Influence of Geometric Shapes on the Hydrodynamic Lubrication of a Partially Textured Slider With Micro-Grooves

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Jinghu Ji ◽  
Yonghong Fu ◽  
Qinsheng Bi
Keyword(s):  
Multigrid Method ◽  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Hydrodynamic Pressure ◽  
Groove Depth ◽  
Geometric Shape ◽  
Groove Width ◽  
Operating Parameters ◽  
Average Pressure ◽  
Area Density

The effect of partial surface texturing in the form of parabolic grooves, rectangular grooves, and triangular grooves on the hydrodynamic pressure is investigated in the present work. The dimensionless hydrodynamic pressure generated by the partial surface texturing is obtained by the multigrid method. The effect of the texturing parameters on the dimensionless average pressure is analyzed for a given set of operating parameters. The results indicate that the geometric shape, area density, groove depth, and orientation of the grooves have an obvious influence on the hydrodynamic pressure. However, the groove width has little effect on the dimensionless average pressure. The results of the present work demonstrate that surface texturing design is very important to generate additional hydrodynamic pressure according to the operating parameters of the mechanical components.

Hydrodynamic Lubrication of Conformal Contacting Surfaces With Parabolic Grooves

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Yonghong Fu ◽  
Jinghu Ji ◽  
Qinsheng Bi
Keyword(s):  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Orientation Angle ◽  
Groove Depth ◽  
Groove Width ◽  
Hydrodynamic Effect ◽  
Geometrical Parameters ◽  
Average Pressure ◽  
Minimum Film Thickness ◽  
Effect Of Surface

The effect of surface texturing in the form of parabolic grooves on the hydrodynamic lubrication properties is investigated in this paper. Numerical simulation of the pressure distribution of lubricant between a textured slider and a smooth, moving slider has been performed. The evaluation criterion of hydrodynamic effect of dimensionless average pressure is calculated and presented with the variation of minimum film thickness, groove width, groove depth, spacing and orientation angle. Optimum values of geometrical parameters such as the dimensionless groove depth, spacing and orientation angle are obtained which correspond to maximum average pressure. It is also noted that the average pressure increases monotonically with increasing groove width. The results show that the hydrodynamic effect can be improved by employing optimized surface texturing design.

Effect of Elliptical Dimples on Hydrodynamic Lubrication

2015 ◽  
Vol 645-646 ◽  
pp. 474-479 ◽  
Author(s):  
Jing Hu Ji ◽  
Hao Wang ◽  
Yong Hong Fu
Keyword(s):  
Analytical Model ◽  
Inclination Angle ◽  
Hydrodynamic Lubrication ◽  
Grid Method ◽  
Hydrodynamic Pressure ◽  
Hydrodynamic Effect ◽  
Operating Parameters ◽  
Geometrical Parameters ◽  
Average Pressure ◽  
Lubrication Performance

This paper develops an analytical model to investigate the effect of elliptical dimples on hydrodynamic lubrication of surface contact. The hydrodynamic pressure generated by elliptical dimples is solved by the multi-grid method. The evaluation criterion of hydrodynamic effect of dimensionless average pressure is calculated and presented with the variation of elliptical dimple depth, area density, slender ratio and inclination angle. The results indicate that geometrical parameters of elliptical dimples have an obvious influence on the hydrodynamic pressure. The hydrodynamic lubrication performance can be ameliorated by optimizing the geometrical parameters of elliptical dimples according to the operating parameters of the mechanical components.

The influence of partially textured slider with orientation ellipse dimples on the behavior of hydrodynamic lubrication

2014 ◽  
Vol 66 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Jinghu Ji ◽  
Yonghong Fu ◽  
Qinsheng Bi
Keyword(s):  
Pressure Distribution ◽  
Design Methodology ◽  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Grid Method ◽  
Hydrodynamic Effect ◽  
Operating Parameters ◽  
Average Pressure ◽  
Content Type ◽  
Proper Design

Purpose – The purpose of this paper is to investigate a partially textured slider of infinite width with orientation ellipse dimples in liquid application. Design/methodology/approach – In this paper, the pressure distribution of lubrication between a partially textured slider and a smooth sliding slider is calculated by the multi-grid method. For the same dimple area, the influence of the ellipse dimple with geometric parameters, and distribution and orientation on the hydrodynamic lubrication is evaluated in terms of the dimensionless average pressure for a given set of operating parameters. Findings – In the present work, the magnitude of the dimensionless average pressure seems proportional to the slender ratio. Consequently, the slender ratio may be chosen as large as possible based on fabrication techniques. The longer axes of ellipse dimples placed parallel to the direction of sliding always show the better hydrodynamic effect. Furthermore, the results show that the ellipse dimples can greatly improve hydrodynamic effect of partially surface textured slider of infinite width by proper design of these texturing parameters. Originality/value – This paper develops a partial surface texturing infinitely width slider with orientation ellipse dimples for improving hydrodynamic lubrication.

scholarly journals Hydrodynamic Lubrication of Partially Textured Gas Parallel Slider Bearings with Orientation Ellipse Dimples

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Fuxi Liu ◽  
Zhanlong Li ◽  
Chunjie Yang ◽  
Hongbao Wu ◽  
Huazhu Yin ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Hydrodynamic Lubrication ◽  
Orientation Angle ◽  
Hydrodynamic Pressure ◽  
Geometric Parameters ◽  
Average Pressure ◽  
Sliding Speed ◽  
Slider Bearings ◽  
Lubrication Performance

The hydrodynamic lubrication performance of partially textured gas parallel slider bearings with orientation ellipse dimples is investigated in this paper. By using the multigrid finite element method, the pressure distribution between a partially textured slider and a smooth slider is obtained. The geometric parameters of the ellipse dimples are optimized to maximize the average pressure under a given sliding speed. The numerical results show that geometric parameters such as orientation angle, depth, slender ratio, and area density have an important impact on hydrodynamic pressure. Besides, the effect of textured fraction on hydrodynamic pressure is investigated under a given sliding speed. It is observed that the optimum textured fraction for maximizing the average pressure is dependent on the sliding speed.

Numerical Analysis of Grinding Fluid Field in Grinding

2010 ◽  
Vol 97-101 ◽  
pp. 2944-2950
Author(s):  
Guang Yao Meng ◽  
Ji Wen Tan ◽  
Shan Shan Shang ◽  
Chang He Li
Keyword(s):  
Mathematical Model ◽  
Multigrid Method ◽  
Hydrodynamic Lubrication ◽  
Hydrodynamic Pressure ◽  
Grinding Wheel ◽  
Fluid Field ◽  
Grinding Fluid ◽  
Crude Model ◽  
Hydrodynamic Lubrication Theory ◽  
Good Agreement

Based on hydrodynamic lubrication theory, a mathematical model of grinding fluid field in flood is sets up in this paper. Hydrodynamic pressure and velocity of grinding fluid are calculated by multigrid method. Additionally, crude model about the coarseness of grinding wheel and workpiece is built on the basis of slick model and solutions are obtained by multigrid method. Solutions of slick model and crude model are compared. Result shows that the solution of slick model is in good agreement with the crude model and verifies the experimental analysis.

Static Characteristics of Journal Bearings With Square Dimples

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Hiroyuki Yamada ◽  
Hiroo Taura ◽  
Satoru Kaneko
Keyword(s):  
Hydrodynamic Lubrication ◽  
Numerical Models ◽  
Experimental Studies ◽  
Surface Texturing ◽  
Hydrodynamic Pressure ◽  
Journal Bearings ◽  
Friction Torque ◽  
Operating Conditions ◽  
Static Characteristics ◽  
Lubrication Performance

Surface texturing is a technique for improving frictional and hydrodynamic performances of journal bearings because microtextures can serve as reservoirs for oil or traps for debris and may also generate hydrodynamic pressure. Over the past two decades, many researchers have experimentally demonstrated that texturing of various tribological elements can reduce friction force and wear, contributing to improvement of lubrication performance. Some numerical studies have examined the hydrodynamic lubrication conditions and reported that surface texturing affects the static characteristics of journal bearings, such as their load carrying capacity and friction torque. However, the validity of these numerical models has not been confirmed because of a lack of experimental studies. This study proposes a numerical model that includes both inertial effects and energy loss at the edges of dimples on the surface of a journal bearing in order to investigate the bearing's static characteristics. Experimental verification of journal bearings is also conducted with a uniform square-dimple pattern on their full-bearing surface. The results obtained by the model agree well with those of experiment, confirming the model's validity. These results show that under the same operating conditions, textured bearings yield a higher eccentricity ratio and lower attitude angle than the conventional ones with a smooth surface. This tendency becomes more marked for high Reynolds number operating conditions and for textured bearings with a large number of dimples.

scholarly journals Fast laser surface texturing of spherical samples to improve the frictional performance of elasto-hydrodynamic lubricated contacts

Friction ◽  
2021 ◽  
Author(s):  
G. Boidi ◽  
P. G. Grützmacher ◽  
A. Kadiric ◽  
F. J. Profito ◽  
I. F. Machado ◽  
...  
Keyword(s):  
Surface Texturing ◽  
Hydrodynamic Pressure ◽  
Friction Reduction ◽  
Laser Surface Texturing ◽  
Textured Surfaces ◽  
Engineering Applications ◽  
Lubricated Contacts ◽  
Fluid Uptake ◽  
Direct Laser ◽  
Frictional Performance

AbstractTextured surfaces offer the potential to promote friction and wear reduction by increasing the hydrodynamic pressure, fluid uptake, or acting as oil or debris reservoirs. However, texturing techniques often require additional manufacturing steps and costs, thus frequently being not economically feasible for real engineering applications. This experimental study aims at applying a fast laser texturing technique on curved surfaces for obtaining superior tribological performances. A femtosecond pulsed laser (Ti:Sapphire) and direct laser interference patterning (with a solid-state Nd:YAG laser) were used for manufacturing dimple and groove patterns on curved steel surfaces (ball samples). Tribological tests were carried out under elasto-hydrodynamic lubricated contact conditions varying slide-roll ratio using a ball-on-disk configuration. Furthermore, a specific interferometry technique for rough surfaces was used to measure the film thickness of smooth and textured surfaces. Smooth steel samples were used to obtain data for the reference surface. The results showed that dimples promoted friction reduction (up to 20%) compared to the reference smooth specimens, whereas grooves generally caused less beneficial or detrimental effects. In addition, dimples promoted the formation of full film lubrication conditions at lower speeds. This study demonstrates how fast texturing techniques could potentially be used for improving the tribological performance of bearings as well as other mechanical components utilised in several engineering applications.

Effect of shape/size and distribution of microgeometries of textures on tribo-performance of crankpin bearing

2021 ◽  
pp. 135065012110105
Author(s):  
Nguyen Van Liem ◽  
Wu Zhenpeng ◽  
Jiao Renqiang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Contact Force ◽  
Distribution Density ◽  
Hydrodynamic Lubrication ◽  
Operating Conditions ◽  
Asperity Contact ◽  
Combined Model ◽  
Obvious Effect ◽  
Area Density

The effect of the shape/size and distribution of microgeometries of textures on improving the tribo-performance of crankpin bearing is proposed. Based on a combined model of the slider-crank mechanism dynamic and hydrodynamic lubrication, the distribution density, area density, and shape of spherical textures, square-cylindrical textures, wedge-shaped textures, and a hybrid between spherical texture and square-cylindrical texture on the crankpin bearing's tribo-performance are investigated under different operating conditions of the engine. The tribological characteristic of the crankpin bearing is then evaluated via the indexes of the oil film pressure p, asperity contact force, friction force, and friction coefficient of the crankpin bearing. The research results show that the distribution density with n = 12 and m = 6, and area density with α = 30% of various microtextures have an obvious effect on ameliorating the crankpin bearings tribo-performance. Concurrently, at the mixed lubrication region, the shape of the square-cylindrical texture on improving the tribo-performance is better than the other shapes of the spherical texture, wedge-shaped texture, and spherical and square-cylindrical texture. Particularly, all the average values of the asperity contact force, friction force, and friction coefficient with a square-cylindrical texture are significantly reduced by 14.6%, 19.5%, and 34.5%, respectively, in comparison without microtextures. Therefore, the microtextures of the spherical texture applied on the bearing surface can contribute to enhance the durability and decrease the friction power loss of the engine.

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.

Hydrodynamic Pressure of Thrust Step Bearings

2009 ◽  
Author(s):  
Shuangbiao Liu ◽  
W. Wayne Chen ◽  
Diann Y. Hua
Keyword(s):  
Analytical Solution ◽  
Coordinate System ◽  
Laplace Equation ◽  
Analytical Solutions ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Hydrodynamic Pressure ◽  
Finite Width ◽  
Cylindrical Coordinate ◽  
Lubrication Models

Step bearings are frequently used in industry for better load capacity. Analytical solutions to the Rayleigh step bearing and a rectangular slider with a finite width are available in literature, but none for a fan-shaped thrust step bearing. This study starts with a known solution to the Laplace equation in a cylindrical coordinate system, which is in the form of infinite summation. An analytical solution to pressure is derived in this paper for hydrodynamic lubrication problems encountered in the fan-shaped step bearing. The presented solutions can be useful for designers to maximize bearing performance as well as for researchers to benchmark numerical lubrication models.

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