Effect of Dimple’s Internal Structure on Hydrodynamic Lubrication

Shen, Cong; Khonsari, M. M.

doi:10.1007/s11249-013-0225-8

Cited by 92 publications

(55 citation statements)

References 23 publications

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“…The elasto-hydrodynamic lubrication (EHL) modelling results showed that a larger hydrodynamic lifting effect generated with converging sloped bottom dimples than the flat bottom one [43]. Unanimous conclusions were achieved by another modelling work [44] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 3 were generated from an experimental and numerical work by Shen and Khonsari in 2013 [45]. The aim of their work was to check the lubrication effectiveness of dimples with various internal structures.…”

Section: Introductionmentioning

confidence: 95%

The use of anisotropic texturing for control of directional friction

Lu¹,

Wood²,

Gee

et al. 2017

Tribology International

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This paper presents a study on the influence of anisotropically shaped texture arrays on friction behaviour of an oil lubricated sliding contact, especially on directional friction control based on the diverging and converging characteristics of the textures. Experiments have been conducted on a TE77 reciprocating cylinder-on-plate test rig, where steel rollers were used to slide against steel plate samples with or without textures. A mineral base oil was used to lubricate the contacts. Three geometries of dimples were designed and laser textured on the steel plate samples with varied 3-dimensional features, including Square Flat (SF), Square slope (SS) and Triangular Flat (TF) shapes representing the shape in x-y (top view) and x-z (side view) planes respectively. These shapes were chosen to vary the converging and diverging properties of the lubricated contacts depending on the sliding direction. Relatively large dimple sizes (side length ~ and depth ~ ) have been used in this study to enable observation of the effect and easy control of the texturing process. The texture density has been kept at as most literature suggested. The large dimple sizes resulted that the dimples were not be fully covered by the contact area, i.e. the dimple sides were bigger than the Hertzian contact width of the roller-flat contacts. This has eliminated the 'lift' or 'load bearing' effect discussed in most papers thus focuses on other effects investigated in this study. The results show that beneficial effects of the anisotropic textures present in all lubrication regimes including the boundary, mixed and hydrodynamic lubrications, especially under prevailing boundary lubrication conditions. Using high sampling rate for the friction data during the tests, it was able to study local friction effect due to individual dimple array especially at their leading and trailing edges. The results show that a local friction reduction is observed at the leading while an increase at the trailing edge. Overall directional friction effect of the anisotropic textures has been observed that the converging shape in both y-z plane and the x-y plane reduces friction. Furthermore, it was found that the triangular shape dimples have a greater local frictional response at each dimple array, while the sloped bottom square dimples have a more significant overall directional fricition effect.

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Section: Introductionmentioning

confidence: 95%

The use of anisotropic texturing for control of directional friction

Lu¹,

Wood²,

Gee

et al. 2017

Tribology International

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“…The role of surface texturing in improving the tribological properties varies based on the contact conditions-whether they are hydrodynamic (full), mixed, boundary or dry conditions. In the case of full hydrodynamic and mixed lubrication conditions, the micro-craters serve as micro-hydrodynamic bearings that increase the hydrodynamic pressure due to asymmetric pressure distribution, which results in greater hydrodynamic lift or larger fluid film thickness [14,15]. In mixed lubrication conditions, this additional lift in hydrodynamic pressure alters the balance between hydrodynamic and boundary lubrication, and consequently, the number of asperities in contact decreases, and friction and wear likewise decrease [16].…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of Grease Friction Properties on Sliding Textured Surfaces

et al. 2017

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There is comprehensive work on the tribological properties and lubrication mechanisms of oil lubricant used on textured surfaces, however the use of grease lubrication on textured surfaces is rather new. This research article presents an experimental study of the frictional behaviours of grease lubricated sliding contact under mixed lubrication conditions. The influences of surface texture parameters on the frictional properties were investigated using a disc-on-ring tribometer. The results showed that the friction coefficient is largely dependent on texture parameters, with higher and lower texture density resulting in a higher friction coefficient at a fixed texture depth. The sample with texture density of 15% and texture depth of 19 µm exhibited the best friction properties in all experimental conditions because it can store more grease and trap wear debris. The reduction of friction is mainly attributable to the formation of a stable grease lubrication film composed of oil film, transfer film and deposited film, and the hydrodynamic pressure effect of the surface texture, which increases the mating gap and reduces the probability of asperity contact. This result will help in understanding the tribological behaviour of grease on a textured surface and in predicting the lubrication conditions of sliding bearings for better operation in any machinery.

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“…Progress toward the improvement of tribological performance of frictional surface by means of surface texturing can be found in Refs. [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Improving Bearings Thermal and Tribological Performance with Built-In Heat Pipe

Xiao

Khonsari

2015

Tribol Lett

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A recent experimental investigation revealed that a mechanical face seal with built-in heat pipe can significantly reduce the interfacial contact temperature (Xiao and Khonsari in J Eng Tribol 228(5):498-510, 2014). Further experimental tests are set up to investigate the effect of thermal and lubrication characteristics in a thrustbearing configuration with built-in heat pipes either in the stationary or in the rotating component. During the tests, the rotating disk slides against the stationary disk in an oil reservoir filled with SAE 10 engine oil. Both disks are made of heat-treated stainless steel 17-4 PH with the same hardness. Rubbing face temperature and surface friction coefficient are measured from both the heat pipe and conventional disk pair and the conventional disk pair. The test results show that both the heat pipe stationary and rotating disks are capable of reducing the temperature and friction coefficient.

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Effect of Dimple’s Internal Structure on Hydrodynamic Lubrication

Cited by 92 publications

References 23 publications

The use of anisotropic texturing for control of directional friction

The use of anisotropic texturing for control of directional friction

Experimental Analysis of Grease Friction Properties on Sliding Textured Surfaces

Improving Bearings Thermal and Tribological Performance with Built-In Heat Pipe

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