scholarly journals Experimental and Numerical Investigation of Friction Coefficient and Wear Volume in the Mixed-Film Lubrication Regime with ZnO Nano-Particle

2020 ◽  
Vol 13 (3) ◽  
pp. 993-1001
Author(s):  
R. Gholami ◽  
H. Ghaemi Kashani ◽  
M. Silani ◽  
S. Akbarzadeh ◽  
◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Numerical Investigation ◽  
Wear Volume ◽  
Nano Particle ◽  
Lubrication Regime ◽  
Mixed Film ◽  
Zno Nano Particle ◽  
Film Lubrication

Porous Retainers for Rolling Bearings

1981 ◽  
Vol 23 (6) ◽  
pp. 263-271
Author(s):  
R. Gohar ◽  
H. So
Keyword(s):  
Ball Bearing ◽  
Porous Matrix ◽  
Critical Value ◽  
Eccentricity Ratio ◽  
Rolling Bearings ◽  
High Coefficient ◽  
Lubrication Regime ◽  
Permeability Parameter ◽  
Mixed Film ◽  
Film Lubrication

A theoretical analysis is made for the lubrication of ball bearing retainers made of porous material. The results show that at low Sommerfeld reciprocals, the eccentricity ratio tends to unity with a high coefficient of friction. At a certain critical value of the reciprocal, a minimum friction occurs, thereafter followed by hydrodynamic operation. The critical value depends on the permeability parameter of the porous matrix and increases with its porosity. Experiments suggest that at low Sommerfeld reciprocals or with the oil supply coming only from the retainer pores, mixed film lubrication occurs, friction being less than that obtained theoretically. Such a lubrication regime would still allow sufficient oil to be carried by the balls to the races for their lubrication.

Improved dielectric and electro-optical parameters of ZnO nano-particle (8% Cu2+) doped nematic liquid crystal

2013 ◽  
Vol 1035 ◽  
pp. 371-377 ◽  
Author(s):  
Pankaj Kr. Tripathi ◽  
Abhishek Kr. Misra ◽  
Shashwati Manohar ◽  
Swadesh Kr. Gupta ◽  
Rajiv Manohar
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Optical Parameters ◽  
Nano Particle ◽  
Zno Nano Particle

Numerical Modeling of Mixed Lubrication and Flash Temperature in EHL Elliptical Contacts

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Neelesh Deolalikar ◽  
Farshid Sadeghi ◽  
Sean Marble
Keyword(s):  
Surface Deformation ◽  
Elastohydrodynamic Lubrication ◽  
Mixed Lubrication ◽  
Asperity Contact ◽  
Lubrication Regime ◽  
Predicting Performance ◽  
Pure Rolling ◽  
Rolling Element ◽  
Contact Pressures ◽  
Film Lubrication

Highly loaded ball and rolling element bearings are often required to operate in the mixed elastohydrodynamic lubrication regime in which surface asperity contact occurs simultaneously during the lubrication process. Predicting performance (i.e., pressure, temperature) of components operating in this regime is important as the high asperity contact pressures can significantly reduce the fatigue life of the interacting components. In this study, a deterministic mixed lubrication model was developed to determine the pressure and temperature of mixed lubricated circular and elliptic contacts for measured and simulated surfaces operating under pure rolling and rolling/sliding condition. In this model, we simultaneously solve for lubricant and asperity contact pressures. The model allows investigation of the condition and transition from boundary to full-film lubrication. The variation of contact area and load ratios is examined for various velocities and slide-to-roll ratios. The mixed lubricated model is also used to predict the transient flash temperatures occurring in contacts due to asperity contact interactions and friction. In order to significantly reduce the computational efforts associated with surface deformation and temperature calculation, the fast Fourier transform algorithm is implemented.

scholarly journals An Investigation on Tribological Properties and Lubrication Mechanism of Graphite Nanoparticles as Vegetable Based Oil Additive

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yu Su ◽  
Le Gong ◽  
Dandan Chen
Keyword(s):  
Friction Coefficient ◽  
Tribological Properties ◽  
Volume Fraction ◽  
Wear Volume ◽  
Lubrication Mechanism ◽  
Step Method ◽  
Antiwear Properties ◽  
Physical Deposition ◽  
Graphite Nanoparticles ◽  
Friction Reducing

This paper used graphite nanoparticles with the diameter of 35 and 80 nm and LB2000 vegetable based oil to prepare graphite oil-based nanofluids with different volume fractions by two-step method. The tribological properties of graphite nanoparticles as LB2000 vegetable based oil additive were investigated with a pin-on-disk friction and wear tester. Field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDS) were used to examine the morphology and the content of some typical elements of wear scar, respectively. Further, the lubrication mechanism of graphite nanoparticles was explored. It was found that graphite nanoparticles as vegetable based oil additive could remarkably improve friction-reducing and antiwear properties of pure oil. With the increase of volume fraction of graphite nanoparticles, the friction coefficient and the wear volume of disk decreased. At the same volume fraction, the smaller particles, the lower friction coefficient and wear volume. The main reason for the improvement in friction-reducing and antiwear properties of vegetable based oil using graphite nanoparticles was that graphite nanoparticles could form a physical deposition film on the friction surfaces.

Improving the ethanol sensing of ZnO nano-particle thin films—The correlation between the grain size and the sensing mechanism

2011 ◽  
Vol 152 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Thanh Thuy Trinh ◽  
Ngoc Han Tu ◽  
Huy Hoang Le ◽  
Kyung Yul Ryu ◽  
Khac Binh Le ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Nano Particle ◽  
Sensing Mechanism ◽  
Ethanol Sensing ◽  
Zno Nano Particle

A Mixed-TEHL Analysis of Cam-Roller Contacts Considering Roller Slip: On the Influence of Roller-Pin Contact Friction

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Shivam S. Alakhramsing ◽  
Matthijn B. de Rooij ◽  
Aydar Akchurin ◽  
Dirk J. Schipper ◽  
Mark van Drogen
Keyword(s):  
Friction Coefficient ◽  
Thermal Effects ◽  
Mixed Lubrication ◽  
Contact Friction ◽  
Sudden Increase ◽  
Low Friction ◽  
Pure Rolling ◽  
Lubrication Performance ◽  
Cam Follower ◽  
Film Lubrication

In this work, a mixed lubrication model, applicable to cam-roller contacts, is presented. The model takes into account non-Newtonian, thermal effects, and variable roller angular velocity. Mixed lubrication is analyzed using the load sharing concept, using measured surface roughness. Using the model, a quasi-static analysis for a heavily loaded cam-roller follower contact is carried out. The results show that when the lubrication conditions in the roller-pin contact are satisfactory, i.e., low friction levels, then the nearly “pure rolling” condition at the cam-roller contact is maintained and lubrication performance is also satisfactory. Moreover, non-Newtonian and thermal effects are then negligible. Furthermore, the influence of roller-pin friction coefficient on the overall tribological behavior of the cam-roller contact is investigated. In this part, a parametric study is carried out in which the friction coefficient in the roller-pin contact is varied from values corresponding to full film lubrication to values corresponding to boundary lubrication. Main findings are that at increasing friction levels in the roller-pin contact, there is a sudden increase in the slide-to-roll ratio (SRR) in the cam-roller contact. The value of the roller-pin friction coefficient at which this sudden increase in SRR is noticed depends on the contact force, the non-Newtonian characteristics, and viscosity–pressure dependence. For roller-pin friction coefficient values higher than this critical value, inclusion of non-Newtonian and thermal effects becomes highly important. Furthermore, after this critical level of roller-pin friction, the lubrication regime rapidly shifts from full film to mixed lubrication. Based on the findings in this work, the importance of ensuring adequate lubrication in the roller-pin contact is highlighted as this appears to be the critical contact in the cam-follower unit.

Fabrication and Hierarchical Structure of ZnO Nano Particle Using Green Fuels: Cyclic Voltammetry and Impedance Analysis

2018 ◽  
Vol 5 (10) ◽  
pp. 22547-22553
Author(s):  
K.N. Shravana kumara ◽  
H.P. Nagaswarupa ◽  
M. Mylarappa ◽  
D.M.K. Siddeswara ◽  
K.R. Vishnu Mahesh ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Hierarchical Structure ◽  
Impedance Analysis ◽  
Nano Particle ◽  
Green Fuels ◽  
Zno Nano Particle
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