Tribological performance of textured parallel sliding contact under mixed lubrication condition by considering mass conservation condition and couple-stress parameter

Author(s):  
Annadi Ramana Reddy ◽  
Syed Ismail

To enhance the tribological performance of mechanical parts, one of the reliable methods is surface topography modification, in which the surface of one/both interacting contacts were to be modified. Surface texturing is one of the surface modification techniques. In the present work, a numerical code is developed to address the effect of texture shape (elliptical and triangular), size and distribution (parallel and zigzag) on the tribological performance parameters (minimum film thickness, percentage of hydrodynamic load from the total generated pressure and frictional coefficient) under mixed lubrication regime for a known value of load support. In the present analysis, the mass conservative, i.e. Jakobson-Floberg-Ollson (JFO) cavitation condition and couple stresses of lubricant are considered. In addition, surface irregularities are considered by using the flow factors of Patir-Cheng model. The results show that texture shape has a significant effect, whereas the texture distribution has a slight effect on the tribological performance parameters. Moreover, the couple stress of lubricant has a prominent effect on the tribological performance.

Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Shuwen Wang ◽  
Xiaohong Ding

In recent years, the efforts to better control friction and wear have focused on surface topography modification through surface texturing. To study the mutual influence of surface roughness and texture features, this paper developed one comprehensive mathematical model of mixed lubrication to study the tribological performance of the rough-textured conjunction. The typical ring-liner conjunction was chosen as the research object. In particular, the effects of skewness and kurtosis were considered based on the non-Gaussian distribution of asperity height. In this way, the influences of non-Gaussian distribution properties and surface texturing on the tribological performance were analyzed. The results show that the influences of skewness and kurtosis on the tribological performance are nontrivial and should not be neglected in the mixed lubrication. Compared to the Gaussian distribution, considering the non-Gaussian distribution can represent the physical rough surfaces more accurately. Surfaces with negative skewness were found to generally result in better tribological properties. Moreover, the tribological performance improved by surface texturing can also be improved or reduced by the effect of skewness and kurtosis. As a result, the optimization of surface texturing should take the effects of roughness parameters into account.


Author(s):  
Bifeng Yin ◽  
Shao Sun ◽  
Bowen Wang ◽  
Yanqiang Qian

With the increasingly stringent requirements on energy saving and environmental-friendly for internal combustion (IC) engine, new concepts like novel combustion mode and surface texturing technology have emerged. In order to have deep understanding about the application effects of surface texturing into IC engine with new combustion mode, a mixed lubrication calculation model considering surface textures on cylinder liner together with different combustion modes has been built in the present work based on a four-cylinder diesel engine. The numerical research was conducted on the change of the surface tribological performance of textured cylinder liner under different combustion modes. The simulation results indicate that compared with the conventional combustion (CC) mode, the combustion phase of premixed charge combustion ignition (PCCI) mode and retarded injection (RI) mode varies and their in-cylinder peak pressure is different at the beginning of power stroke due to different injection strategies applied, which lead to significant differences between piston ring radial working loads. Near TDC, the mixed lubrication duration of PCCI and RI mode increases slightly in comparison to that of CC mode, and these three boundary lubrication durations are almost same. However, the thickness of lubricant film between friction pair of three modes is quite different, resulting in their different tribological properties. Among these parameters, the dimensionless total friction force (DTFF) and the dimensionless friction work of PCCI mode increase by 82.37% and 18.41% at most, respectively, while those of RI mode decrease by 36.50% and 12.45% at most, respectively, compared with the same parameters of CC mode. Therefore, the variations in tribological property of the textured cylinder liner–piston ring (CLPR) with different combustion modes should not be ignored.


2016 ◽  
Vol 18 (8) ◽  
pp. 785-796 ◽  
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Youbai Xie ◽  
Di Zhang

This article employs a mixed lubrication model to investigate the performance of the textured surface. The Jakobsson–Floberg–Olsson model is used to obtain the hydrodynamic support of the textured conjunction, while the calculation of the asperity contact load is based on the load-sharing concept. Based on the simulated Stribeck curves of the smooth surface and the textured surface, comparisons are conducted to study the effect of texturing under different lubrication regimes. It appears that the transition of lubrication regimes is influenced by the texturing parameters and the convergence degrees of conjunction. The presence of textures delays the appearance of the mixed lubrication regime and the boundary lubrication regime.


Author(s):  
Ramana Reddy Annadi ◽  
Ismail Syed

Surface texturing is a viable technique to enhance the tribological performance of sliding interacting contacts. Single-scaled surface textures exhibit better tribological performance only at hydrodynamic lubrication regime (fluid film pressure) but not in mixed lubrication regime where fluid film pressure and asperity contact pressure co-exists. In most of the machinery with the increase in load and/or decrease in speed, there is a shift of lubrication regime from hydrodynamic to mixed lubrication. To address this, the present work proposed a multi-scale (a combination of shallow and deep) textures concept. A numerical model is developed to study its effect on the tribological characteristics of parallel sliding contacts by considering mixed lubrication regime and mass-conservative cavitation condition. It has been observed that multi-scaled textures exhibit superior results in comparison with single-scaled textures. Moreover, improved tribological characteristics are observed when shallow surface textures are placed first towards the fluid inlet flow.


Author(s):  
JC Atwal ◽  
RK Pandey

Performance parameters such as power loss, minimum film thickness, and maximum oil temperature of the sector-shaped tilting pad thrust bearings employing the new micro-structural geometries on pad surfaces have been investigated. The lubrication equation incorporating the mass-conservation issue is discretized using the finite element method and the solution of resulting algebraic equations is obtained employing a Newton-Schur method. The pad equilibrium in the analysis is established using the Newton-Raphson and Braydon methods. The influence of attributes of micro-structures such as depth, circumferential and radial positioning extents have been explored on the performance behaviours. It is found that with the new micro-structured pad surfaces, the performance parameters significantly improved in comparison to conventional plain and conventional rectangular pocketed pads.


2019 ◽  
Vol 132 ◽  
pp. 265-274 ◽  
Author(s):  
Abdullah Azam ◽  
Ali Ghanbarzadeh ◽  
Anne Neville ◽  
Ardian Morina ◽  
Mark C.T. Wilson

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Junru Wang ◽  
Quandai Wang ◽  
Yueyan Li ◽  
Meiling Guo ◽  
Pengyang Li ◽  
...  

Purpose The purpose of this paper is to investigate the effects of surface texture with roughness orientation considered on tribological properties under a mixed lubrication state numerically and experimentally. Design/methodology/approach Based on the average Reynolds equation and asperity contact model, the impacts of surface texture parameters and roughness orientation on lubrication properties have been calculated using finite difference method. Tin–bronze samples with various prescribed surface texture geometric parameters and roughness orientation were fabricated by laser surface texturing technique, and the tribology performance of the textured surface was studied experimentally. Findings The effects of surface geometric parameters and roughness orientation parameters have been discerned. The experimental observations are in good agreement with the numerical prediction, which suggests that the numerical scheme adopted in this work is suitable in capturing the surface texture and roughness effect under mixed lubrication state. Originality/value By meticulously controlling the surface roughness and surface texture geometric characteristics based on the laser surface texturing process, samples with prescribed surface texture parameters and roughness orientation consistent with that in theoretical studies were fabricated and the theoretical model and results were verified experimentally.


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