evaluate texture-induced variations in tribological performance parameters. Findings Results have showed remarkable improvements in frictional response. Moreover, micro-textures on the journal surface alter the cavitation response and film-reformation in the hydrodynamic conjunction of the plain bearing. Originality/value Operating condition-based comprehensive exhaustive optimization of texture geometry is performed to generate widespread conclusion.

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

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.

Design and Development of Permanent Magneto-Hydrodynamic Hybrid Journal Bearing

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
K. P. Lijesh ◽  
Harish Hirani
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Magnetic Bearing ◽  
Operating Conditions ◽  
Fluid Film ◽  
Test Setup ◽  
Fluid Film Bearings ◽  
Lubrication Regime ◽  
Load Carrying ◽  
Hybrid Bearing

Fluid film bearings (FFBs) provide economic wear-free performance when operating in hydrodynamic lubrication regime. In all other operating conditions, except hydrostatic regime, these bearings are subjected to wear. To get wear-free performance even in those conditions, a hybrid (hydrodynamic + rotation magnetized direction (RMD) configured magnetic) bearing has been proposed. The hybrid bearing consists of square magnets to repel the shaft away from the bearing bore. Load-carrying capacities of four configurations of hybrid bearings were determined. The results are presented in this paper. The best configuration of hybrid bearing was developed. A test setup was developed to perform the experiments on the fluid film and hybrid bearings. The wear results of both the bearings under same operating conditions are presented.

Modeling a Hydrodynamic Bearing With Provision for Misalignments and Textures

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Shuwen Wang ◽  
Xiaohong Ding
Keyword(s):  
High Efficiency ◽  
Journal Bearing ◽  
Effective Means ◽  
Surface Texturing ◽  
Tribological Performance ◽  
Journal Bearings ◽  
Time Varying ◽  
Hydrodynamic Bearing ◽  
Proposed Model ◽  
Effect Of Surface

Abstract Surface texturing is one effective means to improve bearing performance. Available studies are mainly focused on the perfectly aligned journal bearing with textures. The studies involving the effect of surface texturing on the misaligned bearing are still limited. In the present study, a transient mixed lubrication model that allows predicting evolution of friction characteristics with high efficiency was proposed. The misalignment of journal bearing under the time-varying applied load was considered using two deflection angles. The performance of journal bearing with provision for misalignments and textures was studied using the proposed model. The results involving the orbits of the journal center and the energy loss of different misaligned journal bearings were obtained. The influences of misalignment degree and surface texturing on these parameters were analyzed. The results show that along with the increased deflection angles, the effect of texturing on the tribological performance of journal bearing would turn beneficial into harmful.

CFD analysis of load-carrying capacity of hydrodynamic lubrication on a water-lubricated journal bearing

2015 ◽  
Vol 67 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Gao Gengyuan ◽  
Yin Zhongwei ◽  
Jiang Dan ◽  
Zhang Xiuli
Keyword(s):  
Carrying Capacity ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Radial Clearance ◽  
Load Carrying Capacity ◽  
Cfd Analysis ◽  
Hydrodynamic Load ◽  
Oil And Grease ◽  
Content Type ◽  
Load Carrying

Purpose – The purpose of this paper is to improve hydrodynamic load-carrying capacity of a water-lubricated journal bearing by a new bush structure. Water-lubricated bearing is becoming more and more popular since it is environmentally friendly and saves energy. However, contrary to oil and grease-lubricated bearings, water-lubricated bearing is limited in many situations due to its low hydrodynamic load-carrying capacity. Design/methodology/approach – The present article proposes a new bearing bush, with a transition-arc structure, which is favorable for increasing hydrodynamic load-carrying capacity. Hydrodynamic load-carrying capacity was calculated by means of three-dimensional computational fluid dynamics (3-D CFD) analysis. Several variants of a journal bearing with a transition-arc structure of different dimensions are analyzed, while the radial clearance of the bearing, eccentricity ratio and the velocity of the journal remain unchanged. Findings – The results show that obvious changes are found in hydrodynamic load-carrying capacity of a water-lubricated journal bearing. For different width over diameter (L/D) bearing ratios, the relationship between hydrodynamic load-carrying capacity and the magnitude of the transition-arc structure dimension is researched. Originality/value – The research presented here leads to a design reference guideline that could be used by the designer engineer to design smart journal bearings for improving the hydrodynamic load-carrying capacity.

scholarly journals Two-scale homogenization of hydrodynamic lubrication in a mechanical seal with isotropic roughness based on the Elrod cavitation algorithm

2021 ◽  
pp. 135065012110176
Author(s):  
Yanxiang Han ◽  
Qingen Meng ◽  
Gregory de Boer
Keyword(s):  
Surface Topography ◽  
Carrying Capacity ◽  
Hydrodynamic Lubrication ◽  
Tribological Performance ◽  
Stribeck Curve ◽  
Polar Coordinate System ◽  
Load Carrying Capacity ◽  
Mechanical Seal ◽  
Macro Scale ◽  
Load Carrying

A two-scale homogenization method for modelling the hydrodynamic lubrication of mechanical seals with isotropic roughness was developed and presented the influence of surface topography coupled into the lubricating domain. A linearization approach was derived to link the effects of surface topography across disparate scales. Solutions were calculated in a polar coordinate system derived based on the Elrod cavitation algorithm and were determined using homogenization of periodic simulations describing the lubrication of a series of surface topographical features. Solutions obtained for the hydrodynamic lubrication regime showed that the two-scale homogenization approach agreed well with lubrication theory in the case without topography. Varying topography amplitude demonstrated that the presence of surface topography improved tribological performance for a mechanical seal in terms of increasing load-carrying capacity and reducing friction coefficient in the radial direction. A Stribeck curve analysis was conducted, which indicated that including surface topography led to an increase in load-carrying capacity and a reduction in friction. A study of macro-scale surface waviness showed that the micro-scale variations observed were smaller in magnitude but cannot be obtained without the two-scale method and cause significant changes in the tribological performance.

Effectiveness of multi-shape laser surface texturing in the reduction of friction under lubrication regime

2016 ◽  
Vol 68 (1) ◽  
pp. 116-124 ◽  
Author(s):  
Dawit Zenebe Segu ◽  
Pyung Hwang
Keyword(s):  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Textured Surface ◽  
Content Type ◽  
Laser Ablation Process ◽  
Specific Formula ◽  
Steel Surfaces ◽  
Lubrication Conditions

Purpose – The purpose of this paper is to investigate and discuss the effect of multi-shape laser surface texturing (LST) steel surfaces on tribological performance. Design/methodology/approach – The textured surface with some specific formula arrays was fabricated by laser ablation process by combining patterns of circles and triangles, circles and squares and circles and ellipses. The tribological test was performed by a flat-on-flat tribometer under dry and lubrication conditions, and results were compared with that of untextured surface. Findings – The results showed that the textured surface had better friction coefficient performance than the untextured surface due to hydrodynamic lubrication effect. Through an increase in sliding speed, the beneficial effect of LST performance was achieved under dry and lubrication conditions. Originality/value – This paper develops multi-shape LST steel surfaces for improving the friction and wear performance under dry and lubrication conditions.

Porous exponential slider bearings lubricated with MHD-couple stress fluid

2018 ◽  
Vol 70 (5) ◽  
pp. 838-845 ◽  
Author(s):  
N.B. Naduvinamani ◽  
Shridevi S. Hosmani
Keyword(s):  
Couple Stress ◽  
Numerical Solutions ◽  
Transverse Magnetic ◽  
Operating Conditions ◽  
Couple Stress Fluid ◽  
Content Type ◽  
Electrically Conducting ◽  
Slider Bearings ◽  
Load Carrying ◽  
First Time

Purpose The purpose of this study is to examine the magneto-hydrodynamic (MHD) effect on porous exponential slider bearings lubricated with couple stress fluid and to derive the modified Reynolds’s equation for non-Newtonian fluid under various operating conditions to obtain the optimum bearing parameters. Design/methodology/approach Based upon the MHD theory and Stokes theory for couple stress fluid, the governing equations relevant to the problem under consideration are derived. This paper analyzes the effect on porous exponential slider bearings with an electrically conducting fluid in the presence of a transverse magnetic field. Semi-numerical solutions are obtained and discussed. Findings It is found that there is an increase in the load carrying capacity, frictional force and decrease in the co-efficient of friction in porous bearings due to the presence of magnetic effects with couple stress fluid. Originality/value This study is relatively original and gives the MHD effect on porous exponential slider bearings lubricated with couple stress fluid. The author believes that the paper presents these results for the first time.

Simulation studies on static thermal behaviour of true elliptical and orthogonally displaced non-circular journal bearing

2016 ◽  
Vol 68 (3) ◽  
pp. 349-360 ◽  
Author(s):  
Amit Singla ◽  
Amit Chauhan
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Current Trend ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Film Pressure ◽  
Content Type ◽  
Oil Film ◽  
Ellipticity Ratio ◽  
Oil Film Pressure

Purpose The current trend of modern industry is to use machineries which rotate at high speed along with the capability of carrying heavy rotor loads. This paper aims at static thermal analysis of two different profiles of non-circular journal bearings – a true elliptical bearing and orthogonal bearing. Design/methodology/approach The Reynolds equation has been solved through finite difference method to compute the oil film pressure. Parabolic temperature profile approximation technique has been used to solve the energy equation and thus used for computation of various bearing performance characteristics such as thermo-hydrodynamic oil film pressure, temperature, load capacity, Sommerfeld number and power loss characteristics across the bearing. The effect of ellipticity ratio on the bearing performance characteristics has also been obtained for both the elliptical and vertical offset bearing using three different commercially available grades of oil (Hydrol 32, 68 and 100). Findings It has been observed that the thermo-hydrodynamic pressure and temperature rise of the oil film is less in orthogonal bearing as compared to the true elliptical bearing for same operating conditions. The effect of ellipticity ratio of non-circularity on bearing performance parameters have been observed to be less in case of elliptical bearing as compared to orthogonal bearing. It has been concluded that though the rise in oil film temperature is high for true elliptical bearing, but still it should be preferred over orthogonal profile under study, as it has comparably good load-carrying capacity. Originality/value The performance parametric analysis will help the designers to select such kind of non-circular journal bearing for various applications.

Performance of Stern Tube Bearings under Different Lubrication and Operating Conditions

2009 ◽  
Author(s):  
Jan H. Andersen ◽  
Hiroyuki Sada ◽  
Seiji Yamajo
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Water Soluble ◽  
Analysis Tool ◽  
Test Rig ◽  
Experimental Performance ◽  
Shaft Alignment ◽  
Alignment Analysis

This paper presents the results of an investigation into the theoretical and experimental performance of oil lubricated journal bearings. DNV has developed a new calculation tool for the analysis of journal bearing performance as part of shaft alignment analysis. The results of the calculation tool have been compared to other research and analysis methods under static and dynamic conditions. In addition, white metal bearings were tested with decreasing Sommerfeld number until loss of hydrodynamic lubrication. The experiments were carried out in a bearing test rig and with three different lubricants, normal mineral oil, emulsifying oil, and water-soluble oil. The tests were done with increasing water content in the lubricant. Results from the test were compared with calculation using the DNV analysis tool.

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