scholarly journals Lubrication theory stucly with differentiated geometry parameterization and applications in hydrodynamic bearings

2021 ◽  
Author(s):  
Júlia De Araújo Mota ◽  
Juliana Vianna Valério
Keyword(s):  
Lubrication Theory ◽  
Hydrodynamic Bearings ◽  
Geometry Parameterization

scholarly journals Water lubrication of graphene oxide-based materials

Friction ◽  
2021 ◽  
Author(s):  
Shaoqing Xue ◽  
Hanglin Li ◽  
Yumei Guo ◽  
Baohua Zhang ◽  
Jiusheng Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Lubrication Theory ◽  
Lubricant Additives ◽  
Water Lubrication ◽  
Broad Application ◽  
Water Dispersibility ◽  
Metal Processing ◽  
The Relationship ◽  
Ph Concentration

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.

First Paper: Effect of Under-Lip Temperature on the Lubrication of Rotary Shaft Garter Spring Seals

1966 ◽  
Vol 181 (1) ◽  
pp. 185-190 ◽  
Author(s):  
D. J. Lines ◽  
J. M. Lawrie ◽  
J. P. O'Donoghue
Keyword(s):  
Coefficient Of Friction ◽  
Operating Temperature ◽  
Lubrication Theory ◽  
Fluid Film ◽  
Hydrodynamic Parameter ◽  
Accurate Knowledge ◽  
The Coefficient Of Friction ◽  
Surface Thermocouple ◽  
Sealing Mechanism ◽  
Film Lubrication

Although rotary shaft garter spring seals are widely used throughout industry, very little is known about the sealing mechanism of the lip-shaft interface. It is now generally accepted that some sort of fluid film separates the lip and the shaft. Previous workers have also postulated a relationship between the coefficient of friction and a non-dimensional hydrodynamic parameter, as in standard lubrication theory. This present paper clarifies this relationship, and shows that seals can also operate over the mixed friction, as well as the full film lubrication region. The results were obtained by accurate knowledge of the operating temperature under the sealing lip. Two types of surface thermocouple were developed to do this and these are described in full.

Stability of steady rotation of a rotor about its vertical axis on hydrodynamic bearings

1987 ◽  
Vol 23 (12) ◽  
pp. 1189-1195
Author(s):  
N. V. Derendyaev ◽  
V. A. Senyatkin ◽  
V. M. Sandalov
Keyword(s):  
Vertical Axis ◽  
Hydrodynamic Bearings ◽  
Steady Rotation

scholarly journals Extended lubrication theory: improved estimates of flow in channels with variable geometry

2017 ◽  
Vol 473 (2206) ◽  
pp. 20170234 ◽  
Author(s):  
Behrouz Tavakol ◽  
Guillaume Froehlicher ◽  
Douglas P. Holmes ◽  
Howard A. Stone
Keyword(s):  
Stokes Equations ◽  
Perturbation Expansion ◽  
Accurate Estimate ◽  
Higher Order ◽  
Lubrication Theory ◽  
Channel Height ◽  
Fluid Films ◽  
Flow Characterization ◽  
Systematic Perturbation

Lubrication theory is broadly applicable to the flow characterization of thin fluid films and the motion of particles near surfaces. We offer an extension to lubrication theory by starting with Stokes equations and considering higher-order terms in a systematic perturbation expansion to describe the fluid flow in a channel with features of a modest aspect ratio. Experimental results qualitatively confirm the higher-order analytical solutions, while numerical results are in very good agreement with the higher-order analytical results. We show that the extended lubrication theory is a robust tool for an accurate estimate of pressure drop in channels with shape changes on the order of the channel height, accounting for both smooth and sharp changes in geometry.

scholarly journals Run-Up Simulation of a Semi-Floating Ring Supported Turbocharger Rotor Considering Thrust Bearing and Mass-Conserving Cavitation

Lubricants ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 44
Author(s):  
Christian Ziese ◽  
Cornelius Irmscher ◽  
Steffen Nitzschke ◽  
Christian Daniel ◽  
Elmar Woschke
Keyword(s):  
Reynolds Equation ◽  
Energy Equation ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Reliable Prediction ◽  
Two Phase ◽  
Hydrodynamic Bearings ◽  
Thrust Bearings ◽  
Run Up ◽  
The Impact

The vibration behaviour of turbocharger rotors is influenced by the acting loads as well as by the type and arrangement of the hydrodynamic bearings and their operating condition. Due to the highly non-linear bearing behaviour, lubricant film-induced excitations can occur, which lead to sub-synchronous rotor vibrations. A significant impact on the oscillation behaviour is attributed to the pressure distribution in the hydrodynamic bearings, which is influenced by the thermo-hydrodynamic conditions and the occurrence of outgassing processes. This contribution investigates the vibration behaviour of a floating ring supported turbocharger rotor. For detailed modelling of the bearings, the Reynolds equation with mass-conserving cavitation, the three-dimensional energy equation and the heat conduction equation are solved. To examine the impact of outgassing processes and thrust bearing on the occurrence of sub-synchronous rotor vibrations separately, a variation of the bearing model is made. This includes run-up simulations considering or neglecting thrust bearings and two-phase flow in the lubrication gap. It is shown that, for a reliable prediction of sub-synchronous vibrations, both the modelling of outgassing processes in hydrodynamic bearings and the consideration of thrust bearing are necessary.

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