Influence of lubricants on the performance of journal bearings – a review

Kumar, Sunil; Kumar, Vijay; Singh, Anoop

doi:10.1080/17515831.2020.1712112

Cited by 16 publications

(3 citation statements)

References 146 publications

(199 reference statements)

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“…The contact angle hysteresis (CAH) is ∼11.1°. Because surfaces with such a high CAH are difficult for electric field-driven droplet transport, in consideration of hydrophobicity, evaporation, heat resistance, chemical inertness, surface tension, and so on, Krytox GPL 103 fluorinated lubricating oil (∼0.5 mL, surface tension γ oil < 20 mN/m, density ρ ∼ 1.92 × 10 3 kg/m 3 ) was chosen. ,,− The Krytox was spin-coated (1500 rpm, 1 min) at the AF-HS surface (Figure f) and then the LIHS was fabricated completely. The fabricated LIHS was then connected to external voltages (Figure g,h).…”

Section: Resultsmentioning

confidence: 99%

Electric-Field-Induced Selective Directed Transport of Diverse Droplets

Wu,

Li,

Lin

et al. 2024

ACS Appl. Mater. Interfaces

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Droplet directional transport is one of the central topics in microfluidics and lab-on-a-chip applications. Selective transport of diverse droplets, particularly in another liquid phase environment with controlled directions, is still challenging. In this work, we propose an electric-field gradient-driven droplet directional transport platform facilitated by a robust lubricant surface. On the platform, we clearly demonstrated a liquid-inherent critical frequency-dominated selective transport of diverse droplets and a driving mechanism transition from electrowetting to liquid dielectrophoresis. Enlightened by the Kelvin−Helmholtz theory, we first realize the directional droplet transport in another liquid phase whenever a permittivity difference exists. Co-transport of multiple droplets and various combinations of droplet types, as well as multifunctional droplet transport modes, are realized based on the presented powerful electric-field gradient-driven platform, overcoming the limitations of the surrounding environment, liquid conductivity, and intrinsic solid−liquid wetting property existing in traditional droplet transport strategies. This work may inspire new applications in liquid separation, multiphase microfluidic manipulation, chemical reagent selection, and so on.

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Section: Resultsmentioning

confidence: 99%

Electric-Field-Induced Selective Directed Transport of Diverse Droplets

Wu,

Li,

Lin

et al. 2024

ACS Appl. Mater. Interfaces

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“…Under normal operating conditions, the bearings in a planetary gearbox do not have oil jet lubrication devices. Therefore, the rolling bearings and gears are lubricated with churning oil [1][2][3]. Oil jet lubrication, which has the advantages of reducing lubricant consumption, easy control, and excellent lubrication effects, is used to lubricate highspeed bearings.…”

Section: Introductionmentioning

confidence: 99%

Transient Simulation Analysis of Needle Roller Bearing in Oil Jet Lubrication and Planetary Gearbox Lubrication Conditions Based on Computational Fluid Dynamics

Gao,

Hou,

et al. 2024

Lubricants

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The transient lubrication conditions of rolling bearings are different in gearboxes and bearing testers. It has been observed that samples of qualified rolling bearings tested in rolling bearing testers often fail and do not meet lifespan requirements when employed in other lubrication conditions. This may be caused by different factors affecting the bearing in testing and applying lubrication. Needle roller bearings were selected for this study to investigate the causes of this phenomenon in terms of lubrication. Based on the computational fluid dynamics (CFD) method, fluid domain models for the same type of rolling bearings with different lubrication conditions were established. The transient flow fields of rolling bearings with oil jet lubrication in a tester and splash lubrication in a planetary gearbox were simulated. The air–oil transient distribution of rolling bearings in two kinds of lubrication was analyzed. The results indicate that the rotational speed significantly affected the oil jet lubrication of the needle roller bearing. The average oil volume fraction rose by 0.2 with the increase in the bearing speed from 1200 r/min to 6000 r/min and by 0.06 with the increase in the oil jet velocity from 8 m/s to 16 m/s. The splash lubrication of the bearings in the planetary gearbox was directly related to the immersion depth of the rolling bearings in the initial position. Meanwhile, the splash lubrication of the bearings was also affected by other factors, including the initial layout of the planetary gears. The increase in speed from 1200 r/min to 6000 r/min made the average oil volume fraction of splash lubrication decrease by 4.4%. The average oil volume fraction of the bearings with splash lubrication was better than that with oil jet lubrication by an average of 41.9% when the bearing speed was in the low-speed stage, ranging from 1200 r/min to 3600 r/min. On the contrary, the bearings with oil jet lubrication were better than those with splash lubrication by an average of 31.8% when the bearing speed was in the high-speed stage, ranging from 4800 r/min to 6000 r/min.

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“…Significant costs for overcoming friction forces make the problem of finding more perfect friction pairs constantly relevant [1]. For plain and journal bearings, this task involves the improvement of lubricants [2], bearing design enhancement [3], and the development of new antifriction materials [4]. Along with antifriction behavior, such materials must have sufficient bearing capacity to withstand the load of the counterbody.…”

Section: Introductionmentioning

confidence: 99%

Study of Adaptation Processes in Tribofilms during Friction of Antifriction Aluminum Alloys for Journal Bearings

Podrabinnik,

Gershman,

Mironov

et al. 2023

Metals

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This paper provides results on the tribological behavior of experimental Al–Sn–Pb–Si–Cu–Mg–Zn aluminum alloys and describes the adaptation phenomena that reduce wear intensity during friction with steel. The main focus is on tribofilm formation, which plays an important role in friction energy dissipation. The alloys were tested in a rig imitating a journal-bearing shaft couple, and the friction surfaces were studied by the scanning electron microscopy, energy-dispersive analysis and X-ray photoelectron spectroscopytechniques. Based on the analysis, a conclusion on processes and tribochemical reactions was made. Compared to the initial state, eight new compounds were found on the friction surface. In the most wear-resistant alloy, magnesium precipitated from a solid solution with the subsequent oxidation. The same process was detected for zinc in the least wear-resistant alloy due to its low magnesium content. Furthermore, CuSn3 and PbS compounds, which require >600 °C temperature to compose, were found in tribofilms, indicating that the rubbing body lost thermodynamic equilibrium during friction. The revealed processes are non-spontaneous and decrease the wear intensity of the alloys, as they are accompanied by negative entropy production and dissipation of friction energy. Stepwise depth XPS analysis also showed the functional levels of the tribofilms.

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Influence of lubricants on the performance of journal bearings – a review

Cited by 16 publications

References 146 publications

Electric-Field-Induced Selective Directed Transport of Diverse Droplets

Electric-Field-Induced Selective Directed Transport of Diverse Droplets

Transient Simulation Analysis of Needle Roller Bearing in Oil Jet Lubrication and Planetary Gearbox Lubrication Conditions Based on Computational Fluid Dynamics

Study of Adaptation Processes in Tribofilms during Friction of Antifriction Aluminum Alloys for Journal Bearings

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