Variational Rayleigh Problem of Gas Lubrication Theory. Low Compressibility Numbers

2018 ◽  
Vol 53 (4) ◽  
pp. 471-478 ◽  
Author(s):  
Yu. Ya. Boldyrev
1995 ◽  
Vol 30 (6) ◽  
pp. 826-832 ◽  
Author(s):  
Yu. Ya. Boldyrev ◽  
S. V. Lupulyak ◽  
Yu. K. Shinder

1999 ◽  
Vol 85 (8) ◽  
pp. 5594-5596 ◽  
Author(s):  
Soo-Choon Kang ◽  
Robert M. Crone ◽  
Myung S. Jhon

1970 ◽  
Vol 92 (4) ◽  
pp. 766-781 ◽  
Author(s):  
C. H. T. Pan

The asymptotic analysis of the gaseous squeeze-film bearing has been extended to obtain 0 {σ−1/2} effects in accordance with the isothermal gas lubrication theory and the method of singular perturbation. 0 {σ−1/2} corrections are identified to contain not only edge effects (inner problem) but also edge-interior interactions which are analogous to the boundary layer displacement effects in aerodynamics. The latter features can further be recognized to be related to mean-gap taper, squeeze taper, and cross-edge sliding. These results are discussed from the point of view of “global bearing properties” including the temporal mean as well as the in-phase and quadrature synchronous components of the fluid film force and moment. The edge effects are presented in terms of universal functions which can be used directly as corrections in the global properties. The edge-interior interactions must be determined by solving the asymptotic p.d.e. with boundary condition also expressed in terms of universal functions. Formulations applicable to cylindrical, conical, and spherical bearing geometries are outlined. Illustrative numerical examples are provided. Conditions affecting the validity of the isothermal gas lubrication theory (neglecting inertia effects) as related to the magnitude of the squeeze number are discussed.


Friction ◽  
2021 ◽  
Author(s):  
Shaoqing Xue ◽  
Hanglin Li ◽  
Yumei Guo ◽  
Baohua Zhang ◽  
Jiusheng Li ◽  
...  

AbstractWater is as an economic, eco-friendly, and efficient lubricant that has gained widespread attention for manufacturing. Using graphene oxide (GO)-based materials can improve the lubricant efficacy of water lubrication due to their outstanding mechanical properties, water dispersibility, and broad application scenarios. In this review, we offer a brief introduction about the background of water lubrication and GO. Subsequently, the synthesis, structure, and lubrication theory of GO are analyzed. Particular attention is focused on the relationship between pH, concentration, and lubrication efficacy when discussing the tribology behaviors of pristine GO. By compounding or reacting GO with various modifiers, amounts of GO-composites are synthesized and applied as lubricant additives or into frictional pairs for different usage scenarios. These various strategies of GO-composite generate interesting effects on the tribology behaviors. Several application cases of GO-based materials are described in water lubrication, including metal processing and bio-lubrication. The advantages and drawbacks of GO-composites are then discussed. The development of GO-based materials for water lubrication is described including some challenges.


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