A Molecular Dynamics Study on the Synergistic Lubrication Mechanisms of Graphene/Water-based Lubricant Systems

2021 ◽  
pp. 107356
Author(s):  
Chenjie Li ◽  
Weiwei Tang ◽  
Xiu-Zhi Tang ◽  
Linyan Yang ◽  
Lichun Bai
Keyword(s):  
Molecular Dynamics ◽  
Water Based ◽  
Lubrication Mechanisms

Equation of state of water based on the SCAN meta-GGA density functional

2020 ◽  
Vol 22 (8) ◽  
pp. 4626-4631 ◽  
Author(s):  
Gang Zhao ◽  
Shuyi Shi ◽  
Huijuan Xie ◽  
Qiushuang Xu ◽  
Mingcui Ding ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Equation Of State ◽  
Ab Initio ◽  
Molecular Dynamics Simulations ◽  
Density Functional ◽  
State Of Water ◽  
Water Based ◽  
Dynamics Simulations ◽  
Better Than

By ab initio molecular dynamics simulations, the newly developed SCAN meta-GGA functional is proved better than the widely used PBE-GGA functional in describing the equation of state of water.

Effect of Temperature on Rheology and Nanoparticle Movements of Water Based Nanofluids by Molecular Dynamics Simulation

2016 ◽  
Author(s):  
Wenzheng Cui ◽  
Zhaojie Shen ◽  
Jianguo Yang ◽  
Shaohua Wu
Keyword(s):  
Heat Transfer ◽  
Molecular Dynamics ◽  
Cooling System ◽  
Combustion Engine ◽  
Dynamics Simulation ◽  
Effect Of Temperature ◽  
Water Based ◽  
Apparent Reason ◽  
Transfer Properties ◽  
Dynamics Method

Employing nanofluids is an innovative way to enhance heat transfer in cooling system of internal combustion engine. the reasons for the significantly enhanced heat transfer properties of nanofluids are various. On one hand, the markedly increased thermal conductivity is the most apparent reason; on the other hand, the changed rheology properties of base fluid due to the disordered movements of countless nanoparticles is even more important. Because the size scale of nanoparticles is too small, in some cases of computational simulations nanofluids is simplified as single-phase fluids. However, the influence of nanoparticles for flow behaviors of base fluids distinctly should not be ignored. By means of molecular dynamics method, a nano-scale simulation on the rheology of nanofluids could be conducted, therefore the movements of nanoparticles could be directly observed, which is conducive to reveal the influence of movements of nanoparticles for rheology of nanofluids. The present work is intended to perform a molecular dynamic simulation on the rheology of water based nanofluids. By applying temperature difference, the velocity and temperature distribution of fluid zone are calculated to evaluate heat transfer through nanofluids. Moreover, the influence of temperature for the movements of nanoparticle is discussed.

Molecular Dynamics Simulation of Water-Based Nano-Lubrication

2013 ◽  
Vol 773 ◽  
pp. 585-588
Author(s):  
Su Mei Zhang ◽  
Pei Hong Guo ◽  
Jia Nan Zhu ◽  
Xiao Ping Wen
Keyword(s):  
Molecular Dynamics ◽  
Reduction Rate ◽  
Dynamics Simulation ◽  
Water Molecules ◽  
Stabilization Time ◽  
Shear Rates ◽  
Water Based ◽  
Dynamics Simulations ◽  
Metal Wall ◽  
Number Of Particles

Molecular dynamics simulations of water-based nanolubrication in Couette flow are carried out. The water molecules are simulated by the TIP3P model. Three different shear rates are 20 m/s and 40 m/s and 60 m/s, and the vertical pressure acted on the metal wall are 10GPa, 20 GPa, 30 GPa and 40 GPa respectively. The simulated results show that the greater pressure, the smaller the stable value of friction spacing, while the reduction rate of the stable value becomes small. Meanwhile, as pressure increases, the stabilization time is longer. However, under the same pressure, shear rate of influence on the friction spacing is not obvious. The friction spacing increases with the number of particles, showing that the presence of nanoparticles can enhance the bearing capacity.

Lubrication mechanisms of hexagonal boron nitride nano-additives water-based lubricant for steel–steel contact

2020 ◽  
pp. 135065012094017
Author(s):  
Mohd Fadzli Bin Abdollah ◽  
Hilmi Amiruddin ◽  
Muhammad Alif Azmi ◽  
Noor Ayuma Mat Tahir
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Stribeck Curve ◽  
Lubrication Regime ◽  
Lubrication Performance ◽  
Water Based ◽  
Wear Reduction ◽  
Mixed Lubrication Regime ◽  
Worn Surface ◽  
Lubrication Mechanisms

This study intends to explore the lubrication mechanism of hexagonal boron nitride nano-additive. Synergistic analysis comprising worn surface observation, surface wettability testing, and the Stribeck curve principle is used to test this water-based lubricant on steel–steel contact. Distilled water and 0.1–5.0 vol.% hexagonal boron nitride nano-additive is used to prepare a mixture using sonification technique. A viscometer is employed to determine the viscosity of the nanolubricant. A four-ball tribometer is employed to determine the tribological characteristics and lubrication performance. Hamrock and Dowson equations are used to determine the minimum film thickness needed for lubrication. Surface morphology characteristics are inspected using energy-dispersive X-ray spectroscopy, scanning electron microscopy, surface tension meter, and profilometer. The efficacy of the lubricant as friction and wear-reduction additive is determined to have a mixed lubrication regime with the optimum concentration of 1.0 vol.% hexagonal boron nitride. Protecting film, mending effect, rolling effect, and polishing effect have been recommended as the lubrication mechanisms. Increasing the addition of hexagonal boron nitride additives may lead to a change in the lubrication regime from mixed to hydrodynamic, where agglomeration is observed in the nanoparticles, and an increase in friction is observed.

scholarly journals A Comprehensive Review of Water-Based Nanolubricants

Lubricants ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 89
Author(s):  
Afshana Morshed ◽  
Hui Wu ◽  
Zhengyi Jiang
Keyword(s):  
Friction And Wear ◽  
Green Manufacturing ◽  
Environmental Issues ◽  
Future Research ◽  
Testing Methods ◽  
Research Directions ◽  
Water Based ◽  
Different Types ◽  
Future Research Directions ◽  
Lubrication Mechanisms

Applying nanomaterials and nanotechnology in lubrication has become increasingly popular and important to further reduce the friction and wear in engineering applications. To achieve green manufacturing and its sustainable development, water-based nanolubricants are emerging as promising alternatives to the traditional oil-containing lubricants that inevitably pose environmental issues when burnt and discharged. This review presents an overview of recent advances in water-based nanolubricants, starting from the preparation of the lubricants using different types of nanoadditives, followed by the techniques to evaluate and enhance their dispersion stability, and the commonly used tribo-testing methods. The lubrication mechanisms and models are discussed with special attention given to the roles of the nanoadditives. Finally, the applications of water-based nanolubricants in metal rolling are summarised, and the outlook for future research directions is proposed.

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